Still Running Lean?

[Dpenta13]

hello, this is the first blaster I have done any work on,

I believe it is a 96, has the stock head pipe with an FMF slip on.
I bought the motor used and it was said to have stock porting which it looked like it did, and I believe a +2 stroke, it has a spacer under cylinder.
I have a twin air foam filter with the air box lid on. TORS removed.
I ride pretty close to sea level, looked at a map and it said 85ft above.
Has a Mikuni Carb, I believe it's a 26mm.

the problem i am having is it seems like it is still running lean.
it had a 230 main jet in it so I ordered a 240 and a 250 main.
I put the 250 in last night and it still seems to be running a little lean.
Mixing screw is about 1.5 turns out maybe a bit more. Ran it with a used plug for a couple min and the coloring on the plug looks ok but looked very dry. Witha new plug after running for a few min it still looked like a new plug, no coloring.

when u rev the motor up it seems to take a few seconds to return to a normal idle, the RPMs will drop at what seems to be a slower rate than normal.

Bigger jets? air leak?
Any suggestions what to check.

Thank u

 

[sam0840]

I can't really say for certain but sure could be some kind of leak. Do you have a leak down tester? thats were I would start first. while you r doing your test and have the carb off the motor i would make sure to take the carb apart and clean it real good and blow out all the passages. If you need a tester a member on here Awk08 makes and sells them. I bought one from him and it works real nice. I think it was 32 shipped. all you need is a bike pump.
I've never messed with the TORS on mine so I am not an expert in adjusting things with the TORS removed but that could whats causing the slow return to idle. I am sure someone else will chime in on this. but just for overall security i'd leak test the whole motor and go from there.

 

[Dpenta13]

Ok i will take a look a look at a leak tester.
thank you for the info.
I have cleaned the carb out twice when i was changing the jets. but one more would never hurt.

thank you

 

[Dpenta13]

i will see if a frien of mine has the leak down tester

is there a certain psi i should be testing at or the motor should hold?

 

[Blaaster]

7 psi, no more!