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Author Topic: Powerband too short  (Read 22549 times)

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Offline 81cr450

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Re: Powerband too short
« Reply #15 on: July 06, 2013, 02:40:36 PM »
Quote from: Foxx4Beaver on July 06, 2013, 12:46:42 PM
another thing you can try for the surging...is adjust the idle screw so that it WON'T idle....I learned this off this site a while back because mine used to surge like mad.....it didn't completely stop the surging,but it made a huge difference.

That surge can be eliminated with the powervalves not over closing Foxx.
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Offline Foxx4Beaver

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Re: Powerband too short
« Reply #16 on: July 06, 2013, 08:22:59 PM »
mine don't over close...and from watching Gages videos,his weren't either.
it's just in the K5s nature to surge at some degree...some do it worse than others.
take an old YZ490 for instance....I rode a friends 82 that would shoot me right over berms every time.
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Offline Gage

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Re: Powerband too short
« Reply #17 on: July 07, 2013, 02:27:35 AM »
For a 88mm bore would my head needed to cut to fit? If so maybe that's the problem I have.
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Offline Pmcg

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Re: Powerband too short
« Reply #18 on: July 07, 2013, 03:44:33 AM »
I bought a motor that had an 87.5 piston and stock head. As a result the head gasket went and the front of the piston was destroyed. I have a picture somewhere ill see if I can find. But I would say you defineately should modify the head to fit. Site sponsor Pinsonnault racing did mine. 
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Offline Foxx4Beaver

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Re: Powerband too short
« Reply #19 on: July 07, 2013, 05:39:22 AM »
Quote from: Gage on July 07, 2013, 02:27:35 AM
For a 88mm bore would my head needed to cut to fit? If so maybe that's the problem I have.

that's a pretty important piece of info you left out in the beginning...I agree with Pmcg...you should have the head cut/matched....but I'm still not sold on that being 100% of your problem....you still have jetting issues that need to be fixed.I don't know if anyone on here is running a 165main,that's just too lean...I run a 168 and that's on the lean side,but my bike hardly ever sees WOT,so I can get away with it....and your low circuit jetting is causing your black oil/spooge problem.
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Offline Gage

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Re: Powerband too short
« Reply #20 on: July 07, 2013, 09:54:34 AM »
I don't wale on the throttle to much. So should I even ride it anymore? Or try to jet it? It sounds good at idle and it doesn't leak. I emailed Pinsonnault Racing from ebay because the site was down. I probably call tomorrow, will I just have to send off the head and tell them to cut it and resurface for an 88mm bore or what? Will they need the piston? And does any one know how much this will run?
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Offline Foxx4Beaver

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Re: Powerband too short
« Reply #21 on: July 07, 2013, 10:04:37 AM »
wait and see what Todd from Pinsonnault recommends,that's what he specializes in.
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Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline Pmcg

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Re: Powerband too short
« Reply #22 on: July 07, 2013, 11:16:51 AM »
Todd is really good. Very competitive prices quick turnaround and really good work. I'm sending him my crank for balancing this week.
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Offline Goat

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Re: Powerband too short
« Reply #23 on: July 07, 2013, 02:55:40 PM »
I'm running a 158 Main jet in my 87 and my 98 had a 160 main jet. Im at about 600ft elevation in Michigan.

Before anyone tells you what clip position on the needle tell us the numbers stamped on it. It may be the wrong needle for the kx500. I'm currently running a kx250 needle.

The head and gasket need to be for an 88mm bore or it will never run right no matter how much jetting you do.

Check the timing. If it's off to much it wont burn all the fuel and will cause black spooge even if you are jetted properly.

32:1 is a good ratio. I've been using that in all my bikes for 20 some years and never blown one up.
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Offline conbread

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Re: Powerband too short
« Reply #24 on: July 07, 2013, 03:16:09 PM »
my bike is running a 160m and a 52p with the clip in the 2nd spot and my plug still stays a lil dark and im rough on this ole bitch.. hahhahahaah
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Offline Foxx4Beaver

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Re: Powerband too short
« Reply #25 on: July 07, 2013, 08:37:48 PM »
160mains...my bike would meltdown in minutes if I threw in one of those...then again,I'm running a few mods....and with Gage running an 88mm bore...I'm skeptical about it being able to survive on a smaller main...I went to an 87mm bore and that forced me to fatten up my jetting.
It's better to see him start off a little on the richer side and work down...than start off too lean and have an expensive preventable meltdown....USMC 500 can verify what happens when running too small of a main....no offense USMC.
« Last Edit: July 08, 2013, 09:11:51 AM by Foxx4Beaver »
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Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline Gage

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Re: Powerband too short
« Reply #26 on: July 11, 2013, 12:59:01 PM »
Took the head off today going to mail it tomorrow to Pinsonnault Racing, having the head resurfaced and cut to fit 88MM. I'm going to order this http://www.ebay.com/itm/COMETIC-TOP-END-GASKET-KIT-88MM-KAWASAKI-KX-500-91-04-/330759879969?pt=Motorcycles_Parts_Accessories&hash=item4d02d33d21&vxp=mtr and this http://www.ebay.com/itm/KEIHIN-CARBURETOR-SIZE-55-SLOW-JET-FOR-PJ-PWK-PWM-/290529527013?hash=item43a4e8c4e5&vxp=mtr. I have a 70,75,80,85 mains. Think I'm good?
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Offline Foxx4Beaver

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Re: Powerband too short
« Reply #27 on: July 11, 2013, 08:58:18 PM »
start with the 175main....do a WOT chop run,then check the plug color,and adjust from there.
Pay attention to how it runs at slow speeds with the 55pilot...if it feels/sounds blubbery or like it's loading up,then you'll need to drop one more size.
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Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline alward25

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Re: Powerband too short
« Reply #28 on: July 12, 2013, 04:02:01 AM »
Pinsonault might be able to get you a good price on the gaskets too.  They sell them with their kits.
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Offline Gage

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Re: Powerband too short
« Reply #29 on: July 12, 2013, 07:29:03 AM »
Quote from: alward25 on July 12, 2013, 04:02:01 AM
Pinsonault might be able to get you a good price on the gaskets too.  They sell them with their kits.
Ill ask about them thanks
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