XR50 Jetting

[Woody_393]

What can anyone (Faded?) tell me about the XR50 carb? What brand etc, and are different jets available for it?

Mine's a running a bit on the lean side. I've got a hanging idle when it get warmed up (probably fixable with just a fuel screw adjustment, but I've not had time to mess with it yet).

Anyway, what has anyone else with a stock XR50 had to do to clean up the jetting? Just looking for tips etc.

[Redscooter]

Woody-

You can try playing with the air screw 1/2 to 1 1/2 turns out but as far as jetting, I have talked to a few of the big fiddy companies and they all recomend not rejetting it because of not only the chances of hurting the motor but also, the bike only produces about 2.5 HP. (But I think adjusting the air screw will help to clean it up a little) I have ridden a stock 50 and one with only a BBR pipe- with comes with a jet and there is a small noticeable difference.

Hope that helps

[mxrider]

Why does everyone say a xr50 has 2.5HP??? on the certificate they give you when you buy it, it says it has 3hp........IDK where everyone gets 2.5..lol

[nappers]

Woody, it has been told to me that all the XR50s start out running lean and will run much better if you lower the clip one notch. This is where I found this info a long time ago:



[Only registered and activated users can see links. ]

[Faded]

What can anyone tell me about the XR50 carb? What brand etc, and are different jets available for it?

Keihin 13mm round slide. Pilot and main jets are available at your dealer's parts department.

Mine's a running a bit on the lean side. I've got a hanging idle when it get warmed up (probably fixable with just a fuel screw adjustment, but I've not had time to mess with it yet).

FYI, the carb is 2-stroke style and has an air screw, not a fuel screw. It also has 5 positions on the needle. Mine was lean on the bottom with the stock pilot in all but 90*+ degrees, I ended up going up one size and playing with the air screw to adjust for the weather. There is an off-idle bog that occurs when there is an abrupt transision from nothing to WOT that is really hard to get rid of. Just keep playing with it though because you can get rid of 99.9% of it.

I (think! hard to remember) that I ran the needle in the 4th clip and one size smaller main in hot weather (80*+) and the stock main when it was less than 80*. Of course I was also running a UNI pod filter after the third day I had it. I would get one again too, it definately helped and was only $13-15.

What I do remember is buzzing down the road at almost 40mph (38.9 verified by GPS and the car next to me) with me on it. I miss that little bike.

[Woody_393]

thanks for the link nappers.

I've got a service manual on order, so hopefully I'll get it next week or late this week.

THANK YOU Faded for that info about the carb. I had what I thought was the fuel screw turned all the way out to 2.5 out. Now that I know that's an "AIR" screw, I'll go adjust without wondering what the crap??? I should have known though, just because of the location.

I'll go drop the clip one notch and see how it goes.

I think for sure I will get an Uni or K&N shortly, because that stock unit SUCKS to change. Let along the restriction, it's just a pain to work with.

Thanks again.

[Faded]

Just be sure to pay attention when installing your clamp-on filter of choice, it's all to easy to overtighten the clamp and make the filter want to slip off of the carb bell.

Oh yea, have fun with it!

[Woody_393]

Thanks man! I have to keep reminding myself, it's not yours...

Actually, I really haven't ridden it at all. It's their bike, not mine. Besides, I'm a pretty big guy...

[nappers]

Funny Woody, Faded helped me with the "Fuel Screw" issue. I was turning it the wrong way as well when I first started adjusting for a bottom end bog

That Faded, you just gotta love him :

[Woody_393]

Yeah that faded is one smart cookie.

[Woody_393]

Originally posted by Faded
FYI, the carb is 2-stroke style and has an air screw, not a fuel screw. It also has 5 positions on the needle. Mine was lean on the bottom with the stock pilot in all but 90*+ degrees, I ended up going up one size and playing with the air screw to adjust for the weather. There is an off-idle bog that occurs when there is an abrupt transision from nothing to WOT that is really hard to get rid of. Just keep playing with it though because you can get rid of 99.9% of it.

I (think! hard to remember) that I ran the needle in the 4th clip and one size smaller main in hot weather (80*+) and the stock main when it was less than 80*. Of course I was also running a UNI pod filter after the third day I had it. I would get one again too, it definately helped and was only $13-15.
[/B]

I've got the bog you mentioned. I've got my air screw at 1.25 turns out. Is the bog Lean related or a rich bog. it's not to bad, unless my boys snap the throttle open really quickly.

Seems like the less air I give it, the less the bog, so I'm guessing it's lean.

I also guess, that I shouldn't do anything with it until I get the new K&N installed.

I pulled the plug on teh bike and it was really sooty, which tells me I'm pretty rich for the most part, but it would seem that the bike is somewhat all over the place on the jetting side.

I'll go pick up 1 smaller pilot, and be prepared to do some dialing.

If I take the carb off, do I need replace the gasket? or can I use it again?

[Faded]

On mine the bog was from being lean, air screw ended up being right at 1 turn out most of the time.

I reused the gasket, but sprayed it with the areosol copper gasket sealant.

[Woody_393]

Thanks again Faded. I really appreciate your help with this.