Topic: Building of a CB500 classic racer

[turboguzzi]

The answer is: 65,2 RWHP at 9700 rpm
[youtube=425,350]http://www.youtube.com/watch?v=vL-vWu_TugA[/youtube]

congrats!, good work!

[bwaller]

Oh nicely done Howell, that engine sounds great too.

I remember a guy on here that was planning to do some engine work and dynoed his stocker first and found 36.8rwhp.

[MRieck]

Oh nicely done Howell, that engine sounds great too.

I remember a guy on here that was planning to do some engine work and dynoed his stocker first and found 36.8rwhp.

I'm very anxious to see what "Waller's Hammer" puts down

[Howell]

Today we were on the Dyno.
We made three runs , first run gave 60 hp at the rearwheel.
Second , little adjustment of the ingnition, a little bit more power.
Than we changed the main jets from 115 to 120 and that made a big difference , see the result:



Movie ::http://www.youtube.com/watch?v=vL-vWu_TugA


We are very happy with the result , for this time we are satisfied.
Now we go testing on the circuit so that the bike has run a few more miles , because everything is new in it.
And after that we will go back to the Dyno again to find some more HP.
Now the bike is 99,9 % ready , friday we go to a suspension specialist.

Foto impression of the complete bike:












 

[Howell]

The answer is: 65,2 RWHP at 9700 rpm
[youtube=425,350]http://www.youtube.com/watch?v=vL-vWu_TugA[/youtube]

I just read that my son Yrjo has already announced the power  

[Howell]

Very nice Howell - are you going to paint the bike or leave it white? (never mind the dyno - what colour is it?!  )

Looking at the video, it hangs onto its revs a long time, is that just you letting the throttle off slowly or is there some other reason?

The colour stays white , WHITE POWER  
You were right , it hangs to long on the revs because of a bad throttle cable.
Today we made a new one and now he reacts good.

[chris]

Hello,

I am René from Holland and I am new on this forum.
I am building a CB500 Classic racer for my eldest son.
My eldest son wil ride the bike in the national dutch classic championship in 2010.
At the moment we are building up the chassis and a good friend of my will tune up the engine.
He is very experienced in tuning classic Honda fours.
He has already made two CB750 engines for me , one with 820cc and one with 860cc.
Another friend of my is already racing a CB500 with a engine of him with 65 hp at the backwheel.
My son has made a website for building the 500 racer , it is in dutch language.
But there are many pics on it.
www.yrjo.nl




Chassis specs:
Stock Honda frame
CB750 type Dresda swingarm
Frontfork Yamaha RD350LC
Alu yokes from Voxonda (member on this forum)
Yss shocks
Honda RC162 replica frontbrake from Budamotor Racing in Hungary:http://budamotor.hu/index.php?language_id=2&menu_id=1
Honda XL250 hub and rearbrake with AFAM sprocket 520
Tarozzi clipons and footrests

Some things to get more power out of the engine:
Head flowed and ported
Camshaft from Webcam
Renault car valves
Honda Dax pistons
Lightened CB500 crank
Suzuki GSX1000 rods
Barnett clutch plates
Close ratio 5 speed gearbox from :http://www.mpe07.co.uk/
CB650 oil filter pan
CB650 oil pump
CB650 outer clutch
Keihin CR29 mm carbs
4 in 1 exhaust with WRP alu silencer

At the moment we are waiting for the gearbox which will be delivered in the second week of januari.
The chassis is almost ready and after that we have to spray the chassis and the tank/seat and fairing.
I will update the topic frequently.

My Honda CB750 with the 820cc engine:

My CB750K2 1973:




Regards René

[chris]

I am very interested in your progress and it appears that you are doing a beautifull job of this and wish you the best I am currently racing a CR 750 Replica in Aus and I love these old bikes.Really looking forward to seeing the finished bike Cheers Chris

[Howell]

I am very interested in your progress and it appears that you are doing a beautifull job of this and wish you the best I am currently racing a CR 750 Replica in Aus and I love these old bikes.Really looking forward to seeing the finished bike Cheers Chris

Thank you Chris,

The bike is alreay 99,9 % finished yet , tests on the circuit will give us input to change things.
And then we hope the bike is 100 %.
I am also a fan of the CR750 , as you can see I have a totally restored CB750 K2 and a CB750 F2 legal street racer (822cc).
After this 500 project I'm gonna change the engine from the F2 into a 860cc , this engine I have made already a year ago.
The cilinderhead of that engine is tuned the same way as the 500.

[turboguzzi]

howell, been comparing our curves, it's really nice that you dont get the dip in power at 6000 like in my motor. I guess these are the velocity stacks doing their job. Should mount them too....

your motor seems to be going on breathing better on high rpm, bigger than stock inlet valves, right?

Still, the theory that our sohc's cant really rev well beyond 10K seems true. Maybe with a 650 head? Might be worth a try...

Cheers and good luck on track!

TG

[paulages]

wow, very impressive numbers... 5HP less than my engine, with 115cc less displacement. i wish i could have a pint with your tuner.

[Sam Green Racing]

The answer is: 65,2 RWHP at 9700 rpm
[youtube=425,350]http://www.youtube.com/watch?v=vL-vWu_TugA[/youtube]

I just read that my son Yrjo has already announced the power  

Kids spoil everything Rene

Welcome Yrjo and Chris down under.

Sam.

[SteveD CB500F]

A reminder to all who have dyno runs under their belt.

A while ago I started an album in the gallery to store these dyno printouts as they get lost in these enormous threads!

email them to me and I'll upload them: http://gallery.sohc4.net/main.php?g2_itemId=13118

Steve
steve.dennis@nirvana-motorcycles.com

[turboguzzi]

A reminder to all who have dyno runs under their belt.

A while ago I started an album in the gallery to store these dyno printouts as they get lost in these enormous threads!

email them to me and I'll upload them: http://gallery.sohc4.net/main.php?g2_itemId=13118

Steve
steve.dennis@nirvana-motorcycles.com

how much you pay for each? 

[SteveD CB500F]

You get the Kudos of being on the same page as the $Million CB!

 

[Howell]

howell, been comparing our curves, it's really nice that you dont get the dip in power at 6000 like in my motor. I guess these are the velocity stacks doing their job. Should mount them too....

your motor seems to be going on breathing better on high rpm, bigger than stock inlet valves, right?

Still, the theory that our sohc's cant really rev well beyond 10K seems true. Maybe with a 650 head? Might be worth a try...

Cheers and good luck on track!

TG

Hi TG,

We have bigger inlet valves than stock , now 29mm.
We may not use a Cb650 head by the dutch classic rules.

[MRieck]

Larger valves make a big difference in these engines. Boring the ID of the seat to 90% must be done to take advantage of the larger valve.

[iomtt9]

Hi my name is Colin i'm from the North East of England, i'm new to the forum. This is a photo of my 500/4 Classic Racer.Its not a very fast bike but the sound from the 4 meggas is superb, we like to go racing, having fun and a few beers.
I have just returned from Phillip Island in Australia where we raced in the Island Classic, a great time was had by all. I hope to race this year with the CRMC and the Dutch Classic Racing club.

[Yrjo#54]

Here is a picture of my 500/4 racer

You have raced last year in Oostende Belgium??

[iomtt9]

Yes i did i am friend of Frank Lemstra and no 46 van der brom.

[Yrjo#54]

I saw some pictures on www.racefan.be

[iomtt9]

I hope to be at Assen and Ostende a week later, so i will look for you, success in you and your sons racing.
Col

[Howell]

Hi my name is Colin i'm from the North East of England, i'm new to the forum. This is a photo of my 500/4 Classic Racer.Its not a very fast bike but the sound from the 4 meggas is superb, we like to go racing, having fun and a few beers.
I have just returned from Phillip Island in Australia where we raced in the Island Classic, a great time was had by all. I hope to race this year with the CRMC and the Dutch Classic Racing club.

Nice looking bike Colin , I hope we have more speed then sound
Ernst Hagen is this year also competing with a 500/4
http://www.cmsnl.com/news/ernst-hagen-is-preparing-for-this-years-racing-season_news639.html
Now there will be 4 or 5  Honda Cb500/4 in the championship.

[turboguzzi]

Larger valves make a big difference in these engines. Boring the ID of the seat to 90% must be done to take advantage of the larger valve.

well, sounds like I am going to have to accept your proposal from waaaay back, remember?

TG

[MRieck]

Larger valves make a big difference in these engines. Boring the ID of the seat to 90% must be done to take advantage of the larger valve.

well, sounds like I am going to have to accept your proposal from waaaay back, remember?

TG

Yes....I remember. That's why I said it.