G1 engine build project

[MXTex]

First post here. Hello everyone. Anyway, I'm doing a G1 engine build on our 1986 cart. This will be a full rebuild from top to bottom. I'll post as many pics as possible. Here are some pics of the cylinder head work. From stock to cutting to complete. Stock volume was 37cc's. Modified volume is now 20cc's. Cylinder was bored to accommodate a .5mm over piston. It now has a nice clean more with .002 skirt clearance. Cases will get a new crankshaft, seals and bearings. Still figuring out what I'm going to do with carburetor and exhaust. Suggestions are welcomed.

[TheGDFP]

Sounds like a pretty aggressive compression ratio.

[1989Marathon]

Welcome to BGW.
Have you measured the squish yet?

[MXTex]

No I haven't measured the squish yet. And yes, compression ratio should be up considerably.

[1989Marathon]

The squish should have been measured before machining the head so you know how much you can machine off. What is your target measurement for squish?

[cgtech]

If you need a good used g1 cylinder head, let me know .

[slonomo]

You should be ok. When I did mine, there was plenty of clearance, although you have completely removed the lip of the compression chamber on yours. I'll be interested to see what you come up with when you assemble.

If you want some real power, I'd suggest the Enticer 250 cylinder and head combo, much more aggressive porting in stock form, and can be ported for more.

What are your plans for carb and pipe?

[MXTex]

What is your target measurement for squish?

0.045" maybe tighter

If you need a good used g1 cylinder head, let me know

thanks!

What are your plans for carb and pipe?]

still contemplating this. I've removed the exhaust manifold flap and welded it up.

[sho305]

Some have cut the cylinder on them to keep the chamber shape or some of it. You might play with the holes in the trigger plate so you can advance forward more, I did that and it helped. I also raised the exhaust port about 1 mm. I still ran the stock pipe and jetting, stock tires too lol but got it to over 30mph. Head was cut. Cant recall what else I did to it but no governor of course. I may have worked on the clutches. Some yami sleds then they would cut the cylinder then put double gaskets under the bottom to raise all the ports. You have to cut the top or head to keep the comp ratio right. IIRC the G1 is like 6:1 comp stock. Using a better pipe would be great but finding the right one and clutching it also is a chore. There is a place that will port it for you that has posted on here. You can use the ignition on the enticer motor and keep reverse, issue is that is a piston port engine and so you lose bottom end, you need to keep the enticer pipe to get all the extra power it makes. I forget about bravo engines some have used them and posted. Personally if I ever got into one I would put a small twin in just for the sound alone, a 340 enticer would run 60mph in a sled the 250 about 50...the 440 about 85 if tuned...very light sleds.

[MXTex]

I've got the cases cleaned up and ready for new bearings, seals and crankshaft. But before I start assembly I've been considering plugging up the boost bottle ports located in the right case. I figure if the boost bottle technology is 'all that', that modern 2 strokes would have them as well. What are your thoughts?