Jump to content
Sign in to follow this  

XR 250 R Carb issues

Recommended Posts

So my total rebuilt 250 is great. starts right up, runs and rides great. that is until I get into the woods and start bouncing around. When I get into the woods and start banging around on the rocks. my bike start to bogg and wants to stall. to make it stop. I have to half choke it for a few seconds and then turn it off. So I have to make ir rick. Hmmmm. My thought is that I need to adjust the float level. any thoughts

Share this post


Link to post
Share on other sites

That was my first thought.

Set the floats minimum drop to the manuals spec., then set the max drop only 5mm more than that. Max drop is usually set way too much from the factory. That big range between min and max drop allows the float to flop around between float stops on rough terrain.

The theory is, when you encounter a big enough bump that would cause the float to be forced down, it momentarily displaces fuel in the bowl. The jet orifices are so small that a sudden displacement of fuel by the float causes raw fuel to be shot up thru the jets into the carb throat, causing the engine to stumble.

Share this post


Link to post
Share on other sites

Ok can someone walk me through this. It is my first time messing with the float. Can this be adjusted with out pulling it apart

Share this post


Link to post
Share on other sites

Ideally, the carb should come off, but if you want to try to do it with the carb on the bike, the float bowl has to come off, minimum.

I'm guessing this is your '86 XR270 we're talking about? Download this free shop manual to show you how to do it.

https://docs.google.com/leaf?id=0B7-qz8FhJsvFYmYyZGQ2NWMtMTI5Zi00YTQ1LTgxNGMtMWY2ZmVhZTY3MjBj&hl=en

I made this simple tool out of a piece of tin metal, scribed with lines for my min and max float levels.

FloatGauge.jpg

  • Like 1

Share this post


Link to post
Share on other sites

Hey Bro!

Yes it is the 86. The 91 is tore down to the frame. hahaha. theat has a pumper carb if I am not mistaken. Thank you very much. I already have the carb off and will work on it tomorrow while I wait all day for the cable guy to show up.

Ideally, the carb should come off, but if you want to try to do it with the carb on the bike, the float bowl has to come off, minimum.

I'm guessing this is your '86 XR270 we're talking about? Download this free shop manual to show you how to do it.

https://docs.google.com/leaf?id=0B7-qz8FhJsvFYmYyZGQ2NWMtMTI5Zi00YTQ1LTgxNGMtMWY2ZmVhZTY3MjBj&hl=en

I made this simple tool out of a piece of tin metal, scribed with lines for my min and max float levels.

FloatGauge.jpg

Share this post


Link to post
Share on other sites

Page 4-7 shows you where everything is at. Page 4-11 and 4-12 show setting the float level with a gauge. It's spec is 12.5mm. I would set max drop to 17.5mm. Set the gauge or your scale on the bowl rim inline with the main jet.

Share this post


Link to post
Share on other sites

Ok my lazy ass just took my carb off. now lets see If I can get this done today....

Share this post


Link to post
Share on other sites

Ok, I took the carb off this morning. Lets see If I can actually get this done sometime this year! haha

Share this post


Link to post
Share on other sites

Ok so I took the bowl off and this is where the float sits at 12.5mm

100_4113.jpg

Then I made a litle tool to gauge the float

100_4116.jpg

I then followed the directions that were in the book. Actually I have the book that came with the bike and the Cymers book as well. Buth give different directions.

100_4119.jpg

I put the carb at a 45 angle facing down and allowed the float to rest in the down postition getting the reading you see above.

I then carefully bent the bracket till the float reached 17.5mm

100_4117.jpg

I have to tell you. This does not look right to me. If the float is pushed down, wouuldnt that leave less fuel in the bowl. At 17.5mm it is quite low to the bottom of the main jet.

12.5mm

100_4115.jpg

17.5mm

100_4125.jpg

What do you think.

Share this post


Link to post
Share on other sites

I also noticed that I am missing that plastic dome on the bottom of my jet. could that be an issue as well. I do not have one on my XRL250 either

Share this post


Link to post
Share on other sites

No, that doesn't look right. Let me do a little photo doctoring.

This picture has nothing to do with the 12.5mm min. drop because of the way you're holding the carb. This picture shows max drop.

http://i39.photobucket.com/albums/e158/Rangerfng/XR%20250%20Carb%20mod/100_4113.jpg

These are the tangs you bend for each setting.

FLOATSETTING.jpg

Edited by Trailryder42

Share this post


Link to post
Share on other sites

You're measuring it wrong. Look at page 4-12 in the manual. Note that the carb is not held vertical; you tip the carb on it's side and lean it until the float tang just touches the float valve (the little tiny nipple part). Then you measure from the carb body machined face to the BOTTOM of the float (lowest point, but it should be fairly level, taking into consideration it's tipped on its side). :thumbsup::ride:

XR250Rcarbfloats.jpg

Please don't use the Haynes or Clymers manuals or any other besides the official Honda Service Manual; Honda designed and built the bike, after all.

One last note - the amount of gunk on the inside of the carb and on the jets is not acceptable. Remove the jets and replace them with new jets. Clean the inside of the carb until you can see bare shiny metal; don't use a wire brush, but consider using a plastic brush and carb cleaner fluid. Clean all other parts inside the float bowl; overflow tube, baffle plate, float valve, float pin, float. Do not open the air cut valve, the small chamber on the side of the carb body. Parts inside are costly and are generally ok if you don't open the chamber.

Edited by ramz

Share this post


Link to post
Share on other sites

Ok Brother! Thank you so very much for the advice! I followed the directions from the wrong book. I, this time followed the Honda manual. I had the minimum drop set at 17.5 and the max drop at god knows what. Following the correct directions I have the correct reading of 12.5/17.5

100_4128.jpg

100_4127.jpg

100_4133.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By 661Bran28den661
      What’s up guys. Totally new here picked up an XR400R I live in the desert so I’m riding often and enjoy it. But I am having some issues with my  01 XR400R. I brought it out this morning for a putt and it seems to be choking up in the top of second. Like a bog an go bog an go. First seemed fine and third I didn’t make it high enough into the rpms to see. Before I brought it back to the garage. Yesterday I also changed the air filter back to an uni. I had seen the other one had a hole in it and the box was dirty gunned up and oily. I removed the airbox gave it a good clean out wiped everything down very well put a piece of screen over the snorkel Or where it used to be I should say. “Lightly oiled the filter.Also the spark arrester an tip for the bike it did not come with I ended up making one with a piece of flat steel and drilling holes. Whilst doing this. I found also a crack in the pipe. It almost sounds as like there’s a vacuuming or whistle? When revving.The first one I had made worked fine I had no issues. This one I am wondering maybe if it’s a cause of a little too much back pressure.So I’m assuming it’s either a Carb or exhaust problem. Or something that could totally be minuscule. Or major issue. Would definitely like some second opinions and any advice would be greatly appreciated. Thanks guys! 
      TWISTIN THROTTLES & CRACKN BOTTLES


    • By ddickinson
      My lanky 14 year old boy started showing an interest in riding MX/Off-Road so I sourced the best beginner friendly, yet dirt worthy, bike I could find: an Ol' Honda XR250R (2004). So far I've replaced a few clutch levers and perches with stock parts. That's gotten old and I'm looking to upgrade to an ASV or Torc1 type fold-able clutch/perch brake combo. Went to purchase online today and to my surprise there were no such parts listed for the XRs. I saw plenty of CRF/CRF-X choices and they seem to differ depending on generation. Obviously I can use nearly any perch/clutch combo as long as the two match; but I was wondering if anyone knew which of these levers was closest to stock? Also, will the first gen CRF250X brake lever work on the XR? These may be stupid questions to some; but I'd rather ask a dumb question than drop money on an ASV brake lever I can't use. Thanks for any help.
      #xr250r#hondaxr  
       
       

    • By TheLastByte
      Im currently in the market for an xr400r, and considering buying one that's had some heavy engine work done. The current owner claims to have bought it from a friend who's an XR enthusiast. The PO installed a big bore kit and high comp piston, as well as a xrs only pumper carb, rsw triple clamp, aftermarket clutch, street lights, and a whole bunch of bling.
       
      My main concern is the effect the upgrades will have on the engine's longevity. How much quicker will I be going through top ends with the setup on this bike as opposed to a stock setup, and should I be worrying at all about bottom end longevity as well? I wouldn't mind having to eventually redo the top end, but I don't want to deal with a race bike type top end rebuild schedule on an XR. 
      Is there anyone here who's running a bike similar to this one who can give some advice? 
    • By Ralph303
      I have a 2001 Honda XR400R. It has a whirring/grinding sound in the lower end and a vibration in the top end. I pulled the valve cover and everything looks good. Decompression lever looks to be in order. Anyone know where I should start looking or just rebuild the whole engine. Ballin on a budget, but really love this bike. It looks like it’s new otherwise. Oil was jet black and thin. Thanks in advance! 
    • By junglePIG
      Hi, I have an Xr250r with a buckled/ wobbling front wheel, after trying to true the rim i have broken a spoke.
      I am wondering if it is possible to lace any 36 hole aftermarket rim to the oem hub, also will i need to buy an xr250r specific spoke set. also could i take a 36 hole rim from another front wheel and lace that up???? thanks
×