2006 TC250 hot starting issues

[T.Read]

I've searched all over this site and got a lot of things to check out, but in case there's more to it than valve clearance and jetting.

I have a 2006 TC250 with an electric start. Up until yesterday, it's been easy to start when hot. In the mornings on first start up in warm weather, a little choke, fires right up with E-start. Can also kick it maybe once or twice and it'll fire right up.

Once I get in the woods and take a break. Hot start out, fires right up on E-start everytime.

Yesterday I went riding in some really tight single track at a higher elevation, but not enough to make me think the jetting could be that far off. As it got hotter, the top end got noisier. Enough to scare me for sure, but it still ran fairly good until I'd try and climb hills and it got a little more clattering up top. Loss of some power as well. I had just changed the oil with some Rotella 15W-40 that I got from the guy I bought the bike from. I also had adjusted the Rekluse Z-Start to have a lower stall speed.

So it would pop and flame out sometimes at random, mostly as I was trying to climb hills and goosing the throttle to get over roots. Sometimes just going down a flat section and turning a corner. Then it would take 4 of us taking turns kicking it to start it. Starter would barely turn it over after so much running even though I charged the battery before going riding.

Today I washed the bike off and gave a little choke, e-start fired it right up like always.

A friend told me he was having similar symptoms on his 450 and 525 KTMs he'd had and it ended up being a bad stator. Replaced them with Trail Tech stators and no more issues.

I am planning on pulling the carb and double checking the jetting(I wrote down the specs it had when I had to replace the intake boot that was separating but I can't find where I wrote them down), then double checking the valve clearance.

Does the bad stator, or other electrical issue seem feasible?

 

[T.Read]

Still having trouble with this bike starting when hot.

Thought I had it figured out a few weeks ago as I was riding up in Kentucky and it was really hot and humid. I had turned the fuel screw in pretty much all the way in. It ran much better than the last few times and was easy to start when I shut it off for a break or if it died on me. Sometimes through a tight single track area, it would randomly just die as I was coming around a turn. Usually it would fire right back up with the starter while I was still rolling along.

I figured since it's liking the leaner fuel screw adjustment, I'd change the pilot to a leaner one and see what happens. I put a 40 in, ran around my tiny backyard until it was pretty hot, and started adjusting the screw again. The sweet spot seemed to be around 3/4-1 turn out. I was going riding the next day to a place in Mid TN and hoped I had it mostly figured out. In the yard it was starting easy and I wasn't able to re-create the stalling I was getting in the single track before.

The next day the temperature was much cooler than it has been. Kinda chilly actually, for me anyway. Morning temps in the 60s where it's been 80s-90s up until this day. The bike started up pretty easy with choke on, started riding the loop and as soon as it got hot, it started getting the noisy top end problem again. I tried richening the fuel screw some to deal with the cooler temp, but nothing seemed to work. It stalled after hopping a log in the trail and started up ok, but not easily, on the starter. I then got to spot and killed it for a second to figure out which section to go through next and I was there kicking for a half hour. Finally got it to fire and got back closer to my van and it died again coming up out of a little ditch. I sat there and tried getting it started for about another 30 min. I finally got fed up and just left it there for a second. Pushed it down the trail a little to where I was within 50ft of my van and got the richer pilot out to replace it and try that. It fired right up with the 42 and maybe 1 turn out(I tried so many screw settings I can't remember where I was at this point.)

I got it back to the van and ran around the pit area until it was hot again and started adjusting the screw. Got it to where it seemed good and shut it off to see if it would start up easily before going on another attempt. It did a few times, but I went for a short loop of a grass track area close to the van and came back to get all my gear back on and it wouldn't start again.

I messed around with it for a while and gave up. Let it sit for probably about an hour then tried it again and went down to a grass track course close to the pit with everyone and it was starting easily there. I was barely cracking the throttle open and it was firing right up. Came back and tried a loop and made it through ok, but it was still a bit noisy up top. I shut it down in the middle of the loop at one point to check on a friend that was stuck on a hill and it took me a few minutes to get started again. Wouldn't kick over, and I randomly tried the starter, with hot start, and fired right up. I figured the battery would be too dead at this point to start it.

Sorry this is so wordy, but I'm pulling my hair out on this thing. I really like it when it runs properly, like the last time in the hot/humid/muddy conditions. But I'm not having any fun when it starts running like this and won't start obviously.

Another thing that was weird when I got home. I tried kicking it over to ride it back to my shed from the driveway and the kicker was turning the starter motor over and was really hard to kick through. Got more frustrated and just left it in the back yard. Tried it again later and it finally broke loose and fired up. Could this be contributing to something?

 

[OlderHuskyRider]

Get the bike to the "heated up and hard to start". Pull the plug and have a look at it.

To me, if the rejetting is not really helping, you have to look somewhere else. My 450 would start when cold, but when hot and engine off, my pressurized coolant system would push coolant past a leaking head gasket and drown the spark plug. This may not be your problem, but your symptoms are similar to mine, and it's easy to diagnose.

 

[T.Read]

Thanks, I'll give that a shot. I looked at the plug at the last ride when I was sitting around by my van trying to figure something out. It looked a bit rich, hard to see where the heat range was, possibly a little on the hot side but it was clouded by the darkness around the end of the plug.

I sat the plug against the head to make sure I was actually getting spark and it did, but it was kinda weak. I was going to recheck the valves, change the oil, put a new plug in and check the coolant again(it was low before the ride in the hot and humid conditions). I figure I might take it out to my parents' place and ride it around down there so I can get a bigger area to try it out and see what it does then. I'm about to leave town though for work, so it may not be until after the beginning of October.

 

[MotoXotica]

I had one of those bikes.it had too big of a pilot jet stock.what pilot jet is in it?i went down to a 40 at the time.did some other jetting changes as well.a jd jet kit is a good option as well.dan

 

[T.Read]

I had a 42 and that's when I turned the fuel screw all the way in and it ran great in the hot/humid weather. I put a 40 in it and it ran like shit again in the cooler weather, even after I tried turning the screw out even more than 1 turn out. I have the JD kit in it and it didn't seem to change much other than the mid range seemed better. The pilot he sent was the 42, but I already had a 42 in it.

It started up first kick again just now with the choke on and I was able to take the choke off fairly quick. I just rode it to the front of the house to load it up and take it to my shop and start checking stuff. See what I can come up with later today just riding it around the neighborhood.

 

[MotoXotica]

kind of getting confusing as to what the problem might be at this point.the intake manifolds have been an issue cracking and letting air in,have a look at that.has the valve adjustedment been checked?

 

[OlderHuskyRider]

Thanks, I'll give that a shot. I looked at the plug at the last ride when I was sitting around by my van trying to figure something out. It looked a bit rich, hard to see where the heat range was, possibly a little on the hot side but it was clouded by the darkness around the end of the plug.

Coolant in the combustion chamber will mess up the combustion, making it look rich when it's just a crappy combustion.

I sat the plug against the head to make sure I was actually getting spark and it did, but it was kinda weak.

The crappy combustion makes the plug a bit carboned, thus the poor looking spark. Put that new plug in the cap and see if you get a fat, blue spark before you install the plug.

...... and check the coolant again(it was low before the ride in the hot and humid conditions).

Loss of coolant is a dead giveaway for a leaking head gasket.

 

[OlderHuskyRider]

I had a 42 and that's when I turned the fuel screw all the way in and it ran great in the hot/humid weather. I put a 40 in it and it ran like shit again in the cooler weather, even after I tried turning the screw out even more than 1 turn out. I have the JD kit in it and it didn't seem to change much other than the mid range seemed better. The pilot he sent was the 42, but I already had a 42 in it.

Hold the jets up to a light, side by side, the 40 jet might be gunked up around the diameter of the hole, effectively making it a much smaller jet.

To make sure the jet is clean, get a piece of copper speaker wire, one of the single strands of a multi-strand wire. Cut a piece about 2 feet long and wrap it around your finger, making a spring-like shape. Thread it into the jet and pull it thru, do this a couple of times. See if the hole looks any bigger in the light.

 

[T.Read]

kind of getting confusing as to what the problem might be at this point.the intake manifolds have been an issue cracking and letting air in,have a look at that.has the valve adjustedment been checked?

That was an issue a while back, but I replaced it with a brand new one before all this started happening back in late May, early June. Then I changed the oil, adjusted the clutch(Rekluse Z Start), cleaned the filter. This was only my third time riding the bike by the way and none of my rides at this point were long. So that was the first time changing the oil. At the time, I didn't know about the two screen filters on the left side. They have been cleaned out since then.

The valves were checked 2 rides ago and it was doing the same thing. The next ride out after that one was the ride where everything worked fine. None of the rides I'm doing are much longer than 30 miles at a time if that. The valves were slightly off, one valve per side was off while it's mate was ok. I reset everything to where the intake was .005" and exhaust was .007".

 

[T.Read]

Hold the jets up to a light, side by side, the 40 jet might be gunked up around the diameter of the hole, effectively making it a much smaller jet.

To make sure the jet is clean, get a piece of copper speaker wire, one of the single strands of a multi-strand wire. Cut a piece about 2 feet long and wrap it around your finger, making a spring-like shape. Thread it into the jet and pull it thru, do this a couple of times. See if the hole looks any bigger in the light.

The jets were brand new. Plus I clean them out with some B12 carb cleaner and blow them out with compressed air when I change them to be sure.

 

[T.Read]

So, I drained the oil and cleaned out the screens yesterday. A few pieces of swarf on the magnet, but I'm not sure when I should be alarmed as I expect a little to be there anyway. The screens had miniscule spots of stuff on them, but it didn't seem to be metal as much as it was oil and a few random specs of RTV.

Checked the clearances this morning after it cooled off from draining the warm engine oil, and they were pretty much spot on except the left intake was .003" and right was .004". The exhaust was also a thousandth off from each other, but to the good.....006" on the left and .007" on the right.

After checking other stuff, sticking a magnet in the screen cavities and sump to check for extra bits of metal, I looked at the radiator. I couldn't see any fluid, so I took a beer bottle and started pouring water in to see how much it needed. Took about 32oz. before it filled it up. Then I started seeing water dripping down on my lift. It was steadily coming out of the T connection. Wondering if the loss of coolant is my main issue here and hoping it didn't damage anything.

I filled up the radiator at some point recently after the first time I had a hard time with the hot starting issue, but I can't remember if it was before the ride where it ran great or not. I'm pretty sure it was. I'm going to replace the coolant hoses and T connection and fill it back up and see what happens then.

 

[Coffee]

Wow. Yes you would need to have water in the bike to keep it cool, or all sorts of not fun stuff will happen.

Random thoughts:

if there is still RTV coming out during the oil changes, then it could be a very low hour bike, that was common in 2006.
If it were me, I'd look and see what leak jet you have, because to me it sounds like you could have a 35, 45, or even a blank (no hole) leak jet. More info: http://www.cafehusky.com/threads/how-to-re-jet-a-carb-video.1160/

 

[T.Read]

I have a 35 leak jet. Pretty sure that was in the JD kit as well. Don't have it in front of me at the moment. I want to believe it's a low hour bike, but it had it's issues when I got it for sure. Makes me believe that someone has been into it at some point, but can't be sure.

Previous owner was a bit RTV happy when putting the valve cover back on as well as the oil filter cover. But he also destroyed the rear shock body by using a chisel to adjust pre-load and cross threaded it. I had to replace that...not cool. Got the suspension revalved, sprung, lowered 1" and replaced the Ohlins body for $700. Not too bad considering all the work that went into it, which is why I really want this thing to work for me after sinking all this cash into it. Never had this many issues with a bike. This is the newest thing I own, and it gives me the most trouble.

 

[Coffee]

I would put in a 65 or 55 leak jet if you could. With a 35 or 45 there is simply too much gas squirted into the carb with each twitch of the throttle.
More info here, especially image #6 showing fuel quantity vs leak jet size: http://www.cafehusky.com/threads/in-search-of-snap…-is-this-stuff-useful.6411/

Note that thread is for a 2006 TE250, which had a throttle stop and Accelerator Pump (AP) disabled from the factory to meet emissions.

EDIT: I had trouble on warm days flooding the bike going up steep bumpy hills with the lower numbered leak jets.

 

[T.Read]

I saw one post of yours with the adjustment to the AP screw. I was going to try that once I got through all these checks I'm doing now. I'll double check I didn't change the leak jet already later this week. For some reason I'm thinking I changed it. I have my notes written down in the manual at my shop.

I have had many times where the bike would pop and die after tackling a particularly steep hill and letting off the throttle. More than once at the last ride where there would be a log to jump in the middle of the hill. And if there's one thing Middle TN has it's plenty of fairly gnarly hills.

 

[Eaglefreek]

Tony, you better get this figured out or there will be a bonfire with your bike being the "guest of honor". I'm just glad the one time your bike ran right, was the time I flooded my bike in the creek and you were able to tow me back to the car.

 

[OlderHuskyRider]

Sounds like you've been running the bike with no coolant, which these engines will do. Scott Summers and I have proved it, Summers on a 510, me on a 450.....

The high heat generated by running with no coolant will do several things, all the things below happened to me:
killed 1 rad hose
destroyed the intake manifold
loosen head bolts, after a couple of more heat cycles
destroyed the water pump seal and scored the shaft
cause the head gasket to develop leaks

 

[T.Read]

Rick, if it doesn't work, I'm going to be the first to start the fire!

I'm hoping it didn't loosen the head bolts or any of that other stuff. Makes me wonder how long it's been like this and if the previous owner was having that issue. I'm never buying a used bike again...unless it's another vintage bike, but I'm getting buried in broke down old motorcycles right now.

 

[T.Read]

Finally got around to pulling apart the radiator hoses and the T union is damn near melted on one barb, and there looks like it melted a bit in the middle which is about where the water seemed to be coming from. Going to order a new one tomorrow and hope that I didn't ruin anything else running out of coolant. The hoses all looked fine, so holes I can see.