atc 90 rebuild

[turbo]

alright, i have my 90 all apart, cuz it was starting to blow blue smoke whenever i nailed the throttle. the rebuild is no big deal to me, have done several motors. my problem is that the motor is bored out, and my father just told me he bought the kit to do it, but does not remember the name of it. i went to my local shop and they measured everything, and said it is bored to 118cc's or a 55mm piston, and the stroke brings it up to 124, because it was also stroked when bored out. my problem is that i dont know the name of the kit, shop said it was probably a Big Al's big bore kit???? because they where made in the 70's and 80's and where the most common kit used. this kit is no longer made, so i cannot get a piston and rings for it the same size, reason i cant get rings, is because all of the pistons where specifically made for this kit, and are also no longer made, and they had rings made specifically for this also, atleast that is what i was told. so my question is, what should i do with it, just replace all the gaskets, and run it with this piston,( which is fine and still inside of specs for wear,) and rings, or should i bring it back down to stock specs, with a different jug that i have, which is stock. not sure if i can get piston and rings for it though. and i cant find out if my rings are still in specs or not, because i dont know what kit it is, and they cant get numbers any way.

[turbo]

anybode? still puzzled on what to do, any advice, any real cons of leaving the big bore on it? which is what i would like to do, because if i switch back to stock, which again, i already have everything cept piston and rings, i have to pull the case apart and pull the stroker kit out also.

[jenndnn3]

Turbo is the last year they produced the 90 was the the year 1979?....Is there anyway that a 110 is compatible??

[turbo]

im not sure what the last year they where made was, most of the parts are compatible. but i cant get a piston big enough from a 110 to fit into my bore. so if i went that route, i would have to get a new jug, or bore out one i have here.

[ATCnut]

I might get ahold of the guy that runs www.atc90.com. It seems to have the most comprehensive information about the 90.

[jenndnn3]

So turbo what exactly on this fast boy is left that is stock do you know?

[turbo]

all that i know that is stock on it, is the frame, forks, seat, fenders, rear axle, and high range, all of low range, except 1st and 2nd where taken out, geuss it was supposed to make shifting easier in high, and conserve weight??? i know the clutches are different, not sure what kind though.

[jenndnn3]

I would definatly go with atcnut suggestion and pick your pa apart for info...cause it will get exspensive going back i would think..I could be wrong but I wouldnt know what interchangeable.

[turbo]

i have been asking him about it, and he doesnt know any of the specs on it, because the previous owner did some of the work, and he finished it. but all my dad did was bring it to the shop, and say what he wanted done. and doesnt remember all of what was done, because it was 9 years ago or more when it was completed. it would not be that expensive for me to go back to stock, because i have 3 90 engines sitting here for parts, and replacements if i want to go that route. so all i would need is gaskets, piston, rings, and alot of time.
that site does not work for some reason???

[jenndnn3]

oh well I always think stock is best....the ring specs are definatly different on the 110 but maybe if you cant achieve the rings for 90 then you could look into going to the 110 specs?? Also with a large bore that is supposebly on it now...I would look and see if they are instead availble for the 110....they might not be for the 90 but just listed as 110( i hope this makes sense)....They are incredibly close..

[turbo]

i would be nice to just put a 110 in it, except my bore is still 8 cc's bigger, and i would have to take the stroker out of it because the pistons would be different. im prolly going to end up just putting it back in, and putting new valves in, and see if that is the reason why it is smoking when i hit the throttle hard.

[ATCnut]

Sorry, got the link wrong.

http://atc90.tripod.com/hondaatc90/