Hello, I am helping a buddy out with his 98 king quad rebuilding the topend (piston, rings, etc.). I made timing marks when I took it apart to aid in a fast reassembly but after double checking it appears I am off 1 tooth from TDC and the original timing marks on the cam.. it all matches up a few degrees after topdead though right when the piston starts traveling downward.. but it is not perfectly TDC... in order to get this I would have to set a tooth back. It ran low on power before and it smoked.. but I could get 50mph and some change from it on a long straight away...

DO you think i should put it back the way it came apart or reset the timing...?? Thanks...

Also, when I removed the head I noticed the piston was not tight in the bore like it was an undersized piston... I could see the rings... cylinder is in great shape and I reinstalled a std piston that fits much better... makes me wonder if it has been taken apart before or the piston was just that worn..

 

update*

Went ahead today and put it together with the timing marks that it was taken apart with and it seemed to have a bit of a back fire at idle and did not want to run with the choke off.. my buddy stated it has always been like this and it is still not running right but it is not smoking anymore... I guess I will set the timing a tooth up to get everything inline like I was thinking at first... so much for my timing marks for a quick reassembly.. it is not that bad though to reset.. is there anyhting else I should check before resetting the timing that would cause the engine to backfire?? Thanks..

 

the valve clearance is the most important next step..get the specs and have fun..{got to make sure those valves are closed at tdc}

 

alright thanks for the reply I got caught up in other things here lately... i checked the valve lash it is good... but the exhaust is getting slighly red at idle but fires right up and appears to have ample power.. soo maybe this is normal... ???

 

personaly if the top was torn apart i wouldnt trust thoes timing marks. i would put it at the factory marks and it should run better.....and if the exhaust,airbox,etc is stock and the jetting hasnt been messed with then i dont think the header should glow....just my .02

 

I think that he did set it to the factory marks the second time, but not 100% sure?....

 

Yes I set it to the factory marks it is running well now I apparently found a vacuum hose that was not connected now I guess i need to find out where it goes... but running good no smoke... no red hot exhaust with vaccumm hose plugged... wish i could have found a high compression piston for this thing... but he talking about buying a bigbore anyway..

 

does anyone make a big bore kit if so who and is it a high comp piston . i was looking at installing an oversized quadsport piston in mine . the bigist size i could find in weisco was a 68mm . but the 280 kingquad comes with 68.5 stock. I know the strokes are different, but the wrist pin height is the same. so it boils down to someone has to make a 68.5 high compression quadsport piston. The odds are better than finding one for a kingquad.