Thread: WOT bog while turning hard
09-08-2013, 11:27 AM #1
WOT bog while turning hard
I just got my gpr back together after going through the carbs; mikuni rebuild kits, osidebills carb recipe, 125/110 jets, 1.5n/s, 45psi pop off, flame arrestors, dplate, acc pump removed. It runs great now, idles perfect, starts immediately, and throttle response is very snappy... It is bogging hardcore during tight turns when going WOT... It doesnt quite fall flat on its face but bogs and won't clear up until it going straight and you let off the throttle and go back to WOT. At this point, there is a small lapse in time where it lags and then takes off hard. I just pulled the fuel pickup and the flapper looks ok. Powervalves cycle when shutting down ski, but i havent taken the covers off. I should mention that it did this both before and after carb rebuils and mods... Is it possible for the powervalves to stick intermittently? What should i check next?
Edit: comp is 110 all cyl. Drilled carb returns with 95 main jet in 1st carb return line, premix
Last edited by theprophet; 09-08-2013 at 11:52 AM.
09-08-2013, 01:04 PM #2
Pulled the covers on the pv's, only the pto cyl.one is functioning..guess that might be it
Broken pv coupler
09-09-2013, 10:35 AM #3
be carefull and always use the yamaha oring gaskets. they are thicker .made by mikuni for yamaha dont come in mikuni kit .will leak fuel not good
09-09-2013, 12:47 PM #4
Another member mentioned that, but I was unable to find any info on here, pwctoday, or riva forums...I used Mikuni rebuild kits made specifically for the 66v/67x Yamaha carbs
09-09-2013, 12:57 PM #5
I assume these were the correct kits...measured the oring thickness on the factory ones- .10 and the new ones were the same...
just took it out for a quick test run...couldn't find pv couplers in stock within 50 miles so i epoxied the pv coupler back together, lasted ten minutes, but confirmed that the bog during heavy engine load and WOT was pv related. didn't hold together long enough to get a top speed number, but this thing is nuts! off idle it jumps out of the water (still have to address the cavitation issue). midrange power is crazy and it revs up quick to an indicated 7K rpm (factory gauge). no hesitation, doesn't load up through idle speed zones...amazed at how 'on' the carb settings seem to be. so glad i waited and saved $$ to do F/As, d-plate, re-jet
hopefully this post will help someone else chasing the same issue...
Last edited by theprophet; 09-09-2013 at 07:54 PM. Reason: problem resolved, info added
09-11-2013, 01:21 PM #6
cool that kit should be good .who did you get it from
09-12-2013, 09:09 AM #7
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