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2006 Honda Xr650l - Hot Start Issues

mototireguy said:
Update...

All is perfect.

City miles per gallon went from crummy 34mpg to 40mpg. Clearly it was running rich due to the fuel float valve leaking.

Operating temps according to the oil dipstick thermometer increased from 180-200f to the 200-220f range.
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Fuel economy advancing from a "crummy" 34mpg to a "less crummy" 40mpg is still crummy fuel economy for a thumper. My DR gets 50-52mpg, same as my previous KLR. Or is this just a Honda thumper thing?

Lex
 
Lex Talionis said:
Fuel economy advancing from a "crummy" 34mpg to a "less crummy" 40mpg is still crummy fuel economy for a thumper. My DR gets 50-52mpg, same as my previous KLR. Or is this just a Honda thumper thing?

Lex
Click to expand...

Rider size may have something to do with it. :laughing

Great bike :thumbup. I put an Edelbrock carb on mine, but a good stock unit with Dave's mods is the best way to go.

Are you just leaving things alone, or do you plan on doing any long distance bush whacking with the thing?
 
Lex Talionis said:
Fuel economy advancing from a "crummy" 34mpg to a "less crummy" 40mpg is still crummy fuel economy for a thumper. My DR gets 50-52mpg, same as my previous KLR. Or is this just a Honda thumper thing?
Click to expand...
I'm getting 40-45 from my XR650L, but I NEVER ride it in a manner that would get great mileage. I've never ridden a DR650, but I'm definitely getting more power than any of the KLRs that I've ridden. :cool
 
40-41mpg so far on the stop-n-go mean streets of SF.

Got 44mpg with mixed freeway use.

A full freeway run yet to be done, I suppose 48mpg possible.
 
I got 45-50mpg with the Eddy carb and FMF power core exhaust. 20-30mpg on Mexican Pemex.
 
Update...

Every so often maybe once a month I still get the full power crank but no start when hot. Typically when the engine is hot then shutoff for 5-15 minutes.

My old trick for getting started was to simply stand around for 10 minutes and then it would fire right up.

The key update/workaround I found is any kind of small push/hill bump start will 100% immediately start the bike.

Beginning to think maybe trying a new pulse generator?
 
I'm going to guess that you've not had the bike on a dyne to confirm that the jetting and mix adjustments are correct. 'May not help with your problem, but I can't recommend doing this enough. Getting everything spot on can make a world of difference, even on a bike that you think is running fine.
 
mototireguy said:
Every so often maybe once a month I still get the full power crank but no start when hot. Typically when the engine is hot then shutoff for 5-15 minutes.
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Has it ever done this when you've shut off the fuel half a block before parking it?
 
Would it be possible to add a hot start lever? I use the decompression lever on my XR650R to pump out extra fuel if I my bike ends up on its side.

pro-taper-profile-clutch-perch-hotstart-assembly
 
ScottRNelson said:
Has it ever done this when you've shut off the fuel half a block before parking it?
Click to expand...

I've tried turning off the petcock and running the carb dry. Will still do it.

Bike starts easy and runs awesome everytime otherwise when hot or 35f cold mornings, so 95% sure not jetting issue.

The idea is that when this issue happens it immediately jumps to life within one revolution of the engine from any bump start gets me thinking spark / pickup sensor or something electrical.
 
I'm not positive but I think if Pulse Coil is bad ... then bike won't run at all.
But perhaps it can be intermittent ? Dunno?

But the Pulse Coil (AKA pick up coil) is not to expensive, not too hard to replace. They DO fail from time to time ... (one on my old XL600R failed)

When you tore Carb apart ... you DID check the float height level? Right?
And ... did you float have any liquid inside?

Just for fun I'd replace the O rings in there too. They dry out over time.
Fresh factory ones are best. ALL BALLS and some carb kits are crap ... and will leak.

Also, several have mentioned the Wide Open throttle technique for starting.
This works great for Hot Starts when flooded. I'm sure you tried it already ... but if not ..?

I would also suggest getting in touch with the guy who's kit you put in your Carb. I'm sure he would have suggestions on what the issue might be.

Good luck! :Port
 
Rumbo Sur said:
I'm not positive but I think if Pulse Coil is bad ... then bike won't run at all.
But perhaps it can be intermittent ? Dunno?
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The Pulse Generator can be intermittent. I've been through that on mine before, and it gets worse when it's hot. It might be a good move to just replace it to rule out one other possible cause.
 
The XRL had what seemed to be a flooded carb issue. Cleaning the carb seemed to have solved the problem for a while but now it's back. I had a similar issue with my DR, a flooded carb; rebuilt the carb as it was at 35k miles, ran perfect for a week then problem re-appeared. Cleaned the tank, first time ever: a half gallon of dark-colored heavier-than-gasoline sh!t came out, along with a gallon of good gas. Along with some rust, as expected. I suspect bad fuel that sat at the bottom of the tank, a little bit mixed with good gas was no problem but when I went on reserve the carb was seeing mostly the bad sh!t. Closer inspection of carb internals showed very light coating of clear/white precipitate, did not notice this when I rebuilt the carb it was that unapparent until a "real" mechanic friend with a magnifying glass pointed it out to me. Problem solved.

Float needle: you need to inspect the tip with a magnifying glass, plus run a fingernail on it, to see/feel any wear - just a look won't do. If your tip is rubber, that is. At this point I'd replace any O-rings, as mentioned earlier, and the needle or seat, whichever is replaceable.

If the petcock is activated by a vacuum: does fuel flow when there is no vacuum? Always good to check this type of petcock occasionally, it's the first line of defense against a flooded carb. The float needle is the second.

Lex
 
mototireguy said:
I've tried turning off the petcock and running the carb dry. Will still do it.

Bike starts easy and runs awesome everytime otherwise when hot or 35f cold mornings, so 95% sure not jetting issue.

The idea is that when this issue happens it immediately jumps to life within one revolution of the engine from any bump start gets me thinking spark / pickup sensor or something electrical.
Click to expand...

I would agree. While it's possible that float needle isn't sealing properly or getting clogged from a dirty tank (petcock isn't vacuum activated, at least not in my mine), that wouldn't be heat related IMO. XRL float levels can't be set on the OEM CV carb. They either float or don't if old and holed or logged (unlikely)... Bit that also wouldn't be heat related. A new float needle and good fuel line filter would eliminate those possibilities after a thorough cleaning.

What is very possible is that the pulse generator is intermittently failing when hot (they often do). You could make the pulse generators harness clip accessible, ride until it gets hot, return to your garage to shut down and hopefully it doesn't restart, then test it. If it does start. repeat and return to your garage until it does fail to start, then test. Or bring multimeter with you on a ride. Or just replace. I think they are less than $60. You could also borrow a good CDI. Less likely the fault, but potential fault. I'm no professional, but that's how I would proceed.

My XR is up north in Lake County or I'd offer you my CDI to borrow. If you did make the long trek up there after Christmas, welcome to to try it. Or you could remove the pulse generator and heat it up to test. That could be hit or miss though. I'd prefer to make it fail, and test imediately on bike.

I chased a erratic idle on this CV carb for two weekends before properly diagnosing an improperly routes vacuum line from a previous owners desmog job. That was frustrating and completely unrelated to this ....

Bottom line, I agree this seems electrical and not fueling.

Good luck!:thumbup
 
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Bring a can of electric contact cleaner with you and, if possible have the pulse generator cover off.
Ride it till it is hot.
Turn off and verify it won't start.
Spray a good bit of contact cleaner on the pulse generator which will cool it and try to restart.

If it starts you've verified it is a heat induced electrical problem.
 
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OaklandF4i, the float needle would cause the mixture to be richer. It's possible that, when cold, it's a little on the lean side to begin with and when hot, it's a little on the rich side to begin with. Add the extra (unwanted) fuel and it won't start hot.

I don't know if that's the case, but it's a plausible explanation for why it happens hot but not cold.
 
Junkie said:
OaklandF4i, the float needle would cause the mixture to be richer. It's possible that, when cold, it's a little on the lean side to begin with and when hot, it's a little on the rich side to begin with. Add the extra (unwanted) fuel and it won't start hot.
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Remotely possible.

Except as noted previously, issue still sometimes happens when fuel has been shutoff and float bowl is empty.

99.9% certain jetting is not the issue.
 
Junkie said:
OaklandF4i, the float needle would cause the mixture to be richer. It's possible that, when cold, it's a little on the lean side to begin with and when hot, it's a little on the rich side to begin with. Add the extra (unwanted) fuel and it won't start hot.

I don't know if that's the case, but it's a plausible explanation for why it happens hot but not cold.
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Possible, but not very likely on this bike and this carb. 5 or 6 years ago I had a float needle that wouldn't seal properly on my annual Baja trip. It was so bad that the carb was puking gas out the vent tube and fuel mileage dropped to mid 20's. But, it always started hot or cold. Scotch brite on the valve seat and smooth concrete to lightly sand the rubber needle finally got the needle to seal and restore my fuel mileage for the rest of the trip.

This bike and carb just isn't that sensitive to float level like some bike and carb combos. Plus the OP has said nothing about a puking carb, loss of performance, or mileage. It really leads me to believe and agree with him that it's electrical due to it intermittent nature and relation to heat.

Agree on principle, just not this time. Of course we could all be wrong and this could be caused by faulty muffler bearings he purchased from Chris Dove using Hobo dollars.
 
OaklandF4i said:
Scotch brite on the valve seat and smooth concrete to lightly sand the rubber needle finally got the needle to seal and restore my fuel mileage for the rest of the trip.
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WOW! That's some McGyvering! :thumbup
OaklandF4i said:
Of course we could all be wrong and this could be caused by faulty muffler bearings he purchased from Chris Dove using Hobo dollars.
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Now there's a name from the past! I wonder how many reading this know the reference?

Lex
 
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