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Discussion Starter #1
Hello all,
I have a 2002 limited 660 raptor that I’ve owned for two years. This machine was running great until last weekend. I was running hard in the snow with 6 other machines for about an hour. We stopped for a ½ hour rest. When I went to head off again (after a warming up the machine), I made it about 100 yards then lost power then she died. It would not restart.

I spent two days defrosting all of the snow and ice off the machine and still not luck.

I have a good spark and good fuel flow. I can’t even get it to fire up using starting fluid.
I did get two large back fired out of the exhaust after trying to start with the starting fluid.

It’s a stock machine with a new one-way starting clutch and I replaced the stator last year with one from Ricky-stator. I rebuilt the carbs last year, but I tour them apart and gave them a good cleaning anyways. I readjusted all five valves to .006” (intake) and .008” (exhaust) at TDC. I pulled the side cover off to inspect the stator and the large magnet for any obvious issues. All looked good. I disconnected the PB switch and cleaned the rev connection under the small sprocket.

I’m almost thinking I may have a mechanical issue with the piston or one of the valves or a crank positioning sensor problem.

My next check will be a compression test once I buy a gage with the correct thread and then check the timing with a timing light. I need to buy a new one anyways.

What do you think?

Thanks for your feedback,

Jeff
 

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I am unique
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Hello all,
I have a 2002 limited 660 raptor that I’ve owned for two years. This machine was running great until last weekend. I was running hard in the snow with 6 other machines for about an hour. We stopped for a ½ hour rest. When I went to head off again (after a warming up the machine), I made it about 100 yards then lost power then she died. It would not restart.

I spent two days defrosting all of the snow and ice off the machine and still not luck.

I have a good spark and good fuel flow. I can’t even get it to fire up using starting fluid.
I did get two large back fired out of the exhaust after trying to start with the starting fluid.

It’s a stock machine with a new one-way starting clutch and I replaced the stator last year with one from Ricky-stator. I rebuilt the carbs last year, but I tour them apart and gave them a good cleaning anyways. I readjusted all five valves to .006” (intake) and .008” (exhaust) at TDC. I pulled the side cover off to inspect the stator and the large magnet for any obvious issues. All looked good. I disconnected the PB switch and cleaned the rev connection under the small sprocket.

I’m almost thinking I may have a mechanical issue with the piston or one of the valves or a crank positioning sensor problem.

My next check will be a compression test once I buy a gage with the correct thread and then check the timing with a timing light. I need to buy a new one anyways.

What do you think?

Thanks for your feedback,

Jeff
This what I want you to do.................Read this thread............
http://www.raptorforum.com/forums/showthread.php?t=39381
 

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Master of the Electron
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Find TDC of the piston (using a screwdriver lightly through the spark plug hole, while turning the engine from the flywheel bolt, to feel top of piston travel), then compare to the TDC I mark on the flywheel - if the I is not there or damned close to there, your woodruff key between flywheel and crank has sheared, and so ignition timing is way off.
 

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Discussion Starter #4 (Edited)
Hello WillyKiller,
I read your post a few times today. Good information.
Your post got me thinking of the trigger sensor/coil.
Question, would a timing light pickup a bad trigger sensor?
 

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Discussion Starter #5 (Edited)
Hello Quadmaniac,
I also checked TDC with the screwdriver and the mark is right on.

PS I also pulled the volt reg connector for S&G. Still no start.

???
 

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Hello WillyKiller,
I read your post a few times today. Good information.
Your post got me thinking of the trigger sensor/coil.
Question, would a timing light pickup a bad trigger sensor?
No it will not.............
 

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Master of the Electron
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Have you checked compression?
 

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Discussion Starter #8
No, not yet.
My compression gauge has a thread that does not match up with the smaller raptor spark plug thread. I will look for a new gauge or an adapter after work today.

Hoe does testing the compression work with the decompression feature on one of the exhaust valves?
 

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Master of the Electron
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The decomp reduces but doesn't eliminate compression... as I recall, with the decomp operating, one should still measure sometning above 100 psi compression. Anything below 80 and there's definitely an issue.
 

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Discussion Starter #10
I just got backing town and checked for compression.
I have zero.
Only thing I can think of causing zero compression is: rings, valves, hole in piston, or timing between valves and piston.

Should I start by pulling the cylinder head off, or just pull the entire engine out?
 

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Master of the Electron
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Most anything causing 0 compression will be related to top end or jug, so there's no need to remove the whole engine unless bottom end becomes the issue - all else can come off with the engine in place.
 

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Master of the Electron
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Hope its something simple, like a stuck valve.
 

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Discussion Starter #14
The piston/rings/cylinder is shot.
After using a pin puller and wiping the thread off of the threaded rod,
I cut the piston in half to expose the piston pin. I used a bigger threaded rod (1/2-13 thread) with my home made puller. I pulled the piston pin against the con rod along with a heat gun on the rod and finally got the pin out (2 hours). I have a little debris in the con rod bore. Can this be honed out?

What do you recommend for an over size piston? How much can I expect to pay for boring and honing the cylinder?

Thanks again for you help.
 

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The piston/rings/cylinder is shot.
After using a pin puller and wiping the thread off of the threaded rod,
I cut the piston in half to expose the piston pin. I used a bigger threaded rod (1/2-13 thread) with my home made puller. I pulled the piston pin against the con rod along with a heat gun on the rod and finally got the pin out (2 hours). I have a little debris in the con rod bore. Can this be honed out?

What do you recommend for an over size piston? How much can I expect to pay for boring and honing the cylinder?

Thanks again for you help.
Then you must change the rod...............
 

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Discussion Starter #16
Willykiller 13,167 post,
Thanks for your insightful recommendation. Maybe I’ll just go out and buy a new quad, but I rather fix the con rod if possible.
FYI,
I found out you can clean out the small end of a con rod with a small ball hone.

QuadManiac, thanks for your detailed feedback.
 

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Willykiller 13,167 post,
Thanks for your insightful recommendation. Maybe I’ll just go out and buy a new quad, but I rather fix the con rod if possible.
FYI,
I found out you can clean out the small end of a con rod with a small ball hone.

QuadManiac, thanks for your detailed feedback.
You can, but, check the clearance of the rod to pin clearance, anymore then the maximum can cause the rod to break.......
I have seen some messy engines come into my shop, because of too much upper rod play, rod breaks and block ususally gets destroyed............
 
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