overheating on idle

[billy budge]

Hello to all, im after some advice please because im at my wits end with this overheating problem ive got with my trx.
The problem is that after only 5-6mins of idling the temp gauge has gone up to 80-90 degrees and still climbing, in the 11 years ive had it it has always sat around 70 degrees and only gone to the fan kicking in twice and that was on mega hot days with lots of abuse!!
After the 5-6mins of idling the coolant was steaming hot as i drained some to see what was happening, you cant touch the rad/rad hoses/cylinder block for it being soooo hot either. The rest of the engine seems fine but what i have also noticed is that the over headers ive got are unbelievably hot but only after about a minute of idling, dont know if this is normal or linked to the problem or not?? The system has been turned into a 2 into 1 system but someone but not very well, he just chopped the collector box in half, peened it over and welded it up. I thought maybe the exhaust gases were backing up and causing things to heat up more but it has been on a dyno in this condition and nothing was detected??
Ive tried several decent rads for comparison, ive got silicon hoses and use a race grade coolant, theres no air in the system that i can see after many tests, ive used several temp sender units and stripped and tested the t'stat and everything works fine. The only thing i have left to check is the water pump but can this be removed and checked in situ or has the engine got to be out and in bits to do this, and more importantly is this worth checking??
Any advice is greatly appreciated as i cant understand after 11 years of no problems and not touching anything that its gone pear shaped, i just wanna get riding again. Cheers in advance.

[trixynut]

Billy,

Not much help this, as you've checked everything already, but I'd tend to agree with you that its the pump.

Wouldn't know how to go about checking it though.....?

Also, race-grade coolant (whatever that is) is probably not as good as road coolant, but whether it would make such a difference...?

Dave

[billy budge]

Hi Dave, good to hear from you bud.

The coolant is just a ready mixed putoline jobby but with slighty higher/lower temp ranges than normal, was recommended but cant see it doing much difference as you say.

I read through the haynes as thats all ive got to go by and they say to check for play in the impeller and to see if it rotates freely. Now seeing as its on drive gear etc should it be checked as it is on the engine or when its out??? Never tackled this before so im abit in the dark about it, if its checked in situ in the engine then the impeller dont move for shit...im hoping ive got it all wrong. Come on you experts help us out pleeeease.

[HansJ]

Do i understand you correctly that nothing's been changed? You've had the exhaust like that before? One thought was that it's running lean for some reason, this could make it run hot, or, but this is a longshot, that maybe the valves/seats are burnt and not sealing as they should? Water pump is an obvious check of course. From memory, it's not difficult to remove the waterpump, but i think there was a small risk of dropping some of the washers on the rear side of the pump. They should not be too difficult to get out if that happens.

No oil in the water or air in the water? (Blown head gasket?)

The worst thing that could be the cause, is a major failure, some bearing that's been stuffed and is running hot, but let's hope that's not the case. I imagine You'd noticed this, by sound or looking at the oil for "metallic" looks

[billy budge]

Hi Hans, cheers for the input.

The only things that ive changed is putting fcr41's on and the over exhaust system, no engine mods etc. I thought it was running lean and hot and so i put it on the dyno but it was almost running bang on so it kinda ruled that out.
A supposed expert modified my exhaust and im disgusted by it to be honest, i was hoping he would have made a new section of pipe from where the headers join the collector box and made that and the link pipe section a slighty bigger bore to allow for 2 exhaust ports worth of gases instead of one. Could this cause overheating if the gases are building up??

No signs of a blown head gasket either mate.

Any tips on how to remove the water pump then??

[HansJ]

was it bang on at idle as well? Dyno runs are mostly run through acceleration... The new carbs might need a different idle jet? Other than that, i don't have a clue re the 2-1 pipes. Your guess is as good as mine... Maybe it's worthwhile to put the original back on, will at least tell if the problem is elsewhere.

Removing the pump is pretty straight forward. The outer housing can be taken off once the bolts have been removed, and IIRC the inner housing is just pushed in, so with some pullling/wiggling it should come out fine. I doubt that Youcll find something interesting though.

Is it only on idling it's running warm?

[billy budge]

Dont know for sure if it was checked at idle on the dyno, would have to ask the tester.

It seems to hold at that 80-90 degree temp whilst riding, on the 3 times ive been out on it, but as soon as you become stationary it begins to climb. I dont want it to be near the top limit temp all the time, cant do it any good and its the fact thats its never done it before that bugs me mate.

Im hoping someone with fcr's can advise on idle jet sizes but from what ive read all that gets changed is mains jet sizes.

[dandywarhol]

I've heard of waterpump impellors come off TDMs

[Killerwhale]

Dont know for sure if it was checked at idle on the dyno, would have to ask the tester.

It seems to hold at that 80-90 degree temp whilst riding, on the 3 times ive been out on it, but as soon as you become stationary it begins to climb. I dont want it to be near the top limit temp all the time, cant do it any good and its the fact thats its never done it before that bugs me mate.

Im hoping someone with fcr's can advise on idle jet sizes but from what ive read all that gets changed is mains jet sizes.

Oh crap, been writing for 5 min and pressed wrong button...
Well, where the carbs new? One dude had crap in the carbs wich made it so lean on idle the headers started glowing almost instantly.
Sonic bath and ok!
I´ve changed slow jet but to smaller...and fuelscrews out a bit.

[HansJ]

Dont know for sure if it was checked at idle on the dyno, would have to ask the tester.

It seems to hold at that 80-90 degree temp whilst riding, on the 3 times ive been out on it, but as soon as you become stationary it begins to climb. I dont want it to be near the top limit temp all the time, cant do it any good and its the fact thats its never done it before that bugs me mate.

Im hoping someone with fcr's can advise on idle jet sizes but from what ive read all that gets changed is mains jet sizes.

If it's running that hot while riding as well, forget about idle jets. Exhaust system, or as Dandy says, waterpump then (which seems more likely in the light of his comment).

[billy budge]

Impellers come off!!!! yikes thats not good, i better get the bugger out and check it then i suppose and report back.

Might just bget the exhaust re-done just for peace of mind and that it looks like an abortion anyway.

Killer - the carbs are new buddy, did have a problem where fuel was pissing out of the breather pipe. On a strip down there was a wee bit of adhesive, that they put on the bowls to seal them, this had stuck th the float valve enough to wedge it open!!

[Killerwhale]

Killer - the carbs are new buddy, did have a problem where fuel was pissing out of the breather pipe. On a strip down there was a wee bit of adhesive, that they put on the bowls to seal them, this had stuck th the float valve enough to wedge it open!!

Hope not a tad of that clogged a slow jet as well...but as Hans says...mine runs at 65d when rolling along..

[Smithers]

The water pump theory sounds possible given the temperature at idle rises fast and high.....even when travelling your temperature sounds a little on the high side (but lower than when stationary due to air flow through the radiator). Thermosyphon would possibly account for some water circulation......anyways, I reckon you could inspect the water pump by simply removing the outside cover (that the hose coonects to) and seeing if the impellor is fixed properly to the shaft and you could also see if the whole shaft is not free-wheeling, therefore not rotating when the engine is going. The cover has an "O" ring for a seal. Nothing else will be disturbed inside the engine if you only take off this cover....... sounds an interesting dilemma....good luck

[DOBBO]

Try removing the radiator cap and running the engine , when the thermostat opens the fluid should start flowing through the radiator if pump is working. Always try easiest things first before tearing engines apart. Good luck with it.

[pbear62]

Hey Billy Budge, Did you get to the bottom of your overheating problem? If so, what was the cause? Always good to get an answer to these problems in case anyone else has a similar experience later on.