2-1 exhaust

[billy budge]

I have had the stat out of the housing Pete and tested it as per Haynes manual and it all checked out fine, dont know if there is a test to check it whilst in the housing and in operation on the bike?? Whats the test for the head gasket then?? Havent got any obvious signs but worth a shot if i know what to do.

Hans - ive had no engine mods whatsoever, just fcrs which ive had set up by a very good dyno guy. As soon as the bike is started the temp gauge just goes up and up and doesnt stop so hot weather etc hasnt even come into it, i could live with that. Its the fact that its getting blistering hot after several minutes of idle?? And ive got a bespoke dual core rad fitted too so should be more than adequate. Have tried the standard rad too but still get the same results. Just wish one of you chaps were near to me and could pop round, would be great to have a fresh pair of eyes looking at it.......im starting to go blind!!

Probably a stupid theory but just remembered i replaced the original oil filler cap with one of those oil temp gauges that doubles up as a cap, that wouldnt cause a build up of pressure to cause a problem would it???

[HansJ]

And how is it when rolling? Does it cool down then?

So the change in behaviour is after a workshop installed the FCRs? Nothing else was done? (It probably has nothing to do with it, but original there's a pass-through via the manifold heating, which allows the coolant to pass without the thermostate being open, thus possibly cooling down the bike a wee bit more from the start. This is normally blcoked when mounting FCRs. If it had been an issue, then my bike had been running hot before my mods, as i had the FCRs from the beginning.)

Daft question, have you installed the thermostate the right way (can't recall if it's possible to turn it the wrong way...)

Head gasket, check the coolant reservoir, if yo have air bubbles while engine is running, that's one sign. Water in the oil is another, or oil in the water. Also, a compression tester will normally show leaks.

[billy budge]

Doesnt really drop that much when rolling, maybe 2 to 5 degrees. Its the physical heat that you can feel from it when you are near it or riding it that worries me.

The fcrs were fitted by me Hans and are spot on, the workshop did the mods to my exhaust system but it was a nasty job. I would like to think ive put the stat in the right way round and think it can only go on one way round but i will re-check it. I usually check everything at least 10 times before im happy thats its ok!!! I can only recall blocking up the 2 little hoses that used to warm the carbs but i was told to do this by someone who had already fitted fcrs.

[HansJ]

The blocking is OK, was just a thought, but like i said, not probable as mine was also blocked, and i didn't have any probs before the tuning.

Another thought, try to run without the thermostat installed. Will take longer to get the engine up to temp when running, but will indicate if there's something wrong with the thermostat (if it isn't still over-heating).

Nothing done with cams lately? Tightened the bolts too hard and they are about to shear down in the head?

[billy budge]

That was the check for the stat whilst running, well done hans!! Couldnt remember it, will give that a go.

Now that you mention it, i do recall checking the valve clearances a while back but cant recall the exact date. What i do remember though is that i didnt change or adjust anything, just checked the gaps and all was ok and then put the cover back on. Could valve clearances do this?? Wonder if i need to recheck them.

[HansJ]

I don't think valve clearances would affect engine temp. If they're tight, or even negative, it would only cause a less than perfect combustion, and although possible that the heat disperses through the inlets a bit, i don't think it's a plausible explanation. (But i am not 100 5 sure).

I was just thinking that the camshaft shells (the ones that hold the cam down) were tightened too hard, and that they might be wearing down now, and this caused excessive heat. But if you haven't touched them, it's unlikely.

[phuk72]

If the thermostat is working fine and there is no oil in the water / rad then I'm stumped unless there is a big airlock in the system?

[HansJ]

... unless there is a big airlock in the system?

I was also thinking along those lines, but i've never ended up with that. It's not a very complex coolant system, unlike some car makes. Worth a try though if everything else fails to explain the problem...

[billy budge]

Cheers guys for the help, really appreciate it. Gives me a few things to try and i will report back.

Any tips on getting rid of air locks, have done the way the book says but maybe there is a blockage.

[Killerwhale]

Hi Dave, how you doing??

Its quite a bizarre thing that it does now, from memory its never really been above 75 degrees and ive only ever heard the fan come in once. However now within 5-8 mins its up to 90 plus degrees and does not cool down alot when moving. The rad and rad hoses, headers and the front of the engine (header region) gets untouchably hot but not alot else. Dont want to run it anymore until i know whats going on, scared its gonna melt something!! Dont recall hearing the fan but then i tend to shut it off before it hits that temp range. Yet to try it without the silencer, just got to put the waterpump cover back on and re-fill the coolant.

Could you´ve got crap in the carbs? Now of people who after a groundsite had crap blocking fuel in the carbs and they ran VERY lean making headers glow...just food for thought....

[billy budge]

Cheers KW, my 'to do' list is getting longer and longer!!!!

Might be worth a look buddy while ive got the tank off then, i had a problem when i used the bike after the dyno run with fuel pissing out of the overflow pipe and couldnt understand why.
Turned out that due to us opening the bowls up 3 times for jet changes, we disturbed some of the brown sealing adhesive that Keihin had used and a teeny tiny bit had come loose and jammed the float open. Maybe theres some more crap in there now???

[billy budge]

Just been looking through the yamaha service manual and was reading through the cooling system section, i would like something cleared up please.

The water pump section says to note that after installation to check that the impeller shaft rotates freely. I thought that the pump was driven so when the bike isnt in gear and rolling then the shaft wont rotate, or is this not the case?? If it should rotate freely then mine is solid and does not move at all.

[slow codger]

One other thing, did you check that the thermostat is opening, boiling water on the hob, a thermometer and thermostat hooked to a piece of wire!.

Dave E

[billy budge]

One other thing, did you check that the thermostat is opening, boiling water on the hob, a thermometer and thermostat hooked to a piece of wire!.

Dave E

Check!!!!

[HansJ]

It sure says so in my manual as well, but after looking at the pics from my re-build, i can't see how it could. One can see the crankshaft with the counterweight to the left, the balance shaft, and the white sprocket that drives the waterpump. IIRC, they are all fixed in position, and as soon as the crank is rotating, the waterpump would turn as well. So i have hard to understand how the waterpumpshaft can rotate freely, but i might be wrong?

Sorry for the bad pic quality, it was pre-DSLR...