Topic: Building of a CB500 classic racer

[fastbroshi]

Bravo, tell him to chime in here!

[Flying J]

Yes would love to hear about that dry clutch

[Sam Green Racing]

What a fantastic test session with the bike and Yrjo improving lap by lap. Here's hoping he can do it again in April, good luck Rene and Yrjo.

Good video Rene, shame the camera man was not as good as Yrjo

Sam.

[bwaller]

The team looks to be in synch Rene, hopefully you and Yrjo have "shaken the gremlins loose" 

[fang]

The video was fantastic.  It really got my blood pump-pump-pumping the few times you captured your son making strong passes out there.  Fantastic!

[z1100r]

 What a fantastic thread....!!!! just spent all morning reading this.  Just a few things that I remenber :-
  Love the gearbox, but are those gears hard enough, thats a tremendous amount of wear for such little use.  That head steady.. not for me..sorry, the crank pistons and rods..superb. The front brake - awesome. Very like my old Yamaha TD2B brake with 50mm spokes.

 The crank blow up...yeah.. something weird happened when you re-assembled. I raced my Honda 600 four for 2 years - it started with a lovely stock very low milage 550 engine, i did loads of races and loads of pratices and tests on it - in the process winning a club championship..I had no lubrication problems at all.
   The following season I bought a TZ350 and went national racing selling my Honda to a mate.....he fell off it left side damaging the gear lever so he replaced the lever but there was something more serious, he had problems selecting gears, it had also bent one of the selector forks. So he took the bottom off the engine and replaced the fork. Next race he did exactly as you did and seized my lovely crank. 1 and 2 big end and gen side main bearing. WTF...!!!

 I dont know what he did to this day...!!! I took it apart and repaired it for him using a secondhand crank and its been fine ever since...I bought the engine back in the end and its still in my road bike now..running as sweet as a nut.

An absolutely brilliant read Rene, made my day, what the internet was invented for.

PS.    Get used to a race change Yrjo - 1 up rest down. You do get used it very quickly and personally I found it no problem adjusting to one change for racing and another for road.

[Howell]

First race in Assen on 3 april.

First qualification practice on saterday :
-  Yrjo was riding trough the paddock to the start area for the first qualification practice and suddenly the clutch didn't work any more. I inspected the cable because I thought the cable was broken or had come loose from the clutch lifter sled , but none of that.
So back to our camper to look at the problem and missing the practice.
I removed the clutch cover and saw immediate what has happened , the complete clutch had came loose on the shaft.
The circlip from the centerclutch has came out of the notch and that after 600 km testing without a problem.
 I mounted another stiffer circlip and the clutch was working again.

Second qualification practice on saterday:
- Everything went went well and Yrjo took a 11th starting place.
But the practice time ( 25 minutes) was to short to get a good ritme.
On sundaymorning there was still a warmup training, to get a better ritme.

Sunday , raceday.
- Warmup training: Yrjo was 2 seconds faster than in the 2nd Q.practice.
A good basis for the race.
- Race: Yrjo made a good start and was on 8th place the first lap and was riding good laptimes.
His fastest time was 2 seconds faster then in the warmup.
He finally finished on 5 th place , we where very happy with the result after all the problems we had last year.

So now up to Spa/Francorchamps on the 17th of april.

Our friend on a 500 Honda (nr 4) finished second.
 

[voxonda]

Well done René and Yrjo, finally the results are there.

Cheers, Rob

[Howell]

PS.    Get used to a race change Yrjo - 1 up rest down. You do get used it very quickly and personally I found it no problem adjusting to one change for racing and another for road.

We tried that in the beginning  but Yrjo didn't like that , he is used from his roadbike to change gear the normal way.
And thanks for your positive comment.

[turboguzzi]

PS.    Get used to a race change Yrjo - 1 up rest down. You do get used it very quickly and personally I found it no problem adjusting to one change for racing and another for road.

We tried that in the beginning  but Yrjo didn't like that , he is used from his roadbike to change gear the normal way.
And thanks for your positive comment.

Congratulations Rene! happy to hear that things start working for you. Sounds like yrjo likes the head steady too
I am with you on the shifting Rene. i ride a lot on the road and find it risky to do "upside down" shifting just on the track. When everything is going fine, then sure no problem, but the first moment you have bit of an emergency and you instinctively shift into a lower gear instead of higher, you really risk wrecking an engine or worse by over reving. The risk is just not worth the -0.3 seconds a lap or less that you can (maybe) save. at least not for me.

TG

[Howell]

Tomorrow up to the second race at Spa-Francorchamps , we'll meet Colin (IOMTT9) there.
Last Tuesday we were on the Dyno again because last race at Assen the revs wouldn't come out really good.
On the Dyno we find out that the mixture was a little bit to rich at 8500 rpm , so we put in one size smaller main jets.
The power was still a 65 RWHP.

[Howell]

Back from Spa-Francorchamps

Result: 8th place.
We had no mechanical problem at all , but Yrjo made a bad start , his own fault ,  a combination of clutch and throttle miscontrol.
Otherwise another top five position had been possible.
But we are happy with another top ten finish.

[Sam Green Racing]

Getting reliable now Rene, well done the team.

Sam.

[turboguzzi]

Rene, Yrjo,

Sounds like you are starting to have some fun, no?

About time

Cheers

TG

[Howell]

Rene, Yrjo,

Sounds like you are starting to have some fun, no?

About time

Cheers

TG

Hi TG,

Indeed we have some fun now and have some time during the raceweekends to drink a beer instead of solving mechanical problems.
Colin (IOMTT9) finished as 13th , he had some problems, because he made to much nose with his megaphone's  he had to install a 4 in 1 exhaust with to little ground clearance.
In the last lap he ran out of fuel.
We had also to little ground clearance in Assen and setup the bike  1,5 cm higher for Spa ,which was a big improvement.
Yrjo said the bike has now a perfect handling.
Friday we go to Assen for testing , 5 sessions of 25 minutes we can do then and we will try fo find a good setup for the next race also In Assen on 15th may.
 

[Howell]

picture gallery race Francorchamps , nr 19 Colin IOMTT9

[CB750faces.com (Lecram)]

very nice pictures, Rene. What a beautiful race track. It is a shame that there is no MotoGP there

[Howell]

We need a dentist missing some teeth.

Today on Assen in the last lap of the first session of a trainingday ,at full speed in 4th gear a terrible rattling noise came out the gearbox.
Yrjo immediately stopped and got of the track.
First we thought it was the clutch but it was okay.
Then we drained the oil and removed the oilpan , it was a disaster in the oilpan , a lot of gearsprockets teeth in it.
We went home immediately and opened the engine.
Four gearsprockets are totally destroyed ,see the pirtures.
Even a shaft has some damage.
How this could happen I don't know.
For the next race we will install the normal Honda gearcluster.

[Sam Green Racing]

Getting reliable now Rene, well done the team.

Sam.

 

Sam.

[turboguzzi]

 OMG..... make sure you disassemble everything to check for little pieces, crank, head, etc....

[bwaller]

Oh man I'm sorry to see this Rene. I thought you had left your bad luck behind.

[paulages]

Wow Rene, I'm really sorry to see this. It's hard to even imagine what would have caused this..

Regarding the clutch circlip... I'm sure you know this, but you should be sure to install it with the rounded shoulder inward.

Good luck on the clean up.

[Howell]

Wow Rene, I'm really sorry to see this. It's hard to even imagine what would have caused this..

Regarding the clutch circlip... I'm sure you know this, but you should be sure to install it with the rounded shoulder inward.

Good luck on the clean up.

I know that about the circlip installation , but this was no circlip problem , we don't know what the cause is.
The shiftdrum workes well , the forks are not bend.
I inspected the complete gearcluster and shifting mechanisme together with our tuner but couldn't find anything wrong.
Today I installed the MPE mainshaft together with the MPE countershaft lowgear , these ones are interchangeble with the Honda ones , no undercut.
First gear has now a ratio of 2.000 instead of the original 2.353 , the other gears and transmission counter shaft are original Honda now.
I hope this works well and is reliable.

[turboguzzi]

and still, Yrjo is lucky not to have the rear wheel lock up on him....

[Howell]

and still, Yrjo is lucky not to have the rear wheel lock up on him....

Indeed TG , that's the only 'luck' we had in these machine defect.