New Carb Questions-38mm

[hawk77]

Couple quick questions for any carb experts. I have an 87 250r with FMF SST pipe and silencer, K&N Airlfilter with no lid, a Boyesen Rad Valve and just picked up a 38mm Keihin PWK(not the A/S). My question is, it came with a 165 main, the slide in the carb has a "7" on it, and the needle has N28R on it and its clipped in the middle groove. I know a little about the jetting, but have no clue if the needle is going to work and what the number on the slide means.Do I need a bigger main jet, or should I try it with what I have? Any help is appreciated. I am in Texas and its hot as hell here, if that helps. I just do not want to mess this motor up...

[zedicus00]

the only thing going rich will hurt is the plug. so when in doubt start out RICH. maybe start witha 180 or something and work down.

the number on the slide is for the slide cut. they say 6 is optimal on 250R's but iv ran lots ranging from 4s up to like 9's. there isnt a huge difference so u should be o.k.

the needle, im gunna guess its silver in color? thouse things are a pain to deal with. get online sumwhere and grab a standard numbered brass colored needle. its been too long sincwe i been in the carb i dont remember the optimal one, sumone else can chime in with its number.

also set the low speed jetting and stuff before you start trying to dial in the highspeed jet.

[bushwesl]

optimal needle = CEJ

Also, check out this website for addressing jetting questions:
http://www.duncanracing.com/techfaq/Tech_keihin-carburetion-jetting.phtml

[hawk77]

thanks for the assistance. I just checked the pilot jet and its a 58. I am not going to worry about the slide, but is the needle going to make a huge difference? I know I am going to have to order parts for it, but can I get a ride out of it this weekend, or will it not run right?

[zedicus00]

try it. the worst that can happen is an engine seize.

actually you can prolly get it close enough with the main jet and needle clip to make it runable for a while but for the sake of sane tuning get a standard needle in there at some point.

[hawk77]

thanks....I just stopped by the shop and picked up a 180, 175, and 172 main jet and a 60 pilot jet. No where carries the needles, so I will make do with this for this weekend, and order a new needle.

[kiesta00]

What kind of cylinder do you have? is it ported? I have a 38mm a/s on a drag ported stock cylinder, and my 55 pilot is too fat and I have a 170 main. I'd try a 52 pilot and stick with that 165 main and see what your plug reads with that.

[hawk77]

Well, I put in the 175 main jet and have a 58 pilot to start. I don't think this will hurt anything, probably be too rich if anything...I can swing by and get another pilot in the morning. Any suggestions? I am on the stock cylinder, bored .030 over with a Weisco piston. I am new to jetting, so any suggestions/comments are appreciated.