ATC 110 back from the dead (sorta)

[Rollme110]

Hey y'all
I bought a lil 1985 Honda ATC110 from a dude about 4 hrs ago. Overall, its a pretty clean bike. The gas tank is rough but that's fixable. My main issue is that I can't get it to run. I'm a total noob with these things. This is the first time I've even seen one in person, much less stepped on this forum. It REALLY tries to run, but it just won't. The carb is cleaned but I don't really know the plumbing situation b/c I don't have the tank on it right now. It has a really good blue spark, but doesn't run when you dump gas down the intake. It pops, farts, smokes, you name it but it won't actually fire up. It would have helped if I hadn't been turning it over backwards with a drill half the night, but it really doesn't do much more spinning it the correct way. As I said, it really tries, and the plug is wet and (to my knowledge) sparks. It doesn't really have the best compression but I think it might be passable. Also, would a chinese 110 carb work on this? It would eliminate the somewhat sketchy, leaking petcock.
Thanks for the wisdom
rM:drool:

[shortline10]

Spark , fuel , compression all at the right time and it will run .
If you don’t have a compression tester , hold your thumb over the plug hole and crank it over , you shouldn’t be able to stop air from coming out .

[DAM shop]

i agree with Mike here but may I add that you purchase a manual so you know how to work on it. There are a few other things you can check but without a book you are shooting in the dark. Stick with the stock carb those china ones for the most part are junk only adding to your problem.

[Rollme110]

I'll mess with it a little bit today. If the compression is still to low, how can you bump it up without putting a top end in it?

[Brandon_Reiko]

I'll mess with it a little bit today. If the compression is still to low, how can you bump it up without putting a top end in it?Idk what you mean by a top end. I did rings on mine and she runs mint. Didn't do a piston or cylinder head just rings

Sent from my SM-G950U using Tapatalk

[Rollme110]

Well, as I suspected, the compression just isn't there. The gauge says like 50 lbs. Time for rings.

[Rollme110]

Alright so I put a piston and some rings in it. The cyl is really clean but it still has like 30-50 lbs of compression. It seems to try to blow your finger off when you put your finger over the hole but when the plug is in it doesn’t have much.
Any ideas?
Thanks

[shortline10]

Did you check the valves to see if their leaking ?

[Rollme110]

I’m gonna try that tomorrow. Also a new head gasket just for extra safe measures. I’ll let y’all know how it works out.

[ps2fixer]

Yea I'd guess valves as well, unless it's timed wrong both before and after you put the head back on, pretty unlikely I'd think though.

Also you can get the service manual free. It's not the greatest manual in the world, but for most things it's fine.

http://www.oscarmayer.net/atc/manuals/

Also, when you put new rings in, did you gap the rings, or hone the cylinder? Honing just gives it a fresh surface for the new rings to break into, gaping them makes sure they are not too large or too small for the cylinder's wear/size

[Rollme110]

Ok so both valves leak like hell and they failed a fluid test miserably. If I took the valves out and lapped them, would that work? Would it be worth the time to take it all apart and lap the valves or would it be more sensible to just buy a new head with working valves?
Thanks xP

[shortline10]

Pull the valves and make sure their now bent , clean all the carbon off , lap them in and do the leak test .

[Rollme110]

Welp, they were BOTH bent. Not really sure how that happened but whatever. I bought a new head and assembled it and the thing runs now. It wouldn't run with the original carb so I slapped a chinese 110 carb on it and it RAN. But not very well. The springs were really weak on the spark advancer so I used some off of an XR75 from 1978 and they seemed to fit right and be the right size. Pretty much, the thing starts up, but it WILL NOT rev at all. I've advanced, retarded, etc the timing and it won't rev. If you really go slow on the throttle it might, but usually it spits a fireball out the intake an catches on fire (about 5 times it's done this). I don't know if it's just way too rich or if the advancer is messed up. I know the engine timing is right. One other thing. How do you set the ignition timing on these things? There was no fire mark on the flywheel so I set the ignition timing to like 1/2 inch before TDC. Is this right?
Thanks a ton
rM

[ps2fixer]

Fly wheel should have a F and T mark, the little cap on the side cover is the access to see it.

Also for the spark advancer springs, get the right ones at the link below. I've sold over 100, not one person has had issues with them + they are Honda and new.

http://shop.3wheelerworld.com/index.php?route=product/product&path=304_307_314&product_id=403

You probably could have gotten away with buying just new valves, guides if needed, and valve stem seals, but a new head shouldn't hurt lol.

Anyway, the fire ball out the carb sounds like ignition timing is way too advanced, guessing the springs you put in are not the right strength/size or something. I've had a couple people message me about the springs I sell because they have tried other springs and they didn't work right, I tell them about the sales I've had, no complaints etc, and I never hear anything about issues, so they must be spot on, and there's something out there that's not right.

Carb tuning could be part of the rev problem too, but the fire ball out the intake is most likely ignition timing, or worse case mechanical timing (crank vs cam). How did you time the engine with out timing marks on the flywheel?