86 250r what carb?

[william16339]

hey guys i have a 86 honda atc 250r that i have basically replaced everything on. i have v force 3 reeds, its fully rebuilt, fmf fatty and DG silencer. i have a 38 mm carb on it now. im currently getting a drag port done or topend port done by flowtek. should i run my 38 mm air striker? or should i consider a 39 mm? im looking for around mid to topend. what do you think would run best 38 or 39? would it even make a noticeable difference?

and yes i know the fatty pipe is a mid range pipe, but there are absolutely no pipes for 250rs other than the ESR pipes wich are outrageous in price... thanks - will

[3wheelrider]

IMO - just run the 38 PWK mainly cause you already have it. Not so sure its seat-of-the pants noticeable from one to the other anyway. Either way-you will be satisfied.

[rg97]

Yeah, 1 mm (0.5 on each side) wont give you a noticeable difference. Stick with the air stryker. Just tune it when the mods are done

[barnett468]

hi,

A 38 mm carb is good to at least 9.200 rpm on a 250, a 40 is good to at least 11,000. With your pipe, you are not likely to see over 9500 no matter how much it is ported. If it ever gets close to 10,000 it might hurl a rod if not sooner.

[82 250r]

there are absolutely no pipes for 250rs other than the ESR pipes wich are outrageous in price... thanks - will

Paul Turner High Rev (Available)
BDT has a 250r pipe (Available)
ESR has a 250r pipe (Available)
Bills pipes (ebay... if you can find one)
CT Racing (ebay... if you can find one)

All these pipes have good reputations.
All these pipes will be "outrageous in price"
This is the world we live in.

Marc

[RIDE-RED 250r]

Also look at NOS_350x for an in-frame drag pipe. He has a stellar reputation, and the next exhaust I buy will be one of his.

Not sure if Matt Shearer does ATC pipes, but he is another with a great reputation for 250r pipes.

But keep in mind, if you think the ESR pipe is expensive, those who build custom hand coned sectional pipes are nearly double in price to the ESR.

I run the ESR system on my 350 big bore with ESR's TRX9 porting. I am very pleased with the way it runs.

[william16339]

my air striker says PJ

[Xowner]

Ask flo tech what he wants you to run

[El Camexican]

my air striker says PJ

Without running out to the shop to look I'm going to speculate that you don't have an Air Striker if it says "PJ38" on the base and not "PWK". Is your choke and idle adjustment on the same knob? If so you have a PJ.

[william16339]

yes it is on the same knob. so its not a 38mm?

[El Camexican]

yes it is on the same knob. so its not a 38mm?

It can still be a 38mm (I have one) but as far as I know only the 35mm and 38mm PWK can also be Air Strikers

Go to these sites and get caught up on these carbs.

http://www.sudco.com/keihin.html
http://www.jetsrus.com/a_jets_by_car..._selection.htm

[BWard]

if your in NY, Check out Dyno-Port, Rich makes a nice pipe too

[barnett468]

yes it is on the same knob. so its not a 38mm?

The size of all stock motorcycle carbs can EASILY be determined, simply measure the id of the exit side of the carb bore/venturi.

If you do not have a metric caliper or ruler etc., simply measure it in inches, convert the inches into thousands [.250" = 1/4", .500 = 1/2" etc.], then divide the thousands by 25.4.

A 38 mm carb = 1.496" [.004" less than 1 1/2"].

This measuring method will not work on carbs with a tapered bore. You need to measure close to the slide with a special expandable tool and mic to get the proper bore/venturi size on one of those carbs.


Happy Holidays!

[C.J]

Ok so I was wrong an you're running a PJ38 like what I've got lol.

PJ is a Steller carb, kinda finicky to tune and pretty freakin susceptible to weather changes.

I'd stick with it