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Discussion Starter #1
I'm planning on racing a CB350 at Willow Springs this month in the Novice Historic Production class in AHRMA and have heard that the cam chain and follower wheels are the weak link and need to be replaced with better quality items than the stock parts. This bike has an unmodified engine. What's the real story on this?
 

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you can probably run a slipper tensioner with a tsubaki cb750 chain. although im not up on the rules for the class 100%. you know youll have to split the cases though to run an endless chain. unless you use a riveted chain. i personally would rather use a non riveted worn original bit than rely on a riveted one. even though alot of them are riveted. you will also have to do some light clearancing on the head to get the slipper to work. also, one of my slipper units was assembled incorrectly, so check it when you get it to make sure the axles fit through the holes properly. i dont know where tyo tell you to go to get one. they are called "ka tensioners".

jc


aaron, send my wheel.
 

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Although it is not recommended and none of the real racers do it, I run the stock chain and tensioners. My current motor is stock but I have run heavily modded motors in the past too. I have never had a problem with the stock parts. I also carefully adjust the chain to keep it tight and monitor the condition of the tensioner parts. I suspect that clean quality oil may play a part in keeping things together. Next time I split my cases, I will probably go with a heavier chain as long as I am in there. I suspect other people have differing experience with the stock cam chains, but they work ok for me.
Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

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If you decide to use stock stuff...I've sorted through a ton of tensioners on 175's (same setup at the 350), destroyed a few of them racing....the key for the stock parts is to find parts where the rollers are still kind of soft and rubbery...the ones that are harder and brittle will starting coming apart in a few races. The ones that are brittle have been in engines have have run way too hot for way too long. I've got a stock setup in one of our race bikes that has held up well for a couple of years now.
JohnnyB
 

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i agree with both of those opinions also. this is the first motor ive built with a slipper setup. the prior 9 or so years and several motors all had stock setups and worked well. id say, especially for a novice, you need track time more than anything else. so if you can, concentrate on that if your bike is running ok.

jc


aaron, send my wheel.
 

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Just to agree with JohnnyB and Joe, (cause I am an agreeable kind of guy), partt of making stock stuff work is to have a bunch of spares to sort through and use the best pieces or new if you can find it.
I have 4 motors and only 1 is running. The others can or will be for spare parts.
Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

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oh yeah, if you use the cb750 chain, you will have to make room on the cam sprocket for it. the little black rubber isolator on the sides of the sprocket will prevent the larger cb750 sidepates from settling onto the sprocket correctly. i completely milled my rubbery bits off. and i liked it.



jc


aaron, send my wheel.
 

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Discussion Starter #9
You guys are a wealth of knowledge and I appreciate your replys. I will change my oil again and concentrate on my riding. I just finished Reg Pridmore's CLASS at Streets of Willow to get my AHRMA license. The big track looks much faster. Oh boy! AHRMA member #8216. Race number 824. See you at Willow?
 

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Yes Joe that is a starter gear...needed a little care full lathe work to bore out the center... Then I turned down the OEM upper roller till all the rubber was gone...turned it to about .003" larger than the starter gear ID...pressed on the starter gear till it was centered...used a 6mm bolt instead of the OEM riveted pin (that get's torn up taking it apart) to hold it in the OEM side plates. Used it all last year...seems to be holding up great. Still has the OEM needle bearings inside. Makes a tad more noise than the stock part though. And I imagine it's a bit rougher on chains. I keep it pretty tight to prevent the slop from banging around and the chain seems to be holdling up.
JohnnyB
 

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I have extra slipper tensioners for CB350 if anyone needs one. They are teflon sandwiched in steel. You do need to relieve the cam tunnel in the head to put them in, which can be done on a mill or with an airtool, which ever you have. They are $125.00 plus $5 for shipping. You don't need to split the cases to put it in, only if you replace the chain.

The chain is the Tsubaki CB750 SOHC cam chain. Joe was saying you have to grind off the rubber, but his was the first one I have ever had to do that on in 6 years. Those chains are about $35 and are endless. You can split it an duse a CB450 master link, but endless is better.

If you want a tensioner, e-mail me directly [email protected].

I only looked here cause Joe made me.

Chris
 
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