07 250f hard to start with new Yoshi full system exhaust

I just put on a new Yoshimura full system stainless exhaust on my 07 YZ250f and the bike now takes 8-10 kicks to start when cold whereas it would start on 1-2 kicks with the stock system.

Jetting changes only include a 50 leak. This was done last year so the stock pipe has been working great with this. Otherwise I think it is stock (too many bikes in the barn...can't remember what changes I made to which bike :worthy:)

Once the bike is warm, it seems to start up ok. I have only ridden around the block (neighbors love me) but it felt good with no popping. Also idles very smooth.

The one abnormal thing I can think of is the installation instuctions called for reusing the "stock exhaust port gasket" and I did not see any gasket.

Any ideas?

I have the same bike with the same exhaust. Keep the jetting stock, but you need to adjust the fuel screw. It's set at 1 7/8 out, you need to change it to 1 1/2 out. I had the same problem with starting it until I moved the fuel screw out. Now it starts like it once did and runs fast and smooth.

I have the same bike with the same exhaust. Keep the jetting stock, but you need to adjust the fuel screw. It's set at 1 7/8 out, you need to change it to 1 1/2 out. I had the same problem with starting it until I moved the fuel screw out. Now it starts like it once did and runs fast and smooth.

I think I am sitting a 2 turns out so I will adjust to 1 1/2. Thanks for the input!

BTW, you happy with the exhaust? I got a good deal ($295 out the door) so I figured it was worth a shot.

I think I am sitting a 2 turns out so I will adjust to 1 1/2. Thanks for the input!

Turns out I was closer to 2 1/2 turns out. Adjusted it to 1 1/2 and it fires right up.

Thanks again for the help!

Mark

That's a great deal for that pipe, and yes I am very happy with it. The exhaust made a huge difference in the performance, couldn't be happer.

I'm glad it all worked out for you.

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