Dear Rick;
I haven't had the time to call you yet so here's the problem.
On my wifes 2002 250 TB. We had you port the cylinder, mill the head, top end pipe, bore carb 31.5mm, lightened flywheel and orange clucth spring.
At first everything seemed ok but the wife complained that theres no second gear. Well we know theres no second gear. You know that I figured that the 190 main was to rich, after I rode it, sure enough the top end or WOT would not clear out. So I put the 165 main in. Boy were her eyes big when she got back, great. However?

Upon decelleration, throttle completly closed, at lower rpm, say around 2000rpm there this knock or pinging going on, the hotter it gets or longer it runs the worse it gets, to a point.
I've tried two sizes larger on the pilot jet but its clear that this is not a cure.
The only things let are,
Timings off,
Air leak at manifold to cylinder
or maybe the wrong spark plug. Accidently put a BR8EV in. Would that really cause it to knock/Ping?

Funning thing is though is that when the 190 main was in it there, there was no pinging. however it was only riden for 30 minutes or less until I put the 165 main in.

Thanks
Steve
Moreno Valley, California

 

Did you put a Wiesco piston in it?

 

I received your Email , I will try to phone you tommorrow . A bigger pilot should fix this , and we need to get it fixed ASAP , it will cause problems .

Talk to you tommorrow ~


Rick

 

Hope you don't call before 11:00 am pst. You'll get the answering machine. Thanks.

No used the stock one. With so little hours on it I just put new rings in it.
It won't matter what kind of piston is used. I'm not talking about piston SLAP, I'm talking pre-detonation here.

 

Thanks for the return call Rick.
We agreed to retard timing a couple of degrees to see if that will fix the problem.
I'll let ya know when I can.
I didn't think of it when he called but its possible that the timing is/was off from the factory.
My 1988 Honda Accord was like that for the first 80,000 miles. Bought it new.[img]i/expressions/face-icon-small-blush.gif[/img]

 

hey rick.....since you have all that aftermarket stuff done to your fourwheeler....make sure you have the oil injection turned up in there because it will be running at higher rpms with not enough oil.......that may help stop the knocking and all them noises you hear in there......that i what i did for one of my customers....

 

Doesn't the oil pump turn in relation to engine RPM? If not, why not?
Some day I'm going to use the block off but I have 5qts of injector oil to use up.

 

Polaris oil injector does not increase with rpm. It is controled by the throttle cable only. It needs to be adjusted every once and a while as the cable stretches. It can be adjusted to give more oil if needed. The cable splits in two, one cable goes to the carb and one to the oil injector. This way you get more oil with more throttle.

 

Hi Rick thought you might want to see these.
TB 250 O Ring
and
TB 251 O Ring
after changing the jets I decided to take the manifold off, I remember looking at the ring before I reinstalled the manifold but I didn't actully take the ring out of the manifold cause it looked smooth and ok. This time I removed it only to find the casting had a very rough edge about three/eights long at one of the four points that help to hold the ring in place.
So this should fix the pinging. $8.00 from Polaris and one week after its ordered, .58¢ from ACE hardware and installed today.

I tried to check the timing after everything was put back together but the pipe is in the way and I can't look through the sight hole. I have to move the pipe anyway cause its riding the frame, so I'll try the stock one to see if I can see the timing marks.
I couldn't ride it today but running in the garage it sounds good.[img]i/expressions/face-icon-small-smile.gif[/img]