Topic: CB 500 Racer

[DeppJones]

Hello,

I am Achim from Germany and I´m building a CB500 racer together with my dad. He wants to ride it in this years classic championship. It´s my firtst attempt on a 4 cylinder.
The front fork, yokes, brakes are from a 750 bol d´or. We wanted the bike to run on spoke wheels but didn´t know which hub would fit. So we decided to construct our own hub out of aluminium (7075) on a lathe. The frame is the stock honda frame but we removed everything we don´t need and I think I´m going to weld some reinforcements. I´m also thinking about welding a swingarm because at the moment we´re using the original one. The dampers are from Koni. The engine it stock at the moment but we will fit a webcam camshaft and Keihin CR 29. The starter and the cushdrive will be eliminated. The ignition is an electronic one. The head will be ported and I´m still searching for pistons with a higher compression. Can anyone help me? Also I´m not sure about the rods...any tips? I think that I´m going to build the manifold on my own but where can I get some of the nice megaphones? Or what kind of muffler would you suggest?
I will build the rearsets on my own and the tank you see in the picatures has to be made out of aluminium because I´m afraid that the one out of glassfibre is not strong enough.
I´m looking forward for opinions and tips!

Regards
Achim

[Howell]

Wilkommen Achim,

I'm gonna follow this thread with big interest because I build last year a CB500 racer.
Look here how I build our racer , you can find there many answers at your questions  : CB500 racer
There is a lot of experience on this forum about building and tuning look also here:turboguzzi
Turboguzzi has some more threads about the CB500 racer.
The tank (CR750model ) on your pictures looks the same as I use on my CB750 , mine is resistant against modern fuels with ethanol and it is strong.
My 750 is an F2 model , same fork as the Bol d'Or, and wheels with spokes.
I used a CB750 K hub and brakecalipers,brackets and discs from a CB900 Bol d'Or .
The K hub has six holes , but the discs have five , I filled up the holes by welding them and made six new holes to fit them on the hub.
If you want to see my bike , it's an one hour drive from Köln to my place.
By the way a friend who is also racing with a CB500 has two tuned engines for sale, one with 52 rwhp and one with 61 rwhp. (€ 1000 and € 1500)

And don't let your 'old' dad ride on it , do it yourself 


gr.René

[DeppJones]

Hoi René,

thanks for your interest. I read the thread about your CB500 racer and I got a lot of information from it. I should have read it before I posted my thread!
I bought the tank from a guy in Holland. It is sealed and should be resistant against modern fuel (ethanol) but I´m afraid that it would burst in case of a crash although it looks strong.
I didn´t want to weld the hub so I decided to build a new one. The only work left is to mill the holes for the spokes.
Would you mind telling which rods you exactly used (which year of construction)? I found some pistons, even with a 15mm pin but I don´t know if they are useable because of the height. Have you measured your pistons? For which engine (ccm) are they?
I think about taking a look at your bike...
And thanks but I don´t need these engines from your friend. I have to save money!

Regards
Achim

[turboguzzi]

hi Achim

Welcome to the 500 road racing club. Nice build already.

The piston question comes up often here and there are no simple solutions. Search the forum for high compression 500 pistons. The quickest solution is XL125 pistons where you will actually have to reduce the crown to lower CR to 12:1.

http://forums.sohc4.net/index.php?topic=38006.75

I been racing four seasons with the stock swingarm, it works quite well. The bimota replica swingarm is still available from motocicliveloci if you have the $$$$ 

Are these forks 35mm? many vintage organisations will not let you use bigger than 35.

Are you looking for a 4 into 1? if yes, I am using a Marving 4-1, they are still available new.

keep us updated

[Howell]

Hoi René,

thanks for your interest. I read the thread about your CB500 racer and I got a lot of information from it. I should have read it before I posted my thread!
I bought the tank from a guy in Holland. It is sealed and should be resistant against modern fuel (ethanol) but I´m afraid that it would burst in case of a crash although it looks strong.
I didn´t want to weld the hub so I decided to build a new one. The only work left is to mill the holes for the spokes.
Would you mind telling which rods you exactly used (which year of construction)? I found some pistons, even with a 15mm pin but I don´t know if they are useable because of the height. Have you measured your pistons? For which engine (ccm) are they?
I think about taking a look at your bike...
And thanks but I don´t need these engines from your friend. I have to save money!

Regards
Achim

Hoi Achim,

Did you buy the tank from John Clarijs in Eindhoven ?
Of course a fiberglass tank is not that strong as a alu tank , but also a alu tank can burst at a crash , but fiberglass is easy to repair.
The rods we use are from the 2002-2004 models Suzuki GSX-R1000 , type 40F. You can find them cheap on : Ebay.
But the Suzuki rod is 4 mm longer as the Honda stock  and a little bit wider at the bigend , see the picture.
The 57mm pistons we use are for the Honda minibikes like Dax and Monkey and have a 13mm pin.See pictures for the measurement , red line = 13mm.
But you have to do some work on the rods , 13mm  bushings in the smallend and make them fit on the bigend side.
Even on the pistons is some work to do.
If you are interested ,our tuner can make that fit for you for a reasonable price.

Regards René

[DeppJones]

hi Achim

Welcome to the 500 road racing club. Nice build already.

The piston question comes up often here and there are no simple solutions. Search the forum for high compression 500 pistons. The quickest solution is XL125 pistons where you will actually have to reduce the crown to lower CR to 12:1.

http://forums.sohc4.net/index.php?topic=38006.75

I been racing four seasons with the stock swingarm, it works quite well. The bimota replica swingarm is still available from motocicliveloci if you have the $$$$  

Are these forks 35mm? many vintage organisations will not let you use bigger than 35.

Are you looking for a 4 into 1? if yes, I am using a Marving 4-1, they are still available new.

keep us updated

Yes, the fork is 35mm. We had that in the back of our heads when we bought the fork.
I don´t want to buy a Bimota (replica) swingarm, because I don´t want to spend that much money on a swingarm AND (much more important) I like building things!
I know that the 4 in 1 is still available but, as I said, first I´d rather try to build things myself. I would like to know if the 4 in 1 (or selfbuild) manifolds are bigger, concerning the inside diameter.

Regards
Achim

Did you buy the tank from John Clarijs in Eindhoven ?
Of course a fiberglass tank is not that strong as a alu tank , but also a alu tank can burst at a crash , but fiberglass is easy to repair.
The rods we use are from the 2002-2004 models Suzuki GSX-R1000 , type 40F. You can find them cheap on : Ebay.
But the Suzuki rod is 4 mm longer as the Honda stock piston and a little bit wider at the bigend , see the picture.
The 57mm pistons we use are for the Honda minibikes like Dax and Monkey and have a 13mm pin.See pictures for the measurement , red line = 13mm.
But you have to do some work on the rods , 13mm  bushings in the smallend and make them fit on the bigend side.
Even on the pistons is some work to do.
If you are interested ,our tuner can make that fit for you for a reasonable price.

Regards René

Hoi René,

yes I bought the tank from Clarijs.
You´re right when you say that a fibrerglass tank is easier to repair but a tank made of aluminium would resist much more impact before bursting.
Thanks for the information about the rods!
I could make the bushings for the rods on my lathe. But I wonder how you solved the problem with the big end. I found a lot of pistons for Dax/Monkey. they go from 56/56,5/57mm and some even got a 15mm pin. But I don´t know which one I should try...maybe I´ll just try my luck with one or two of them.
Or I´ll take the way to your tuner
I´d be happy if you could tell me a vague price (pn me if you like to).
...by the way...I really like the way you "connected" the engine to the frame. I think I´ll copy that!

Regards
Achim

[turboguzzi]

Yes, the fork is 35mm. We had that in the back of our heads when we bought the fork.
I don´t want to buy a Bimota (replica) swingarm, because I don´t want to spend that much money on a swingarm AND (much more important) I like building things!
I know that the 4 in 1 is still available but, as I said, first I´d rather try to build things myself. I would like to know if the 4 in 1 (or selfbuild) manifolds are bigger, concerning the inside diameter.

Regards
Achim

Hi Achim,

Good attitude, i also try to build most of my stuff, but from my experience, building certain things is just not so time efficient and time is money too... dont forget also that every special part you build can be damaged in a crash and then you will need spares too. in my first racer i've done a lot of stuff that now, with four years experience was just not worth the effort. The way i look at it now is that its worth spending time on things that simplify your life or will have high value in terms of lap times, I am not working till 02:00 in the morning to save 100 grams anymore

Good luck on building your 4-1, just remember that in exhaust systems, unlike the inlet port/carbs, bigger is not necessarily better, in the exhaust its important to keep good flow speed.   

[Retro Rocket]

A fibreglass tank made from woven matt will be around 3 times stronger than the alloy tank. Fibreglass won't tear like aluminium and is far easier to repair....Epoxy glass tanks are even stronger....Just saying..

Mick

[fastbroshi]

I thought fiberglass tanks might be a problem because some fuels, how you'd know is beyond me, eat into the fiberglass.  Exactly like what happened to Howell's 500.    Do you just have to line it with Kreem, and that's that? 

[Retro Rocket]

I am really surprised no one seems to be making bike tanks using epoxy resin instead of the normal glass resin, if they were made using fuel resistant epoxy you would never have a problem.,...

Mick

[Howell]

Is there any progress ?

[Ricky_Racer]

I am really surprised no one seems to be making bike tanks using epoxy resin instead of the normal glass resin, if they were made using fuel resistant epoxy you would never have a problem.,...
Mick

Mick, for the umpteenth time.... we use a special epoxy resin formula that has proven itself in years of building tanks for top fuel and pro stock drag bikes. Our Read-Titan (and other notable designs to follow this year) tanks are guaranteed for five years to not delaminate. So yes, it can be done and someone is doing it. We don't believe in producing anything marginal. Thanks!  RR

[fastbroshi]

dang Ricky, wish I was still in San Diego so I could take a look at your shop.  You very far from PB?

[Retro Rocket]

I am really surprised no one seems to be making bike tanks using epoxy resin instead of the normal glass resin, if they were made using fuel resistant epoxy you would never have a problem.,...
Mick

Mick, for the umpteenth time.... we use a special epoxy resin formula that has proven itself in years of building tanks for top fuel and pro stock drag bikes. Our Read-Titan (and other notable designs to follow this year) tanks are guaranteed for five years to not delaminate. So yes, it can be done and someone is doing it. We don't believe in producing anything marginal. Thanks!  RR

Sorry RR forgot about you just like you forgot to send me pics of the HB1 style tank....
I've always known it can be done, i work with epoxy all the time.....

Mick

[Ricky_Racer]

Oooooooooooooooooooo, s-h-i-t-e! Well... it's only been about, what, six months since you asked? Whatchyerhurry?

Seriously... sorry, Mick. Blame it on Al's Hammer. Since we're expanding into the tank/seat biz early this year and will soon be able to produce, I'll get the photos out to you asap.

When things are really ready to roll, I'll probably announce publicly. I beg your indulgence and thank you for your patience.    RR

[Retro Rocket]

Oooooooooooooooooooo, s-h-i-t-e! Well... it's only been about, what, six months since you asked? Whatchyerhurry?

Seriously... sorry, Mick. Blame it on Al's Hammer. Since we're expanding into the tank/seat biz early this year and will soon be able to produce, I'll get the photos out to you asap.

When things are really ready to roll, I'll probably announce publicly. I beg your indulgence and thank you for your patience.    RR

No worries mate.....just checking....
{easy to forget eh..... }


Mick

[fastbroshi]

What about the website Ricky?  It's still under construction?   

[DeppJones]

Is there any progress ?

Hoi René,

I´ve made some progress but not much. The holes in the Hub have been milled. If anyome likes to take a look at it i can post some photos. Then I have started to overhaul the front brake callipers (glas blasting, painting, new gaskets...) and to mill a pair of yokes. I´ve made some little progrss with the tank...made a 3d computer model of it and in the next weeks I´d like to have it cnc-milled (wood) by someone so that i can use it as a mould (or profile? I hope you know what I mean) to form a aluminiumtank out of it. I definitely have to make it ouf a few sheets of aluminium and then weld them together. Hopefully that will work out the way I want it to!
I have found someone in Holland who will sell me some megaphones with dampers. As soon as they arrive I have to start building some manifolds. As you can see there´s a lot of work to do...mainly if a take a look at my other projects (my Monster has to see the streets again this year and I´m building a Ducati TT replica with a 1100ccm Monster engine).

Regards
Achim

[Ricky_Racer]

What about the website Ricky?  It's still under construction?  

Yeah, go ahead Bro. Shame me!

Actually, the Gallery at www.classiccyclecity.com/gallery has been up forever and we get a ton of people checking out the rare parts collection and European race pics, but we've held off on enabling the front end because we felt we didn't have enough products to offer. That's changing quickly, and I'm starting to change my feeling about leading with just a few excellent items, especially products we manufacture.

So expect to see the front end working reasonably soon. Thomas, my talented biz partner, has recently finished coding the software to integrate various sales channels into our internal accounting program, so most of the back end is completely done. We expect 2011 to be our year for exciting new product introductions, growth, and (hopefully) expansion. We sincerely thank every single member of this board who has supported our eBay sales for the last year. You've kept us going to this point!    RR

[bwaller]

Achim,

One thing you need to learn about this place is you never need to ask if anyone would like pictures...we're challenged in lots of ways except visually. 

Sounds like you're a hands on type of guy, good deal, it makes for the most satisfying project. Race bikes are the cooooolest.

[Sam Green Racing]

after drag bikes. 

[bwaller]

You're relentless Sammy Boy.

I'm still in your corner though dude. 

[turboguzzi]

Is there any progress ?

Hoi René,

If anyome likes to take a look at it i can post some photos.

Yep, we likes a lot to take a look, so post MANY photos, not just some...  

TG

[Howell]

Is there any progress ?

Hoi René,

If anyome likes to take a look at it i can post some photos.

Yep, we likes a lot to take a look, so post MANY photos, not just some...  

TG

Indeed , photo's !!!!!!!

[DeppJones]

Hello,

sorry that it took so long to post some photos. I´ve got lots of work beside the Honda
This is the final version of the front hub. I´m going to post some more photos...probably tomorrow.