64 250 with possible cam issues.

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Motorelic
Posts: 11
Joined: Thu Jan 25, 2018 1:16 am

Re: 64 250 with possible cam issues.

Postby Motorelic » Mon Jan 29, 2018 3:03 pm

ecurbruce wrote:Hi Sean, and welcome to the forum...
I don't know if this will be of any help, but I've been kinda where you are now,
If you haven't already, take a look at this thread, maybe it will be of some help, or not... viewtopic.php?f=3&t=1606&hilit=Off+one+tooth. Read through the entire post #17 in that thread.
Anyway, One tooth off on the lower bevel gear shouldn't cause the problem you're experiencing, I run my monza one tooth advanced on the lower bevel gear, and one tooth retarded on the upper bevel gear to manipulate the cam timing. One difference is this is on a mild monza cam...

Bruce


Thank Bruce! I sent you a PM.

Motorelic
Posts: 11
Joined: Thu Jan 25, 2018 1:16 am

Re: 64 250 with possible cam issues.

Postby Motorelic » Tue Mar 20, 2018 12:57 pm

Its been a while but i wanted to post what finally got this thing idling and running great. First I want to thank everyone who posted. I really appreciate it. Bruce walked me through a few things and lead me to Malcolm at Sid's Cycle. I talked with him a while and he agreed to swap cams with me. Well once my cam got to him he quickly found out that my cam was a very stock monza cam. Needless to say I was bummed because I was sure it was a cam issue. While waiting for the cam to return I ordered a piston stop. I was fairly confident without one but just covering all the bases. With the cam back in and the piston at TDC (same with or without stop) I rechecked my timing marks. As I had mentioned before, the cam timing and the ignition marks are not 100% lined up at the same time. Malcolm agreed that this was fine and to set the ignition timing by the degree wheel not the marks. That where i messed up from the start. I set everything from the cam marks set at straight up and down. This moved the ignition timing to about 25° ATDC. Whoopsie! Setting it with the degree wheel showed the cam marks off center. But i went with it. All assembled i check my valve open/close degree and low and behold it was spot on by the book specs!! Got it all together and she fired right up! Tweeked the carb a bit and it acted exactly the same. Very erratic idle. Soooo frustrated. Now stay with me because here comes the happy accidental fix. While it was running I was tired of hearing it so I held a towel over the muffler. The engine instantly settled and idled. Towel off higher idle. Towel on correct idle. Happy revs and stable. I machined a baffle for my aftermarket open muffler and the little engine couldn't be happier. A freaking BAFFLE fixed my idle. Im so relieved this saga is over. My customer has their bike and I can move on with other things!! Cheers!


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