In search of more HP for G1

[eg196]

I’m looking to get more power out of the g1, whilst maintaining the stock form and function. I’ve been reading about people shaving down the heads to increase compression ratio and messing with the ports to get more out of the stock head. What is realistically achievable this way? Is there any loss of low end? I’ve also been reading about the enticed 250 swap. Stock muffler and clutches, what is possible? Is there any loss of low end there, compared to stock g1? Any help would be appreciated thanks

[Dave in VA]

http://www.plowmanscarts.com/parts_g_1.html

[mikeasis]

Originally Posted by eg196

I’m looking to get more power out of the g1, whilst maintaining the stock form and function. I’ve been reading about people shaving down the heads to increase compression ratio and messing with the ports to get more out of the stock head. What is realistically achievable this way? Is there any loss of low end? I’ve also been reading about the enticed 250 swap. Stock muffler and clutches, what is possible? Is there any loss of low end there, compared to stock g1? Any help would be appreciated thanks

Dave is pointing you in the right direction. I see you posted in slonomo 's enticer project. READ all of it before taking the leap. The stock g1 is about 8HP unless its the 82 j17 then probably less. I think plowmans offers a top end he ports and you can send your head for shaving plus his exhaust and clutching then maybe advancing the ignition a bit im sure it would be night and day to stock but how much of an increase? 5 hp maybe stretching it, so possibly 13 hp but that's me spouting off at the mouth. Taller tires will get you more speed but hinder bottom end some.

Im attempting a Yamaha Bravo 250 swap but its going slowly. I will be able to retain reverse to. By no means a direct swap but I think the bravo was rated around 25 hp. heres a link to what Im partially copying. again read the whole thread. BTW he has posted in forever.

http://www.buggiesgonewild.com/big-b...lockin-g1.html

the start of my slow project.
http://www.buggiesgonewild.com/big-b...lockin-g1.html

[eg196]

Has anyone had any experience with the porting? What would need to be done to improve it? Thanks for the help guys. 5 hp would be a tremendous increase I think. So far do you think the bravo will have less or more at the bottom end?

[mikeasis]

Plowmans for the porting. http://www.plowmanscarts.com/carts.c...1517586808&v=2

I wouldn't swear to a 5hp gain, like I said spouting off at the mouth. Im new to 2 strokes.
The bravo will have less bottom end than the G1. I know it sounds weird but the G1 has the power band of a 4 stroke, low to mid range, The Enticer and Bravo are like most other 2 strokes, Midrange and topend. I chose the bravo engine over the enticer because ive "read" it has a milder powerband than the enticer. to me that means better midrange power as opposed to the more top ended enticer engine, all speculation at this point.


Ill be honest, Im thinking bang for buck plus EASE of installation, a good bottom end with plowmans goodies is the way to go. If you can fabricate, tune a CVT clutch then the possibilities are endless.

Im new to all of it but that **** bravo buggie is stuck in my head
a.k.a http://www.buggiesgonewild.com/big-b...lockin-g1.html

[Golf cart guy]

Old school was to put the motorcycle head gasket on (thinner) and double up on the base gasket ( changed port timing) These worked well. the Motor is based on Yamaha motorcycle engine of its day.

[mikeasis]

The G1 is based off the enticer 250 which probably shares family ties with the motorcycles of its day. I say this because early G1 shares the same case set
(same part numbers) as the late model enticer 79-81 ish, so its basically a detuned, under bored enticer engine.

[CAMPERCART2013]

X2 on plowmans at least call and talk to him

[sho305]

Best I could find the G1 is based of the GP era sleds in the 70s, the enticer was also based off them, the bravo is yet another newer evolution. The G1 is also a reed induction the sleds rarely are they are piston port which has much less low rpm power but rev better. Although once I worked on a 76 YZ and it was reed. What I did is cut the head about .030 if you go more you get into the chamber that is not good, you would need to cut the cylinder to go more. They are 6:1 compression stock iirc for substandard fuel GC sometimes used. I also advanced the timing far as the screws allow, that made it go faster and reverse was slightly sluggish in comparison. I sanded the top of the port a little, I don't know maybe .030 not sure. Problem is you raise the port for more rpm power and you lose the compression so you need to cut more than you raise it. All that made it faster and more power everywhere running stock tires. You also need a tight top end, you will never get good power out of a 2 stroke if the bore is worn.

[dezrcr822]

Originally Posted by Golf cart guy

Old school was to put the motorcycle head gasket on (thinner) and double up on the base gasket ( changed port timing) These worked well. the Motor is based on Yamaha motorcycle engine of its day.

Do you remember which bike headgasket you used? The 81 yz 125 looks similar in design, not sure about dimensions though.