BGF T80 total teardown

Tohri, how did you go about dremeling out the combustion chamber? Did it make the squish band wider? Drilling out for 8mm studs is easy. Do you possibly have pictures of what you did? It is something i would try if there was some instruction or picture guide.

Tohri said:

Rustypath: Both are squish bands. But a Home shopping network 30$ special replica katana, and a Hittori Hanzo sword are both technically Swords.

The difference is not in kind, but in degree. One does what it's supposed to, the other doesn't.

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ok T, I'll agree with that, but a 25acp will plant u just as permanent as a 45acp.

... mof, the LH head looks to be higher compression !
...don't u think so?
rc

Checking & Adjusting Squish Clearance : Two-Stroke Scooter Help - YouTube

Note: I've noticed there there tends to be quite a bit of "rod stretch" w/these motors, you may wish to take that into account w/the minimum tolerances

No worries, it's jus' with these sloppy lil engines there may be a bit of slop lol & BTW, the reason I used quotations is because much like "chain stretch" it isn't just the rod, but bearing/bushing/race/wrist pin play as well - none of which will show clearly when bench testing clearances, so a lil extra may be needful

Richi: What I did was take a stock puch head and bore it out. The correct highcomp head should work just fine with the m6 holes drilled out for M8's if you've got them.

meaning: the highcomp head from treatland already has a squishband machined into it. I made a hemi head for my brother's bike.

Thanks Tohri, I think for $30 ill check it out, i just didnt want to get into somthing that was going to be way overcomplicated.

Hey Biknut, sorry for the thread bump. But was wondering about any updates on this build of yours. Gonna start with some good SKF, or NSK bearings and go up from there!

I haven't read every post but there was a question about installing the piston rings (broken ring upon installing). Since installing new (or reusing) rings, that means that the cylinder is off. Remove the piston from the wrist pin (only take 1 snap ring off) Once you get the rings on the (proper position) piston, take the cylinder and place it on a flat surface (head side down) that's easy to work with. Insert the piston in the cylinder, the rings will keep the piston from inserting. Now with your thumb and forefinger (on each cut out side of the cylinder) squeeze the top ring, and lightly tap the piston down, stopping short of the bottom ring. Next work with the bottom ring. The cylinder is beveled outward on the bottom and helps sliding the piston in, acting like a ring compressor. Once both rings are up in the cylinder, you can install the cylinder on the wrist pin (remember to install the snap ring) and onto the case.. In 50 years I have never broken a ring when installing a piston, these Chinese cylinders makes it very easily. Remember, only a light bump on the bottom of the piston is all that is needed...any more then that, the ring is not ready for instillation.

biknut said:

Still nothing yet about this motor. At this minute it's totally disasimbled, and sitting in a box. I'm waiting to hear about the crankshaft.

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^^ Cool, thanks for the update. Your luck sounds about like mine, when it comes to getting outside work done quickly!

Great thread. I just received my bgf Z80 last week. Guess I should unpack it and check it out.

i can't see any of the pictures. is there something wrong with my computer or did they get taken down?