1992 Yamaha G9 Too fast and smokin

[kgsc]

Agreed. When I first got my G9 the return spring was missing on the carb and that made things interesting.. Got that replaced then did some adjustments and got it where it would crawl at low speed but mid 20s wound up.. Also worked on a cart one time that the local neighborhood kid had “sped” up… Put a new idle screw in and all the way in. Cart was 3/4 throttle as soon as it started..

Edit. Smoking may quit after a while. May have some oil if the exhaust that needs to burn out.. Also may need the valve seals changed.

[eph78]

Maybe the muffler is having issues. They sell new ones for the G2/G9 if you think that is the culprit. People BBQ the oil out of them sometimes as well.

[Paulzy123]

Originally Posted by kgsc

Agreed. When I first got my G9 the return spring was missing on the carb and that made things interesting.. Got that replaced then did some adjustments and got it where it would crawl at low speed but mid 20s wound up.. Also worked on a cart one time that the local neighborhood kid had “sped” up… Put a new idle screw in and all the way in. Cart was 3/4 throttle as soon as it started..

Edit. Smoking may quit after a while. May have some oil if the exhaust that needs to burn out.. Also may need the valve seals changed.

Thanks will have to look and see if the return spring was at fault too. The governor did not seem to return quickly to its home location, so we maybe on to something here too.

As for the Smokey. I think I may just go ahead and rebuild the engine. Doesn’t look like a whole lot of work.
Any suggestions on where to order a gasket and ring kit from?
FYI Serial Number or cart is JG5-117886.

[Paulzy123]

I did find a kit on eBay

https://www.ebay.com/itm/272331612723

Not sure ebay is the best source for parts tho.
Is there a preferred vendor?
I did try partzilla and they were not able to help.

[raydhd]

Partzilla you would need each part # wanted. Certainly they do not have a kit and not any yamaha parts sellers that I have found. ONE note you need to measure piston/ring/ cylinder sizing before ordering any parts.

[Curt-IA]

I would get the parts right from Yamaha. Thier parts website is a little different, but you will get used to it. Get the OEM part numbers and enter them at partzilla or wherever. When I did mine I got the stuff from buggies unlimited, and in the end didn't save hardly any money and the rings were not labeled like the OEM ones. I should have know better, but was uncertain of the whole machine when I started to rebuild. Also the BU valve seal was super sketchy, but it does not smoke anymore. I believe these G9's only have one valve seal.

Like they said pull it apart and measure the piston/ bore to see if it has been bored out. Mine smoked pretty bad. The compression rings were actually in spec, but the oil ring(s) was shot. I almost put the original compression rings back in as it had over 120 psi when I started, just smoked.

The only other snag I ran into was the books talks about ink marks and 3 different sized rod bearings, and it appears then only sell one size bearing nowadays. They had super tight tolerances when new. I needed a crank and rod. Got lucky and found a NOS rod on ebay and the crank was actually cheaper from Yamaha than aftermarket. The rod was on backorder from Yamaha.

Depending on where you are with bore wear, you can get the next size bigger rings and file them for ideal end gaps. I was surprised how little wear there was in this poor little almost 30 year old engine.

[kgsc]

Also may want to consider putting an aftermarket motor in there.

[Paulzy123]

Originally Posted by kgsc

Also may want to consider putting an aftermarket motor in there.

Do tell, curious where you'd get an aftermarket engine and what all is involved?

[CP241]

Originally Posted by Paulzy123

Do tell, curious where you'd get an aftermarket engine and what all is involved?

Pick up a predator, lifan, etc 420cc engine. They’re China clones of the Honda gx390. Vegas carts makes adapter plates and the other parts you’d need to install it in the cart relatively easily

[Paulzy123]

Originally Posted by Curt-IA

I would get the parts right from Yamaha. Thier parts website is a little different, but you will get used to it. Get the OEM part numbers and enter them at partzilla or wherever. When I did mine I got the stuff from buggies unlimited, and in the end didn't save hardly any money and the rings were not labeled like the OEM ones. I should have know better, but was uncertain of the whole machine when I started to rebuild. Also the BU valve seal was super sketchy, but it does not smoke anymore. I believe these G9's only have one valve seal.

Like they said pull it apart and measure the piston/ bore to see if it has been bored out. Mine smoked pretty bad. The compression rings were actually in spec, but the oil ring(s) was shot. I almost put the original compression rings back in as it had over 120 psi when I started, just smoked.

The listing I had found on ebay claimed all the parts were Yamaha genuine oem parts... But one never knows..

I am going under the assumption all is good inside, just skipping a step to get the ol' cart up and running.

I also read that some of the oil lines up the back can also cause smoking, is this the case for a G9 too?

This is looking like more than a Sunday afternoon job at the cottage.. lol.
I've seen a few videos to replace the gaskets and it doesn't seem to terribly hard, but that piston/bore may kill the entire job.