Wierd Running with some smoke too!

[simsport]

Hi there.
I took my Euro zx550 out to a vintage jap bike meet this weekend and the thing was not too good.

The symptoms are that it runs hot, almost all the way over to the right of the guage. I have balanced the carbs, set the pilots at 2.5 out (UK spec) and have flushed the system plus tested the thermostat. The fan runs when I stop.

Any ideas why it might still be hot?

The other problem was a strange stumble, more like a 2 stroke seize for just a moment when running hard through the gears. This added to the fact that the bike behind me saw a puff of blue smoke from the left pipe makes me wonder if the thing has nipped up. However it idels fine, the plugs look ok (front is a little sooty but not wet or oily) and there is no smoke when I rev the thing.

There may have been a slight overfill of oil but nothing too radical. It obviously is less happy when its hot.

Sorry to pester you guys again but help!

Thanks
Simon

PS Have bought the airbox kit from a guy in the US, I asume it will help me?

[Extent]

As long as it's not over into the red it's probably ok if your fan is coming on.  I find it runs really hot if I don't keep up a speed of about 25 mph or so, like when sitting in traffic or waiting at stoplights, but that's normal for this bike.  I switched to pure water + water wetter a while ago and I've seen much lower running temps than with normal glycol coolants, but your local climate may limit your choices there.

Stumble while running through the gears is probably the age old vision stumble.  Clean, synched, properly adjusted carbs with a non-leaking YICS will make it go away.  2.5 turns out on the pilots is a good starting place, but they need to be custom tuned to your specific machine.  If you're sure everything else is in order play with then 1/4 turn at a time and you should be able to dial the stumble out.  Doing the airbox mod should help as well, but everything has to come together for it all to work.

[MotorPlow]

Just curious, when you flushed the coolant system, did you burp the system through the bolt on the top coolant hose? You need to burp and and then fill a little more through that bolt to complete the coolant changing proceedure.

[QBS]

Antifreeze has corrosion inhibiters that distilled water does not.  Be aware that everything that the coolent touches is aluminium.  You really don't want to fill your radiator passages with aluminim corrosion.  Get antifreeze into your cooling system.  The V cooling system is very robust and, when properly filled, needs nothing more or less than non silicate, non phosphorus antifreeze to function very well.

[Extent]

Water wetter is a corrosion inhibitor, it just dosen't lower the freezing point of the coolant any (can also be mixed in with water/coolant blends)

[simsport]

I did bleed the air out from the 'T' bolt over the engine.

What I have read says that the test bikes never got this hot...does anyone else have one running this warm or might there be another problem?

Also the smoke?
If the engine stumbles in the way people expect with the usual running fault would that cause it to smoke for a moment?

I'm gonna do a comp check when I can.

Cheers
Simon
OH, And I cant see the oil level either....darn window is stained.
Love riding the bike though, great noise.

[simsport]

Can anyone confirm how the temp guage should read?
Should it be straight up most of the time, or is what I am seeing (over to the far right) in fact normal for this bike?

I have bled the system yet again and still it is running hot. Running out of ideas now.

cHEERS
sIMON

[kiawrench]

1. check your thermostat, be sure it is installed spring in ,,  as in spring goes in towards main bulk of engine

2. a "normal" reading on most visions is 1/2 to 2/3 across the gauge ,and then fan should come on

3. look for the simple stuff,,, is fan coming on when 2/3 or more,,, is anything blocking air flow   did someone in the past take the fan apart - remounting the blades backwards,,,( that is possible, hard but possible)  are the fins on cooler assy in good order, all straight , etc .

4. is the radiator plugged up _ use temp gauge to check  rad temps in 8 or 10 spots, should all be close, higher in infeed port, lower on out feed

[Tiger]

???....Are you actually getting a true temp' reading... ??? Where you "bleed" the air from the coolant at the top hose....there are two Temp' unit's installed...one is for the fan and the other is for the temp' gauge.....Either test and/or replace these to make sure you have an over heating problem..... :o

[YellowJacket!]

Very good point Tiger.

David

[h2olawyer]

When temps are over 80F and I'm in stop & go traffic or riding twisties under 30 - 35 MPH, my gauge runs to the top of the green.  In those situations, I just flip on the manual fan override switch and keep the fan running for a while.  It really helps keep the temps down.  It didn't run that hot for many years.  Then, I was out on a hot day & noticed I was getting a very warm reading on the gauge.  The fan fuse had blown.  Didn't get out of the green but still was hotter than it had ever been before.  Since then, it has tended to run warmer but never above the top of the green on the gauge.  Tends to vary from 1/2 to top of green depending on riding situation & ambient temps.

Look for a little coolant weeping from the small hole near the thermostat housing.  If you see some signs of coolant there, your water pump seal is leaking.  Mine was doing that for a while.  I got some waterpump sealer / conditioner from an auto parts store & put it in the cooling system.  It didn't entirely stop the leak, but now I only get a drip on rare occasions.  The bike also runs a little cooler after that treatment.

After getting that leak mostly stopped, I switched to Engine Ice coolant.  That made a little more improvement in the bike's cooling ability.  I didn't want to have that sealant / conditioner running through the system for too many miles.  I changed it after about 250 miles.  I have the parts to rebuild my water pump and plan on doing it next winter.

H₂O