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Discussion Starter · #1 ·
I'll try to keep this brief but I need some expert advice. I went to pick up my quad at the Yamaha dealership after the VERY experienced mechanic installed the Rocket Factory 734 kit. Extreme head port, stage 3 web cam, 12:1 piston. He couldn't make it idle worth beans. It would idle when it was cold for about 5 -7 seconds then it would seem like it's loading up and then die. When he restarted it and reved up a little, around 2000 RPM it would idle but seemed a little rough, that might have been cause it was cold? I installed the map that was provided by Rocket Factory after I arrived and thought this would solve the problem, but same thing. We removed the PC111, and STILL the same thing, it wouldn't idle. He finally changed the throttle linkage and that seemed to keep it running but it wouldn't idle down, and the throttle response was eratic. Then he changed the butterfly in the throttle body to keep it part way open and relaxed the throttle cable, it is rideable like this but same thing, it won't idle down very fast after giving it gas. Today he is going to see if possibly there is sand in the injector that is causing it not to close completely causing it to run too rich at idle?? any suggestions would be appreciated. I took it for a ride last night (briefly) and it Frigg'n Get's it ON, I will keep you all posted as to my findings and progress. :help:
Grant
 

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Im very curious to se what the out come is. Im looking into a similier setup.
Hard to say you have an injector problem now after it was done if you didnt have one before. Im thinking its got to be somthing in the porting and that very wild cam.
 

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Did Rocket Factory install the mods? What do they say? I would thing they would know more than a factory Yamaha service guy. :grin_nod:
 

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It sounds like a fuel problem, or throtle postion sensor problem. Check all your conections on the PC3, also the throtle postion sensor plug, and clean the injector. Also do you have a shop with a dyno in your local area if so you might want them to build you a map.
 

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sparky - i have the 11:1 piston, stage II cam, head ported.... so which fuel do you think i should be running? i run 3gal of 91 with 2 gal of 113.... right now...

thanks
Plattner
 

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With the 11:1 setup, you should be just fine with premium pump. Thats what I run on my 11:1 with zero problems. :thumbsup:

before my 700, I ran permium pump in my 720 stroker with the 11:1 for years without worry. The only time I'd go up to a race/ pump combo would be 12:1 or higher....
 

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plattner said:
sparky - i have the 11:1 piston, stage II cam, head ported.... so which fuel do you think i should be running? i run 3gal of 91 with 2 gal of 113.... right now...

thanks
Plattner
Thats basicly what Im runnin in mine. Noticeable difference when I run straight pump gas, just not as snappy. I also run what I know to be safe especially since we dont have control over the timing on these things yet. I will say that I run race fuel mainly for the higher quality fuel moreso than the octane.
 

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Discussion Starter · #11 ·
Yes, I was running Pump gas yesterday and then added some 110 directly into the tank just to try it and see if that helped (but it didn't seem to) I am sure it's not the PC111 because when it was disconnected it still ran poorly. Thanks for your advice guys, keep brain storming for me, and we will get this problem solved. Yes I called rocket factory and he said maybe there was a vacuum line off somewhere or something like that, they hadn't heard of this kind of problem even with a stock map they are supposed to idle and run ok,,,,, just pop and snap cause they are too lean. Honestly this mechanic of mine has about 20 years of mainly Yamaha hands on experience and he is stumped....??
 

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Discussion Starter · #15 ·
When I was there last night trying to get it running right, He took the timing chain cam cover off AND the inspection screw in cover off of the crank,,,, making sure the timing was right. That was my first question too, is it timed right and are the valves set right?? thanks for the ideas......
 

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Discussion Starter · #17 ·
Machy, the first time We tried the quad it did not have Race gas, It was what ever gas was in the tank, Premium pump gas. Do you think it would have that much effect on the idle? Before I took it for a ride I dumped about a gallon of Race fuel in the tank to make aprox 50-50 mix.
 

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I personally dont think straight pump gas with make it not idle on 12:1 compression. And now that you did a mix you def. shouldnt have a problems with the fuel. 12:1 mix would be just fine. And pump might make it ping but, the pining will start at a high rpm first I believe. I really dont think its a fuel problem.

You have some other great ideas that were thrown at you already. Throttle position sensor? Timming?
 

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Discussion Starter · #20 ·
NEWS--I just talked to the Mechanic and he took everything off of the Quad back down to the head and closely inspected everything: Checked the timing,,, and reset the valves with slightly more clearance, checked the injector (there is a screen that won't let any debris into the injector). Installed a new plug, changed a sensor (not sure which one) that he knew was working off a different quad, checked valves to make sure they seat by pressurizing ---and no leak off, reset the throttle position, reset butterfly in throttle body, and completely reinspected everything closely and put it back together. He said it starts fine (as usual) and will idol now but as it runs it hesitates like it is going to die but picks back up and continues to run. He rode it and it is very ridable now. He said it does NOT "run on" like it did the other night, and now it idols down after gassing it. He thought it was still a little rich at idol but maybe I could fix that by programming the PC111. I Get to pick it up tomorrow morning and RIDE ! Thanks for everyone's advice, I think collectivley (and with positive Carma) We solved this problem. I'll Post my ride experience and new found power tomorrow night.....Thanks again, GG
 
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