3 stroke Posted March 23, 2009 Report Posted March 23, 2009 just got my cheetah cub with a 4mm crank together running 111 octane and 19 cc domes, runs great at low to mid range but cuts out at top end unless i advance the timing +8 degrees, is that safe or do i have another issue? . . . . need input, thanks Quote
sheerider1026 Posted March 23, 2009 Report Posted March 23, 2009 have you checked your squish? compression?? im not sure about the cubs, but on stock cylinder 4mm setups you usually have the domes cut for the added stroke, i am thinking that the cub cylinder has a higher deck height, but i am not sure.. i have a stock stroke 392 cub, they do love timing, i think i ended up running +6 or 7 on the timing.. hopefully someone more knowledgable will chime in, so do not take my settings as a DEFAULT setting for your setup.. Quote
locogato11283 Posted March 23, 2009 Report Posted March 23, 2009 i run my 10mm cub at +7. youre sure its the timing causing this problem?? Quote
sheerider1026 Posted March 23, 2009 Report Posted March 23, 2009 LOCO, sup NUKKA!! do you run stroker domes on your 10 mil?? or is the deck height of the cylinder designed to use the standard big bore domes?? Quote
3 stroke Posted March 23, 2009 Author Report Posted March 23, 2009 I'm pretty sure, i had timing at +4 and it ran like poop at top end pulling a hill, advanced to +7 and it all went away. . .i did noticed that with a low load(flat land) 3/4 throttle high rpm it didn't sputter. BTW I'm running 35 mm pwk's with a 155 main Quote
moneybags Posted March 23, 2009 Report Posted March 23, 2009 I ran my 421 cub at +7 and went up from their. Quote
wesw Posted March 23, 2009 Report Posted March 23, 2009 sometimes a weak stator will cause high rpm pops and cut outs. and to the guy talking running stroker domes on cub you need to research your stuff before you throw that out they and flat decked unless they are machined or setup the be about the deck by the builder. Quote
sleeper06 Posted March 23, 2009 Report Posted March 23, 2009 I run +7 on my 4mil cub drag set-up,your jetting could be a lil rich,try a plug chop at both timing ranges and see the diffrence Quote
sheefreak Posted March 23, 2009 Report Posted March 23, 2009 What kinda compression you runnin? If you are in the 180+ area you may solve your problem by closing the plug gap to .022. .018 for alky.... Quote
dajogejr Posted March 23, 2009 Report Posted March 23, 2009 It shouldn't need that much timing to cause it to not cut out. I ran my 4 mil cub on race gas with a TON of initial timing, like 4 or 5 on the plate PLUS the advance in the Dyna. I'd start checking electrical as well...on gas, if you have to gap it down to .020 to .022...you have weak spark. Could be a few things. Too large pickup gap to flywheel, bad stator, coil caps, etc. It could also be too rich, but running that much timing causes more heat and it's burning more of the mixture with that much advance... Quote
dajogejr Posted March 23, 2009 Report Posted March 23, 2009 LOCO, sup NUKKA!! do you run stroker domes on your 10 mil?? or is the deck height of the cylinder designed to use the standard big bore domes?? He runs a cylinder that is designed for a 10 mil stroke, like I do. That's how we bought our castings. Some guys like to run a bigger casting on a shorter stroke and mill some off the top...but it's always easier to get the casting for your intended crank you're gonna use. That's the beauty of an aftermarket cylinder.... Quote
badassbanshee479 Posted March 23, 2009 Report Posted March 23, 2009 my cub was doing this on gas... went to a nology coil and problem went away.... Quote
3 stroke Posted March 24, 2009 Author Report Posted March 24, 2009 all electrical is new, wiring harness has been taken apart and inspected, swapped all parts one at a time from old to new and back (stator, coil, regulator and CDI) with no change. also i noticed the pipes are starting to discolor from heat(cpi in frame) so i don't think im too rich, if anything i'm lean. . . .thanks for the input Quote
badassbanshee479 Posted March 24, 2009 Report Posted March 24, 2009 did you try a new flywheel? buddies bike was breaking up in the mid to top end and we found the flywheel had a broken magnet in it..... Quote
shanYE west Posted March 24, 2009 Report Posted March 24, 2009 whats pickup coild gap set at? and what type of timing plate? I've seen issues with the trinity style plates when timing is changed the pickup coil gap changes. Quote
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