Cam Help!! Im loosing my mind

[Sazbo]

Any help would be appreciated, I got a 1975 (447-121558) barn find, I'm doing a complete rebuild of the engine,bottom end done.
Now I'm in the process of putting the top end together, Here's where i go down the rabbit hole, the cam that was in the engine when i tore it down was shot, so i had to get a replacement, my connecting rods are stamped 447 so i logically figure i have a 447 engine so i find a 447 cam that's in perfect condition, so I'm ready to install the cam and notice that my old cam has 34 teeth and the new one has 36....OK so i have a new cam chain from Mikesxs that is for a 36 tooth cam but it won't go on, it seems like it doesn't fit the teeth on the cam....I'm getting dizzy just writing this....also are the crankshaft cam gears all the same?

 

[Sazbo]

correction, the old cam is 36 tooth and the new cam is 34 tooth, so i guess all im asking is can i us the 34 tooth cam and just get a cam chain for a 34 tooth cam and will it be ok on the crank cam gear.

 

[NONclow]

Regardless of the chain, 36 tooth cam sprockets have a corresponding 18 tooth crank sprocket for a 2:1 ratio, so the cam with a 34 tooth sprocket will NEED a 17 tooth crank sprocket to work at all.

Keep the chain.

Sell the 34 tooth (447) cam and get a useable 36 tooth (256) cam. Done.....

OR:

Get a smaller chain (or remove a link if it isn't an endless chain), and
1) Change the cam gears (plenty threads on that here), or 2) Split the cases AND the crank to fit a 17 tooth sprocket.

 

[650Skull]

correction, the old cam is 36 tooth and the new cam is 34 tooth, so i guess all im asking is can i us the 34 tooth cam and just get a cam chain for a 34 tooth cam and will it be ok on the crank cam gear.

36 Tooth cam is for a 447 Motor.

No you can't use a 34 tooth cam to replace a 36 tooth cam because the crank sprocket has different amount of teeth for the 256 and 447 motors so a crank sprocket has to be changed to accommodate a change in cams.

Get a 36 tooth cam and the chain should fit the sprocket.

I read your first post, corrected in your second.................as the cam you bought has a 34 tooth sprocket and the chain you bought won't fit that sprocket. A 36 tooth cam was already in your engine so the chain should fit that 36 tooth sprocket.

Get a 36 tooth cam and the chain should fit the sprocket.

 

[scabber]

You can change cam sprockets put the 36 on the good cam.

 

[grizld1]

Sure he can change cam sprockets, Skull. But I wouldn't recommend it unless he has the ability to degree in the cam. Since he didn't know that the 4-stroke cycle requires that crank and cam must be geared 2:1, I'd really tend to doubt that.

Sazbo, having a shop do the job would cost a lot more than buying a 447 cam; just think of the extra cost as the price of not doing your homework.

 

[650Skull]

Wasn't suggesting the sprocket to be changed over, it did read a bit like that when rereading, i was suggesting he buy another 36 Sprocket, 447, Cam. Also the posts were very confusing and i tried to unscramble without any confusion...............Guess i failed, lol

 

[Sazbo]

Sorry for the confusion guys, other then eBay is there anywhere else I could get the proper cam, I have a like new 477 34 tooth cam for trade if that can help me, perfect condition, no signs of wear at all, it might even be a new cam. Thanks for all your help, I've learned so much from you guys thru the years but I have so much more to learn. Thank you

 

[grizld1]

Unless somebody took off the original 36 and pressed on a 34 tooth sprocket, you don't have a 447 (there is no "477") 34 tooth cam. All 447 engines used the 18/36 sprocket combination. If it is in fact a 447 cam with an early sprocket retrofitted by a PO, the numbers "447" will be cast in it prominently.

And my apologies, Skull--the sprocket swap was scabber's suggestion, not yours!

 

[Sazbo]

Yes 447 is stamped on the cam, so I guess that's the case. Oh well like you said grizld1 this was a costly education, so now on with the search for a proper usable. I hate buying from eBay, it's hard to know what you getting sometimes from pictures.

 

[650Skull]

If the cam you bought is defiantly a 447 cam with a 256 34 tooth sprocket you could swap your original 447 cams sprocket over to the one you bought.

Here are 2 links to threads on doing this with all the info on how to degree it in as well. The second thread is linked in the first thread as well.

http://www.xs650.com/forum/showthread.php?t=29831

http://www.xs650.com/forum/showthread.php?t=6867&highlight=camshaft

The secret to buying off fleabay is to ask every conceivable question. Ask how many teeth are on the sprocket, explain why you need to know, explain the differences and problems you have had with other sellers, if relevant. A seller is often ignorant of some facts and they usually respond in kind and if they don't i won't buy from them, even if it looks to be what i want. Better to pass up on something not sure of than to buy and loose money.

I have bought a lot of XS650 parts, for my bikes, and imported to Australia using this formula i have been successful in my purchases. Have got caught for sure, and one bad buy means i have to have 3 good ones to make up a saving so learn't real early not to let this happen and lots of questions solves this issue.

 

[Sazbo]

Thank you all for your help