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Re:Looking for advice I can't go past half throttle?
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TOPIC: Re:Looking for advice I can't go past half throttle?
#1017963
Dragonman (User)
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Looking for advice I can't go past half throttle? 7 Months ago  
Hi I have an 03, put on short shots with quiete baffles and a k&N filter with stock air box, took off the AIS system, rejetted with vance & hines used jet DJ165, adjusted mixture screw 3 turns out and put the clip on the needle 4th grove.

Everything runs great no poping good idles but my problem is at half throttle its like if i'm runing out of fuel and the symtom is like if i was reaching the engine cut off, if from half throttle I move it up very slowly i can accelerate a little more.

Not sure what screw to play with? not sure if it might be a timing issue or runing out of fuel issue, or if I should change the jet, I have to many options to play with and not sure which way to go.

But the bike runs fine and usable no problem as long as i shift before half throttle....

Would anyone have an idea?

I'm thinking that I'm simply runing out of fuel but it may be something else too I'm not sure?
 
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#1017964
Bradspeedstar (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
My gut says you need to pull the carb back apart and male sure you didn't tear the diaphragm when you jetted the carb. Also make sure you got the Jets seated properly and they aren't loose. If you used proper jetting for your setup that's the only thing I can think of. Good luck!
 
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#1017965
SKWEARpeg (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Dragonman wrote:
Hi I have an 03, put on short shots with quiete baffles and a k&N filter with stock air box, took off the AIS system, rejetted with vance & hines used jet DJ165, adjusted mixture screw 3 turns out and put the clip on the needle 4th grove.

Everything runs great no poping good idles but my problem is at half throttle its like if i'm runing out of fuel and the symtom is like if i was reaching the engine cut off, if from half throttle I move it up very slowly i can accelerate a little more.

Not sure what screw to play with? not sure if it might be a timing issue or runing out of fuel issue, or if I should change the jet, I have to many options to play with and not sure which way to go.

But the bike runs fine and usable no problem as long as i shift before half throttle....

Would anyone have an idea?

I'm thinking that I'm simply runing out of fuel but it may be something else too I'm not sure?


Your main jet is pitifully small. You have opened up the exhaust and intake, and choked your fuel supply back to way less then the bike was jetted stock.

You should be running a 167.5 Mikuni, at the very least. The DJ165, is about the same size as a Mikuni 153(stock in your bike with the restricted airflow and exhaust, is a Mikuni 165, which is about the same as a DJ175.5). You quite literally run out of fuel.

By the way, if you reach the rev limiter, you'll know it. The ignitor cuts power to one coil, until the revs come down below the cut off again. Its very noticeable.

You could put the proper Main in, and up your Pilot to a Mikuni 37.5, and turn your PMS in to about 2 3/8 and you should be dandy.
 
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#1017977
Dragonman (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
I like your idea of starving the bike with the jet makes a lot of sense, but i did followed the instructions of the vance and hines kit... I'll try the rejet if your sure I reduced fuel instead of increrasing it make perfect sence!

The kit i have the largest jet is a DJ175, so if I understand its about the same as the stock one?
 
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Last Edit: 2017/07/25 09:06 By Dragonman.
 
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#1017991
texasscott1 (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Actually it's a tad smaller. There's a conversion table in the tech articles.
 
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#1017993
SKWEARpeg (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Dragonman wrote:
I like your idea of starving the bike with the jet makes a lot of sense, but i did followed the instructions of the vance and hines kit... I'll try the rejet if your sure I reduced fuel instead of increrasing it make perfect sence!

The kit i have the largest jet is a DJ175, so if I understand its about the same as the stock one?


If you use the jetting I mentioned, you should get in the mid to low 40's mpg, driving somewhat conservatively. The bike will pull like a freight train all the way into the triple digits. The DJ 175, will still be small, but better. A DJ180 would be about right. The jetting I mentioned, is a tried and true recipe here on the Clinic. If you like a bit more performance, even the 40 Mikuni Pilot, and the 170 Mikuni Main will work, although I wouldn't go richer with a 1600.

If you haven't yet, pull the rubber noise boot out of the bottom of the intake. It increases the amount of air that can enter the stock box, and takes two extra bends out of the air flow. I drilled an extra 1 1/4" hole on the trailing edge of the stock air box, low down on the black half(not the side facing the motor). This adds even more air access to the filter surface. They call it a Poor man's BAK.here on the Forum.
 
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#1018062
Dragonman (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
When buying the mikuni jets for which card do I need to look for, are they all the same jets for mikuni carbs?

Is this what we have? Mikuni HSR 42/45/48
 
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#1018067
SKWEARpeg (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Dragonman wrote:
When buying the mikuni jets for which card do I need to look for, are they all the same jets for mikuni carbs?

Is this what we have? Mikuni HSR 42/45/48



Ours is a 40CV. If you have an HSR, then my advice can go right in the trash.

Pilot
http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_N224-103_pilot.htm

Main
http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_N100-604_main_Large_round.htm
 
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Last Edit: 2017/07/26 07:09 By SKWEARpeg.
 
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#1018107
Dragonman (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Thanks for the info!!
 
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#1018278
Dragonman (User)
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Re:Looking for advice I can't go past half throttle? 7 Months ago  
Hi is there another place then jetsrus to buy these jets, I've been emailing them all week trying to buy and getting no responce from them, they wont ship to Canada unless I tell them what I want by email and pay by email but getting no answers....

I need the 40 pilot and 170 main and trying desperately to find where to buy this...

Thanks
 
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