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Discussion Starter #1
Hey guys I'm pretty new here but I am in the process of perfecting the jetting on my bike. Here is my dilemma
4th gear top speed 70mph @9500-10000 rpm WOT
5 th gear top speed 70mph @8000-8500 rpmWOT
Why will my bike not push out that extra 2000rpm's in 5th??
 

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Discussion Starter #2
Bump. Most forums have a few grease monkeys who know about this stuff and I usually get quick replies. I've posted here a few times and hardly get any responses. Am I posting in the wrong category?
 

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Need to give more information on the make and model Of bike you have
 

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Discussion Starter #4
I know its not a real supermoto and I will probably get criticized for it. But its a qlink xf200 I'm running 16t front 44t rear 127.5 main jet
35 pilot. Float bowl raised 1mm, cold air intake, Modified exhaust.
 

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Drag, the little bike doesn't have enough power left to over come the parasitic air drag at that point. You could try going down a tooth up front or up 4 out back should give you those extra revs and a few extra mph.

My old yz450 would fall out at about 100mph 4th wound out but 5th had a few more rpms but just wouldn't do it, till the next owner went from a 2.8 ratio to a 3:1 ratio (15/45). After that it revved quicker etc and he got those upper R's in 5th as well as another 5-7mph

Your gear ratio is just way too tall.

Z
 

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cold air intake:) sorry

I agree with pro, your bike just doesnt have the power BUT modding exhaust and intake aren't something you just do. Its possible you actually lost some power by modding the exhaust depending on what you did to it. Everything has to work together. If you put a larger exhaust on, or opened the air box up but it still has a stock profile cam set in it, then you might just be making more noise. For instance the volume of air in a factory airbox is calculated based on the motor. Having an open filter on the end of a carb usually makes power worse unless everything is tuned properly because the air no longer has a large volume to pull from and a nice intake tract to get to somewhat laminar state. Having the turbulent air enter the carb right away means that when the carb wants that nice laminar flow to help suck fuel out of the bowl, you have a bunch of different currents in there and you end up with poor fueling. The exception to that is at WOT with a motor that can achieve the intake air speed and suck the air in so fast(like a drag bike).

The quality of the air flow is going to be much more important in this case.
 

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Discussion Starter #7
I do have a new can to be put in. Its the lt230s cam. I've read around in some forums that it is supposed to make a huge improvement in performance. Might jut put it in today. =D
 

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well guys I listened to all of you and changed back the rear socket to a 48T and left the 16t up front then I changed the cam to an lt230S cam. Then readjusted the valves to spec. I'm easily hitting 80 now and tons more low end! :rock:
 
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