cam timing and engine losing power ATC70

[slothminx]

Hello recntly my friend let me have a go on his klt200, and now i am hooked on trikes. :TrikesOwn i went out and bought an ATC70, :w00t: (it needed to fit in our car) it has a load of spare engines. but what i need to know is how to time the cam up (changed the head) and the engine runs fine for the first 5 mins of running and the it loses all its power but if i leave it idling for 2 mins it gets its power back do you guys have any idea for what i could try. i am going to be cleaning the carb tomorrow to see if that makes a difference. i searched for an answer but i could not find exactly what i need :confused:

thanks will

[Wickedfinger]

The only way to adjust the cam timing is to put a different duration cam in it like an XR70. Sounds to me like its overheating in some way and cycling through it, although, 5 minutes dosent sound like enough. You didn't say if it happened while you were riding. I would think it might also be an "electrical" overheating - like a bad CDI - HOWEVER - there isn't one (points), so maybe a bad coil?. You said you put a new "head" on it (meaning cylinder head, not valve cover) - was it a "stock" ATC70 head?. Was it shaved in any way?. Was the head gasket the stock thickness and not thinner?. What octane gas are you using? (not sure how they rate it over there). When it was overheating, was it "pinging" or dieseling at all?. Are your cooling fins clean?.

[slothminx]

the trike looses power when riding and when i stop riding but keep the engine running for about 2 mins its back to normal for 5 mins. are you talking about the coil in the flywheel if so i have another one i can try but if its the main spark coil i dont know where i can get one of those the head to is off a standard 70 engine could it be the valve clearences(sp?)
thanks

over hear the gas im using is 95 ron its not knocking or dieseling at all when it runs well for the 5 mins its got loads of power ohh and as for the cooling fins they were very dirty thick with mud but it also does it when ithas been cleaned

[slothminx]

has anyone else got any ideas

thanks will :confused:

[jenndnn3]

Does it happen right when you shift into gear from neutral or is it graduel loss? It could be compression, valves like you mentioned. It could be electrical like Wicked mentioned. It could be simple fuel delivery.

Clean air filter, Clean carb and check for complete/continous(sp?) flow of fuel. Check compression, Adjust valves. A common misconception, is these things do not need the compression to idle, however when under load, you will notice it. Your points will effect the fuel burnout as well. So they need to be checked, and timed. I highly recommend if you do not have, a manual.

There is a little O on your cam sprocket. There is a indent on the head probably hidden by the gasket, it will be facing towards the front of the trike. Kinda hard to find at first, but once you do its obvious. Line the O to this indent, with engine TDC, rockers loose, on T. T is of course on the flywheel. Adjust valves while you do this. Cannot remember valve spec. I will get it if someone doesnt beat me too it. Once that is done, chain tight, move to points and adjust those. I recommend it due to your already at the flywheel might as well do it. If you need specs on that, I will get it as well but a simple search on board, will also tell as well. Might even find valve clearences.

[slothminx]

Hello
I got the bike running today and then it just cut competely, i checked for a spark.. nothing so i disconnected the coil from the stator and then turned the engine over with the stator wire rubbing against the frame. A spark so i then reconnect the coil to the stator no spark again is it common to get a coil fail :cry: ? im gonna try and get hold of a coil off a 50 honda moped my friend has will this work? i hope so i need to ride the beast this weekend
thanks will

if anyone has a coil for sale quite cheap that will ship to the uk please let me know

[slothminx]

hello i cleaned the oints up and then tried it again. a beautiful spark on my plug :) :w00t: but it still had the low power i talked about earlier so i took the carb apart and the main jet tube was clogged i gave the carb a really gd clean after that and fitted it back to the engine. when i fired it up the difference was so clear it revved up nicely with no bogging and had so much more low power. its now ready for its big ride tomorrow:)
:TrikesOwn
thanks for all your help
will