1/4 to 1/2 throttle surging

M

mormud

Free Member

Feb 6, 2010

168

5

18

Munising, Mi.

• Jan 28, 2017

• #1

2009 assault, motor ran good it was having a little stumble around 5 to 6000 rpm and would only hit 7900 wot. i read a post that some of the exhaust valve gaskets had too big of a center hole and were blowing out, so i checked my and they were blown out.i cleaned them and the small hole going into cylinder was plugged. cleaned everything and put gasket from a 2015 in it. now it will bog right out at half throttle and if you hold it there it will surge up and down. runs fine full throttle and idles good. does hit 8200 now.is there a reason this gasket wont work?

 

XCaSSAULT

Well-known member

Lifetime Membership

Dec 9, 2016

246

83

28

• Jan 28, 2017

• #2

Do the holes line up the same? What exactly is different between a 2015 and a 08-10? If it's a gasket from a 2015 axys 800 then it won't work cause the axys 800 uses electronic control exhaust valves not combustion pressure to control the valves.

I'd start by using same gasket that was there before, making sure your valves are good and clean and check your bladders and springs

 

M

mormud

Free Member

Feb 6, 2010

168

5

18

Munising, Mi.

• Jan 28, 2017

• #3

the four small holes looked the same. didnt see any other difference, just the center hole is smaller

 

M

mormud

Free Member

Feb 6, 2010

168

5

18

Munising, Mi.

• Feb 3, 2017

• #4

Been working on it, still can't figure it out. Here's what I have done. Put new springs in exhaust valves, checked TPS with the PCV, that was real smooth and close on voltage. Changed primary spring. Disconnected the pcv.

 

C

Caleb Young

Free Member

Nov 20, 2017

3

1

3

ALASKA

• Nov 21, 2017

• #5

Did you figure the problem out, or a solution??? I am having the same problem with mine and have been trying to figure it out.

 

M

mormud

Free Member

Feb 6, 2010

168

5

18

Munising, Mi.

• Nov 25, 2017

• #6

Sorry haven't replied on this. The motor blew up and destroyed the Piston, crankcase and cylinder. After rebuild I have been having troubles with injector wiring and running lean. Waiting for snow to do some testing.