Is this signs of a dirty Carb ?

13 replies to this topic
  • Nige_Uk

Posted November 14, 2001 - 02:20 AM


I've got a bit of a problem, normally the blue beast starts 1st kick from cold or hot, but recently from cold I'm kicking my nuts off trying to get fired up, then it runs very poorly( won't idle). Here's what I used to do -
- Pull choke out
- Piston at TDC
- Kick - the beast's alive !!!
Here's what I have to do at the moment
- Pull choke out
- piston at TDC
- Kick - nothing, not even a murmer
- Piston at TDC again
- Twist throttle to give a squirt of petrol (my old 98 model needed this to fire up after standing a week !)
- Kick - starts but dies very quickly (not touching anything)
- Kick - nothing, not even a murmer
- Kick - nothing, .........etc

Petrol coming from float bowl under carb (via pipe)

After alot of sweating, cursing etc, the bike starts, runs rough, won't idle, need to keep the rev's up with the throttle. Riding the bike with the choke off (feels like the bikes serging, & back-firing).
Once the bikes fully warmed up, the bike starts 1st kick again & perfoms like it used to do.
The jetting I think is standard (never had it appart - scares me !!!)
Exhaust is a white brothers E series 6 discs
WR timing
New spark plug (started ok when fitted & ran ok until above for 3 weeks)
I've ordered 45 pilot jet & 172 Main jet (info from tables given on 'Technical'at beginning of forum)

Am I on the right lines with the above problem ???

  • MN_Kevin

Posted November 14, 2001 - 02:44 AM


Pull it apart & THOROUGHLY clean it.

There is nothing to be afraid of. NOTHING will fall off the carb when removing the carb off the bike. Read your manual on carb removal and disassembly.

According to one engine tuner, a thorough carb cleaning is the first thing to try to restore lost performance, ESPECIALLY if your performance has gone away over time.

You'll be fine Dude!! :)

  • LarryCO

Posted November 14, 2001 - 05:19 AM


Do a search on the "BK Mod"...there's very good directions on how to remove the carb. And while you have it off, you can even think about spending the $15 and doing the mod itself! Highly recommended, by the way...and very easy. If I could do it, anyone could! :)

I must admit I didnt understand your point about "Petrol coming from float bowl under carb (via pipe)" you mean the soft plastic/rubber drain line running from the bottom of the carb?

FYI...I learned quite a bit about how my bike operates by taking the carb off and looking at it...

  • MN_Kevin

Posted November 14, 2001 - 06:42 AM


If you have fuel running out of a hose, I'd bet money you have a stuck/sticking/out of adjustment float which is causing fuel to come out your carb OVERFLOW line...

This in itself will cause poor performance, let alone allow your bike to even run.

Disassemble the carb OVER AN AREA WHERE ANY DROPPED PARTS ARE EASILY SEEN. Check to be sure all o-rings are removed to prevent any suicidal tendencies from trying to locate the little o-rings that rolled off yonder. Use compressed air to blow all air passages. Check and set your float height, seriously check out the BK mod (JK mod for 98/99's :D ).

Nige, EVERYONE of our TTalk members started out just as you, very hesitant and anxious about working on our bikes. Through anti-anxiety medication and beer, we have all slowly delved into these machines to increase our understanding and save a few yen on the way. It is also good insurance that prevents us from getting ripped off from not-so-honest dealers.

The old saying, "Knowledge IS Power".

Now, Nige, jump in with both feet! You WILL be OK!! :)

  • LarryCO

Posted November 14, 2001 - 08:22 AM


Just so you know...What NH Kevin means by "anti-anxiety medication" is Jim Beam. Go by a handle and start medicating! :)

  • KLXer

Posted November 14, 2001 - 03:44 PM


Beer? Did I hear beer? I'll take the stuff apart for a beer. :D Sometimes I even get it to go back together right :)

  • Dan_Lorenze

Posted November 14, 2001 - 04:48 PM


Guys, My WR has been really good to me, starts really easy ,cleans out really nice too, but lately she's been back-firing and spiting just a little too much. I let this go on for a couple of races (Vegas to Reno and Lake Elsinore GP). It has gotten so bad that I had to do something about it. Visions of Taffy in my head got me to rip the carb apart and look inside ya know,"C'mon you bloody Yank! get off your lazy a$$ and pull it apart". I couldnt believe my eyes what I saw, I saw a carb that looked like it had been drug thought the Blackwater Enduro behind some type of high performanc ATV. Im serious this thing was lined with a brown thick coat of muck!!!! :) So today I took the carb apart and cleaned out all of the dirt that was in there as well as blew all passages out, Im serious this thing was dirty!!!!!!! Tonight I'll go back into the garage to put the thing back together and I feel confident that the bike will work like it did when I bought it.

What caused this?????? Im (pretty) sure that both boots were on correctly and Im very sure that my air filter(s) have been installed correctly. Any thoughts why this was so bad???????
Kev? Any thoughts? Taffy?

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  • MN_Kevin

Posted November 14, 2001 - 05:26 PM


Dirt in your fuel, Dan, or if you have a 98/99, the accordian boot on your accelerator pump actuation rod. My AP was packed with dirt and water with 4 hrs on it. I now silicone all joints on my carb.

Never underestimate dirt getting around your filter, or a bad seal. Also the rubber "Manifold" between your airbox and the carb. I pulled mine, coated all sealing surfaces with RTV silicone and put it back onto the airbox. [This is a spot that has been susceptible on all bikes]. Put your finger inside the rubber manifold and swipe the inside surface. If you feel/see grit, there is one of your problems.

  • Dan_Lorenze

Posted November 15, 2001 - 09:08 AM


Kev, Thanks man!

  • robman

Posted November 15, 2001 - 01:55 PM


sounds like you need a new plug.
mine did that one time so I put in new plug and and it hasn't happened anymore.

  • Dan_Lorenze

Posted November 15, 2001 - 02:17 PM


Robman, Good idea!!!!

  • The_Missile

Posted November 16, 2001 - 06:46 AM


For gods sake dont lose any O rings when you pull it apart. Be especially careful of the Fuel Screw as there is a little metal washer and a rubber o ring that may stick in there when you remove the screw. Tap the carb to remove them.

Also count how many turns to bottom it out, so you can reset when you reassemble.

  • Nige_Uk

Posted November 18, 2001 - 10:30 PM


Found the problem !!!!!!!!!!!!!!
Stripped the Carb down - clean as a whistle - wasn't as bad as i'd imagined,pretty straight forward. While I had the tank off, changed the spark plug - jet black ! - poped new one in.
Tried to start it - no joy !!
Took air filter off - caked in dirt !!!
Tried starting bike without air filter on (made sure no dirt could be sucked in !)
Doh !!! should have checked the basics before assuming the carb was at fault first - but at least I know hoe to strip it now !!
What was happening was due to the air filter being blocked, not enough air could be drawn in, hence more petrol than needed, hence flooded & a saw foot from trying to kick the bike off in trainers - LESSON LEARNT !!!!
I'm going to do the BK Mod this week & put different jets in Main 172 piolt 45 my needle is already at Pos.4 so might leave it there but I'll give it a try

Thanks guys for all your inputs


  • MN_Kevin

Posted November 19, 2001 - 01:56 AM



Congratulations on the start of your WR home maintenance carreer!! :)


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