Tires and Rims Deciphered

When you get a vintage bike, you inherit the bodges of the owners before you. Some of these bodges are fantastic and merit preservation and others are aren't. I consider each bodge on my Norton Model 7 from several perspectives. First, I make sure that it is safe particularly in Houston, Texas. Second, I make sure that it s mechanically sound and that it is not a shortcut that will endanger the integrity of the bike. Finally, I view it from an aesthetic perspective.

I've mentioned it before on this blog that the bodges of previous owners are very much part of the bike's soul and I try to preserve as much as I can with the above criteria in mind. My bike came with a Manx style front fender  that seemed out of place with the lines of the bike.

My Bike

The Ideal

I personally feel that the original fender balances the lines and for that reason I have spent a great deal of time and money sourcing an original fender. Immediately upon its arrival I installed it and admired its lines. The problem arose when I quickly found that the front wheel wouldn't rotate freely. Inspection revealed that the tired rubbed against the fender bridge. Despair! Checking the rim and tire, I noticed that it was a 19 inch WM2 while the handbook indicated that the original specification was for a 21 inch WM1 wheel.

Well, how hard can that be to source I just found an NOS fender? Well, very hard. The rim itself is not common and after a great deal of searching I found what I was looking for at the Racing Norton Website. It's important  to realize that along with rim size  the dimple pattern and angle are relevant to proper fitment to the hub. The proper tire is not much easier to find in the 21 inch size. Currently, 21 inch wheels are favored by chopper builders because of the enhanced handling of it's larger size. Not really the look for a 1951 Norton Model 7 but I found what I was looking for at Universal Tire.

I turned to my friends at the Model 7 Forum on Yahoo. The conversation was confusing at first largely because a wheel, the combination of tire, rim, and hub, has several sizes associated with it. Not only that but for each type of rim has several different nomenclatures based on era and can accept several different tire sizes. I don't think I am alone when I say that too many choices proves confusing. In order to prevent others from suffering my travails I offer the Rosetta Stone of tire and rim sizes. Go here for a very help chart.

New Feature- Vintage Literature Review

I have written periodically about the classic motorcycle hobby and how to get started in it. Like many, my initial forays were filled with anxiety. I was an absolute novice with minimal mechanical experience. I knew that a great deal of satisfaction would come from the self-sufficiency of maintaining the motorcycle myself. The real question was where to find the technical know-how to be a true motorcyclist in the traditional sense. Certainly, there are plenty of internet sites, blogs, and forums where one can ask questions about how to fix discreet issues. What many of these sites can't do is impart the techniques and methods our forebears used in taking care of their motorcycles. Depending on where you live, you may be fortunate enough to have a mentor. In my case, vintage British motorcycles are rare enough much less someone with the knowledge to work on them. The solution was to develop my own knowledge base through period technical literature. I have for a while collected a combination of period books and articles with the aim at building a technical library and historical library that would allow me to repair my motorcycle and enjoy the context in which it existed.

Part of motivation of this blog is to share my knowledge with others. To that end, I have decided to start a new feature in which I review vintage literature to help guide others in building their own libraries. My desire is that readers will get involved and hopefully share their literature as well. Stay tuned for the first review.

Panning for Gold........

I wish!!!!! At today's prices those flecks would pay for new rims and spokes. No, this is swarf when I cleaned out the oil tank a few weeks back. Not very reassuring about what is going on in the motor. These old bikes were never equipped with oil filters and relied on large oil ways and single weight, non-detergent oil to lubricate the entire engine. There is a great deal of debate about retro-fitting oil filters to these bikes to reduce wear and tear.I personally have come down to leaving well enough alone and run with single weight oil. I figure that running the bike under the conditions it was engineered is the way to go. After seeing this, I am not so sure.

I have a vintage filter system that would do the trick. The problem is finding a logical place to install it that is functional and aesthetically pleasing. I have tried a couple of options and none of them have really been suitable. Right now, I'll stick with the original option. Can't wait to see what I find in the sump.....hopefully gold doubloons!

Restoration Work---Carburetor Rebuild Part 2

It has been a while since Part 1 was written in large part due to the expanding scope of my restoration work. "Mission Creep", as the Army likes to call it, is the nemesis of any classic bike owner quickly transforming a simple fix into a major tear down. Despite being in deeper than I would like, I did finish putting the carburetor back together so I thought it would be a good time to pick up where I left off.

I alluded in Part 1 to the fact that the carburetor is the lung of the motorcycle. Carburetors depend on the venturi principle to accelerate air through its body to create a vacuum that vaporizes gasoline to form the combustion mixture. The elegant mechanism of jets, needle, and throttle slide all depend on the system being airtight. The same goes for the lung in which an air leak is termed a pneumothorax leading to compromised gas exchange even death.

Consequently, the first task during dismantling is the evaluation of all parts for wear that may lead to unwanted air leaks. Amal Carburetors are built from soft metals namely pot metal and brass and over time will wear. The photo below demonstrates a common wear pattern.

Throttle slide wear.

Notice that the wear pattern is eccentric. The inside of the carburetor body bears the same eccentric wear pattern; therefore, one cannot simply plop in a new slide. It's like fitting a circle into an oval and leads to an even bigger air leak than what you had before. This larger leak makes it impossible to tune the carburetor and probably explains the frustration many have with the Amal carburetor. The solution to this situation involves three options. The easiest remedy is just to buy a new carburetor. Buying new when one doesn't need to violates the central ethos of a classic motrocyclist and is an expensive proposition. It may also be impossible to find a new version of some of the rarer varieties. Recall from Part 1 that pre-monobloc carburetors within a certain type are not interchangeable. The code like 76AK/1AT fitted to my bike is a specifc combination of components of body and float bowl that vary in pitch, bore, and jetting. The other option is to ignore the situation and just put the old slide back and make due. In the middle is re-sleeving which in generic terms involves reestablishing the concentricity of the slide and body.

I opted for a solution that really isn't re-sleeving but a two-step process involving boring out the body round then making a stainless steel slide to fit the new bore of the carburetor body. An example of the slide is shown below:

The result is an airtight seal with enhanced durability thanks to the steel slide. My work was expertly done by Lund Machine and the throttle action is smooth as silk. At Lund Machine, they take your whole carb, clean it, modify it, and send it back at a pretty good price.

The other area of air leakage often overlooked is the junction of the carburetor to the manifold and manifold to the cylinder head. These mating interfaces need to be perfectly flat and generally suffer from years of mistreatment. This can be remedied by grinding both faces on a plate of glass with paste then fitting a new gasket. Resist the urge to reuse gaskets!! Also, don't over tighten the mounting bolts since that can lead to distortion ruining one's diligent work.

The other area that requires attention are the jets. Many enthusiasts clean jets with brass wire and the like but no matter how gentle one may be this changes the jet size. Over time, one inherits jets that are way out of specification leading to difficulties in tuning. I believe that all jets should be replaced with new ones. I would even go so far as to say that several different sizes should be purchased to take into account changes in gasoline formulation and sparkplug technology. A small variety of jets will provide the flexibility required to accurately adjust the carburetor settings. Fortunately, these adjustments are done in a stepwise fashion by component. Next time, I'll go through the mysteries of tuning the carburetor and we'll see the outcome. I promise that the next installment won't take so long.

Clutch Restoration----Part Three

Last post, I inserted the cork friction material into the plates and chain wheel. The real work is sanding the corks down even and to the right thickness. The photo below shows how proud the unfinished plates are within the chainwheel.

I have received a great deal of helpful advice on how to finish these from much more experienced gentlemen such as Pete Young and Rick Parkington. The constant theme appears to be that sanding these down is "knuckle-busting" work. Fortunately, I found the right tool--a Black and Decker palm sander. It spans several corks and lets me slowly sand them down evenly.

chainwheel being sanded

In similar fashion, I have been sanding the friction plates. It's tedious work requiring frequent measurements to ensure that the plates are close to the same thickness. My concerns are starting to build as more material is removed. If I leave the cork too thick, it will be be difficult to adjust the clutch. Furthermore, cork expands as it heats impacting clutch performance to the point that some advocate leaving the bike in neutral while at a stop. This violates the Motorcycle Safety Foundation's rule of staying in gear to theoretically avoid getting rear ended. Good theory but I don't know about the practice. If the corks are too thin then reliability goes by the wayside. We'll see how this progresses.

Clutch Restoration- Part 2

If you are just jumping in to this post you can quickly go here to catch up from the beginning. At any rate. I finished preparing the plates and planned to use old school friction material. The original asbestos material is really the best stuff  but for obvious health reasons cork is the only alternative. I could have used modern bonded plates but I was curious as to how the oldtimers did it and really didn't feel like paying and arm or a leg for them either. With a few tips from none other than Rick Parkington at Classic Bike magazine I got on with it last week-end.

Here's me at the stove boiling up corks to soften them up for fitting much like you would corks for a petrol tap. This is definitely the one time that something I cook tastes like it should! Great care should be taken when fitting because the corks while soft are thin and fragile. The cork inserts will have uneven thicknesses after boiling due to the different densities of cellulose in each piece therefore I just centered them in each plate. 

Once completed, I let the the cork inserts thoroughly dry and will sand them flat and to size. I haven't figured that out yet but Rick Parkington said it was knucklebusting stuff. Stayed tuned for a full report.

Clutch Restoration- Part 1

Taking advantage of the Thanksgiving Holiday to get things done on the Model 7, I took the clutch apart mostly because there was some slip and the adjuster didn't seem to work. The plates are pretty knackered particularly the pad material which is considerably thinner than specified in the manual.

The pad material consititutes a hazardous material situation because they are a composite of cloth,steel, and asbestos. I highly recommend wearing a mask when initially taking apart unknown clutches and brakes because of the deadly health risk. I love dismantling the bike because it's often like an archaeological expedition. You get to see the handiwork of previous owners- the good, the bad, and the ugly. In this case, I noticed the clutch mushroom which is a difficult and expensive part to find was replaced at some point by a valve that fits and works perfectly. Genius!

I plan to beburr the plates and replace the asbestos pads with cork. I run a dry primary case with an IWIS self-lubricating primary chain so I have a some doubts about the durability of the cork. The experiment will be an interesting one. More to follow.

Making Headway

The first order of business on the Norton Model 7 was to replace the rocker oil feed line. The original had a a kink where the banjo fitting meets the oil tank union. My concern was that the kink restricted oil flow to the top end impacting its lubrication.

Original line with kink

I purchased a new line from Norvil. Norvil offers two varieties of rocker oil feed lines. There is a one piece version and a two piece. I chose the one piece thinking that the clear plastic tubing wired to the original feed line was a bodge like many other fixes on the bike. The more I thought about it I came to realize that it was a smart modification that did two things. First, the plastic tubing serves as a sort of shock absorber dampening vibrations that could damage the soldered joints. Second, the clear tube serves as a sort of sight glass allowing me to visually ensure that oil is going up the line. It doesn't guarantee lubrication but I figure that between the visual confirmation and the pressure gauge measuring oil pressure off the scavenging side I'll be pretty safe.

First, the tear down started easily until the removal of the oil tank. Stripping off a Model 7 oiltank requires the removal of a screw buried behind the battery carrier. The only problem is that the bolts for the battery carrier are behind the oil tank. Needless to say, a few contortions later and I got the tank off without having to take off the battery carrier.

I did a test run with a length of wire coat hanger and cut the feed line at approximately the point I wanted the clear tubing to be situated. The hacksaw is a british item that stabilizes the blade via a springloaded guided that minimizes wobble providing a nice clean cut. Get it at Garrett-Wade.

Considering that the tunbing is zinc coated copper, bending requires the use of  a tubing bender to avoid putting a kink in the line. The bends were compound ones requiring bends in multiple axes. The tubing bender is available at Eastwood Company here in the USA

After some deburring and polishing I ended with this.

The final product fits very well although the picture above is one step shy of completion. Thinking I was done, I am now taking the opportunity of easy access to the gearbox adjuster now that the oil tank is removed to do a much needed clutch/primary drive overhaul. Stay tuned for that adventure. 

Restoration Work---Carburetor Rebuild Part 1

If the cylinders are the heart of a motorcycle then one could consider the carburetor to be the lungs. As an anesthesiologist, I deal daily with cardiac and pulmonary function. I am fascinated by the lungs and so it is no surprise to me that I am fascinated with carburetors. Carburetors on classic bikes and their tuning are a never ending source of discussion and for many frustration. Been there and now I am going to divulge all I know. I plan to do this in several installations and while confined specifically to the carburetor on my bike many principles are transferrable to all makes.

Like any project, there needs to be a point of departure. In the case of my Model 7, I was interested in using the original carburetor which simplifies matters tremondously in that I was able to go to the original settings and tune from there. Others with more experience may want to upgrade or may not be able to find the appropriate carburetor at which point start with what you have.

Every carb initial setup by make for the period

Carb type confirmed

Initial settings on the bottom line

The carburetor on a 1951 Norton Model 7 is a Amal 76AK/1AT indicating what is conventionally described as a pre-monobloc carburetor, meaning that the float bowl is separate from the carburetor body. Often, Amal 76's will be replaced with 276's since the latter are generally more available.. These carbs are virtually identical and interchangeable down to the parts. The only difference between the two is that the 76 series carb has additional air holes at its base.

Float Bowl Side

Vent holes at base on an Amal 76

Along with the Amal publication mentioned above that includes a comprehensive parts list, here are a couple other references that are helpful in getting started:

Great book series by a real

authority on bikes

Amal Carb UK is a comprehensive site that lets you shop by original part number. Additionally, they have exploded diagrams of each carburetor type and you can select parts that way as well. Great site and great quality for a decent price. Definitely a rare combination!

Next post, we will tackle dismantling the carb, identifying potential faults, cleaning, and reassembly. In the meantime, if anybody needs info please drop me a line.

New Tool for the Tool Chest

As I gain mechanical experience, I have been wanting to venture into more technical aspects of restoration and maintenance. One thing I really want to conquer is timing the engine. Timing is as much art as it is mechanics. The principles are fairly straight forward but I suspect a novice like myself could take a good running engine and turn it into a disaster in short order. I have decided not to launch into this unprepared and have been studying several period books as well as my Norton manual. The manuals provide the settings but not much information about the process. Clearly, this lack of information harkens to an era in which it was assumed one knew how to tune one's bike or there was a specialist nearby to help. Definitely not the case for me deep in Texas. For the novice classic motorcyclist however this assumption is an anachronism that ironically is at the root of the fun of the hobby. Learning to be self-sufficient and  to develop mechanical skills is indispensable to one's enjoyment.

I recently acquired two items necessary for this technical adventure. First is the timing degree wheel. I purchased this reproduction Castrol wheel mostly out of nostalgia. It helps sometimes to look the part.

The other interesting tool I acquired is a modified timing chest cover. I don't like to see the destruction of classic motorcycle parts but in this case the ends justify the means. Turns out that the unsupported halftime pinion could be damaged during the timing process. The cutout timing cover allows support of that pinion while permitting access to the gears.

Now that I am equipped there's little excuse not to get on with it!

Finally settled in......Time to get to work!

Had some time off during the 4th of July week-end to finish up the task I wrote about a few posts ago. I got the workshop cleaned up as well as the parts collection sorted, cataloged, and boxed. Hooray. You'll notice the fan in the backround. It sure is handy in the humid heat of Houston. It rests on top of the other indispensable garage item- the refigerator full of ice-cold beverages. Here are the before and afters:

Before

After

Can't wait to get started. I have a bunch of projects planned. Good times.

Now something practical......

It has been a bit since I have posted something related to bike restoration mostly since I am still in the midst of getting my shop squared away since the move to Houston. I collect parts for my Norton Model 7 but never really catalogued what I had. So I have taken the time to sort through everything and see what I have acquired and properly organize the parts for future use. Needless to say that it's quite a bit of stuff and some of it I think will end up getting sold.

In restoring my Norton, I have found that it's the little pieces like fasteners, special tools, etc. that are difficult to find. When I get ready to start a project, I always start out by sourcing everything first then seeing if they will work like I envision it. This is a bit backwards and some projects have sat around until all the little pieces have come together. With that type of strategy, one needs a supplier of tools and raw materials and here are a couple of spots I recommend.

The first is McMaster-Carr, the true industrial superstore, If they don't have it then it probably does not exist! McMaster-Carr has tools, hardware, raw materials all contained in a website that is easy to use. The prices are very reasonable as well.

Next is Graham Tool. Graham tool has some cool stuff in it. You could probably find it at McMaster-Carr but there are some hotrod and racing applications that might be difficult to find elsewhere. Not the cheapest prices though.

Gardner-Wescott is a fastener specialist that has the most expansive inventory of motorcycle specific fasteners imaginable. If you have a specific need for your restoration I would go there first.

This next site is for the tool fetishist. Garrett-Wade has a carpentry bent to it but there are definitely cool tools for every hobby including gardening. Some might find gardening inappropriate subject matter for a motorcycle site but think about this. Imagine I need some diamond files which aren't cheap so why not grease the skids with the wife with a handy set of japanese pruning shears all found at the same site and arriving in the same package. Win-win!

Best of luck on all of your projects!

Mission Accomplished!!!!!!

After four years of searching, calling, disappointment I have finally acquired the last missing bit of tinware for Rocinante. I believe these vintage bikes have a soul. I don't mean it in some whacked out, new age, metaphysical, crystal worshipping way but classic bikes have a certain character. There have been times where I could tell my Model 7 was unhappy about something. I definitely know the bike was unhappy about having its tail bobbed. It was not an easy task to acquire the rear fender and the whole process has been filled with anxiety.

I won't hide it. I got the part through Ebay and believe me I can hear the groans. The reality is that for someone like myself that lives outside the british classic lines of drift here in South Texas you can trust me that Ebay is a godsend. I am fortunate that my experience with Ebay has been pretty good. No doubt that I have overpaid and been the subject of sniping resulting in a bidding strategy that probably would get me in trouble with the wife. The bottom line is that there is no Kempton Jumble here and Ebay for all its warts has opened classic motorcycling to those who otherwise couldn't including myself.

The secret to Ebay is developing relationships with sellers. I have fortunately developed a network of sellers that know me. I go out of my way to communicate with them and hold realistic expectations about what I am buying. I research their reputation in depth via their feedback and look around for pricing of like or similar objects. Let's face it's no different with an auction house or even a dealer. Classic motorcycling is always frought with surprises. Personally, I cuss them and enjoy them at the same time. It's part of the hobby. Sometimes treasure,sometimes trash.

Needless to say, the goal has been to slowly make friendships and the blog has provided a avenue to do so. I appreciate the support of all those that visit and comment. In return, if I can help you particularly european hotrodders and motorcyclists let me know. You can see by the last post that I have access to things that may be difficult for you all to find or super expensive. Drop me a line and I will help if I can. Anyway, straight from Jakarta, Indonesia I present my rear fender.

Clearly, there is some work to do including the removal of some additional metal work. Basically the same type of welding that I have to do on the front fender. Fortuitous for me in that I can do both at the same time.

Fender Work Progresses

After finding all the little "imperfecions" in the fender  with simple hammer and dolly work, I decided to go ahead and strip all of the surface rust off. I can't tell you how much I detest stripping paint, rust, whatever. The term "surface rust" is a loose one and highlights the vagaries associated with buying stuff on Ebay. I will say that Ebay is much maligned and with some justification. But considering where I live and the total inaccessibility to autojumbles, Ebay is really the only option and I have developed a bit of savvy in sorting the proverbial shit from shine-ola.

Before stripping and after....

 

Anyway the plan from the previous fender post has changed a bit. For starters, it has given me the excuse to buy a new toy- my own welder.  The wife will love that but the reality is I have two petrol tanks and an oil bag that need work as well. Rather than bronze braze the repairs, I'm going to do a proper welding job first. The pitting means that a skin coat of filler is necessary and that will help smooth out the metal work. I'll then spray heavy primer after sanding the filler as low as possible. If it doesn't look like crap, I'll go ahead and paint. Simple enough. Right?

The joy of being a beginner

Well, I got a precious day in the garage with many more to come since I will be on vacation for the next 2 weeks. Good feeling. I have been fettling the carburettor for a while and have gotten it pretty well tuned but decided to buy new jets after reading an article on how cleaning unscrupulously with wire may change the orifice size. I was milling around the intake when I noticed something I hadn't seen before. I had always known that the rocker oil feed line was partially shrouded in plastic tubing.

But I didn't realize that one of the previous owners had incorporated a sight  window of sorts which is just perceptible in the center of the picture. What really concerned me however was the kink at the base of the feed line. I started the bike and flow was visible but my concern is that swarf may eventually clog it . Relieved that I had not been riding around while the top end was dry, I ordered a new feed line from Norvil. The question is whether or not to include the sight window as the previous had. If there are any opinions out there please let me know.

After dealing with the rocker oil feed line, I turned to the subject of a previous post---my front fender project. Clearly the fender had been the victim of some accident and some basic repairs were done. These repairs were mainly brazings of some cracks done prior to dealing with some dents and wrinkles. A few strikes of the hammer and dolly shattered those repairs and now it looks like I am going to learn how to weld.

So with a plaintive cry, I am asking for advice as to how to proceed. My inclination is to continue grinding down the previous welds, reshape the fender, then reweld with a MIG rather than braze. Let me know what you all think. Thanks.

My Holy Grail Part 1

As a newbie to classic motorcycling, I didn't really know what I was getting into when I purchased my Norton Model 7. Quite frankly I still don't but I am steadily learning. It's not the most common bike and living in southern Texas only exacerbates an inaccessability to expertise that for me is pretty much limited to the internet. Credit for much of what I have learned is thanks to the Norton Model 7 Yahoo group. I read a great deal about the interchangeability of Norton parts but it appears that the plunger framed Model 7 has quite a few specific parts as well. This is particularly true for the peaked front mudguard and the elbowed stays.

Interestingly enough, the current front fender on my bike is peaked just like the original but is a poorly painted chrome version that does not require stays. It doesn't look bad but it also doesn't look right either. I do prefer the lines of the front end with the original fender setup.

My Bike

Close-up from the side

Close-up from the front showing the peak

The Standard

One of the most enjoyable aspects of classic motorcycling is searching for those parts and the relationships formed with comrades in the process. My search for a fender started pretty much the day I received the bike and lasted almost three years. I found one on Ebay UK while I was stationed in Iraq. How absurd when I think about it. Imagine being in a war zone bidding for a vintage mudguard in the UK via Ebay USA. I was very fortunate to correspond with a member of the Model 7 Yahoo group regarding the restoration of the fender. My colleague is extremely talented and provided excellent drawings as well as advice to fabricate the stays that can be declared as unobtainium maximum.

The outstanding drawings

The fender itself is in very good condition with some surface rust. It has a few problems like anything 60 years old. The scarcity of fenders is attributable to the fact that it is the most fragile part of the bike and mine certainly shows evidence of having hit something in its lifetime. Some of the metal work has been done and bronze brazing completed on a couple of small cracks.

 I will freely admit that I never have done any metal work and so this will be a new experience. My main concern will be to re-establish and maintain the peak as well as repair the edge bead at the front. All in all it's a job I think I can handle. Keep posted for the progress.

Happy New Year's Day

It's a new year and the slate is clean. For everybody, New Year's Day provides the opportunity to commit or even re-commit to something or perhaps someone. I have owned my motorcycle for three years and notwithstanding my military duties including a deployment to Iraq it has been difficult giving the Model 7 the real attention it deserves. Bernal Osborne aptly described my affliction in his foreword to the second edition of  Modern Motorcycle Maintenance  as "needless tinkering-a pastime at which, I may say, motorcyclists are notoriously adept." I'll digress just a second and say that this is a fabulous little book especially for the novice mechanic. Now, it's time to get in it gear and address the issues.

A definitely good read

Like I mentioned earlier, I consider myself a vintage motorcyclist and so the goal of the "restoration" is a return to its original state rather than a concourse level attempt. Let's look at mine on top versus the standard I would like to achieve on the bottom.

  

The most obvious work to be done is on the tinwork. The front mudguard is incorrect but while I was in Iraq I was able to source a an original one with the front stand. I just need to find or fab some front stays. The rear mudguard was most likely involved in some incident because a good portion has been bobbed off so I'll have to figure something out there. Other things that need attention include:

1. Chrome tank completion

2. Proper silencers

3. Respoke wheels

4. Skim brake drums and new brake pads

5. Complete Carb Rebuild

6. Centre stand completion

7. Rocker oil feed line replacement

8. Sidestand rebuild

9. Complete revision of clutch

10. New seat cover

11. Rechrome a few parts

So there's the list and now it's time to get to work (after I finish my New Year's Bloody Mary). I wish you the very best for the New Year and the best of luck with your projects.