Topic: Racing Piston Supplier?

[CJF]

I'm building a CR750 replica that I plan to race when it is complete.  I'm trying to figure out the best place to get a set of stock bore higher compression racing pistons...10.25:1 or 10.5:1.  Does anyone know of a supplier (other than M3 racing for $700+).  I have searched long and far without a lot of luck.  I'm guessing I'm just looking in the wrong places.  Can anyone help out? 

[Sam Green Racing]

Marks prices are a little on the high side IMO. You could have a word with MRieck when you see him come on or Jay at APE, he'll be on in about 4 hours from now.

Sam.

[CJF]

Thanks Sam...looks like you may have one yourself (based on your pic).  What are you running in yours?

[MRieck]

 Wiseco or JE make pistons. You can increase the compression by decking the cylinders and milling the head. APE can get you either piston. I would like to see the Wiseco come with the XA ring set.

[Sam Green Racing]

Thanks Sam...looks like you may have one yourself (based on your pic).  What are you running in yours?

CJF, welcome to the forum, I figured Mike would have some input, He's the head man when it comes to porting and engine building.

The bike I run is not a full on race motor. It has Wiseco 836 pistons with a Megacycle hotish road cam. It's been ported and runs 5mm stemmed stainless valves, 2mm up on the intakes. It breaths through 31mm CR carbs and gets rid of the crap through 4 open race megaphones. For events with noise limits, we use a 4 into 1 system with a straight through race can.
Although it's not got the power of Mikes Million dollar CB (98bhp) it makes a healthy 86 with 62ftlb of torque, even on high gearing to stop it wheelying, it smokes the rear tyre.

Sam.

[fuzzybutt]

slight hijack.......sam where did you get those 4-4 megaphones and were they very expensive?

[MRieck]

I'm building a CR750 replica that I plan to race when it is complete.  I'm trying to figure out the best place to get a set of stock bore higher compression racing pistons...10.25:1 or 10.5:1.  Does anyone know of a supplier (other than M3 racing for $700+).  I have searched long and far without a lot of luck.  I'm guessing I'm just looking in the wrong places.  Can anyone help out? 

I just reread your post and noticed you want stock bore pistons. Wiseco and JE only supply 836 kits. I apologize for the error. Arias(I know) and JE(I think) will make 4 custom pistons to your specs but it is at laest 600.00 for a set. Wiseco has a minimum order....something like 50 pistons if I remember correctly. Why not use F3 pistons in an early head? You can talk to Mark and see if he can give you a break too.....he's a pretty easy guy to talk to.

[CJF]

Sam, thanks for the welcome.  Sounds like a nice setup you have...and making real nice power.  

I've been collecting parts for the past year or so (and spent a hand full of cash ).  So far, I have an aluminum gas and oil tank from TA Baker and picked up a set of racing pipes from Swarbrick.  I went with the baffled pipes...I was on the fence between baffle vs non baffle but was concerned about the noise rules at some tracks.  I picked up a seat and front fender from airtech and will likely get their fairing.  I have a fairing mount kit from Meed Speed.  The currency conversion was rough with the UK parts.  I wish I decided to build this thing 10 years ago.  I've got a '78 CB750F front end and Chris Schuman is milling and drilling a set of GL1000 rotors to fit with the front end and 6 bolt stock hubs.  At this point, I'm polishing up my welding skills in prep for a few frame mods for the seat, oil tank and fairing mounts.  Still trying to figure out the best way to mount the center mount oil tank??

Mike...thanks for the info on the pistons.  I'll get in touch with APE.  

[MRieck]

Sam, thanks for the welcome.  Sounds like a nice setup you have...and making real nice power.  

I've been collecting parts for the past year or so (and spent a hand full of cash ).  So far, I have an aluminum gas and oil tank from TA Baker and picked up a set of racing pipes from Swarbrick.  I went with the baffled pipes...I was on the fence between baffle vs non baffle but was concerned about the noise rules at some tracks.  I picked up a seat and front fender from airtech and will likely get their fairing.  I have a fairing mount kit from Meed Speed.  The currency conversion was rough with the UK parts.  I wish I decided to build this thing 10 years ago.  I've got a '78 CB750F front end and Chris Schuman is milling and drilling a set of GL1000 rotors to fit with the front end and 6 bolt stock hubs.  At this point, I'm polishing up my welding skills in prep for a few frame mods for the seat, oil tank and fairing mounts.  Still trying to figure out the best way to mount the center mount oil tank??

Mike...thanks for the info on the pistons.  I'll get in touch with APE.  

Be sure to read my second post about the stock bore pistons.

[CJF]

Mike....ya I'm looking to stay within the racing rules with the bore size.  I actually have an F3 that I did a full restore on 2 years ago..love the bike.  I heard the F3 pistons need to be run with the F3 jugs and head due to chamber size differences.  Have you tried running the F3 pistons in the K engine?  Also, Ross Pistons a while back and they say on their site that they can do custom motorcycle pistons for about $400 a set with a 4 piston min.  Have you heard of them?

[Sam Green Racing]

slight hijack.......sam where did you get those 4-4 megaphones and were they very expensive?

Yes, they are expensive to build, We are about $25,000 out of pocket. You having to buy from this God forsaken place will probable end up spending more unless you are able to do a lot of the work yourself.

I have a mate in NZ that is building one (Andynzl) and I sent him loads of pics of where the brackets go, perhaps he could send them to you.

Now to answer Fuzzybutt. They came from the same place Swarpricks. The down pipes are formed spot on but the megaphones came straight and were a nightmare to form to fit. God only knows how you are going to do it if yours have some type of baffle. I only hope the baffle don't go to far down the megga.

Good luck with the build, if you need any further info just yell.

Sam.

[Sam Green Racing]

CJF see the Swarprick thread I just bumped up. If you click on Andies name it will take you into his profile.
You can have a look at his web site, I have not been there for a while but it covers the CR build and his other CB.
Send him a PM to see if he still has the pics I sent.

Sam.

[MRieck]

Mike....ya I'm looking to stay within the racing rules with the bore size.  I actually have an F3 that I did a full restore on 2 years ago..love the bike.  I heard the F3 pistons need to be run with the F3 jugs and head due to chamber size differences.  Have you tried running the F3 pistons in the K engine?  Also, Ross Pistons a while back and they say on their site that they can do custom motorcycle pistons for about $400 a set with a 4 piston min.  Have you heard of them?

Yes...I've heard of Ross. I've never used their pistons personally but I've seen a set of their Harley pistons. 400.00 is real cheap....almost to cheap for custom pistons. CP will probably do 4 too. They make a very nice piston. The F3 piston will fit in a 75K/F and up chamber....it will give you the extra compression you want. You would have to modify the valve reliefs for a real cam and...as Sam mentioned...a forged piston would be a better idea for racing. I'm not a big CR750 buff but I'd have to say the factory race pistons were cast.

[Jim F]

HI CJ and welcome to the Forum

If you need any help with your welding, give me a call at 770-367-7320
or go to my web page for shipping info
I just welded up a sub frame for a GSXR today so the welder is warm and waiting
If you need some small stuff then I can use my Laser welder and get out my .005 aluminum rod also

Jim

www.jmfmicroweld.com

[MRieck]

HI CJ and welcome to the Forum

If you need any help with your welding, give me a call at 770-367-7320
or go to my web page for shipping info
I just welded up a sub frame for a GSXR today so the welder is warm and waiting
If you need some small stuff then I can use my Laser welder and get out my .005 aluminum rod also

Jim

www.jmfmicroweld.com

Jim saved my ass.

[CJF]

You referenced CP in your last post.  Can you tell me what that stands for? 

Mike....ya I'm looking to stay within the racing rules with the bore size.  I actually have an F3 that I did a full restore on 2 years ago..love the bike.  I heard the F3 pistons need to be run with the F3 jugs and head due to chamber size differences.  Have you tried running the F3 pistons in the K engine?  Also, Ross Pistons a while back and they say on their site that they can do custom motorcycle pistons for about $400 a set with a 4 piston min.  Have you heard of them?

Yes...I've heard of Ross. I've never used their pistons personally but I've seen a set of their Harley pistons. 400.00 is real cheap....almost to cheap for custom pistons. CP will probably do 4 too. They make a very nice piston. The F3 piston will fit in a 75K/F and up chamber....it will give you the extra compression you want. You would have to modify the valve reliefs for a real cam and...as Sam mentioned...a forged piston would be a better idea for racing. I'm not a big CR750 buff but I'd have to say the factory race pistons were cast.

[Big Jay]

The F3 piston would be the best choice.  The  promlem with having custom pistons made is finding a supplier with a blank that small. I would think that Wiseco would be the only one, and thy don't do only four pistons. I had them make some CB400F pistons for a customer and I don't remember how many we had to do.

Jay

[CJF]

Thanks Jay...have you ever had to machine valve pockets in the f3 pistons when using them on a K model engine....can it be done given the piston top thickness?  I will also use a racing cam, although I'm not sure which one yet.