g1 bore it out questions

badbowtie · 10-28-2013, 07:18 AM

Well since camping season is over time to start playing with cart. I am really thinking about pulling the jug and having it bored out. I can get .25/.50/.75/1.00 piston kits. I did not find jug and piston kits already done. But what kind of gains have you guys seen doing it with low end torque and top end?
I also am probably going to make a 4" lift or may just do like a 1" and try to run some 20x7x8 tires.

sho305 · 10-28-2013, 09:21 PM

They used to sell whole kits with the jug and piston fitted, if you wanted that, but I've not looked for one for a while. A fresh bore is key with any 2 stroke, if its low on compression/worn it will have more power everywhere and not lose power when hot. I have no idea how worn yours is, but people don't seem to fix them until they are very bad. Your gain is dependent on how bad it is now. You can do some other things like rotate the pickup coil to advance the timing, and get the head cut for more compression. A little advance might make it sluggish in reverse but it will still go ok. You can raise the exhaust port a little but not more than you cut the head, likely less would be better as compression ratio is pretty low factory. That will raise the power band rpm a hair. I sanded the top of the port by hand once, that little bit does not help a lot but helps just the same.

badbowtie · 10-29-2013, 01:27 PM

Well I just did a compression test with a cold motor and it is 120. I will have to take it for a ride and get it warmed up and check it again and see what it is. I have turned the screw all the way in including taking the nut out up to the governor spring and am only getting about 12-15mph. Which from what I am seeing on here is about half of what other guys are getting. Or is the key really in just drilling out the little square hole in the governor arm and let it free spin on the shaft coming out of the rear end to get all the mph out of it. I like the idea of advancing the timing a little have to locate a wright up on how to do that.

slonomo · 10-31-2013, 04:19 PM

Quote:

Originally Posted by badbowtie

Well I just did a compression test with a cold motor and it is 120. I will have to take it for a ride and get it warmed up and check it again and see what it is. I have turned the screw all the way in including taking the nut out up to the governor spring and am only getting about 12-15mph. Which from what I am seeing on here is about half of what other guys are getting. Or is the key really in just drilling out the little square hole in the governor arm and let it free spin on the shaft coming out of the rear end to get all the mph out of it. I like the idea of advancing the timing a little have to locate a wright up on how to do that.

If you are at 120 cold you are good to go. With a good belt, good clutches, and "disconnected" governor, you should run at least 25 mph, maybe push past 30 on level ground. Add a hill and/or some weight and that will change.

Just am over bore on the cylinder will not net any big hp gains on this engine. If you want real power gains. With the 2 stroke, the power delivery always comes into play. To get real power you'll need more compression, bigger ports, and a bigger carb and tuned exhaust. Then, you'll likely find that the power delivery is not very good at low rpm, and it'll be better suited to higher rpm driving.

Check out my Enticer 250 thread...

http://www.buggiesgonewild.com/big-b...0-project.html

After all that work, I'm not going to a clone engine.

badbowtie · 10-31-2013, 06:10 PM

Right know I just have the screw on the governor wound all the way in. I did try to drill out the governor arm and it was really hard to drive I am not sure if I need to drill the bottom side of the hole so it spins on the shaft freely since it was like it just moved and stayed there. It was like full throttle as soon as it took off. I did another compression test today with it warmer and had 115psi. I am only getting like 13 mph still. Drive belt is brand new and clutch feels real strong it will spin tire in grass or gravel taking off and has plenty of pull. The only other thing I can think of is maybe muffler clean out. Which a buddy of mine just bought a 84 g1 and mine is a 80 g1 but his sounds allot deeper and quitter than mine, mine seems more like a 2 stroke. But we did take his little nut out of the governor screw and wound his all the way in also. But I would say his is only about 10-11 mph since I am faster than him, but have not done compression test on his.

slonomo · 10-31-2013, 09:54 PM

Quote:

Originally Posted by badbowtie

Right know I just have the screw on the governor wound all the way in. I did try to drill out the governor arm and it was really hard to drive I am not sure if I need to drill the bottom side of the hole so it spins on the shaft freely since it was like it just moved and stayed there. It was like full throttle as soon as it took off. I did another compression test today with it warmer and had 115psi. I am only getting like 13 mph still. Drive belt is brand new and clutch feels real strong it will spin tire in grass or gravel taking off and has plenty of pull. The only other thing I can think of is maybe muffler clean out. Which a buddy of mine just bought a 84 g1 and mine is a 80 g1 but his sounds allot deeper and quitter than mine, mine seems more like a 2 stroke. But we did take his little nut out of the governor screw and wound his all the way in also. But I would say his is only about 10-11 mph since I am faster than him, but have not done compression test on his.

Listen, I'd recommend just bypassing the governor all together. Route the cable directly to the carb and disconnect all the rods etc that go to the governor and carb. Also, there's a butterfly valve inside the exhaust manifold, remove the butterfly part and just leave the shaft in place. When you take your exhaust manifold off, look inside, you'll see the butterfly valve, remove the two screws, then remove the butterfly.

If you do these two things, you'll get 25 mph plus.

lakehopper · 11-02-2013, 06:24 PM

Just rebuilt mine from bottom up, bbq and shimmed the clutch,done away with gov. Top end I only get to 20 mph but get there purdy quick. I think if you want to go faster you'll need to run bigger rims and tires to get 20 + mph and most of these guys are running bigger rims/tires

sho305 · 11-03-2013, 10:10 AM

G1 will get a lot of rpm if set up right and can hit 30mph completely stock appearing. If you can't get that on the road WOT there is something wrong with it. But it needs a fresh rebuild and some tricks to get there, and you have to wind it up for a while. 12mph is the stock speed with the governor at stock setting, if you are not getting that then something is wrong with the CVT or engine, usually CVT. Some put a longer screw in, even with the little one it should easily exceed 12mph all the way in. You can quick test full throttle with small vice grips on the opposite side of the screw, clamp the spring to the flat part on the side of arm, make sure it clears the intake hose and moves freely, but long term it will break the throttle cable with all that pressure from the governor that is why people disable them.

badbowtie · 11-04-2013, 05:41 AM

Okay I should I have some time today to play with it a little I think I am going to make sure the little arm on the governor arm on top of trans spins free with top drilled out and see if that works. I would make a bracket like you did and just fasten gas cable straight to carb but like the idea of being able to just tighten the little screw and nut and have it slowed back down again if need be. I also read where people have hooked the cables together but the post doing it the pictures have all been deleted. So not real sure how they did that.

10-28-2013, 07:18 AM	#1
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88	g1 bore it out questions Well since camping season is over time to start playing with cart. I am really thinking about pulling the jug and having it bored out. I can get .25/.50/.75/1.00 piston kits. I did not find jug and piston kits already done. But what kind of gains have you guys seen doing it with low end torque and top end? I also am probably going to make a 4" lift or may just do like a 1" and try to run some 20x7x8 tires.
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88

10-28-2013, 09:21 PM	#2
sho305 Vegas modded 420 Join Date: Jun 2009 Location: West MI Posts: 15,443	Re: g1 bore it out questions They used to sell whole kits with the jug and piston fitted, if you wanted that, but I've not looked for one for a while. A fresh bore is key with any 2 stroke, if its low on compression/worn it will have more power everywhere and not lose power when hot. I have no idea how worn yours is, but people don't seem to fix them until they are very bad. Your gain is dependent on how bad it is now. You can do some other things like rotate the pickup coil to advance the timing, and get the head cut for more compression. A little advance might make it sluggish in reverse but it will still go ok. You can raise the exhaust port a little but not more than you cut the head, likely less would be better as compression ratio is pretty low factory. That will raise the power band rpm a hair. I sanded the top of the port by hand once, that little bit does not help a lot but helps just the same.

10-29-2013, 01:27 PM	#3
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88	Re: g1 bore it out questions Well I just did a compression test with a cold motor and it is 120. I will have to take it for a ride and get it warmed up and check it again and see what it is. I have turned the screw all the way in including taking the nut out up to the governor spring and am only getting about 12-15mph. Which from what I am seeing on here is about half of what other guys are getting. Or is the key really in just drilling out the little square hole in the governor arm and let it free spin on the shaft coming out of the rear end to get all the mph out of it. I like the idea of advancing the timing a little have to locate a wright up on how to do that.
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88

10-31-2013, 06:10 PM	#5
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88	Re: g1 bore it out questions Right know I just have the screw on the governor wound all the way in. I did try to drill out the governor arm and it was really hard to drive I am not sure if I need to drill the bottom side of the hole so it spins on the shaft freely since it was like it just moved and stayed there. It was like full throttle as soon as it took off. I did another compression test today with it warmer and had 115psi. I am only getting like 13 mph still. Drive belt is brand new and clutch feels real strong it will spin tire in grass or gravel taking off and has plenty of pull. The only other thing I can think of is maybe muffler clean out. Which a buddy of mine just bought a 84 g1 and mine is a 80 g1 but his sounds allot deeper and quitter than mine, mine seems more like a 2 stroke. But we did take his little nut out of the governor screw and wound his all the way in also. But I would say his is only about 10-11 mph since I am faster than him, but have not done compression test on his.
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88

11-02-2013, 06:24 PM	#7
lakehopper Not Yet Wild Join Date: Apr 2012 Location: Northern Indiana Posts: 23	Re: g1 bore it out questions Just rebuilt mine from bottom up, bbq and shimmed the clutch,done away with gov. Top end I only get to 20 mph but get there purdy quick. I think if you want to go faster you'll need to run bigger rims and tires to get 20 + mph and most of these guys are running bigger rims/tires

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11-03-2013, 10:10 AM	#8
sho305 Vegas modded 420 Join Date: Jun 2009 Location: West MI Posts: 15,443	Re: g1 bore it out questions G1 will get a lot of rpm if set up right and can hit 30mph completely stock appearing. If you can't get that on the road WOT there is something wrong with it. But it needs a fresh rebuild and some tricks to get there, and you have to wind it up for a while. 12mph is the stock speed with the governor at stock setting, if you are not getting that then something is wrong with the CVT or engine, usually CVT. Some put a longer screw in, even with the little one it should easily exceed 12mph all the way in. You can quick test full throttle with small vice grips on the opposite side of the screw, clamp the spring to the flat part on the side of arm, make sure it clears the intake hose and moves freely, but long term it will break the throttle cable with all that pressure from the governor that is why people disable them.

11-04-2013, 05:41 AM	#9
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88	Re: g1 bore it out questions Okay I should I have some time today to play with it a little I think I am going to make sure the little arm on the governor arm on top of trans spins free with top drilled out and see if that works. I would make a bracket like you did and just fasten gas cable straight to carb but like the idea of being able to just tighten the little screw and nut and have it slowed back down again if need be. I also read where people have hooked the cables together but the post doing it the pictures have all been deleted. So not real sure how they did that.
badbowtie Getting Wild Join Date: Mar 2009 Posts: 88

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