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KMS Turbo issues

S
Jan 28, 2019
83
4
8
So I have a 2010 with a KMS turbo setup. Got the kit used. Bike ran fine before the kit was installed. Upon Initial startup after install, engine wouldnt rev pas half throttle, and this is what it sounds like:



It almost sounds like its starving for air/ fuel or misfiring. But as far as I know, the KMS system is standalone and does not mess with the factory mapping or ignition timing, is this correct?
I took the bike out for a ride after install as I thought the issue might be related to elevation mapping, the symptoms persisted but got better with elevation, almost cleared at like 6500-7000' elevation.
I only got to take it out for 1 ride last season. This season after a full top and bottom rebuild, first ride, same problem but has gotten much worse, but I only got to like 4500 elevation. Also because of this issue, its not building any boost.

This is what I have tried for diagnostics:
Unplugging the TPS- same revving issue.
Checked the TPS resistance as per manual- closed throttle reading is good, WOT is reading 3.72. Manual specs is 4-6. I dont think this would be causing such dramatic rev issues.
Cleaned connection and plugged it back in- same issue.
(havent checked TPS supply voltage)
Revving it to the sputter point and squirting starting fluid- chokes out engine so its not fuel delivery, correct?
Unplugged turbo fuel injector- same issue, confirms its not starving for fuel.
Revving it to the sputter point and blowing compressed air (shop compressor) into the intake- same issue, so its not starving for air.
Unplugged factory fuel injector- wouldnt start at all.
unplugged MAF? sensor or whatever sensor it was that went into the airbox (airbox now gone with turbo)- same issue
Spinning the little adjuster screw on the KMS control box- made a slight difference of where in the RPM range it sputters- what is that adjuster screw for anyways?

I cant figure out what else it could be causing that issue.
I do speculate that maybe it may be because I still have these 2 loose end on the KMS harness: https://www.snowest.com/forum/threads/yz450f-kms-turbo-build.447917/page-3#post-4212491
its the connector shown in the pic of post #59 (its hard to see but theres 1 white plastic connector & 2 bullet style plugs) But as was said by some members in that thread, the 2 plugs dont go anywhere....?


Please help! I want to get some more rides in before the season is over....
 

wwillf01

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Aug 12, 2012
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Heber Ut
Agree with above and also on my KMS I did have a power commander fail, and the turbine fail in the turbo... you want to check its play... then your clutch... that kit is highly dependent on your clutch being in good condition to deliver the right fuel at the right time...
 
S
Jan 28, 2019
83
4
8
Agree with above and also on my KMS I did have a power commander fail, and the turbine fail in the turbo... you want to check its play... then your clutch... that kit is highly dependent on your clutch being in good condition to deliver the right fuel at the right time...

Mines is in pretty bad shape also, leaking oil into the compressor side, will be getting a new turbo soon.
Can you please elaborate how it is so dependent on the clutch to for proper fueling? I understand that for perfect A/F map it would depend on solid and consistent power transmission to the track, but this issue is present in neutral and the same when in gear. And I dont feel any clutch slippage when I rode it. It does have the direct drive clutch.
 

wwillf01

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If you leaking a good amount oil then that will be a problem at mid to upper.. does it move a good amount when you press on it... you do not want pieces of that going through the engine... tps can be set by the power commander I think... it's been a while... if the clutch is not slipping then you are fine on that end.... crank seal leak will give you lean issues... had that also but on mine it was intermittent till it mushroomed the top end when it let go. Fyi that was from a fresh rebuild and it let go...
 
S
Jan 28, 2019
83
4
8
If you leaking a good amount oil then that will be a problem at mid to upper.. does it move a good amount when you press on it... you do not want pieces of that going through the engine... tps can be set by the power commander I think... it's been a while... if the clutch is not slipping then you are fine on that end.... crank seal leak will give you lean issues... had that also but on mine it was intermittent till it mushroomed the top end when it let go. Fyi that was from a fresh rebuild and it let go...

Yeah its moving around alot. It wasnt too bad, but I rebuilt it with a chinese seal & bearing kit I got on amazon and it got much worse after. chinese crap. had pretty decent reviews tho. Is there is decent substitute brand of gt2252 turbo you would recommend? This bike is a money pit as is, and I dont want to throw another 1k into a turbo not knowing if this issue can be fixed with an easy diagnostic & tune. For all I know the PC modules could be toast, as well as ECU...

What crank seal are you talking about? The crank doesnt have any seals, its all in an oil bath with tranny and everything...
 
S
Jan 28, 2019
83
4
8
Could anyone confirm the part # for the replacement turbo. Knowing these kits are really sensitive and with so many similar models, I want to make sure I am ordering the correct replacement. The one I currently have may be the wrong one, and may be part of the problem.
 

wwillf01

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The only thing I have is it was a gt2252 on my front mount for a 15 ktm 450sxf

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wwillf01

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Why not just send it to Garrett to be rebuilt?

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S
Jan 28, 2019
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Its pretty shot. The fins have chewed some aluminum of the compressor housing. I think a rebuild will cost more if its rebuildable
 
N
Jan 3, 2008
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Northern Utah
Back when I was in the turbo game I sent my garrett to gillet diesel(a garrett dealer) and they took it in as a core charge for a new cartridge. I think i was around $500. I had a broken shaft so im sure a chewed up fin is no biggie.
 
S
Jan 28, 2019
83
4
8
The fin is fine. Their stainless steel or something. the aluminum housing is chewed up from the cartridge having too much play. So housing + cartridge rebuild would be 700$ at least. new turbo is about 850$. I already ordered a replacement anyways.
 

wwillf01

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It is only ceramic if that was upgraded... could be either.

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wwillf01

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Kms did it but that was from garret directly I thought is where he ordered it.

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