yungchris504 Posted December 14, 2015 Report Share Posted December 14, 2015 Ok. So I just installed VF4's and Shearer SB in frame pipes. With 27.5 pilots and 300 mains (stock carbs) with everything else stock on the bike. Sounded amazing coming from stock exhaust. I know the pipes are too much for stock engine was planning on 4 mil build. My problem is I was racing two yfz450's and on the last race when I got to 4th or maybe it was 5th gear. The engine suddenly lost all signs of power. No power band, and sounded like shit. I had to put put all the way home. But while riding home I had it in 3rd and gave it 3/4 throttle and it took maybe 5 seconds to get in a power band but it still didn't sound right. Spark plugs the insulator was black and at the curve part of the insulator was a lil oily.. Could I have blew the rings? Or is jetting an issue. I'm no dummy with engines. Just want some advice on where to look at and what to check first before I tear it down for no reason when it could be something simple. Anything helps, much appreciated guys Quote Link to comment Share on other sites More sharing options...
Buster91dg Posted December 14, 2015 Report Share Posted December 14, 2015 Try changing plugs Quote Link to comment Share on other sites More sharing options...
yungchris504 Posted December 14, 2015 Author Report Share Posted December 14, 2015 It was right about dark when it happened so I couldn't check my temperature strip I have on my cylinder. I don't run a gauge either. It may have been that. I'll be sure to try new plugs first thing tomorrow when I get home Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 14, 2015 Report Share Posted December 14, 2015 What do the plugs look like? Compression test to make sure it's not hurt internally. Then check the spark out. Quote Link to comment Share on other sites More sharing options...
speeshee Posted January 20, 2016 Report Share Posted January 20, 2016 Cracked reed petal? But I wouldn't think you could crack v force petals. They are pretty high quality Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted January 20, 2016 Report Share Posted January 20, 2016 Cracked reed petal? But I wouldn't think you could crack v force petals. They are pretty high quality Sent from my iPhone using Tapatalk I only get a season, maybe two put of a set of v force reed petals. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted January 20, 2016 Report Share Posted January 20, 2016 I only get a season, maybe two put of a set of v force reed petals.This. Reeds are definitely a seasonal item. I have a list of things I try to keep sesonal which is actually a lot of crap that people find extreme. But certain things can only take so much. Quote Link to comment Share on other sites More sharing options...
Sandking Posted January 20, 2016 Report Share Posted January 20, 2016 Just rebuilt one of my bikes and the vforce4s after a couple seasons are gapping out. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted January 20, 2016 Report Share Posted January 20, 2016 Lots of things can cause OP problems. Reeds probably aren't it though. Quote Link to comment Share on other sites More sharing options...
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