How to time the ATC90

[IceDude]

Ok I have no book for my ATC 90 and it is in bad need of a tune up. If ne of you out there know some specs on spark plug and points gap that would be nice and if ne of u know how to time it. (timing by ear dosen't work the best).

Thanks in advance

[MTS]

the points gap is .003-.004 the valve lap is .002 on intake and exaust...to time it you first take the cam out...take the bolts outa it and just pull the whole dam thing out ...this is the easiest way...leave the gear in..next get the T mark on the flywheel lined up the the timein mark on the stator....some of them ware off...ill see if i can scan a pic of where it is outa my manuel if you cant find it....next once the flywheel is at TDC see where the cam gear bolt holes are if you look on the top inside lip of where the gear is you will see a little mark...line the left bolt hole up with this wile keepin the timein chain taunt...once that is lined up the hole on the right of the gear should be more or less pointing down towards the fly wheel...should kinda line up with the hole that holds cover and every thing on there. then put the cam in so the lobes are pointing towards the flywheel there is a little dowl like pin in the cam on the skinny part of the shaft, that should line up with the notch in the innerlip of the head that i mentiond furether up in the post....once you have the gear and the cam lined up put the time bolts back in with some blue loctite :) thats how i time my atc90 becuse there is no mark on my new cam gear or old cam so. thats how it works...hope this helps...dont forget to tighten up the cam chain after :p

[IceDude]

well that definately helped alot but i still need to know one thing. I was talkin bout the little plate that your points are on. how do you know when u are in time there my timing on the cam is deffinately in cause it runs just fine but I have to retard my timing to get it to run right but I don't want to blow throughmy piston so I need to know how far is too far. Thanx

[MTS]

OH! DOH! lol i wasnt sure sorry....ther should be a little line with a circle on the plate that the points are screrwd to..its on an outer edge...there now there is a little line mark just under a screw hole on a screw hole on the top of the thing that the points plate screws too...its the top 3rd hole on that thingy..what ever you call it..you should see whta i mean its behind the points plate and thats twhat the screws go in to hold the plate in ...so on the top 3rd hole there is a little line mark..its on the smallest hold..you should be able to see it...anways you just line up the 2 marks from the points plate and the mark on that thingy and tighten er down...set the points gap and your in time :)

[IceDude]

ok I did that no problem but it runs like a POS that way. But when I turn the plate slightly to the left of the mark it runs well but I still wnat to know how far I moved it so I am not sparking when the piston is coming up still or if I have the right gap on the points then the marks should work right. oh and the specs u gave me i figured they were but just to make sure that ws .003-.004mm not thousanths right.
Thanx

[MTS]

no that was in thousandths...

[IceDude]

Are you getting that strait form the book. cause .003 thousanths is paper thin literally. does urs run with that kinda gap on it cause mine is set at .020 and besides .003 isnt even enough to make a gap for spark is it

[MTS]

yes mine runs on that...im almost positive thats what the specs in the book is ...im looking in my clymer manuel right now...where i got it from orighinally i know its in hear somewhere its just being elussive right now...lol




FOUND IT! it is 0.3-0.4mm or 0.012-0.016 IN .....i coulda sworn it was IN when i red it....i must be goin mad...sorry for sendin ya on a goose chase..lol :rolleyes: :p :beer

[IceDude]

Alright it is cool. I just thought that was a little small but yes none the less it is all good. well my gap is still too big then cause mine is at .020 IN would that throw off where that plate is suposed to sit then or do u not have a clue

[MTS]

yes it would throw it off if the trike is runnin like POS i would suggest you set the gap and move the plate back.. :)

[IceDude]

well I guess that is what i will do then. So why does your trike **** just cause it is a 90 or what oh and what is the spark plug gap suposed to be

[MTS]

lol my trike dont ****... i was just pissd at the time i made the name lol...it needed valves and a bore..and i gota fix the fenders, fix the light...lol its gettin there tho..:)

the spark plug gap is 0.6-0.7MM or 0.024-0.028 IN :)

[IceDude]

thanks man so u have a 90 right*** what all is done to it or is it still stock cause mine is bored over i don't know how much I bought it off someone for $150 I got one complete Pos trike (the 1 I am asking bout now) I got 1 other frame 1 other basketcase motor all there though and a good bit of motor casings ( for chain slingage insurance)

[MTS]

mine is just 1978 i got for free from one of my mechnic friends...it was burning bluer than a diesel...he had it for his kids for 10 years...didnt get one oil change...lol so i got a 4th oversized cylender off one of my other bikes and new valves new/used cam...its basicly stock for right now it has the fenders all cracked and falling apart, they will be fixd and painted...im workin on a racin 110 motor to put in it..with a nice pipe and a k&n filter..will have soon :)

[IceDude]

lol burning bluer than a diesel. well I got mine to run pretty good but yeah i need to set some more gaps and stuff. need new tires cause right now i got 2 22/10/8 and they are bigg muddin tires called buckshot mudders and my fornt tire is an authentic wooly booger same size but A REAR TIRE!! so hard to turn and so much drag u would not believe. and the basket case of mine will get port poslish new and custom everything swing arm and shocks in front for other frame trying to get to racing it.