How hot should it run?

[Big Daft Lad]

Just got my 1990 FZr600 and i'm a little concerned about how hot it's running. The gauge seems to sit about 2-3mm below the red. Is this normal? if not what should I look at first?

Much appreciated.BDL.

[haunter]

flush the coolant system first unless you know the coolant is recent

[ragedigital]

Don't think I've ever been that hot. Better make sure the coolant is flowing.

You might also look into a manual fan switch.

[yamaha_george]

Don't think I've ever been that hot. Better make sure the coolant is flowing.

You might also look into a manual fan switch.

and buy yourself some "engine ice" from a MX bike shop or fleabay
works in the tropics on hot days here

[Fizzinatorr]

+1 to Engine Ice

nothing works better

[Big Daft Lad]

Just been out working on the bike.

The radiator was cold even when it was in the red so I though the thermostat was stuck closed. I whipped that out tried it and it's cooler but still really hot. I ran a hose through the rad and re-bled the system. I've not got the bike built back up yet but at least the radiator is getting hot now. Is the system tricky to blead usually? I'll build it up and try it tomorrow.

It's getting really frustrating as I've not even ridden the bike for any distance since I bought it . All for minor things like this. I'm sure there is a sweet bike in there somewhere....

[bweight]

While I might try that as well for my bike, as has been pointed out to me, it still doesn't fix the issue of why the bikes running hot. I'm having similar issues, except that my temp gauge goes into the red before the thermostat opens up. I can hear it click when I'm riding and it goes, then I can physically feel the coolant rushing through to the overflow bottle. I've burped the rad and cleared up the air problems I had originally, but it still gets hot.

Now, when the thermostat opens up the temp drops out of the red, but hangs about 1/8" or less below the red. I've changed plugs, thermostat, coolant, thermo swith, thermal unit and it's STILL having this issue..

Here's a pic of one of the old plugs I pulled out:



From what I've been told and can tell by looking at that plug, it's running LEAN.. But I still don't know how to correct that problem. I have stock carbs, and I believe they're not jetted. I haven't actually tore them down yet because if I'm going to do that and there's no adjustments to rectify the problem unless I re-jet them, then that's when I'll pull them off. The ONLY other thing I could imagine it being is the water pump, which again is another PITA to get out of there and I wanna make sure that I do it once, not twice or 3 times..

The main thing I wanna know, is if I pull the thermostat out of there, is it going to help me.. I mean, I did that in my 86 Celica way back when and it kept things cooler, but I also don't wanna damage the bike when it's something fairly easy to tweak..

Sorry to hijack, I'm just tryin to figure this issue out as well.

[Fizzinatorr]

lean will make it heat up if its' really lean the revs will hang - so check that out

otherwise

flush your rad. wire a manual fan switch

[bweight]

RPM's don't hang when I snap the throttle.. And I have a fan switch as well.. in fact, I always run the fan no matter what.. so I've got an issue here that's keeping the engine from running in the right temp. range.. Now I just gotta figure out what that problem is.

[yamaha_george]

lean will make it heat up if its' really lean the revs will hang - so check that out

otherwise

flush your rad. wire a manual fan switch

+1 on lean & heat. that plug is LEAN for sure with our carbs they are sensitive to float height I would check that first.

You can check the thermoswitch as per the manual.

leaving it out is not a problem on other bikes I have had not sure about FZR's as never even in tropics had the problem.

Tumbling the engine but not starting with move the water via pump I tend to leave the rad cap off
but have a bit of rag over stop it splashing far and wide (anti-freeze does not like paint ) shaking the bike pumping the forks helps move any air bubbles around and out too.

HTH

[bweight]

I'm gonna replace the water-pump to see if that's the issue.. found a used one off a 600 that'll work, just waiting for a response from the seller on the condition of it.. If it's all good, I'll buy it and try it.. if not, then I'll keep looking.

[zero9243]

I mean, if you are overflowing that bad and running real far into the red, you may have a blown head gasket

[yamaha_george]

I mean, if you are overflowing that bad and running real far into the red, you may have a blown head gasket

If that was the case you would get white smoke as the water got sucked in at inlet time and the coolant would show signs of contamination oil film bits of carbon black etc.
Also with the engine running the coolant would fill just about everything & blow the soft rubber bung out the o/flow bottle as the volume of air from a cylinder is quite considerable (150cc per pot )

[bweight]

There's no coolant in the oil as far as I can tell.. Don't see any white smoke either.. I don't *think* it's the head gasket, however, it's on the list of items to look at..

[zero9243]

I mean, if you are overflowing that bad and running real far into the red, you may have a blown head gasket

If that was the case you would get white smoke as the water got sucked in at inlet time and the coolant would show signs of contamination oil film bits of carbon black etc.
Also with the engine running the coolant would fill just about everything & blow the soft rubber bung out the o/flow bottle as the volume of air from a cylinder is quite considerable (150cc per pot )

Yah you're right, i sort of jumped the gun there