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Discussion Starter · #1 ·
Today went out riding out in the pit area. run into a little issue.
I bought the motor from cwbugycody about a month ago he had for sale from this site. I have PM for more infor. on the engine.
All I know that it is 686 with stage 2 cam, no head work on it, I believe the valve is stock but I don't know if they put the Knibble spring when they put the Stage 2 cam in there. It got the 35 FCR carb on it.
The motor fire up when it start and no issue there. The issue is when on the mid range to top end starting on 3rd gear It sound like it got fuel stravation or valve floating. But when going thru gears it will go faster as long I am easy on throttle from cranking WFO.
When start the bike no issues, idle fine. Pliot is good
I don't know where the needle set at as right now, but do know the main jets is 148,150. So I am assuming the needle need to redjust by moving the clip down maybe up to 2 clip downs?
It want to go faster but it not there.
Also this carb was on my old motor of 686 too and never been an issue there till now.
So I need some feedback from you guys and point me the right direction as I will look into tomorrow morning.
Thanks for your time.
 

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I would also like to add that it sounded like the motor was hitting.a rev limiter. It has aftermarket cdi. I know it wasen't a limiter cuz my stock 05 rappy was winding higher than my brothers. Any help would be greatly apreciated.
 

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Hey deracer, i replyed to your pm. I am sure its not valves floating simply because i never had that issue on my rappy. The engine was in qu ad when i got it, but it is a 686, with hot cam. I was told it was a stage 2 but cant swear to it. I know it is a hot cam due to the markings on cam itself. Measured cylinder and it is a 102 mm(686). I was, am running a edlebrock carb ,so i was never giving it as much fuel as your fcr will. As far as it sounding like it was hitting a rev limiter i have no idea about that. I never had an issue like that. Like i said in pm i had motor dynoed and no problem getting to high rpms, i have a spare cdi( rev max) if u need me to send u to see if it helps. I belive it will be as simple as getting your carbs set right. Keep me updated.
 

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I will try to locate dyno sheet when we get home from thanksgiving. I dont know if i still have it but will check. Mike at little sahara power sports does all my dyno work. He told me all i needed to have worked on was the head. Not because there was anything wrong with it ,just to make more power. Like i said no port work on head.
 

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Discussion Starter · #5 ·
Thanks Cody, I can't use CDI since my bike is 01 different wiring plug I believe....
So sound like it toward fuel stravation....
Like I say the motor want to run harder but it won't.... also I did redjust the valves before I threw it in... It make it easier...lol

Waiting for Willykiller that he may have an idea and point me to the right direction :)

One way it will be solve....lol

Bill
 

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Today went out riding out in the pit area. run into a little issue.
I bought the motor from cwbugycody about a month ago he had for sale from this site. I have PM for more infor. on the engine.
All I know that it is 686 with stage 2 cam, no head work on it, I believe the valve is stock but I don't know if they put the Knibble spring when they put the Stage 2 cam in there. It got the 35 FCR carb on it.
The motor fire up when it start and no issue there. The issue is when on the mid range to top end starting on 3rd gear It sound like it got fuel stravation or valve floating. But when going thru gears it will go faster as long I am easy on throttle from cranking WFO.
When start the bike no issues, idle fine. Pliot is good
I don't know where the needle set at as right now, but do know the main jets is 148,150. So I am assuming the needle need to redjust by moving the clip down maybe up to 2 clip downs?
It want to go faster but it not there.
Also this carb was on my old motor of 686 too and never been an issue there till now.
So I need some feedback from you guys and point me the right direction as I will look into tomorrow morning.
Thanks for your time.
There is quite a difference between valve floating and fuel starvation, with valve float the engine just loses power and run rough and wont rev any higher and this would be at extreme high rpm, with fuel starvation, the engine just dies................
 

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Could the 01 cdi cause problems? I just dont know . The engine was out of a 02. Anybody know so we can help bill out... After reading willys post, dont really sound like ether one is the problem( fuel starvation or floating valves) . Lets get bill some help..
 

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When i rode the quad today and listened when desracers whent by the bike would rev fine and then just stop. It would bounce at that rpm until you shifted and start screaming through the next gear. Just like a rev limiter. But it didn't sound like it was even reving as high as my stock rappy. That is what led me to think valve float. We adjusted the valves before we put the motor in. Should they be adjusted hot or cold? The motor pulls great to me. Just trying to figure out why it is hitting a wall.
 

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When i rode the quad today and listened when does racers went by the bike would rev fine and then just stop. It would bounce at that rpm until you shifted and start screaming through the next gear. Just like a rev limiter. But it didn't sound like it was even revving as high as my stock rappy. That is what led me to think valve float. We adjusted the valves before we put the motor in. Should they be adjusted hot or cold? The motor pulls great to me. Just trying to figure out why it is hitting a wall.
Maybe the reverse rev limiter is kicking in, check that out, You can ground the green and white wire and see if it eradicates the problem.............
 

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Looks like we found the problem. Stuck plunger sensor located by the shift lever shaft. Bike really winds up now. Plunger was stuck in. We were using the sensor that came with the motor. Swapped it with the old motor and seems to be working. Thanks to all for the help and ideas. Always seems to be the most overlooked item. Happy quadding.
 

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Glad y'all figured it out. Hope y'all enjoy the engine, happy quading to y'all also.
 

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Looks like we found the problem. Stuck plunger sensor located by the shift lever shaft. Bike really winds up now. Plunger was stuck in. We were using the sensor that came with the motor. Swapped it with the old motor and seems to be working. Thanks to all for the help and ideas. Always seems to be the most overlooked item. Happy quadding.
This plunger sensor is most likely the reverse switch, this switch tells the CDI when the bike is in reverse engaging the reverse rev limiter..............:)
 

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The motor is a 02 , he is running a 01 cdi. Could that have caused the issue? I am only asking because it never did that to me. It was my engine.
 

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The motor is a 02 , he is running a 01 cdi. Could that have caused the issue? I am only asking because it never did that to me. It was my engine.
Some 01 motors and cdis have the rever rev limiter...........
It may be your engine but is it your cdi.................
 

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Some 01 motors and cdis have the rever rev limiter...........
It may be your engine but is it your cdi.................
No, I sold him the engine, but he is using his cdi. I always ran a after market cdi for 02 and up.
 
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