Overheating

HKVolty · 04-25-2014, 08:42 AM

Hi everyone,

I have a TU250 Volty, same engine as the GZ. Its a 1998 with 30,000km (20,000 miles)

I bought it about 6 months ago, my first bike. I'm not really hands on with mechanical stuff, but I know most of the bits and pieces and what what they do.

My bike was running fine except the clutch was slipping. So I took it to a mechanic who changed the clutch for me. Rode the bike home and parked it and everything was fine. The next time I took it for a ride, it struggled to maintain power and then started stalling after about 5 minutes on the highway. I nursed it off the highway and to the side of the road and by the time I got it there it had stalled all together and wouldn't turn over. There was smoke coming off the engine and it seemed like it had overheated quite a lot. I was in a rush to get to work so I parked it at the side of the road and walked to the train station.

I came back after work, about 10 hours later and started the bike. It started and ran, but sounded terrible. I nursed it slowly back to the mechanic and left it there for him. He adjusted the valves and told me to come back and get it. I went to pick it up and it was running fine, but on my way home it would still heat up and start stalling at temp. I turned around and took it straight back to his shop to show him. He thought it might be the spark plug cover getting the wire too hot so he changed that and readjusted the valves. The stalling seemed to stop. So I took the bike and got on the highway for about 10 minutes.

Coming off the highway at the first red light I got to the bike stalled and was in the same condition of being overheated (this time the top end had a hint of gold colour) and not being able to turn over. Let it cool down again and started it, same condition with the valves way out of spec making it sound horrible. I nursed it back to the mechanic again. I suspected he might have used the wrong grade of oil when he changed the clutch, causing it to over heat and subsequently throwing the valves out of spec. I left the bike with him and asked him to road test it next time before I come.to pick it up.

After changing the oil and adjusting the valves again, he's ridden it with the same result, the engine runs fine but overheats, struggles and the valves get out of tolerance. He suggests the problem is worm valve guides making the engine over heat and thinks I need a new top end and I should potentially replace the cylinder and piston.

The mechanic keeps blaming the guy who sold me the bike, saying the thing had a weak engine, but I had it for 6 months and it was fine until this guy changed the clutch. Has anyone heard of this before? Do you think I need to replace all these parts?

HK

**jonathan180iq** · 04-25-2014, 09:18 AM

If you go back and read this whole thing as someone who is not you, it started with the clutch replacement...

Why was your clutch slipping? 20,000 miles is not dead clutch territory. And if his solution to an overheating problem was to adjust the valves and give you a new spark plug, then he doesn't know what he is doing - which in turn means you have no idea what was done when the clutch was unnecessarily replaced. Get a new mechanic.

raul10141964 · 04-25-2014, 11:36 AM

the overheating is probably because the engine is running too lean.
check for vacuum leaks, damage on the air box or damaged or missing air filter.
The valves coming out of spec mean that they are stretching and will brake soon and need to be replaced

**jonathan180iq** · 04-25-2014, 04:14 PM

Good points.

If they're actually coming out of spec that quickly when he does whatever he does, they're about to fail. Correct this now before you lose the motor. There are multiple tales on the forum of how hard it is to get the head back to right after a valve drops.

HKVolty · 04-29-2014, 06:23 PM

I agree, I think his guy is a bit lost and it was his changing of thr clutch that has caused the bike to overheat. I'm trying to determine the cause of it overheating though. From what I understand, an air cooled bike either overheats from a lean mixture or a lack of lubrication.. I've ruled out the wrong grade of oil.. Could he have messed with the oil pump when he was changing the clutch?

We've established that I should get new valves. Should I replace anything else since the bike has overheated?

**jonathan180iq** · 04-30-2014, 08:32 AM

The guides themselves, or sleeves, I would go ahead and replace as well. - I'm looking at the parts fiche while I type this so give me a second...

Have you changed your oil since all of this has happened? Have you been able to take a peek at it and see if there are metal shavings in either the oil or the oil filter?

The oil pump is an internally driven gear set that connects to the clutch via the "engine oil pump drive". As that thing spins, it spins the oil pump, which is located behind the oil filter. If these aren't alingned - like, if he missed some shims or spacers or something, then your oil pump isn't actually pumping oil and the only thing getting lubricated would be the crank. And that makes sense because it sounds like you aren't getting any lubrication to the top end, which is where you said it was starting to discolor, right?

The good news we have had people on this site with more serious overheating conditions and they were able to resurrect the bike.

I would get eyeballs on the valve chain guides to make sure they haven't warped or deteriorated. You're going to need to really check that top end for any sign of damage or metal fatigue. Driving 20 miles or so with no oil pressure to the head isn't good. And it's not your fault. See if you can find out exactly what that guy did. If you need to, show him the parts breakdown...

http://www.ronayers.com/CLUTCH--C227893.aspx

HKVolty · 04-30-2014, 05:55 PM

Very helpful, thanks.

The engine did change color a bit and it also heated until it seized and wouldn't turn over until it cooled down.

I actually noticed with the engine running that I would still see oil in the sight window for the oil level. I would assume with a engine operating normally that the pump would suck the oil out of the sump and pump it to the top of the engine and you shouldnt see a normal oil level in the sight window?

blaine · 04-30-2014, 07:20 PM

That's right.If the engine is pumping oil you can't see it in the sight glass when engine is running.

HKVolty · 04-30-2014, 10:46 PM

Well that's huge.

Will have to have a look at where the oil pump is driven from the engine and see if he somehow disconnected it.

**jonathan180iq** · 05-01-2014, 02:14 PM

He must have - it's a gear driven system that has the drive gear on the same shaft as the clutch. It's the outermost drive ring, from what I'm looking at.

Find someone else to repair this.

04-25-2014, 08:42 AM	#1
HKVolty Junior Member Join Date: Apr 2014 Posts: 5	Overheating Hi everyone, I have a TU250 Volty, same engine as the GZ. Its a 1998 with 30,000km (20,000 miles) I bought it about 6 months ago, my first bike. I'm not really hands on with mechanical stuff, but I know most of the bits and pieces and what what they do. My bike was running fine except the clutch was slipping. So I took it to a mechanic who changed the clutch for me. Rode the bike home and parked it and everything was fine. The next time I took it for a ride, it struggled to maintain power and then started stalling after about 5 minutes on the highway. I nursed it off the highway and to the side of the road and by the time I got it there it had stalled all together and wouldn't turn over. There was smoke coming off the engine and it seemed like it had overheated quite a lot. I was in a rush to get to work so I parked it at the side of the road and walked to the train station. I came back after work, about 10 hours later and started the bike. It started and ran, but sounded terrible. I nursed it slowly back to the mechanic and left it there for him. He adjusted the valves and told me to come back and get it. I went to pick it up and it was running fine, but on my way home it would still heat up and start stalling at temp. I turned around and took it straight back to his shop to show him. He thought it might be the spark plug cover getting the wire too hot so he changed that and readjusted the valves. The stalling seemed to stop. So I took the bike and got on the highway for about 10 minutes. Coming off the highway at the first red light I got to the bike stalled and was in the same condition of being overheated (this time the top end had a hint of gold colour) and not being able to turn over. Let it cool down again and started it, same condition with the valves way out of spec making it sound horrible. I nursed it back to the mechanic again. I suspected he might have used the wrong grade of oil when he changed the clutch, causing it to over heat and subsequently throwing the valves out of spec. I left the bike with him and asked him to road test it next time before I come.to pick it up. After changing the oil and adjusting the valves again, he's ridden it with the same result, the engine runs fine but overheats, struggles and the valves get out of tolerance. He suggests the problem is worm valve guides making the engine over heat and thinks I need a new top end and I should potentially replace the cylinder and piston. The mechanic keeps blaming the guy who sold me the bike, saying the thing had a weak engine, but I had it for 6 months and it was fine until this guy changed the clutch. Has anyone heard of this before? Do you think I need to replace all these parts? HK Login or Register to Remove Ads
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04-25-2014, 11:36 AM	#3
raul10141964 Senior Member Join Date: Apr 2012 Location: Elkhart, Indiana Posts: 369	the overheating is probably because the engine is running too lean. check for vacuum leaks, damage on the air box or damaged or missing air filter. The valves coming out of spec mean that they are stretching and will brake soon and need to be replaced Login or Register to Remove Ads Last edited by jonathan180iq; 04-25-2014 at 04:09 PM.
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04-29-2014, 06:23 PM	#5
HKVolty Junior Member Join Date: Apr 2014 Posts: 5	I agree, I think his guy is a bit lost and it was his changing of thr clutch that has caused the bike to overheat. I'm trying to determine the cause of it overheating though. From what I understand, an air cooled bike either overheats from a lean mixture or a lack of lubrication.. I've ruled out the wrong grade of oil.. Could he have messed with the oil pump when he was changing the clutch? We've established that I should get new valves. Should I replace anything else since the bike has overheated? Login or Register to Remove Ads
	0

04-30-2014, 07:20 PM	#8
blaine Senior Member Join Date: Feb 2010 Location: P.E.I. Canada Posts: 3,784	That's right.If the engine is pumping oil you can't see it in the sight glass when engine is running. __________________ If at first you do succeed, try not to look surprised.
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04-25-2014, 09:18 AM	#2
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	If you go back and read this whole thing as someone who is not you, it started with the clutch replacement... Why was your clutch slipping? 20,000 miles is not dead clutch territory. And if his solution to an overheating problem was to adjust the valves and give you a new spark plug, then he doesn't know what he is doing - which in turn means you have no idea what was done when the clutch was unnecessarily replaced. Get a new mechanic.
	0

04-25-2014, 04:14 PM	#4
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	Good points. If they're actually coming out of spec that quickly when he does whatever he does, they're about to fail. Correct this now before you lose the motor. There are multiple tales on the forum of how hard it is to get the head back to right after a valve drops.
	0

04-30-2014, 08:32 AM	#6
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	The guides themselves, or sleeves, I would go ahead and replace as well. - I'm looking at the parts fiche while I type this so give me a second... Have you changed your oil since all of this has happened? Have you been able to take a peek at it and see if there are metal shavings in either the oil or the oil filter? The oil pump is an internally driven gear set that connects to the clutch via the "engine oil pump drive". As that thing spins, it spins the oil pump, which is located behind the oil filter. If these aren't alingned - like, if he missed some shims or spacers or something, then your oil pump isn't actually pumping oil and the only thing getting lubricated would be the crank. And that makes sense because it sounds like you aren't getting any lubrication to the top end, which is where you said it was starting to discolor, right? The good news we have had people on this site with more serious overheating conditions and they were able to resurrect the bike. I would get eyeballs on the valve chain guides to make sure they haven't warped or deteriorated. You're going to need to really check that top end for any sign of damage or metal fatigue. Driving 20 miles or so with no oil pressure to the head isn't good. And it's not your fault. See if you can find out exactly what that guy did. If you need to, show him the parts breakdown... http://www.ronayers.com/CLUTCH--C227893.aspx
	0

04-30-2014, 05:55 PM	#7
HKVolty Junior Member Join Date: Apr 2014 Posts: 5	Very helpful, thanks. The engine did change color a bit and it also heated until it seized and wouldn't turn over until it cooled down. I actually noticed with the engine running that I would still see oil in the sight window for the oil level. I would assume with a engine operating normally that the pump would suck the oil out of the sump and pump it to the top of the engine and you shouldnt see a normal oil level in the sight window?
	0

04-30-2014, 10:46 PM	#9
HKVolty Junior Member Join Date: Apr 2014 Posts: 5	Well that's huge. Will have to have a look at where the oil pump is driven from the engine and see if he somehow disconnected it.
	0

05-01-2014, 02:14 PM	#10
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	He must have - it's a gear driven system that has the drive gear on the same shaft as the clutch. It's the outermost drive ring, from what I'm looking at. Find someone else to repair this.
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