Jay Carnes

what the best bang for your buck in performance for the xr50? ive got a 2003 and want some more power - but dont want to go as nuts as a 88cc big bore, carb & such. Exhaust's add much power? CDI boxes? Lemme know!!

Thinking of doing a fast 50 exhaust, then some day down the road doing a big bore kit. Just can't see taking a brand new engine apart when it only has like 4 hours on it.

birddogg

Trash the stock airbox for a clamp-on filter, UNI UP-4112. Like $15. Raise the needle in the carb to the bottom slot. Take the endcap off the exhaust, cut out the spark arrestor off, and bolt it back on. I did't tell you to do that. Play with the air screw till it feels right and you're done. You will smoke a stocker for less than $20.:p

jaxon23

is the air screw by the idle adjustment screw? which way of turning does it work? lefty less air righty more air?

metal doc

I raised the needle 1 notch . How far d are you guys raising yours ? its so cold here in ohio I cant tell if its running crappy cause the temp or if its the jettin'

later , mike

birddogg

Think the airscrew is the lower of the 2. Definately the smaller of the 2. I just turn it right till it seats, then back it out about 1 to 1-1/4 turns that should get you close to where you wanna be. For the needle I've had better results on the bottom slot, but I do have a different exhaust on mine. I run a 61 mainjet also.

Jay Carnes

damn, now thats what im talkin' bout, thanks bro. sounds like you know your ****!! Im about sea level - so is that needle possition gonna work right for me? Also - when changing the air mixture screw - just do it by ear. ie.... have it idling & when it cleans up the screw is right, also ride it and make sure the power is smooth through the band. Should i change my main jet also? this 50 will NEVER see the dirt so that uni filter is a must. Im gonna look @ the exhaust & hack that **** off. How much of a power increase will I see out of this, noticeable? Or should I do the needle air fliter & buy an exhaust - or is hacking the spark arrester off basically doing the same thing as an aftermarket pipe.

thanks for all the info

birddogg

My bros ran the D&D, FMF, and Pro-Circuit pipes up against my modified stocker and I jest stomp them on a Moto-X track or in the woods. Unless you go with a big-bore kit I really wouldnt worry about getting one right away. I'm always in the woods or on the track with a clamp-on filter, I would'nt cross too many creeks but you'll be fine in the dirt. Don't touch the mainjet, I didn't change mine till built my exhaust and hogged out the intake. Carb is real easy to get tuned, The only adjustments ya got are idle, air/fuel, and needle position. Just go by what I told ya, should put you in the ballpark. Then just play around with it till it's right. Have fun & let me know how it goes. birddogg

HiZ

Thanks pimp idea

I'm going to do it in a little bit cause just got it and wanna break it in for sure great things to come.

Jay Carnes

BIRDDOGG:
Ive got the airbox off for the uni filter now, cut the spark arrester off & droped the needle down to the lowest notch. It brakes up alittle bit when you hold it at a steady throttle. revs fine & idles fine. It got alot better when i put the end cap back on the exhaust (minus the spark arrester)

I tried a few diff needle possitions, but still does it. I even tried it all the way @ the highest notch but it would hardly run. There are 3 screws on the side of the carb. A top philips screw which is the idle screw, a smaller "flat head" screw right below that one which i believe is the air / fuel mixture screw & one @ the very bottom of the carb bowl. I've got my air screw @ about 1 1/4 out - i tried ******* with it some w/ out any success. any idea?

also - when connecting the carb to the intake - there is a little black spacer with a rubber ring gasket on one side. The ring gasket is supposed to touch the intake right? cause there is another ring gasket on the carb to seal the other side.... im just trying to rule out any vacume leaks or anything. There was also what seems to be a crank case vent that connected into the air box before that is now open.

all and all i deff. feel more power - no work @ all to yank it up just throttle. sounds pretty cool too.

50madness

Have you taken a plug reading to see what it looks like? If you are suspecting a vacuum leak, it should show a lean condition on the plug.

Jay Carnes

i'll try that when i get home, good idea. see if its white or covered in black. I played with it alittle more - i got most of the chop & braking up out of it. got my mixture screw like 1 3/4 out. end cap back on the exhaust. power is addicting, now i want a big bore kit!!

Brett256

Don't forget about checking your valve clearance to possibly free up some horsepower. I found after riding my 03 fiddy for about 3 mths that the valve clearance was WAY to tight. I thought it should of been a little loose with all the hard miles I put on it........... I figure it must have been set too tight from the factory. With the gap set to specs now it pulls alot harder in the upper rpm's. I could honestly tell a difference. Takes about 15 min to check/adjust 'em.

Jay Carnes

i'll let mine break in and check the clearance. It looks mad easy to do, just drop the valve cover off & stick a feeler gauge in.

FIDDY NUTS ! but dont' forget the smile.

birddogg

Glad to hear ya got it worked out bro. You do have your intake right but if you still suspect a vaccum leak spray some starting fluid at the connections. Jump in idle will tell ya right away. About that crankcase breather, I just pulled that long pink/clear? hose off the airbox and replaced it with that. You can route it right up the backbone of tha frame. Keep that endcap on, runs and looks like **** without it. Sounds like you have it about right. Might have to mess with it again if the weather ever breaks. Not bad for $15.00 total??

Jay Carnes

yeah, i think the 1st time i had it on i had a vacume leak, its tight as can be now. Filter only cost me like 10.50 w/ my discount - talk about a good mod!! I can beat a stock 50 by quite a few bike lenths.

about the crank vent - vacume leak thing. plug that thing up? There was the one drain that came off the stock airbox - thats in the garbage. There was also another short tube, that went into another thing ( like my termanology?). If i put a finger on it I can feel vacume - i dont know if that is indeed the crank vent? and if so should i plug that, or just.........

sorry if my questions are that of an idiot.

birddogg

You're right about that being crankcase breather. If you already threw that other **** away just pick up some fuel line the next time you're at the shop. I just route it up along the backbone of tha frame to keep it up out of the dirt and ****. Keep it open!!!

Jay Carnes

uv been mad help man. apprecaite it all!!!

taubr unit

HOLY CRAP!!!!!!! We did some mods to mine tonight. Modified the air box, bigger jet(2 sizes up), moved the needle up 1 notch, and 2 full turns out on the air/fuel screw from bottom. WAY faster, just keep in mind.......more fuel+more air=POWER!!!!!!!!!!

work765

not sounding like an idiot..... but how the hell do you adjust the carb needle?? Where the hell is it?

taubr unit

its on your slide where the throttle cable hooks to. There are 5 little slits on it. Stock is the second one down from the top, so move it 3 down from the top, that will allow more fuel to flow through, CHEAP "jet" kit....