250R runs great but should run like crap!! Inside Please!!

[RUNMYTA]

I know this sounds stupid but tell me what you think!! :eek2: This weekend I found that I had the stator side crank seal leaking. I had the seal replaced and the bearing was tight and in excellent shape!! Case is less than 6 months old. What would cause this?

OK, here is what doesn't make sence??::confused:
After changing the "stock cylinder" with a LRD 300 kit I only had to go up 1 size on the main (per ESR). Well I wasn't totally happy with the plug color so I decided to go 1 more size (36mm TMX with 390 main). At first it still popped and missed at high RPM even though the plug looked good!! *** The kicker::: I run the air screw out from 3/4 out to 2 1/2 turns out and she runs like a raped ape again!! No misses or pops, idles fine and is smooth all across the power band. If I am right and I am positive that I am. BY turning the air screw out I leaned out the air/fuel across the entire power band... Shouldn't this have made it run worse?? I even put the air lid on and it would not run at all (popped and missed from idle up) SO I took the lid back off ran it and did another plug chop and the Plug still looks good but this just doesn't make sence:ermm: Do you think I am just covering up another problem somewhere or am I just over reacting?? Later,MIKE

[wilkin250r]

If it runs good, and it's not overheating, then I believe the "If it ain't broke" cliche applies here...

[mx400]

general rule of thumb is always start at 2-2 1/2 turns on the mixture screw and then go from there. if thats were it runs the best then go with it, not what some company said.

on your crank seal problem, did u replace it yourself or did u have it done. if your doing it yourself would reccomend that you coat the inside of the seal with engine assembly lube to make sure that when u put the seal in its not being pinched anywhere. its kinda of like 2-piece rear mains on a chevy small block. then can be reall buggers.

[hondafox440]

That makes sense to me. The pilot cicuit really affects the entire rev range. If you are 2.5 turns out on the air screw, drop the pilot a size and test it. The other thing that may be affecting it is the needle. Once you have the pilot correct, ride the bike between 1/4 and 3/4 throttle. If it bogs at all when cracking it in this range, drop the needle one clip (or get a leaner needle and keep the clip at the same postion for the effect of dropping half a position), and vice versa if it surges on you and just sounds lean. You can't really jet a 2 stroke by a guide (or 4 stroke for that matter). Its really just trial and error.

[RUNMYTA]

So would being to rich cause the bike to miss and stutter in the upper RPMS?? The kicker is that it really never showed signs of being rich!!MIKE

[powerslider]

Originally posted by RUNMYTA
So would being to rich cause the bike to miss and stutter in the upper RPMS?? The kicker is that it really never showed signs of being rich!!MIKE

YES, back off the main until it clears up, the air screw works between 1 and 3 turns out, if it needs to be out of this range you need a pilot change. Your airbox lid told you which way to go, just pay attention......

[AndrewRRR]

Were the plug checks done after running the bike for a while and doing a 5th or 6th gear plug chop? Also was this tuning done with the crank seal leaking?
2 1/2 turns out is the normal starting point for the air bleed screw on most carbs.

[RUNMYTA]

The plug chops where done mostly in 4th and 5th gear. I would run it for a few minutes then come back change out the plug and take off! The crank seal was replaced before I started to rejet. What would be considered to far out on the air screw?

[powerslider]

If you need to be more than 3 turns out go to the next smaller pilot jet...