bike boggs at 8000rpm

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D0n H
Posts: 5
Joined: Tue Sep 13, 2016 8:12 am
My Bike: 1992 Kawasaki ZXR400
Location: China

bike boggs at 8000rpm

Post by D0n H » Fri Nov 18, 2016 8:49 am

Hi Guys

Im running out of ideas what to have a look, at my bike keep bogging out after 10,000 RPM , well more like starving for fuel or air im not sure. So i have cleaned the carb , new fuel pump, new fuel filter as well as bought a K&N air filter for her (the old filter was beyond trash and hard to find in china)
Now she is starving at 8000rpm. The rpm will still climbs but its very slow and not picking up speed when like she should.

Im pleading for some advice. (do i need to reset my card to run with this new K&N filter?)

Thanks

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banner001
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Posts: 2496
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: bike boggs at 8000rpm

Post by banner001 » Fri Nov 18, 2016 9:57 am

try this simple test first, go for a ride and as the bike starts to bog down open the choke, if the bike now wants to keep pulling then you are starved of fuel (most likely explanation), if the bike does nothing or gets worse then you have too much fuel going through.

if your bike gets better you need bigger main jets (you will have seen them when you cleaned the carb), your jets will have a number stamped on them (i.e. 88, 90, 95 etc) you need to go a few sizes bigger so if your jets say 90 then try some 95 jets and see if that makes a difference. if your bike gets worse with choke then go for a smaller main jet, so go from a 95 down to a 92.5

when i fitted a k&n filter i needed to increase my main jet by 2 sizes (from a 95 to a 100).
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

User avatar
D0n H
Posts: 5
Joined: Tue Sep 13, 2016 8:12 am
My Bike: 1992 Kawasaki ZXR400
Location: China

Re: bike boggs at 8000rpm

Post by D0n H » Thu Dec 15, 2016 8:58 am

Hey bro Great advise i deff have to change the jets out tell now if i go to the 100 jet size will i need to reset my whole carb again of can i set it up tp the stands of the manual?

rccaulfield
Posts: 34
Joined: Tue Sep 25, 2012 12:26 am
My Bike: zxr 400l sp
Location: Ireland

Re: bike boggs at 8000rpm

Post by rccaulfield » Thu Dec 15, 2016 12:57 pm

Had the same issue. Changed up the jets ALOT until had no bogging. Didnt need to change needles or pilot jet settings but every bikes different!

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