Gear on cam shaft broke :(

[paasker]

Hi guys

Was doing my first valve clearance check on my long loved NC29 today. When putting back the cam and tightening the two parts of the gears on the cam didn't line up. Thought it just needed to settle and therefore turned the motor a few degrees back and forth.

Then, snap and a part of the gear broke off! Bugger!

Is there a secret to get these gears ligned up? My Haynes didn't give much info on that.
Now i',m in the market for a replacement EX-cam

Any help would be nice :)

Regards
Martin

[Davez29]

Hi Martin, well i have only done this once but before removing the cam it was lined up correctly and i used some tippex to show where a certain tooth was meshed so i could put it back in the right position. I found it wanted to move a couple of teeth, everytime i started tightening. So i held and jammed a driver blade from the rear of the cam cog keeping it from moving, while a friend lightly tightened it down. It took a couple of attempts but eventually went into place. A friend whom you can trust to help is your best option.

[cbr400rrn]

Hi Martin, well i have only done this once but before removing the cam it was lined up correctly and i used some tippex to show where a certain tooth was meshed so i could put it back in the right position. I found it wanted to move a couple of teeth, everytime i started tightening. So i held and jammed a driver blade from the rear of the cam cog keeping it from moving, while a friend lightly tightened it down. It took a couple of attempts but eventually went into place. A friend whom you can trust to help is your best option.

Done this a few times on my own now and I used the same method as davez29' with the screwdriver stopping the camshaft from rotating whilst tightening it down. Was told it was common for the camshaft to be broken upon installation by Graeme France, give him a bell and he will talk you through it as well as sell you another camshaft

[paasker]

Thanks for the replies.

I did also feel that it would jump a tooth when tightening down, ended up holding it in place with one hand while tightening with the other. So maybe another set of hands would be beneficial :)

Will see if Graeme can help me out. At least i have a cam now that I can do a trial fit on not until i get the procedur right
Depending of the price of such a cam i might go for a new engine or new bike.

[cbr400rrn]

Would you not have to do the valve clearances on a new/second hand engine if you went down that route though

[Davez29]

Just to add, when i kept the driver in place it was quite a force just to keep it from moving, hence i slipped a couple of times due to it being oily and of course some of the cam is easy to bolt down but due to the way the cam sits some parts are hard, the trick is trying to keep it level while lightly going from bolt to bolt. Hats off to those who can do it their selves the first time, I know I could not due to trying to hold the driver, mesh the correct teeth on the cog and tighten down with a spanner.

[paasker]

Would you not have to do the valve clearances on a new/second hand engine if you went down that route though

Yes i know, but then I would hopefully be more carefull :)

[paasker]

Got one from GF in the mail now :)