I bought a 1978 atc 90 for the kids and have it all together, but the damn thing will not run!! I have rebuilt the carb, reset the timing and replaced the plug. I have compression, spark at the plug and fuel at the intake....but no bang!! Any advice would surely help, I am by no means an ATC mechanic, but I know the basics.
Thanx,
Bob
sb74@swbell.net
At The Back Of The Pack
Arm chair racerAt the back of the pack
My '79 90 does the same thing. How good is "good compression"? If you can't even get it to pop on starting fluid, than thats about the only thing left. Rebuilding them is incredibly easy. I'd probably get a book if you are shy to the idea of tearing it apart. Rings and honing, or possibly a piston and a bore job. You might need new valves if your old ones are burnt. Thats about it really. You may want to set your valves, I dont know the clearance on those. Take off those plugs on top your jug and you can adjust the clearance.
Thanx for the input. I had been tinkering with in all day and kinda resigned myself that I would have to tear it down. I have bought a book, Haynes, and it looks like it give a pretty good overview of how to do it. I haven't tore down an engine since high school shop class!! I hope the local Honda dealer can get me the parts. Is there a better place to get parts? (I'm not a big fan of my local Honda guys) I bought this at an auction, along with parts enough to build two more (frames, engines, forks, etc) so if I get the hang of it I might try to tackle the other engines. Thanks again for the input, if you have any good tricks please share them.
Thanx,
Bob Morris
Putting Priorities in Order, Busier than ever.
Catch me if you can
At The Back Of The Pack
Arm chair racerAt the back of the pack
Hey Bob. Always go with Howdy first, lol. Rebuild is a worst case scenario, but like I said, its not hard. I think its kind of fun. I can get you new parts for less than the Honda dealer if you need any. My uncle/employer is an auto dealer and I just faxed all our stuff to partsfish.com and get stuff 15% over cost. So I just split the cost between what everyone else gets charged and what I pay. So nothing too special, I just order the parts and ship them on their way.
Thanx for your help guys. I will check the valves and the timing again tomorrow. The book is not terribly clear on how to set the timing, but I followed it the best I could.
BigRed, I will keep youin mind when the time comes to get new parts. If you get a chance, and don't mind, drop me a line at sb74@swbell.net with your email so that we can converse directly when it comes time for parts.
I will keep checking the boards for more info if anyone has any. Thanks again and I will let you know the results.
Thanx,
Bob
First Time Rider
Arm chair racerNew to the board
Go to http://www.atvdoc.com They have an extensive supply of ATC parts
at a reasonable price. I've used them, and would not hesitate to buy from them again.
Methanol, the nectar of the gods!
Just thought that I would let all of you know that I finally got the chance to tear the engine down this weekend. I found a few things that could have been my probelm!! Only 1 set of rings were still on the piston and the valves were burnt and sticking. I have ordered new parts, took the cylinder and head down to be machined and will let you know the outcome when I get them all back together. Thanx for all of your guys' input.
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