Sunday, December 19, 2010

tigcraft update

Prepare to drool...

Friday, December 17, 2010

All forked up

The box arrived from Traxxion Dynamics with my supermono forks inside.  Knowledge and experience are wonderful things, but sometimes come at a cost.  Considering what was done in terms of intellectual property and expertise, the cost was fair.  What I discovered was reassuring, as the problem I had with the forks was legitimate, and the solution I paid for was the only one possible -- so I had correctly diagnosed the problem.
As I said in an earlier blog post, I suspected the fork springs as being too soft for me and the bike.  There was some chatter out of corners, and the o-ring on the fork tube indicated that the forks were bottoming quite regularly, not under braking but under compression while cornering... not good.  While an increase in oil level helped, it was a stop-gap.  A book I recently bought about suspension tuning advocated treating spring rates independent from the damping process -- no amount of preload, compression/damping, or oil weight or level was going to adequately compensate for the wrong springs.  I send the forks to traxxion to get an idea of the fork spring rate, and then if necessary install and set up the correct springs for my weight.
The information I got back was enlightening.  The spring rates were a combo -- .55 in one fork, and .82 in another, for a combined weight of only .68.  Most bikes come with between .80 and .90 springs installed, with over 1.00kg springs available in some cases.  So stock, they were miles off.  Traxxion changed the springs out to .80 in both, revavled the forks, and serviced the assembly as well.  They were shipped back to me and they're ready to go back on the bike.
Bike Club reassembly will continue in the new year.  The student and I re-checked the vavles and they are within spec, according to the manual.  Really easy to do, actually, although if a valve is out, then changing the shim is a bit more complicated.
I'm getting some more responses from my sponsorship proposals, so I might get some additional product discounts and suppies for the season.  I'll post more news soon.
Oh yeah, Dave Pearce has been regularly threatening my marriage with tempting photos of some of his cool projects, both current things and past gems...
This is a MUZ factory supermono that my frame was based you can see, the spec sheet and running gear is a tad higher than my supermono...

That's a self-supporting carbon-fibre tail section, and dymag wheels...
Yamaha 660 engine, bored out to god knows what and making copious horsepower.
This might be the leap at Cadwell Park.  Shipped to your door (in North America) for only 6500 pounds.  Go to for more information.
This is pretty cool as well -- Dave is developing a custom chassis around the Ninja 650 engine.  Has an R6 rear swingarm, linkage, and shock.  Appears to be stock airbox.  Again, a CF tail section and light fuel cell and you'd have a bike to embarrass some 600cc racers!

And the other side -- some airbox tomfoolery possible -- check out the steering stem -- cut away, to perhaps allow a more direct ram air intake into the airbox???

Monday, December 13, 2010

new shoes

It was time to get some proper race kit -- the boots I were using were nice, light street boots, but after reffing for 2 years I saw first hand how important proper gear is -- with the flag, you get to see all the crashes and the results, not just the ones that happen to you or the guy in the pit next to you. does a great job of notifying privateers about sponsorship opportunities -- at my level the best I can hope for is a discount on parts -- I have never, nor will I likely ever get anything for free -- too old and slow for that.  But a discount is a discount, and when I sent my resume off to, it was with the hope that I could get a deal on boots.  They came through.  They distribute prexport boots to North America -- not a popular brand over here, but big in Europe, and these, the spada model, were the top of the line and highly rated.  I got a killer deal on a new set, in the size and color I wanted.  While I was at it I plumped for a chest protector as well, as more and more racers are racing with these in place under the leathers.  Pretty pleased with the result:

Like all race gear, I hope I never have to use them.  Better gloves are next.  We'll see what I can find on eBay...

Sunday, December 12, 2010

a few tweaks

With the bike apart again (bike club 2010), it was time to make a few subtle modifications to the frame.  Very simple, but knocked a pound or two off the overall weight.  As the engine mounts didn't use them, and no kickstand will ever be used, the lower part of the frame rails were removed with my tubing cutter.  Should also allow the fabrication of a slightly better gear change mechanism -- but that won't take place for awhile, until the engine is back in the frame.
You can also see how nicely a tubing cutter works -- a clean cut, with just a dressup with a file to get rid of any sharp edges.  Now just need to find some rubber plugs to stick in the bottom.

You will also notice a different remote resevior -- from a fox shock fitted to a vfr 750.  Checked the spring rates, and it should be in the ballpark for my bike's needs as well.  Triple adjustable and rebuildable as well, whereas the stock 900rr model was a throwaway item... and based on the leaking seal, it was time to throw it away!
In other news, just waiting for the 28mm needle bearings to come in the mail.  Atom-Jet will then bore the swingarm pivots to suit.  As well, with the engine out and at school, its time to check the valves.  Doubtful that they are out of spec, but while the engine wasn't run for long, it was run pretty hard.  Will be interesting to see what comes up.

Sunday, December 5, 2010

swingarm project

I've never been 100% satisfied with the pegaso rear swingarm.  After hours of research, I found that based on photos seen online, that a suzuki rg125 swingarm might work.  Of course, those bikes were never imported to North America, so if I did find one for sale, it would be a bit of a leap of faith to order one and ship it here, in the hopes that it might work.  Like most used parts in the UK, this came cheap -- 9 pounds.  The shipping was a bit steep however. 
As you can see, it is designed to pivot on the rear of the engine case.  As well, it is set up for LHS drive chain, while the pegaso had to be "flipped" -- it also has a cool, GP-like banana arm style to the right -- intended for the expansion chamber to exit with some more room.  Dimensionally, it is quite similar to the pegaso swingarm.  However, in some key details it is different.  It has also been nicely powdercoated, but that is wearing through in some areas, and modification will require it to be stripped anyway.  And, while it has the look of an aluminum piece, it is actually steel.  Oh well, that means I can do any of the cutting and welding needed on the arm itself.

The key work that needs to be done first involves skills and tools I don't have.  First, the swingarm pivot axle needs to be bored out by 1 mm.  In order to use the proper parts, I need to be able to press in a 28x22mm needle bearing.  Currently it will accept a 27mm bearing.  So the front part needs to be enlarged by 1mm overall.  Secondly, in order to use the correct rear axle from the rs125 wheel, the wheel slot and the carrier needs to be bored out to 20mm.  My hope is that this work can be properly done in the first place -- so its off to Atom-Jet tommorow just to see if it is possible.  I really think it is, but it would require some creative jigging on the mill table for it to work.
Depending on how simply I can get this done, there is a slight possibility I can do this mod over this winter.  Luckily, the pegaso swingarm is still "fine", and will be kept as the fallback solution in case I hit a roadblock with this project.