[gt80 and yz80 crank compatibility]

Yeah just bung stuff in and see if it works shall we, no honestly you need to measure everything and if anything is different then forget it as you will end up breaking something. If the crank weights are different then it's a sure bet that other stuff is different to. Similar is not the same as the same. I do wish you luck with it tho. How's the GT80 engine? would that fit complete?

oh and another question, the weights were pretty rusty so I cleaned them up with a wire wheel (yz weights) but there is some pitting. will that throw the weights off balance and cause a problem?

[gt80 and yz80 crank compatibility]

Yeah just bung stuff in and see if it works shall we, no honestly you need to measure everything and if anything is different then forget it as you will end up breaking something. If the crank weights are different then it's a sure bet that other stuff is different to. Similar is not the same as the same. I do wish you luck with it tho. How's the GT80 engine? would that fit complete?

so if the weights are 2 mm slimmer it'll break something? the gt80 engine is missing quite a few pieces, I measured the connecting rod and it's the exact same length as the yz80. the yz has a 2mm difference in piston. and the shaft is the same as well.

[gt80 and yz80 crank compatibility]

picked up a 1978 yz80e the other day and the top end was siezed. split the cases and everything to do with the crank is rusted and pitted to sh#%. but I do have an old gt80 (close in year) and I was wondering if I could use that. it all seems very close, similar connecting rod (if not the exact same) and same crank shaft. but the weights on the yz80 are a bit thicker, anybody know if I can use it? a used crank is like 200$ online

[100 cc engine in my gt80 maybe?]

Well you needed to determin how deep the scratches are in the cylinder,to know if it is borable if the scratches are deeper than .030`` then its junk .

Depending the condition of the rest of he bike you might just be better off to buy something else,a 1978 gt 80 is not a desirable bike and dumping alot of money into it ??? well thats up to you.

You can sell off good parts of the bike how easy or hard that will be ? someone might be tring to have a set of bikes from 80cc to 250 and if you have a good set of original body work???

Godd luck with it.

well I guess I'll have to take a look, everything's mint on it. fresh paint job, engine block is re painted. has original front fender (which apparently is rare) and looks beautiful. how do I post pics off my iPhone? I'd love to share it with you guys.

[100 cc engine in my gt80 maybe?]

It will cost about 200 to bore it and throw a wiseco piston in it ,a new cylinder will be more than that alone.

what is wrong with the motor or why are you saying it ducked?

the cylender and piston are both scored, the exhaust literally spits oil out of it.

[100 cc engine in my gt80 maybe?]

true true and true, except for the last part, she's too old to be on the street, she only reaches about 90km/h (60mph). but ok I'll get a new cylender and piston. I wonder if it'll be cheaper to bore out this cylender and get a new piston... MORE POWAAAA

[100 cc engine in my gt80 maybe?]

Cheap engine swaps dont happen.

Whatever is wrong with the gt it will be cheaper to fix than replace.

You will need to work on the exhaust, air filter/carb. Engine mounts.. it goes on. Not least of all is the insurance will rocket.

[100 cc engine in my gt80 maybe?]

anybody know if I could fit a yamaha 100DX engine in my gt80? my engine is fu@%ed and a guy on my local classifieds said he'd sell me a DX for cheap but I don't want to spend the money and end up with a broken engine and a useless one. -.-

[why so cheap?!]

hi everyone I restored a yamaha gt80 and I've heard people say they're not worth anything. but I've looked on kijiji and eBay and I found 8 of them for sale (in all of canada) and 1 complete bike in terrible condition on eBay for 999.99$ (totally ridiculous) but how can these bikes be so invaluable if they're so rare?

[GT80 Info - Any Gurus out there?]

it's probably the same yes. these bikes hardly changed at all during the years they were made.

[bike still won't shift]

my yamaha gt80 still won't shift, bought a new synchronizer, and sometimes it shifts but sometimes it doesn't... losing my patience with this thing! it must be a common problem with these because I have 2 and neither of them shift properly. anybody have any suggestions? maybe the arm that pushes/pulls the drum? maybe I just take this thing to the scrap yard? :'( also does anyone know if I could possibly get away with dropping a 100 DX engine in it?

[shifter problems on my GT80]

okay I will have to take a look, and then stop at my local used motocross shop. the gear lever looks like it is, but I'll take some more time to check it out. I appreciate the help a lot!!!

[shifter problems on my GT80]

hi everyone! I bought a 1974 (I think) gt80 a while ago and I'm restoring her, when I first got it I took it for a spin of course, however the gears are a huge question mark to me... if I hold the clutch in and push the shifter down and hold it down it sometimes goes to first gear... and sometimes it doesn't do anything! I struggle to even find a gear on it to shift into. and when I do it's usually 2nd or 3rd I'm assuming since the engine wants to bogg out. I split the cases and everything looks good, but the shifter arm that pulls/pushes the piece on the synchronizer either catches one gear or it won't go back into neutral ect. anybody know what the problem is?! so confused

[hey everyone I'm new!]

hey everyone I'm new to this forum, hope I can learn a few things from people who have the same intrests!