Topic: Please help me-----Cam chain problem- 750 sohc

[dragracer]

I'm in the process of resto-modding a 76 CB750F. I tore the engine down to rebuild it and started reassembly this weekend. I was in the process of putting the cam in the motor when i realized that the cam chain was not long enough to go over the cam sprocket. I checked and rechecked my chain routing to be sure it wasnt behind the tensioner(the adjuster isnt installed yet). I rechecked the part number on the box i got from Cycle X and it seemed like the correct part number. I counted the links on the new chain and then counted the links on the old to double check i had the right number of links and i came up with 94 on both.

I am not perplxed as to why this chain appears to be too dang short. Im going to recheck myself tonight and if i have to i will tear the whole fresking thing apart to see what going on.

In the meantime, can anyone chime in and give me feedback on what i may be doing wrong. I hate to waste a new base and head gaslet on tis tear down but i am at a stopping point on what should have been an easy rebuild of a stock motor. By the way. i am using the stock F crank, stock F cylinder but im using a K head on top if that matters geometrically speaking.

Help me out fellas before i pull whats leaft of my hair out in a fot of rage-lol 

[cookindaddy]

In order to get the cam chain in place, you should not have the two bolts in the top sprocket installed. If you look at the top sprocket, it has two circles cut off the main hole which let you pull the sprocket off to the side a bit, get some slack, to pull the chain onto the sprocket and then you slide the sprocket back on the boss on the cam. Then align the sprocket and install the two bolts.
I must admit this is pretty hard to describe. Am I making sense?

[dragracer]

Yeap, i know exactly what you are talking about and used this method. Chain still seems to short. Will go home and give it another try. I can see down the chain galley to the crank sprocket so i know it routed correctly.This is not my first CB750 build but this is the first one to cut my azz.

[steam-powered man]

had a problem getting a cam chain over the sprocket once.  started reading all the posts and found one that solved my problem.  trouble is, can't remember if it was my cb550 or cb750.   

anyhow, i took the oil pan off and noted that the bottom of the tensioner was not fully seated in the pocket under the crank.  felt like it was installed in the pocket, turned out it wasn't.  good luck,
bobp   

[dragracer]

Good news for me. I got the chain on. I guess i was doing too much yesterday in trying to build a Honda motor while simulaneously teaching a friend to disassemble for Kawasaki dragbike motor. I got the chain a bit over half way around rthe sprocket and then slowly rotate the crank to pul the rest of the chain onto the sprocket. I was able to slip the sprocket onto the shoulder of the camshaft after that. I've never had this kind of issue before and can only attribute it to the use of that off brand heavy duty cam chain. The tensioner was seat just fine but i'm still glad that was mentioned in the post above.

I was almost on the path of tearing the top end down tonight when i decided to give it one last chance- very glad i did. What a difference a good nights sleep and a long day at work makes-lol. Will time the cam tomorrow and install the rockers and shafts. Valve adjustment will be the next order of business along with installation of  the clutches and cover, transmission shift pawls and stator cover. I've got a bit of rewiring to do on the chassis and then the motor will be installed by the weekend. Will post pictures in the project thread of both the engine and the chassis.

Thanks again guys for standing by me to get this done.