T-4 slip-on

[BARRY]

i recently just bought a k.n.filter+ jets+t4 slip on exhaust. i followed instruction word for word when jetting. my 400ex runs and pulls much better. iam running stock airbox with lid in place.i have not felt any misses or blips in throttle.ive pulled my plug and it is a dark brown black but not real sooty. i assume i am on the rich side. i am content with the performance and do not want to mess with any more jets if idont have to.will a rich mixture cause damage. also looking for any one who rides near medina ohio

hello, Running rich will not damange your motor however running a motor to lean will, can cause your motor to run hot, overheat and lock up. I would try to lean out your carb either by the main or pilot jets and check your results. Hope this helps.

[fat400]

i too have added the t-4 and a k&n filter and didn't have to re-jet it pulls hard on the bottom end and is great all the way too the top end. if it ain't broke don't fix it. :D

[oynot400]

Barry, to do a more accurate reading use a new plug and check it again. To me it sounds like it is pretty close, may be one size down on the main. ;)

[Texan32]

to answer your question...no, running rich will not hurt you motor. All it will do is run a little cooler and possibably foul out a plug after hours of riding. Checking the plug doesn't always tell the truth. Because of all the additives in gas, the jetting maybe perfect, but the plug could look a little questionable. Here's what i have been told by the dyno jet people. If its running righ, you will feel it hesitate or bog out. If its lean, while you are holding a constant RPM, the motor will rev up and down on its own.

So, if it pulls hard and doesn't bog down....i would say don't worry about it. If you do want to lean it out a little, you can always cut some holes in your air box (or take the lide off completely)

Just my experience/opinion