atc90 help(again)

**Kevin Hoettel** · 01-10-2011, 09:17 PM

alright so my 1977 90 runs decent but i cant get it dialed in. i had the whole top end apart before, new points, condenser, honed w.e. so it starts 1st pull cold but when i try and ride its kinda boggy on the low end, i adjusted the tappets and my recheck but i keep messing with the needle and air screw and dont really seem like its going anywhere any ideas

**Kevin Hoettel** · 01-10-2011, 09:18 PM

has like no torque either

**oneroom42** · 01-10-2011, 09:20 PM

does it run stonger with the choke on? if so that is what my 70 did and it was so frustraighting! the timing was off even after i thought it was set right on.

**Kevin Hoettel** · 01-11-2011, 01:45 PM

i thought the timing may be off but people on here before said it wouldnt run with bad timing

**oneroom42** · 01-11-2011, 08:29 PM

several of mine ran with the timing slightly off...but not good. and like i said they ran better with the choke on. then ran GREAT with the choke off, motor warmed, and timing set properly!

**thestud25** · 01-11-2011, 10:06 PM

Post some pictures of the carburetor. Does the carburetor have the altitude adjustment on it? Even if you have the smallest amount of grime in the carburetor it will affect the overall performance.

**ratvespa** · 01-11-2011, 11:42 PM

is your timing set? like set perfectly? also, is you timing advance stuck? Valve clearance set properly?

**Vealmonkey** · 01-12-2011, 12:16 AM

I just so love these threads. What does "w.e." mean? Have you tried checking the compression? Seems like there is way much more going on here. What about the rest of the trike? Atc90s aren't real powerhouses and messed up wheel bearings or a rusty chain or improper drive chain tension will cause problems as well. Crud in the tank or fuel system. Crappy fuel. Are you running a fuel filter? Have you cleaned out the fuel filter behind the fuel valve? Tons of things can be causing your problems. Improperly set points. Poorly grounded electricals can affect trike running as well.

**Kevin Hoettel** · 01-13-2011, 02:37 AM

ill take some pics of the timing when i get a chance to work on it next and i have a different carb i got off ebay its new, i put a 65 jet in it. i have new chain new points condesor, greased axel well. running fuel filter on both lines that r new

**Vealmonkey** · 01-13-2011, 04:49 AM

Very good. But have you raised the trike off the ground and checked the rolling resistance of the front wheel in the air? Checked the rolling resistance of the rear axle in the air without the chain and with the chain? Have you adjusted your clutch properly? All things that could contribute to poor performance. Checked for proper plug and gap? Checked for proper gap for points? Are you rear brake shoes properly set? You would notice this when you were checking the rear axle for off the ground rolling resistance.