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View Full Version : About to get a 39mm FCR



luvmyex
06-26-2003, 01:23 PM
Well im getting the carb but really know little about it.Just know its a good one.LOL BMW500hp is gonna try to jet it for me somewhat close.Can anyone give me ideas or know about where to start with the jetting?Anything i need to know about it?I want it to be right to get the full effect of it.Mods are below. Not sure of the elevation here.I think somewhere around 1500-1800'

ex kid
06-26-2003, 01:50 PM
i'm guessing you have a pipe, so with the larger flow carb your proably going to want to go a few sizes up in the main jet and crank the air/fuel screw out another turn and screw with the idle. that might be a good start.

JD400exrider
06-26-2003, 01:50 PM
Well i do not have one. Actually i am on the fence on the stock carb mod or the FCR, however i am close to falling off. :D Waiting on pappys seat test :cool:

What i have learned is that the 165 main seems to work in most applications. 42 pilot. At least that is what i think sparks jets his for most applications. The one i was looking to buy was running a 165 main and a 52 pilot. I would start with a 165 main 42 pilot. Also order up one of those fuel screws from C&D for fine tuning. Good luck Lets us know what kind of power difference you see with it and what it does for low end. It should rip on the mid to top. I have about the same mods you have and i am VERY interested.

mikeboone
06-26-2003, 02:02 PM
I run a 165 main and 52 pilot--the pilot is rich--i think a 48 or 50 would work great as I have the screw only 1/2 turn out. Good power gains with the 39mm!

Bad Habit
06-26-2003, 03:28 PM
I put my FCR on about 3 months after my other motor mods and I was extremely pleased with the results. I didn't really notice any gain down low but, like JD said, it rips from mid to top. And overall just gives better trottle response. I gained an honesty 2 bike lengths over 300' of sand.
I don't have any idea of the jetting size. When I asked the guy at Sparks about the jetting, he said don't worry about it. The jet numbers don't correlate with the jet numbers for a stock carb. Maybe I sounded like an idiot on the phone and he didn't want me jacking with the carb after I got it. I told him what mods my motor had and he said we'll get it set up for you. That was a year ago and I have never had to adjust anything. Although it does run a little on the lean (and hot) side. I've wondered if I should experiment a little with the jetting, I can't stand the thought of just putting something on the bike without getting a headache thinking how to adjust it correctly. :p

RytM1
06-27-2003, 02:18 AM
I'm currently running a 170 mj, and 55 pj. I have only used it 3 times, and this last time, it was idling like crap, so I think I'm gonna go down one or two on the pilot. I think I am still running a little rich overall, so I may also try going down another step or two on the main. Depending on where your buddy is getting the carb from, give them your mods, and they may set them up for you, or at least get you in the ballpark. Talk to Colby at C&D, he was helpful in getting mine dialed in a little better than it was, due to having bought it used.

kgbg
06-27-2003, 11:45 AM
I would guess you need a 160-162 main, middle to 1 spot rich on needle, 48 pilot.
I got one from Sparks and it was jetted SUPER LEAN. Burnt my head gaslet up in 10 mins. I was told not to worry about it either. WORRY ABOUT IT, IT COST ME $$$$$$$
He sent it to me with a 155 main, lean position on acc pump, 42 pilot, and 2 lean fron center on needle. I am now running a 168 main, 45 pilot, 3 slots richer on needle. I am at 5000ft.

Chef
06-27-2003, 12:06 PM
Originally posted by kgbg
I would guess you need a 160-162 main, middle to 1 spot rich on needle, 48 pilot.
I got one from Sparks and it was jetted SUPER LEAN. Burnt my head gaslet up in 10 mins. I was told not to worry about it either. WORRY ABOUT IT, IT COST ME $$$$$$$
He sent it to me with a 155 main, lean position on acc pump, 42 pilot, and 2 lean fron center on needle. I am now running a 168 main, 45 pilot, 3 slots richer on needle. I am at 5000ft.

How do you change the accel. pump setting? I am running a 205 Main, 52 Pilot, and the needle in the middle on my FCR41 on my EX. Seems to run fine, but thats also in like 85 degree weather. Prolly have to richen it up tomorrow night...which sucks, because that thing is too big for the airboot as it is. If it comes out, I'm screwed. lol

When I switched from my FCR39 to my 41, The 39 had a 200 Main in it, I went up to a 205, and put the pilot from the 39 into my 41. Just try it out, its not that hard to change should you have to change it.

luvmyex
06-28-2003, 01:20 PM
Originally posted by mikeboone
I run a 165 main and 52 pilot--the pilot is rich--i think a 48 or 50 would work great as I have the screw only 1/2 turn out. Good power gains with the 39mm!

Mike. your close to me so that will probanly close to where i need to be at.I cant wait to get it this week.I cant get mine to idle for some reason.only if i run the idle i little high will it run.My buddy just put his banshee back togeather and is talking crap.I think im close now.Havent raced yet maybe tommrow.I just got my cam back in today.So i dont know if i want to run wtf open yet or not.But when the new carb goes on look out! i think i may have a banshee killer!

kgbg
07-01-2003, 05:05 AM
The wheel on the accel pump has two different setnings . You relocate the arm to the higher one for a richer setting. You can also "bend" the accel. pump arm to richen it up more. A little is a lot. be careful.

bmw500hp
07-01-2003, 05:21 AM
Rick, received payment for the fcr thnx...plan on shipping Wednesday, be in touch...:)

luvmyex
07-01-2003, 11:04 AM
Thanks Mike,Looking foward to hooking that bad boy up.

mbiigambler
07-01-2003, 04:00 PM
I'd look into the fuel screw from Colby at C&D, plus then you get to talk with him and he is really helpful. I run 165, 50 pilot, and I think 3rd notch on the clip. There is another air screw adjustment which Colby had me set at 2 turns out, (its the screw behind the intake port). Not sure how many turns out on the fuel screw as I just kept adjusting the fuel screw until it seemed right. I basically have the same mods as Rytm1, with air box lid on with 6 one inch holes.