I just finished getting my 102mm Ross 10.75:1 pison in and the quad back together. I tried to start her up and one time it sounded like it got stuck on the compression stroke, it started to roll over and then just stopped. I tried again and it rolled over really fast, probably twice as fast as ever before. The thing is, I don't think the piston was moving at all. More than just the starter was spinning, but I know the piston was not moving.

WHAT IS WRONG? I never had problems with the starter clutch before. Can it just instantaneously break like that?

HELP! I have an appointment with the dyno tomorrow morning at 10 and I need to get it going. And I have a race coming up Saturday, my first sand drag.

Thanks for any help you can give.

RR1

 

You sure you got the timing right?

Maybe your decompression mechanism isnt working?

I would tear it down and check everything just to make sure. I know my wiseco gave the starter a BIT harder time but it hasnt broken anything YET. Make sure your battery is nice and charged and give it another try. Hope it aint your one-way.

 

I had the work done and the engine put back together by the Yamaha dealer. I just put the carbs and gas tank and plastic and battery back on.

Should I take it back to them and tell them to fix it? I am sure they will tell me that it is my fault.

RR1

 

By the way, I rolled it over by hand (big nut inside the left case cover) just to make sure there was no binding. Everything seemed fine there.

RR1

 

Sounds like to me that u have gas on top of your piston and it cant compress it. Pull the plug and then turn it over. If gas comes out the spark plug hole then that is ur problem. If this is the case then make sure ur vent line on the carb is running towards the bottom of the bike and make sure it isnt plugged. If that aint it then check the float on the carbs and make sure they aint stuck. Sounds like ur carb is getting to much gas and it is goin on top of the piston. I had this problem and it was my vent line on the carb. I ran it under the gas tank and the overflow needle in the carb counldnt drain the fuel because the vent line was higher than the carb. Hope this helps ya. [img]i/expressions/face-icon-small-smile.gif[/img]Lance

 

Took the plug out, no gas came out when I turned it over. I could feel the air pulses from the plug hole, so I know the crank was tuning and the piston was moving.

Put the plug back in, and same results. It spins real fast but it doesn't sound like the piston is moving. It sounds a little "clancky". I have a little video with audio so you can hear what it sounds like. I can email someone, but I don't know how to post it on the web.

Thanks,

RR1

 

Just like Haulin said, I would take out the plug, and turn the engine over. Make sure your battery is charged good and try again. Good luck... keep us posted on what happens.

 

I know it is not gas on top of the piston. I had the plug out at least 10 times and never had any gas blow out the hole. A couple times it "caught" and cranked a couple strokes till it came to the compression stroke. And then it just stopped again.

What do I try now?

Thanks,

RR1

 

Did you check the charge on teh battery?

If its not that I would have to think either one way or starter... It just don't make sense that it went out all at once like that though. They may not have got the decompresion thing on the cam right when they put it back together. It still should start though. I would check the battery or for a quick and easy test try to put a set of jumper cables straight to the starter and see if it will crank over like that (hook the hot to the post on the top of the starter and then just stick the ground on the footpeg. Make sure the key is on and the on/ off swith is on).

Hope this helps.

Mike

 

Thanks guys for all the help. I finally figured something out. I thought just for fun I would check the valve lash. I tried it with the crank on the I mark - no lash. Ok, rotated it one more time to the I mark, no lash. I thought, thats funny, so I looked at the valves and the cam while I was rotating it and guess what - they didn't move!

So it sounds like either the cam chain broke, is off the gears, or maybe the ears broke off the Hotcams. I am taking it back to the Yammie dealer who did the work and going to try to get them to fix it for free.

Thanks to Bob Craycraft for helping me figure this one out!

RR1

p.s. So basically it looks like I will be sitting around doing nothing this holiday weekend. [img]i/expressions/face-icon-small-frown.gif[/img]