Hard Starting, Fuel Problem

[mcdermott570]

2002 Yamaha Blaster, v force 2 reed valves, Bored out .80 thousands over, FmF Full exhaust, 32.5 pilot jet, 360 main jet, needle clip position 2nd groove. Did Float Adjustment, compression test came to 100psi, Fuel Level Check, New Rebuild Kit in Carb.

Bike is hard to start from a cold start, When it does run it seems to have a throttle problem from off to qtr or half throttle,



Does anybody have any suggestions?? Thank you

 

[Fast6hand]

Compression is low at 100psi. New top end is needed.

 

[Blaaster]

Firstly a #360 main jet is way too rich unless you are in Sub zero temps, well below sea level or running a pre mix ratio of 12:1.

Are you trying to mask a massive air leak, I recommend that you do a leak test.

Secondly 100 psi is the lower limit for a healthy engine.

Thirdly the needle should be in the middle slot.

Did you hold the throttle wide open and kick until the pressure stabilised when you tested the compression?

Is the idle adjusted to specs, it will affect up to 1/4 throttle if incorrectly set.

 

[Herpderplol]

low compression. might not be enough to make easy starting

Did you leak test?

 

[Herpderplol]

Stick with one thread please.

like blaaster said, main jet, compression and leak test should be first priority

 

[speedyslyder]

yup if your gauge is correct then 100 psi is on its limit..it should read at 120psi
What is airscrew set at? should be at 1 1/2 turns out or close
is oil injection delete or not?,airbox lid off or on.

 

[mcdermott570]

yup if your gauge is correct then 100 psi is on its limit..it should read at 120psi
What is airscrew set at? should be at 1 1/2 turns out or close
is oil injection delete or not?,airbox lid off or on.

the airbox is off and ya the air screw is 1 1/2 turns out, i think i found the problem i need new rings

 

[mcdermott570]

Firstly a #360 main jet is way too rich unless you are in Sub zero temps, well below sea level or running a pre mix ratio of 12:1.

Are you trying to mask a massive air leak, I recommend that you do a leak test.

Secondly 100 psi is the lower limit for a healthy engine.

Thirdly the needle should be in the middle slot.

Did you hold the throttle wide open and kick until the pressure stabilised when you tested the compression?

Is the idle adjusted to specs, it will affect up to 1/4 throttle if incorrectly set.

i think i found the problem i need new rings ill let you know from there

 

[mcdermott570]

Firstly a #360 main jet is way too rich unless you are in Sub zero temps, well below sea level or running a pre mix ratio of 12:1.

Are you trying to mask a massive air leak, I recommend that you do a leak test.

Secondly 100 psi is the lower limit for a healthy engine.

Thirdly the needle should be in the middle slot.

Did you hold the throttle wide open and kick until the pressure stabilised when you tested the compression?

Is the idle adjusted to specs, it will affect up to 1/4 throttle if incorrectly set.

i think i found the problem i need new rings, and i incorrectly posted it it is in the middle slot, and no i didnt hold the throttle wide open i just kicked

 

[Blaaster]

Compression tests should be performed with the throttle wide open to allow the maximum amount of air into the cylinder to be compressed.

One can still arrive at a satisfactory test with a closed throttle but it takes a lot of kicking to allow the pressure to stabilise.

If indeed the compression is only 100 psi, I fear that the bore will also be worn more than to specs and will need to be machined to the next size.

 

[mcdermott570]

Compression tests should be performed with the throttle wide open to allow the maximum amount of air into the cylinder to be compressed.

One can still arrive at a satisfactory test with a closed throttle but it takes a lot of kicking to allow the pressure to stabilise.

If indeed the compression is only 100 psi, I fear that the bore will also be worn more than to specs and will need to be machined to the next size.

thanks buddy i think i found the problem needs new rings

 

[mcdermott570]

thanks buddy i think i found the problem needs new rings

i dont think it can go any bigger can it its .80 thousanths over already

 

[Blaaster]

Verify the compression by doing it again with the throttle open, you may be surprise that it may increase.

If it starts with 100 psi, the problem with it faltering with throttle is possibly because of poor jetting not low compression.