Jacobson roll over valve

yammyboy

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My dad and I each got one of these last year and installed them on are nytros and they get to about 7800 rpm and then bog and act up. We replaced them and got new ones thinking it was just a bad product but then the new ones still do it. Any one out there have this problem and or know what might be the fix.
 

yammyboy

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I just went and tried grounding it to the battery and didn't change a thing but then I tried unplugging the valve to see it it was the valve part or the tether part and with the tether still plugged in it still acted up but if you unplug the tether it stops so its gotta be something to do with the tether part of this product not the valve
 

shawnmcgr

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I've got one on a phazer and no problems. works great...not sure why it's not stock.
 

Redturbo

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Just asking. Are you sure its a real Jacobson rollover valve? Or did you guys buy it from Yamaha? If its from Yamaha, its a mpi. At last yami fest, dealers son & 2 customers all had theres act up like yours. But they are the mpi from Yamaha. If its from Bill Jacobson, never mind what I said. Bill is a great guy & will help out.
 

yammyboy

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I checked and they are the yamaha ones and I'm not sure what the mpi is or means, I feel stupid lol.
Do you mean they are made by mpi ?
 
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Trax 2 Treadz

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MPI is Mountain Performance Inc. All the manufacturers are into re-branding now. They simply buy product from a company like MPI and re-brand it as Yamaha or their own product.
 

Redturbo

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Sorry, figured most yami guys new of mpi. My fault for not explaining more. Not sure the issue with there tethers, but it seems to cause weird issues. Hopefully you can get your $ back.
 

Trax 2 Treadz

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Just so that we are clear the Jacobson/Four Stroke Solution kits are not the same as the MPI/Yamaha kits. They are made by two different companies. We have had the Jacobson/FSS kits in our sleds for the last 2 or 3 years and have not had a stitch of problems with them.

Jan
 

Pineapple

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I also installed one before my last trip last spring to Mcbride , and it was doing the same thing intermittently, but had also put on a Barker exhaust and was thinking it was that leaning it out or something. Put their fuel programmer on it, but have not been able to really check it out yet,will have to check out the tether. I believe it is probably the MPI one .
 

yammyboy

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The problem was the relay its garbage go and get a Bosch relay and put it in. I was talking with bill Jacobson and he helped me solve this problem. They sell them at napa for under 10 bucks and then it works perfect
 

bjd68

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I just bought a brand new 2010 nytro mtx and got the dealer to put on a roll over valve so im sure its the mpi one, I hope it doesnt cause any issues, havent got to ride the sled yet still waiting for enough snow!
Does it just cause u not to get to full rpm?
 

yammyboy

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It bogs and such but with not getting full rpm you don't get full amount of power and that sucks its a really easy and cheap fix
 

Lowlife82

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So the mpi one is junk? Just wanna be clear.
 

yammyboy

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No it works good and does what it's susposed to do the relay they use is junk tho if your gonna order one I'd get the Jacobson one but if your just gonna get one from your dealer that's a MPI one just get a borsh relay with it from a auto parts store
 

Lowlife82

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No it works good and does what it's susposed to do the relay they use is junk tho if your gonna order one I'd get the Jacobson one but if your just gonna get one from your dealer that's a MPI one just get a borsh relay with it from a auto parts store


Thanks. Got one a while ago but not installed yet.
 

bjd68

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I just took the relay out of mine and its a 12 volt 40/60amp relay which no auto parts so far dont have, they only have 40/30amp relay will that be ok
 
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