Yamaha G1 Is Very Loud


New Member
I bought a G1 AM5 a few months ago. It was reasonably quiet when I first got it, but after running only 10-12 hours, it now makes a very loud clanking sound. I think it's coming from either engine or clutch as clanking is definitely coming from that side of engine.

Anyone have any ideas of what could be causing this or how to pinpoint it? I appreciate any help possible as I'm just learnng two stroke. I would like to verify oil pump is working as seller indicated. How can I check it.

Also, I got the G1 AM3/4/5 service manual with the cart but the muffler diagram doesn't match the actual muffler on cart or the parts manual diagram. The service manual shows a sensor jet that I don't have. Is this a problem?



These carts have very loud clutches but only while the engine is starting up (no load on weights).

These are also known for piston slap. Sometimes people replace the piston and rings and don`t bore the cylinder to the next size. They run ok but have very loud piston slap.

The other problem on the older carts (79-81) The long bolt under the starter rattles from worn mounting tube.

The other is crankshaft bearings. The spacer (plastic only) that keeps the balls separated breaks and the bearings move around inside the races and make noise. ( try to move clutch up and down).

Last and the worst would be piston rod bearing (rare).

You do not want an aftermarket anything for these carts. The muffler needs tube outlet for the oil metering.

The factory mufflers also have an expansion tune to them for better low end The aftermarket muffler will not give the same power.

If you are mixing oil don`t worry about the jet sensor.

I always use the oil injection on these. I have worked on over 3000 of these and I have only seen two or three fail. The biggest problem these had was Quaker state oil ( turned to gel ) back in the early 80s.


New Member
I tried WD40 and Penetrating oil but I can't get the Primary sheave bolt to budge. It's the 1985 model clutch with the center bolt that holds the sheave cap on.

Anyone have any ideas to get the bolt out?


you need an impact gun. This bolt is very tight like a lugnut on a car tire.

This only takes half of the clutch apart which is fine for what you are

trying to get to.

Remember these only make noise when the cart is cranking over then get

quiet when there is presure on the weights (engine running).