yamaha 4 stroke choke/backfiring

[ajgolf]

Side view

[ajgolf]

And motor....i know it isnt pretty but after it is mechanically sound ill work on cosmetics. We are going to build a top, paint orange, weld something to back, and then weld old geo tracker back seats to that

[ajgolf]

I read that .004 on valves cold and .008 hot is right for valves?

[Spicyunicorn]

Looks like a g2 and yes valve lash should be .004 cold

[carguymn]

It’s very common for the carb adapter to crack also. The part on the engine that the carb bolts to.

There don’t appear to be any rubber hold downs left on the air box lid. Zip tie it down securely to make sure it’s sealed up.

Also check the frame under the battery very closely. Almost all are rotted from leaking batteries.

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[spriddle]

G2. Great cart!!! One of the best Yamaha's ever built!
Unfortunately it has a rev limiter but it don't matter. Let's get it running really good. These tips may or may not help with the current issue but a must for this cart.

There's a fuel filter in the bottom of the tank (follow fuel line down to it). Unscrew the cap/fuel filter, cut out what's left of the fuel filter and toss it. Install an inline fuel filter and clean out the tank.

Unhook the small governor cable, throw it as far as you can. Hook the longer pedal cable directly to the carb and adjust it (10 mm) so the carb completely opens when you press the pedal and (especially!!!) completely closes when you let off the pedal.

Clean, clean, and clean the battery cables and connections to starter and solenoid.

Grease clutches: couple pumps in each. Be careful of the rear, you'll be actually be greasing the bushing on the axle shaft, over grease and it will get on the belt. Grease fitting on inside of inner sheave (triangle looking part).

Make sure air box is sealed. Bungy cord over top and strap it down if you have too.

Make sure the carb spacer to intake isn't cracked. Snug only the 2 10mm bolts. They can crack the spacer very easily.

Run NGK plugs, buy three, they fowl easy!

Check air box for oil. One quart only in crankcase. And you can plug off the line to air box, install a fuel filter (make sure of flow mark going out), on the crank case vent hose and run it out back. It will leak a little but keep the air box clean of any oil. (this is just a suggestion if you can't keep oil out of the air box)

Double check fuel lines. They should be 1/2 and 1/4 if I remember right. Yamaha is very particular on these. You'll have to have stock size or it will not run right.

Triple check the hose going to the back of the engine! It is critical to fuel pump operation.

Another good idea on these is to make sure the outside part of the engine is not clogged up with dirt under the plastic engine cover. It can cause it to overheat.

Another thing to watch is the tension cable under the air box. Make sure it is tight. And keep an eye on the front motor mounts. The rubber can deteriorate over time (weak point).

10w30 oil for engine, one quart only, never ever ever use any sort of additive that is thick!!!!! These engines work on a splash system and you can't splash honey.

75w90 for rear end. Simple drain and fill (you'll see the fill plug on the back)

Keep the shifter cables (forward/reverse) clean and sprayed with wd40. Especially back at the transaxle.

Last but not least, lift it at least 4 inch economy lift, wheels and tires to match, torque spring and spacer kit for rear clutch, ENJOY.

[ajgolf]

Wow thanks so much for taking that kimd of time to detail whay needs done! I promise to do all of this starting this weelend. Will post more veru soon

[brodykmb]

Originally Posted by spriddle

G2. Great cart!!! One of the best Yamaha's ever built!
Unfortunately it has a rev limiter but it don't matter. Let's get it running really good. These tips may or may not help with the current issue but a must for this cart.

There's a fuel filter in the bottom of the tank (follow fuel line down to it). Unscrew the cap/fuel filter, cut out what's left of the fuel filter and toss it. Install an inline fuel filter and clean out the tank.

Unhook the small governor cable, throw it as far as you can. Hook the longer pedal cable directly to the carb and adjust it (10 mm) so the carb completely opens when you press the pedal and (especially!!!) completely closes when you let off the pedal.

Clean, clean, and clean the battery cables and connections to starter and solenoid.

Grease clutches: couple pumps in each. Be careful of the rear, you'll be actually be greasing the bushing on the axle shaft, over grease and it will get on the belt. Grease fitting on inside of inner sheave (triangle looking part).

Make sure air box is sealed. Bungy cord over top and strap it down if you have too.

Make sure the carb spacer to intake isn't cracked. Snug only the 2 10mm bolts. They can crack the spacer very easily.

Run NGK plugs, buy three, they fowl easy!

Check air box for oil. One quart only in crankcase. And you can plug off the line to air box, install a fuel filter (make sure of flow mark going out), on the crank case vent hose and run it out back. It will leak a little but keep the air box clean of any oil. (this is just a suggestion if you can't keep oil out of the air box)

Double check fuel lines. They should be 1/2 and 1/4 if I remember right. Yamaha is very particular on these. You'll have to have stock size or it will not run right.

Triple check the hose going to the back of the engine! It is critical to fuel pump operation.

Another good idea on these is to make sure the outside part of the engine is not clogged up with dirt under the plastic engine cover. It can cause it to overheat.

Another thing to watch is the tension cable under the air box. Make sure it is tight. And keep an eye on the front motor mounts. The rubber can deteriorate over time (weak point).

10w30 oil for engine, one quart only, never ever ever use any sort of additive that is thick!!!!! These engines work on a splash system and you can't splash honey.

75w90 for rear end. Simple drain and fill (you'll see the fill plug on the back)

Keep the shifter cables (forward/reverse) clean and sprayed with wd40. Especially back at the transaxle.

Last but not least, lift it at least 4 inch economy lift, wheels and tires to match, torque spring and spacer kit for rear clutch, ENJOY.

bumping a thread from a month ago here. Thank you for the above post. I too am tuning things up trying to get rid of my backfiring but my attention went into the greasing of my clutch(s). My G2 must be 'the older model' because i cannot find a way to grease the secondary clutch. I do not have a grease fitting like i do for the larger primary. Can you I looked all around the 'triangle part' area and i can't seem to make sense of what or where to grease. Any help? And thanks again!

[brodykmb]

for some reason i could not edit my above post. But to the secondary clutch and grease. I found this entry on another site and wanted to post it and ask about it.

Post:
There should be a grease fitting on the outer edge of the clutch to lube the center bushing. Grease it until grease comes out of the bushing if you have the cover off, then remove any extra grease. If you have the cover on put one pump in only and not very often. Always make sure no lube gets on the belt or belt surfaces, clean it off. With the new style clutch ensure the rollers are working properly. That is about it for the clutch, put the cover back on and go to the secondary.

The secondary clutch is pretty simple, the newer ones have a grease fitting near one of the ramps (and older G2 might not); it also has a center bushing to lube. I clean the shaft inside the spring with brake clean first and check condition of the ramps and pucks. Newer style secondaries have a different type of puck also, the old ones they sit in holes and break much easier. Replace pucks if needed, I think clutch must be removed I always did but maybe not. Ensure ramps are smooth. Grease until you see some come out, again make sure none can get on the belt. You can put the brake on and twist and push in the moving sheave if you have a stock spring in there. G1 has double ramps one set for forward one for reverse.
------------------------

my question is do i hand grease the secondary clutch since it appears that my G2 does not have a grease fitting? what's the scoop?

[sformal]

Originally Posted by ajgolf

Heres one from front

Yeah, we can easily see the airbox is badly sealed...