Warrior 350 Engine Rattle *FIXED*

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Jun 17, 2020
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New Jersey, USA

Just posting this clip I had of this terrible "engine" rattle I encountered mid ride a few weeks ago. This has already been fixed a few days ago but it might be helpful to someone with the same problem. I had the quad down to the bare frame over the winter time and when I put the engine back into the frame I had forgotten to reinstall the top engine mount bolt which is what was making all the noise. My experience with these quads these are what causes rattles is most common to least common.

Issue: Valve train out of clearance.
Tools Required: 5mm Hex (Allen), flat head/Philips head screwdriver, 11/16" socket or wrench, spark plug socket, wrench set, and feeler gauges.

Fix: Remove front plastics, remove fuel tank, remove spark plug, remove both valve covers, remove timing gear cover, remove the flat-head timing inspection plug (left top side of motor), and set the engine to TDC Compression. Remove the recoil starter (1987-88 models) or the flywheel bolt cover (89+ models). Put your finger over the spark plug hole and turn the engine until you feel compression and the timing witness mark lines up with the center of the hole. There are two marks inside there, you are looking for the "T" to line up and you will see the timing gear line up with a dot on the engine head, assuming your engine is in time. Set the valves to the appropriate clearances with feeler gauges. Make sure the engine is cold when performing this procedure and consult the owners manual for your specific clearances. I use these for my 1988': Exhaust 0.16-.020mm (Front of quad) Intake 0.06-0.10 (Carb side).

Issue: Engine mount is loose.

Tools Required: Wrench set, phillips head screwdriver, new bolt (I used 5/16" bolt/nylon nut)

Fix: Remove front plastics, remove fuel tank, check to make sure the 4 bolts holding the top engine mount is secure and apply threadlocker if they are loose (green or blue is fine) and check the security of the actual engine bolt. I stock all hardware from machine size #2 all the way up to 3/4" bolts so I naturally just replaced it with a 10.9 5/16" bolt w/nylon locking nut. It is an easy fix and can fix a upper engine rattle.

Issue: Worn timing chain with excessive play.
Replace the chain tensioner and if that does not fix it go ahead and replace the timing chain. It is fairly simple but If you feel you are unable to then take it to a shop it should be under $400 to have it professionally done.
Issue: Foreign debris inside engine.
It could be anything so it's best to check it if the noise appears after a rebuild or timing work. It could be pieces of a clutch basket, piston wrist cotter pin, chunks of a bearing, pieces of internal engine, and much more.
You need to rectify the problem before it gets destroyed, if any materials get bounced around into the oil pump the drive gear is plastic, good luck with that! Haha!
Issue: Worn camshaft
Issue: Debris on top of the piston
Issue: Worn main crank bearings/camshaft bearings (the metal round ones not the soft ones on the conrod)


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