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View Full Version : suicidal with my atc90. talk me off the ledge.



effort=results
10-23-2013, 11:42 PM
77 atc90 bought with no coil, bad stator, no carb. have 80 atc 110 parts machine . stole coil,stator. had 2 spare carbs from my 83 atc 110 and put the one on i know works. so after much tweaking i knew something was up with valves. sure enough both were bad. replaced valve and had head reseated. now she runs better but still fighting it. this is her current issues. erratic idle. under load motor runs better with choke and sometimes with out it . seems like it never is happy. either seems like it runs to rich and then way to lean. tried another carb that i know is good to go and does exact same. stalls at some rpms , runs good at a mid band,then want half choke then no choke than full. constant battle. it smokes a lil. i could need new rings as the cylinder looks ok. but seems good on compression tho i have no readings. i have tried the parts 110 timing advance and points . better but not right. the timing advance is easy to turn and seems to have play before the springs catch. should there be no play at all. i have triple checked my cam timing and points gap . should there be a condensor under frame. or is the condensor on the coil . i see on there on coil. spark is great. points have been gone thru a hundred times with feeler gauge . cam chain does not feel loose. could points be bad. i get a once in a blue moon spark between contacts. so im gonna kill myself cause i got more time in this motor than the total rebuild of my 110 motor but shes cdi . help heres a vid of the valve and another on pulling here apart to inspect.

http://www.youtube.com/watch?v=Cgt-viXzJHY

http://www.youtube.com/watch?v=uXCzSDpIenk
:mad::mad::mad::mad::mad::mad:

C.J
10-24-2013, 03:41 AM
My uncle told me that sometimes you can run a 110 carb on a 90, sometimes you couldn't cause they didn't jive with stock jetting. Could be you've over carbed it with the later model carb on an early 90. Just one idea

effort=results
10-24-2013, 09:28 AM
The original 90 carb acts the exact same.

C.J
10-24-2013, 10:57 AM
Welllll,,, it's either ignition or an on/off air leak then

What plug are you using?

effort=results
10-24-2013, 01:57 PM
D8ha ngk. All new gasket from doin the valves .

C.J
10-24-2013, 02:07 PM
oh ok. I've seen and heard of Champion plugs acting an azz and causing phantom problems.

I dont know man. I have no idea

rdlsz24
10-24-2013, 04:02 PM
could points be bad.

I got a tip from shortline on here a few years back when I was battling problems on a 110. He suggested replacing the points even if they look good so I did, and it then started right up. If I buy a trike now with points the first thing I do is replace them just to be sure that problem is out of the way. You can get a new set for around $10 on eBay

Rob

effort=results
10-24-2013, 05:28 PM
That what I'm hopin . I have been tryn to get my hands on a compression tester . But no luck . I had a buddy give me the idea of shooting brake cleaner around all gasket areas on intake and if it varys rpm , there's the air leak . Found on but still no good. At dead stop no choke it takes off then at mid rev it leans out then choke and shell rev up then off choke and shell climb then fall on its face .