Atc70 Motor Rebuild

[Mr. Richard]

Well i waited to get this fourm up to start this thread, i rescued a 85 ATC 70 from its untimely death. this thing was so clean i couldn't believe it was at a salvage yard. turns out the sransmission was non working. so i tore it down to do a complete rebuild on it, so i will post ictures and answer all questions while i am at it. i was pretty sure i knew what the problen in the trans was,,so i removed the side case and WOW #1 i was right, #2 it was as clean as the outside . here is a pict of the spring loaded roller arm that was broke,, i have changed several of these over the years,
http://i22.tinypic.com/161lxg7.jpg
i got one from a donor engine i bought a while ago on craigslist,, it was supose to be a runner!!!! ohh man was it far from it,,, here is what it looks like inside!!! its so bad i don't even plan to do anything but use some good parts,,
http://i20.tinypic.com/20gembn.jpg
see what i mean? wow what a mess. i don't think the oil was ever changed EVER!!!! HERE IS WHAT THE INSIDE OF THE 85 LOOKS LIKE ,, THIS IS THE WAY IT OPENED UP TOO,
http://i24.tinypic.com/15egy77.jpg
so i am going to rering it fix the transmission, lap the valves in, hone the cylinder, rebuild the carb, rebuild the pullstarter, new points and paint . here is what the piston looks like,,, OHHH whats it setting on? anyone?
http://i20.tinypic.com/2qi66ms.jpg
oh yeah i am also going to rebuild the clutch,, i measured the discs and most are ok,, the first one was warped when i measured it,, it was several thousands difference in one disc.
http://i23.tinypic.com/34y6y6u.jpg
http://i20.tinypic.com/i3t7dk.jpg
MORE TO COME SOON ,,

[thefox]

Ouch! Now that is what you don't want to see when you open up an engine. Are there any common low end problems with the 70's? I have an '85 engine that I want to go though, the former owner started to take it apart and I have not found the reason why they would have done that.

[Mr. Richard]

well tonight i installed the new roller piece rebuilt the clutch with new discs, and put the side cover back on,, put the new points in reinstalled the stator plate,, and put the flywheel back on,,, now i am waiting for a set of rings,,, i always buy the next set over and end gap them myself. i feel better knowing they are right, this motor is so clean i can't believe it ,, all i did was spray it off a little and it looks like new,,, should run like new too,,,
http://i13.tinypic.com/6bjjv2u.jpg

[Mr. Richard]

today i got my rings form ebay,, honda oem 10 over set.. less than half of the honda store price, so i gapped them,, honed the cylinder,, and put them in,,, i lapped the valves with my special tool.. i used a piece of gasline on the stem hooked to the cordless drill,,, works great since the valves are so small,,, i installed the valves in the head and called it a night,,,,
http://i10.tinypic.com/54mvu5e.jpg

[Mr. Richard]

i guess i didn't get real technical here... i like to work fast and forget to take pictures of what i am doing,, anyway,, i finished it up tonight,,, put the head on set the cam timing, adjusted the valves ,,fixed the pullstarter put it on, bolted the carb on,, i cleaned it up while i was waiting for the rings so it was ready,,, bolted the coil to it,, put some oil in it,,, and fired it up,,,, set the idle and ran it long enough to warm it up,,,, i did bolt a pipe on it too,,,,, sounds good too,,,,
http://i2.tinypic.com/5xebi3c.jpg

[Koggs]

K, did you replace the rope on the pull starter?
Also, was the carb out of adjustment? or did you not mess with the settings?

My 70: after I replace the rope I'll need to fine tune the thing but it was having a hard time starting. .....carb settings? plus the guy I bought it from said it had a new top end done to it so I don't know if the stock settings for the carb will work right... :shrug:

[Mr. Richard]

on the pullstarter i tore it apart and cleaned it up lubed it all and put it back together,,, on the carb i had it alll apart so i had to play with it to get it to idle,,, but i was running wothout an aircleaner so i am sure it will all have to be adjusted again once it is back in a trike....

[Koggs]

:thumbsup: sounds similar so I think I'm close. I need to find a replacement tank, the insides are rusted up purdy good -which doesn't help the situation. Plus the carb is leaking from one of the adjustment screws. :shrug: Might be missing an o-ring >?<

[Jez]

here is what the piston looks like,,, OHHH whats it setting on? anyone?,,

Go on then...........Put me out of my mysery, what is the Westcoast thing the piston is sitting on?

[tigajoe]

Westcoast used to make Seadoo parts.