Stalling and Starting Issues 250cc Titan By scooterfan86 (Read 1,152 times)

[scooterfan86]

Hi there, thanks for all of the great articles on here!  They've been very helpful in keeping my 250cc liquid cooled Titan (also known as the L-Roar) going for the last 2500 miles.  

  I have come up to some issues that I would love the boards input on.  All of these problems have occurred in the last week.  The bike has a very hard start, where the engine needs to be warmed up for it to ignite.  I think this could be a valve adjustment issue, but as of yet have not had luck in getting everything back to normal just through adjusting the valves or the idle screw.  It has a new battery and a new spark plug, plenty of gas and plenty of coolant.  The old battery was more dead than it should be, and I could have put some wear and tear into the electronic system by doing this.

  The coolant will not always flow though.  The thermostat literally doesn't kick in, but then other times it does just fine.  I've also noticed the temperature gage is very much out of wack, with it reading very hot when I've just run the bike around town.  I've also had two occasions where the bike died while it was running at a stop, where I went to accelerate and the engine just completely went out needing to be restarted. 

  And finally, there was a time when I went to start up the bike, and all the electronics went dead.  Turning the key back and waiting a minute re-engaged the electronics, and it started as normal afterwords.  It felt like a grounding or crossed wire issue but I could be wrong.

  Again, these are all within the last week, and outside of the problems the bike runs very well, nice smooth idle, a little bumpy in the first bit of acceleration but it has always been that way when the belt switches from low to high speed.  

  I'm going to be taking the plastic off and begin looking for the problem(s).  Any suggestions?  My first thought is an electrical issue since when the bike is running it's running fine.  The need to warm the engine first makes me nervous since it could be an engine compression issue that would be a monster to fix.. but could the hard starting also have an electronic basis?  Any information would be helpful.. I realize it sounds like this post is all over the place but I'm hoping to be able get my ride back to where its the reliable scooter I know and love  Cheers. 

[alleyoop]

From you posted I gather you have already adjusted the valves. Which IF NOT do that first then adjust the carbs fuel ratio mixture. Now that the temps are cooler motors need a little more fuel and that is probably why it is harder to start PROVIDED you adjusted the valves because tight valves would also cause the same thing.
So Adjust the carbs fuel mixture:
Alleyoop

thescooterprofessor.proboards.com/thread/3001/4-stroke-carb-tuning

[carefulrider]

I can offer a solution to the wacky temperature readings: somehow, air is present in the cooling system. If you bleed the air out I feel confident in thinking that the scoot will operate at "normal" temperatures.
However, patience & the ability to follow the procedure without short cuts is needed for a successful outcome. Please follow JR's procedure for bleeding or burping.

[scooterfan86]

Thanks for the responses, I'll be getting the carb//valves to where they need to be and try to see if burping the cooling system will work.

  I came across this bolt after taking the plastic off of the bike.  It's just above the starter motor under the front of the seat, pointing forward on the bike.  I can't for the life of me figure out what this screwed into, or what it's purpose could be.  So far I can't find any other threads or places for something to be attached.. any ideas of what went here and how I'd go about replacing it?  In any case loctite would definitely be part of the equation!  The other end of the bolt is held in place by another bolt going through it's side, giving it some wiggle, almost like a hinge.  I can get more pictures if needed.  

[scooterfan86]

And just to be clear, the scooter is starting and running and this does not go into anything on the other end, just held in place by a diagonal bolt going through the head.  

[alleyoop]

I have looked at other pictures of that motor and I have not seen anything like that on them. Could you take some pictures not so close so we can see where about it is on the motor and or frame and from the other side as well.
Alleyoop

[scooterfan86]

Ahhh, so frustrated with the bike right now. I'm really confused about an issue that's come up the last couple days while I'm working on it. I've gotten everything started up just fine, cranking the engine into 8-9000 rpm on the center stand. The cooling system is working as it should now. There was a loose wire that needed to be replaced in the temperature gauge assembly and with that fixed the rest of it bumped back into action.

The problem is, even with the bike warmed up, just rolled into the 9000 rpms with no issues on the center stand, I go to pull out and drive and either right away or at a stop the engine stalls out upon acceleration. Repeatedly. To the point where I wheel the bike home and put it back up on the center stand and again, full swing of the throttle, everything looks perfect and again, go to take off and chug, chug, die.

I thought this was a valve issue or possibly something freezing up in my engine.. but could this be the case with what I've described? My battery was just replaced, and my brother was kind enough to get me one with his fancy discount through work.. the CCA are fine but the battery itself is an amp short of my original one. Since the CCA's weren't good in the old one, he gave it to his contact for disposal.

Could the half amp shortage be doing what I'm talking about here? I was thinking this was a serious mechanical problem, but after having it running so well on the center stand and to have it die with the ground under it.. it feels like it could be a juice problem. Does anyone know, or has anyone dealt with something like this before? I'd sure like to be back on the road again.. it's been a rough couple weeks working on this

[scooterfan86]

btw, here's the asked for picture with the mystery threaded bolt in the middle.. I'm still completely at a loss for what it's function is or what it could have connected to. 

[alleyoop]

Concerning the stalling when testing it out Do you have Air filter on the carb? If not that would cause it to bog pretty bad and die.
Also is this the Radiator? Also the Vacuum line to the FUEL PUMP looks bent, I would rotate the pump to get the Vacuum port away from that bracket.
CLICK ON THE PICTURE to expand it SO YOU CAN BETTER READ WHAT I ASKED ON THE PICTURE.

[scooterfan86]

The air box//filter assembly are off of the bike in this picture. They have been reattached. The radiator is under the front of the bike, and the pump, thermostat, and fan have all been working very well since I replaced the wiring to the temperature gauge.

The 'what is this a part of' does not go into anything as far as i can tel... it is held in place by a bracket bar and a bolt going through horizontally. I could take the bolt out and it wouldn't seem to affect anything else.

Can you give any advice on the bike working fine on the center stand and then dying on the road? I have had to tinker with the exhaust valve on the engine a couple times to get things going.. it still feels like it could be off by a hair.. but then again, my mind keeps going to the battery being short. I've got it on a trickle charger now to recoup from todays efforts and will try everything again in the morning.. but to have it die right out from under me, especially when it's running very well and into high rpms on the center stand, scares the s**t out of me. I don't get what's happening.

[alleyoop]

I could be a simply as that bent VACUUM HOSE on the FUEL PUMP, when running at high rpms there is not much suction going on and any rstriction will not pump fuel. So loosen the bolt holding the fuel pump and rotate it so that the VACUUM port on th fuel pump is not bent if you have to cut the hose off where it is bent and reattach it so the vacuum hose is on nice and straight.
Alleyoop

[scooterfan86]

I'll definitely check it out in the morning Alleyoop, thanks for the advice. I think the picture gives the illusion of a pinched hose, where the bracket is actually above the hose entirely.

I also don't know if I'm making it clear that when I put the bike on the center stand, when I get things running I can reach very high rpms without any issues whatsoever. I don't see the center stand vs road conditions adding or subtracting any potential pinch to this hose... do you?

Could it somehow be possible that a valve or some other part of the engine seizes when in road conditions, while not being an issue at all on the center stand? There are still times when things don't start up and I have to fiddle with the right valve adjustment (what I've been told is the exhaust) to get it going. I'm still hoping someone will say the battery could be the real problem here lol, because that would be the easiest fix.

But yes, I'll get the plastic off again tomorrow and double check that hose, take more pictures, and get back to fiddling. Thanks for the advice, I really appreciate it!

[alleyoop]

Well the only difference when on the center stand and when your riding is the LOAD on the motor. When you get on it and ride it does it get up to speed and then only die when you come to a stop? Or does it die when your trying to start off and take a ride and you really never get started.

And your right if the bracket is not in the way AND the hose is NOT BENT meaning restricting VACUUM then it is ok but it sure looks like it has a bend on the hose going down.
Alleyoop

[scooterfan86]

When everything is up and running (which can still take some fiddling with the right valve adjustment), I'll rev the engine to nearly full capacity on the center stand.. going up to 9000 rpm and holding it there for several seconds, down to 5000 for around a minute, making sure the engine is warm. I'll do this a couple times. Then I'll put my gear on, open up my gate, go to take off and around 2000 rpm it dies. Sometimes I'll get up to 3000 or 4000 rpm going through the alley from my house, then come to a stop, and it dies. I've repeated this in its entirety within 15 minutes, dragging the bike back to my house, up on the stand, everything looks good again, then go and dies again.

Do you think it's likely purely mechanical then, or does the electrical effect what the load on the motor can take?

[rks]

Someone has to say this...so here goes

1 - Stop running your engine at 9000 rpm's....this accomplishes nothing and will break something (proper warm up is done at or near idle speed)
2 - Learn the proper procedure to adjust your valves.....do it....and leave them alone

Then you can go to work on the fuel delivery system, for your problem is somewhere between the intake manifold and your fuel tank. Something is plugged, gummed up, cracked, loose, loosing vacuum, or not vented.

You sound intelligent enough....find a tutorial on fuel system trouble shooting, and follow it....