BSA Transmission upgrades for less drag (hopefully)

About halfway through the race weekend in Ohio I had noticed that the trans mainshaft had a considerable amount lateral run out. In my rush to get it together for the May deadline I did not have time for a full rebuild and was planning to do it after speed week but this forced my hand. Upon teardown the problems were apparent. Both mainshaft bearings were the original 60 year old units. These were toast, the layshaft bushings were also fairly worn with more than acceptable clearances. I had discussed with Jason the pros and cons of bushing vs needle roller bearings similar to a unit triumph over a few beers one night at his place. We did both agree that properly set up bushings are LIKLEY better than bearings, however the length of the shaft and the questionable way the 3 pieces of the transmission case mate together led me to think a concentric and repeatable bore through all pieces would be next to impossible to achieve. All tho had me calling Philadelphia Ball and Roller Bearing in the am to find some workable units, you should go there if you in the area good people. The mainshaft bearings were direct replacements and in stock on the shelf, the layshaft units were going to be ordered and some shop work was needed to use them in this box.
The drive side bearing was a direct press in just needed to add a thrust washer for the shaft the kicker side required boring the case to accept the bearing and adding a thrust washer on that side as well.

The inner cover was clamped down to the mill table, indicated true to the old bore and was opened up to allow a .002 interference fit on the new bearing

The inner cover was clamped down to the mill table, indicated true to the old bore and was opened up to allow a .002 interference fit on the new bearing

Here is the cover all bored with the bearing sitting on top and the bushing in the foreground

Here is the cover all bored with the bearing sitting on top and the bushing in the foreground

Since the trans was apart I figured I would give all the shafts and gears a polish to help reduce the drag when shifting and also so there is less windage.

You can see the difference in the metal finish here

You can see the difference in the metal finish here

Last thing was to make up some new high gear bushes as all my sources did not stock any. This was preferable because the shaft has some wear so I could oversize the bushes to get the correct clearance.

Raw 660 bronze as ordered with one cut taken to true the surface

Raw 660 bronze as ordered with one cut taken to true the surface

I had thought about the best way to go about sizing the bearings. I decided the best steps would be turn outside to press fit into gear, chuck gear on ball bearing surface and bore out so both would concentric as they turn together at different speeds in use, ream to final size with .003 clearance.

OD sized, ready to press. you can see how bad the old ones were

OD sized, ready to press. you can see how bad the old ones were

Boring the ID concentric to the bearing surface

Boring the ID concentric to the bearing surface

Reaming to fit the shaft, check fit often

Reaming to fit the shaft, check fit often

Perfect fit!

Perfect fit!

Next week when I return from LA I will put it all back together and give it a test.

Bonneville Motor Prep: Rocker Box and Valve Springs

Hi All,
Ive returned from honestly “the best time in my life” out at Bonneville this year and and determined to get my BSA together to compete for next year. Been drafting a long post with lots of pictures from the trip but havent finished it yet. Stand Ready! Was out in the shop tonight working on the valve train of the race motor. Did a little lightening of the rocker arms, removing the casting flash and polishing out the stress risers. Pics tell the tail.

photo 2

Before and after

photo 3

I reduced the horizontal cross section and took some extra material off the outer most end at the valve.

My main goal with this is to lighten the valvetrain, this works by reducing the inertia of the rocker arms and helping prevent valve float,(we are running tight valve to piston clearance right?) I have already made some aluminum pushrods to replace the steel ones that came stock. Reducing the horizontal cross section does not effect the stiffness of the arm, the final shape is more oval, think of an I beam.

This brings us to the last piece of the puzzle, the valve springs. After much searching and spending a day on the phone and leafing through the comp cams catalog I settled on a ovate wire beehive spring. These represent the latest in spring tech only requiring a single spring as compared to the dual springs we are all used to. The wire and conical shape cancels out the bad vibes that will end my weekend, while allowing lower seat pressures.
If you think its wild that Comp would make springs for a 65 year old motor, your right, they don’t. The springs Im using are a combo of 4.6l 4 valve ford v8 springs, 5.7l dodge new Hemi Titanium retainers and valve locks for a small block chevy. I told you I spent the whole day in the catalog. The good news is these things are priced like your going to buy a whole set of 32 for that super sweet Ford 4.6 to go in your Mustang. Score for us 4 valvers.

I have not weighed this yet but the difference is considerable

I have not weighed this yet but the difference is considerable

Until next time

BSA Land Speed Motor Build Part 1

Most of you that know me know I have slowly been putting a Land speed bike together for the last few years. One of the only major things left to do on it was build the motor. I had been putting this off for a while for any number of financial reasons, (racing is expensive!) and collecting parts when they popped up for not two many clams. This is no ordinary call you local supplier and buy the parts then assemble job. Almost all internal parts need some kind of fitment and machining to work in harmony at 7500 rpm. A brief description of the internals would be 51 BSA A7 500CC cases to fit into the vintage class, I am using a late model A65 bsa crank for its increased journal size for added strength over the stock unit. Its a great idea except it shares almost nothing in common with the early one it will replace, furthermore class rules dictate you can not change the stroke of the motor. Stock small journal crank has a 72.4m stroke and the replacement has a 74mm stroke. Hmmm, this required a rather expensive offset grind to the main journals to reduce the stroke to the stock A7 throw. The BSA has a bushing on the timing side instead of a ball or roller bearing, this needed to be ground down as well to fit the STD bsa case.
The most dreaded part of this all is a bearing adapter needed to be made to mate the drive side bearing to the crank as the A7’s has a larger ID than the A65’s. I ordered a piece of steel from mcmaster in the approximate ID to use for this.

Bushing with the ID bored to size

This was by far the most difficult machinist operation I have performed not because it was complex in steps but the tolerences I was working in were in the .001 range, going to be subjected to high load and my machining equipment is 75 years old.

After boring the ID to size the bushing was heated to expand it before fitting on the crank

Before starting all this I put the crank in the freezer to shrink it down for the new adapter

Bushing on, with the differences in temp it just dropped right on

With all this done I had to machine about .300 off the OD to fit the bearing on. This was no easy task with the weight of the crank throws, it was descry to turn this at very low speed on a dead center. Using a carbide cutter does not give you a nice cut at this speed.

I made many cuts and stopped at .007 to big. I’ve been know to overshoot these things by a mile so it was time to make less aggressive cuts

Bearing installed in new adapter

Here you can see the thinness of the adapter, its about .012 the final .007 was sanded down to fit the bearing. It took a long time and I checked the fit often

Carrillo H beam rods ready to be installed

I can’t tell you the feeling of accomplishment when the new bearing and adapter just dropped right in!

Stay tuned for part 2 and some work on the RODS

Modern Triumph Cheap Fork Upgrade

For quite some time Ive wanting to bring the scrambler it back to a more stock and trail riding friendly height, the previous owner had lowered it and Ive been bashing pipes since day one. This summer I had put some cartridge emulators in my Yamaha and did a fair bit of research on fork theory and different fork valving. I liked what I heard. Despite dampener rod forks being 1940’s technology the come as standard equipment on many new bikes including my scrambler. I had toyed with the idea of getting some emulators but they require dissassembly of the fork to change the dampening settings, less than ideal to tear the forks down on the side of the road with the varying on and offroad conditions I like to ride in. I had heard of guys using 90’s Honda CBR tubes and internals as both bike have 41mm front ends.

Both fork types displayed with the oil flow paths displayed

See HERE for a great discription on the differences of the two. After a few month of searching on ebay for the proper Honda forks the ones I found were bent or to spendy to just try it out.

Wait a miniute, Vinney brought me some broken Suzuki Katana forks last year and they externally adjustable dampening cartridge type. A quick dig out of the parts area yielded them and that they are indeed 41mm as well. I saw no reason that they wouldent work just like the orignial tubes 41mm is 41mm right?

The tops of both forks, triumph on the bottom. The adjuster knob works by changing the size of rebound dampening holes in the fork

After some dissassembly of the the Suzuki and Triumph forks to take measurements it was clear there was some signiffent differences in the two. Now just to figure the workaround.
Continue reading

’59 Chevy HEI Conversion

Cars and trucks are a necessary evil. With that said, if you’ve gotta have one (and motorcycles were my sole transportation in life until a few years ago) you might as well have a cool one that can haul motorcycles if necessary. I’ve had a ’59 Chevy Apache for about five years now. It was pretty raw, but evolves slowly as I make incremental improvements. This latest round had me adding a vacuum advance and rebuilding the stock AC/Delco distributor to house a much more recent vintage HEI ignition. The idea and motivation came from Young Dan, who had done it to his ’59 Ford. Thanks Dan.

Per my usual approach, I did my best to hide these modifications and to use as many original or factory parts as possible. It’s not like you can’t tell it’s there, but I didn’t want some big honking red MSD box hanging off the motor either. Wouldn’t seem right. So about two weeks ago we were hanging around the shop and I dug in. Ripped the distributor out after marking some reference points and started taking things apart. Up until that point I had been running fixed timing as I’d previously welded the two timing clamp pieces together due to a shot advance can. A little surgical grinding and they were free again and ready for reuse.

Without getting too much into it, here’s a little background on what changes were made. You can lookup the benefits of vacuum advance elsewhere. The HEI controller is a contact-less pickup and coil controller (makes the coil fire the plugs at the right time) that costs about $20 at any auto parts store. Dime a dozen. Easy to replace. These means no more setting points, more stable ignition, smoother idle and no regular adjustments of any sort required.

Parts used were the stock Delco distributor, a new advance can, a Chrysler slant-six reluctor and pickup and an aftermarket HEI controller and heat sink. I think the whole project cost around $60.

It came out great. Starts right up and runs like a whole new truck. Details in the pictures.


First step was to remove the point cam and grind/file it down as round as possible. Couldn’t use a cutter on the lathe as this part is hardened and precision ground. Once reasonably round, I made a somewhat thin brass bushing and pressed it over the eccentric area. The bushing deformed to some extent, which is what I wanted. Then I mounted the part in the lathe and turned the bushing perfectly round for an interference fit with the reluctor. Some people use epoxy to mount the reluctor, which might be perfectly functional, but you know I don’t glue things together in the shop! I was careful to mount the reluctor peaks where the old point cam peaks were for proper indexing.

The newly modified reluctor carrier mounted in the distributor with the centrifugal advance weights rebuilt and checked. This particular weight set allows for 31deg of mechanical advance (actuated by increased rpm).

I had to machine the original points plate so that it would fit over the new reluctor while still allowing for mounting the reluctor pickup. One requirement of this project was that all internal parts still be serviceable. Some people (you know who you are) install the reluctor after the weights and plate are installed, leaving you with a permanent alteration and no way to service the weights in the future.

One of the challenges of this conversion was to index the contact rotor (which carries the secondary coil voltage to the appropriate spark plug wire post) properly so that it is adjacent to an internal terminal post when the coil fires. Seems it’d be tough to figure just where the rotor was while setting things up so I made an inspection cap with a hole hogged out (technical term) in it. This made things much easier. Note the scribed line on the rotor and reference marks in yellow on the cap. This allowed me to check rotor phasing while the motor was running with a timing light after all the other work was completed.

Continue reading

Fitting glide risers to an early springer

A few days ago Denny from california called me to bounce ideas about his current pan project. He has these flanders risers that he wants to fit to an early springer. Normally the springer top clamp has two ears that you would put dog bone risers on. He told me V-Twin used to make sell this but has called around and no one has had this for years. After 20 questions and some pictures I decided to turn these up for him.

These are the risers, the bottom is threaded 1/2 x 13

Its hard to see in there but the rear legs are threaded internal 3/4 x 16. The ID of the hole in the top tree 1" and the risers sit on top of the tree not in it. Also notice the ears with the dog bones mounted currently.

I ordered up the hex stock in 7/8 so it will fit in nicely inside the top tree.

This is turning the side for the 3/4 thread to size, the half inch size has been done

RAW and almost finished.

Although Ive tried plenty of times I am never happy with the the threads when using the lathe in single point threading. Most of the time I start the threads with the lathe and get them almost to finished size, then run a die over them to finish. I did the same on these and it worked well.

Finished product, There are three because I wasn't real happy with the 3/4 threads on one

Here is the latest from Den

I bought plenty of extra stock so if any of you are looking for the same thing contact me And yes these are MAIDEN AMERICA

4LS to Roadholder Fork (part 4)

A couple weeks back I got another chance to work on this fork conversion. I just never got around to putting the pics up. Things have been hectic lately.

When we left off, we were modifying the fork to work with the original Suzuki axle for this hub. The answer to the bonus question from last round? I’d bushed one fork leg but not yet bored it to allow access to the fork damper retaining screw. Bill Becker was the first to point this out, just minutes after the article was posted. If anyone has an nit-picky eye for detail (and style), it’s him.

This time I modified the axle and related hardware to finish this job.

Here we go.

I was able to mount the fork leg to the milling machine table vertically with just enough room to get the boring head setup. However, there was no way to keep the leg secure enough with it acting as such a long lever and having limited contact where mounted. I then decided to mount an extra vice we had in the welding area to the table with a large angle plate. This allowed me to hang the leg off the side of the table so it could be clamped closer to the work area.

Big old vise mounted to an even bigger angle plate. This setup worked pretty well, even if I did scar up the fork leg a bit. Nothing a little sanding and polishing won't fix.

Leg after bushing has been bored to match existing bore in axle boss. Now you can get the damper retaining screw!

There needs to be a means to secure the axle while tightening down the axle nut. I don’t want to rely on the pinch strength of the boss on the other leg as it seems lame and likely to stress the leg. It also leads to incorrect installation as the last step of securing the wheel is to tighten the pinch (after axle nut is torqued) so that the legs are parallel and not pinched together. I decide to make a small diameter hole in the axle for insertion of a screwdriver or rod to keep it from turning. Old Harley Hydraglide forks use this setup and it works. In our case there is no axle protruding so I made the hole so that it lines up with the damper retaining screw hole under the leg. Hidden. Functional. I did realize afterward that while I intended to drill the larger end, I messed up and did the smaller end. Dammit.

Axle secured in a v-block. Located under the quill using a "wiggler" for drilling.

Axle drilled. Hole is perfectly centered. Drilling on a milling machine is so much easier.

Whole setup assembled. Note the access hole for securing the axle.

I turned down the axle nut to leave room for a lock washer and made up a thick flat washer to spread the clamping force over the original fork material and the new reducing bushing I installed. The washer has a flat ground in it to engage the lower fork casting so it doesn't rotate when tightening.

That’s it for this session. I have to drop some parts off for chrome and polish the lower legs then we can assemble this and ship it home.


Fixing dented pipes

I picked up this set of beat-up pipes for my current project. They were typical of a 30 year old part and were rife with dents and creases. Ive heard a lot of talk of guys putting water in pipes and freezing them to push dents out. I promise you this will bulge your pipe in ways you don’t want. I decided to pull the dents out using a trick I learned working at an auto body shop years ago.


Flattened area

At the body shop we had this slick little spot welding gun that would weld studs to the sheet metal and you would pull the dents out with a slide hammer. I have neither of those, But I did have some old spokes, a torch and welder to work with.

Spokes welded to the bad areas

Heat and pull hard

After welding the spokes on I heated the area cherry red and slowly pulled to working as I went. Sometimes I had to go back and reposition the studs after I pulled it all out to get the last bit. I finally ground off all the stud mount welds to finish the job. These pipes woulnt be perfect after this but much better than before and they are getting painted soon.

pretty shapely


The RD get a Trick suspension upgrade on the CHEAP!

So from the beginning of building this bike I knew I wanted a bike that handled like a brand new sport bike. Rd’s wernt know for their stellar rear suspension when new and the 40 years of sitting in upstate NY made these ones good paperweights. I had looked into a few different options like Progressive and Koni and was not siked on spending the $400+ on them.

Scrap metal

My wife had been out of town for work a few weeks and I spent lot of nights laying in bed thinking of options. What better way to get modern sport bike handling than with sport bike parts. Did a bunch of research on spring rates using the site and settled on a 07 Honda CBR1000rr showa unit. Its a nice unit with adjustable dampening and rebound and spring preload, plus a healthy aftermarket of parts as well. The spring rate is 11.5kg per mm and with the rd’s feather weight and my 195 lb self this puts me a bit stiffer than stock with tons of adjustments. A quick search of ebay yielded one from a low mileage bike for $25 with free shipping. I find its better to let the big bike mfg’s spend millions on R&D for their new machines and I’ll reap the benefits for my old junk.

New jawn off a 07 CBR1000rr

The next problem was how to make a shock with only 1.75 inches travel work in an application that needs about 5″ total with sag and not use all the fancy linkages that honda uses on there bikes. After much thought my solution was to make second arm attached to the swingarm but shorter to reduce the radius. After a lot of math I hadn’t used in years on paper I settled on needing a 5.5 inch radius from the swingarm pivot to give the proper travel when the 15″ arm moves. I decided to draw it to scale on the welding table to check the math. It worked in practice too.

Drawn out to SCALE

Now was the easy part of tabbing up the mounts. The rear is made out of 1.5″ square stock and the front that I forgot to take pics of is a 660 bronze bush I made on the lathe pressed into some round steel stock with a shoulder on it for the shock mount to ride on.

The start of the rear mount

Tacked in place

I also bent some round stock to act as a gusset for the rear mount and brace the swingarm. This should help with the torsional stiffness af the old arm as well.

Ready for finish welding

Really cleans up the lines without the rear shocks on there

So final verdict is that it feels like a new bike when you sit on it, It only cost $25 and the rest of the stuff I had at the shop or could be had for short money and the fab work wasn’t crazy. Ill take it. Thanks Honda

Using Banshee pistons in your air cooled RD350/400

A few days ago my pistons and cylinders came back from the machine shop. Here is how they went together. The only company making true rd350 pistons now is wiesco big $$. Banshee pistons on the other hand are a dime a dozen and are available in a wider range of oversizes. With a small mod you can use the more plentiful banshee piston in the rd motor. Most places are charging $12-25 to modify this piston for your air cooled. Here were going to do it with no more than a few sharp jewelers files and some patience. There is a small tang under the piston ports you must remove. In the banshee intake there is a bridge in the center to allows this tang to ride. The rd has an open area here and the tang will catch on the bottom of the intake runner, break off and cause all sorts of damage  to the top end. I started by marking with a sharp pencil where I wanted to file off to. I CAREFULLY filed down to this mark just making contact with the scalloped areas to ensure it was flat. When you have it smooth all the way across, use a fine file to bevel the edge as not to catch on anything. As a side note I held this in my hand to do this NOT in a vise. It probably took me longer to write this post than modify both pistons. Make sure to thoroughly wash the pistons with hot soapy water to remove any contamination.

This is how the pistons come stock, notice the small tang on the bottom of the piston under the intake ports

Now with the tang removed

Now to install the rings, there are 2 pins in the ring lands to capture the rings and keep them from rotating into the ports. Look at the rings, notice that the end gaps have a section to correspond with the pins in the pistons. Install them this way. I should also mention you should check the end gaps by installing the rings only in the cylinders and checking the gaps according to the specs listed in your shop manual.

Notice the small pin in the ring land, this is to keep the rings from turning and catching the ports in the cylinders

Since I was working alone this night I decided to try something to install the jugs more easily. It can often be hard to hold the jug and try to compress the rings and assemble it all even with a helper. I know some of you know what I’m talking about. This time I put the pistons in the jugs while they rested on the bench. This allowed me to only have to push the wrist pin in while suspending the jug with one hand, worked pretty well I thought.

Piston in just past the rings.

Paper towel to keep the circlip from falling into the case when I drop it

All together and at TDC

Later that night I put the heads on and did some measuring of the squish band, and started on some major rear suspension upgrades. Come back later in the week for more on that, promise you’ll be impressed.