Problem Starting- Hot Start. Clark/James help?

The only problem during the Moab trip was that my bike was often very difficult to start. At the start of the ride I had no problems. But after a few minutes of riding, if I killed the engine, it would usually fire up if I kicked it immediately. But if we waited a few minutes or longer, It could take 30 + kicks and 5 to 10 minutes. The only change that I made to the bike before the trip was to add the Ty Davis tank (another subject but it was great) and added the handle bar mounted hot start (which I believe may be the problem).

Potential Solutions:

My guess is the problem is with the hot start. Remember, I put this on because my new tank comes down so low. Has anyone had problems with these. A guy a Scott's said he could never get his to work right. Air leaks. I'm going to check mine for leaks but everything looked ok.

Also, I went leaner on the jetting and it helped a little but not that much and I think the richer jetting made the bike run better. ( I was DVP 4th, 180 main, 50 pilot, 1.75 turns out, 100 air jet and I switched to 178 main and 48 pilot). I don't think this is the issue.

Also, some people mentioned that my float bowl or throttle position sensors may be out of adjustment. I haven't had them checked.

Any thoughts are appreciated. Thanks.




2000 WR

Harold, another bit of information that may be useful for the experts out there....

Your bike seemed to backfire once when you killed the engine. Not a loud bang, but it was definitely there. I'm not sure that it factors in, but yours appeared to be the only bike in Moab that did it.



The couple of times I started your bike in Moab, I went through a drill as though it was flooded, and it fired right up.

Therefore, my first guess is that the needle valve controlled by the float is not seating properly allowing fuel to flow after shutdown and thereby flooding the engine. This is the first thing I would check.

The hot start is certainly suspect as it was the only change before you developed the problem, although I can't explain how it would cause the problem. Perhaps if you have the original you can re-install it and see if the problem goes away.

The confusing thing about your bike was the dieseling (run-on) after shutdown. On a car, one would first suspect fuel quality and then timing. On the WR - the same I assume?

The TPS was brought up because mine was out of spec as per the manual and adjusting it did correct a low speed hesitation. I doubt it is the cause of the starting problem.

And lastly, I think 180/50 was too rich for Moab (4-6k) but may be OK for So Cal. Didn't you foul a plug the first day?

Hope all else is well.

Best Regards,



James' second ride : Kicked to exhaustion, slumped over my bike, the other riders waiting, stuck off the low side of the trail, nowhere to go.... cursing mad !! :)

That whole day the bike was hard starting. Often when it sat a few minutes or when it got hot.

Looking back at the settings, the pilot screw was turned too far out and the idle was set too low. We were also riding at a higher altitude.

-Based on that experience, try the 48 pilot with pilot screw at 1-1 1/2 turns out and turn your idle speed 1/4 turn higher than it needs to be.

-Make sure the float level is correct.

-Make sure the hot start is working.



Reading another posting enlightened me as a POSSIBILITY. You are running the check valve (one way valve)in your gas cap, correct? I don't know if the other guys in Moab were running theirs or not. And I do know we were all using the same gas. I do not think the "petrol" (for the Brits and Aussies understanding) was oxygenated...??? I removed my vent check last year after reading the problems guys were running into. Plus, for the first 20 years of mx'ing, we never used the check valves.

If your tank becomes pressurized for any reason (heat, gasses coming out of solution), that pressure will be going into your float bowl and pressurize that too.

I don't know Dude, but it's worth a shot. Be nostalgic and $hitcan the fancy vent check and use a good ole' fasion straight vent line.

You will have just removed a possible problem none-the-less.


99 WZ, all YZ mods, de-octopused, OEM YZ tank and IMS seat, jetting by Clark/James, got forked by Pro Action, DSP airbox, PB Header, Stroker SX-1 SA, Thumper Rad Guards, Acerbis Hand Guards. Canada for 2001...???

[This message has been edited by Kevin in New Hampshire (edited 10-17-2000).]

just an idea. the new tank. sometimes can play silly games with the fuel supply. it's not that the fuel can't get in-it's that it can't swap places with air.

also i find you have to get used, each time you play with the settings, to how long the bike will start with no help, with hot start or with full choke again.

if you follow the line (no pun intended!) of the fuel flow. try using clear pipe for a little while & watch all those bubbles.



I set your fuel screw 1.25 - 1.5 turns out when we (truly a group effort :) ) changed your jetting to the 48/178. Also, your bike was idling considerably higher than the rest - don't remember if you lowered the idle speed or not.

On my '99 the float level was about 1mm low from the factory - might check yours but this would cause a lean condition.

I'm a bit confused because I run the same, except needle as you - 48/178/1.75 FS/DTM #4, no air box lid, stock exhaust w/Thumper insert, set up for Gorman - & my bike starts 1st kick 99% of the time, hot start only after a lame a** stall - including the few miles I rode it at Moab before switching t o the wifes XR250R :D If I remember right, you have YZ timing AND the FMF Powerbomb/Stroker SX1 exhaust. My point - are you lean on the fuel screw? Yeah, I know John went thru the flooded start procedure to get your bike started.

Just some rambling thoughts,



I concur with James Dean's comments. I run a 48PJ, 1.5 to 2.0 on the fuel screw DVP#5 and a 178 MJ. Make sure your Hot Start set up is working correctly and totally sealing when closed.

Remember the fuel tank pressurization problems if you run a check valve in the fuel tank vent line--remove the check valve.

Set the float level 1mm lower than stock.

Good Luck


I too remember killing your bike at the top of that nasty little climb oblivious to your starting problems :) Thinking about the hot start circuit and when it is used (left on) after starting that the engine sputters and especially pops through the exhaust. After bumping your bike down the hill to get it started and turned around (man does that thing rip) :D that there wasn't any excess exhaust poping or sputtereing to think of.It just didn't want to start with the kick start lever. Hope you get it sorted out and that its not the tank causing the problems. I hope to get another chance to try your bike with the TY tank just for kicks and giggles.Good Luck hope to see you on Nov.

if you're going to pull the inline vent out, use a longer pipe & wrap it around the bar support 3 or 4 times then down the TC hole.

this stops the fuel going straight off the bike. the fuel comes back to the tank of it's own accord. you won't loose any & that's quite important on a full tank.

we possibly all heve different needles based upon the likely altitude & humidity in our home countries. in the UK we're no more than 90 miles from the sea & everyone is at sea level to 1,000ft. everything rusts within hours if it's left out.


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