Hi again,

Ok having now replaced almost everything on this bike and waiting for the Dyno Jet kit I decided to take it away for the weekend. I covered 250 miles with luggage to my destination and all was fine. The next day I noticed the expansion chamber for coolant was almost at the overflow point near the rubber cap.

I pulled the radiator cap and couldn't see any water in there so managed to source another cap locally (the other had superglue on it so I thought it might be a temp fix). Both large pipes to the rad get hot when its running and the temperature stays nice and low until i hit lots of traffic where it rises to the top 3rd but never high.

I completed the return journey plus another 100 miles and it ran fine but the level is still right at the top of the chamber.

I changed the coolant about 700 miles ago and didn't notice anything nasty.

Any ideas, should I worry or is it likely there is an air block or something simple ?.

Thanks

 

Could be heat soak after you stop that pushes water into the overflow. Mine would get into the upper reach of the gauge here in California when the air temps were 95+ and traffic. I moved my horn so nothing blocked airflow to the radiator and I wrapped the down pipes to cut heat in the fairing. Some people say that wrapping the pipes will harm them, but mine are still fine after 20 years. Sounds like your fan is working as the temps only go so high. Make sure the coolant is fresh and clear.

 

I'm not sure to the answer but I've got a similar question / inquirie.
I went a a trip that was a little over 300km. Nearly back home and I noticed the temp gauge rising wen behind traffic doin around 50km but on open road sweet as. Then I stopped for gas and noticed coolant from under bike. At time thought it must be an overflow or something to that effect. I checked the old plastic reservoir and water levels look as should so on bike again to home. Next day I pulled fairing off and checked radiator which was empty. Oh no me thinks I was givin it snot a eather worste case blew the head gasket or water pump etc. filled it up bled it and ran it. Found a leak in the bottom left of radiator. Must have been a stone I think. Sweet easy fix. That done bike is running ok again.
Now my question. If the radiator was empty shouldn't the water in the reservoir have been sucked into the radiator?. I mean I thought that was how you checked the levels. Why hasn't it changed? Could there be a blocked hose maybe?
So I'm kind of in the same boat as you... Sort of. Stumped

Any ideas anyone?
KB

 

Fill up the radiator to the correct level, and then start the bike. Watch the reservoir for bubbles coming out of the fill hose. It should only take a couple of minutes of watching or so to see them if they're there. The fact that the radiator reservoir filled up almost to the top and the radiator was low would concern me.

Coolant tank blow-out (radiator low, coolant res full) *could* mean a blown head gasket.

 

Thanks, head gasket was my worry.

Your suggestion exactly what i did last night and the level stayed the same and no bubbles at all in the expansion chamber. I only had the bike on idle for 10 minutes but I would have thought any bubbles would show in this time.

Perhaps I'll need to take it for a run but if it is the head then I would rather not find out this way.

On another note the bike does surge at constant revs and seems to be holding back. I have put this down to a carb clean but is it possible this could be linked to a head gasket issue ?.

 

Exactly, I am out of ideas

 

Are you blowing lots of smoke out of the exhaust? Does the oil look good? If the answers are 1)No and 2) it looks fine... then I would say it's not related. 10 minutes should be enough time to see some bubbles if they were there.

Keep an eye out on the temp gauge and coolant levels. Watch for temp spikes.

I hope it starts to run right for you.

 

oil looks great, not milky and actually looked very clean since the last change 700 + miles ago.
there was no hiss when I opened the rubber cap on the expansion chamber and there is a very small amount of smoke on start up but none after a minute on choke or during ride.
There is no oil in the coolant either, I inspected after flushing it out and it was nice and clean etc..

I have put a lot into this bike (build thread on a UK based site) but with this I don't know if I should work to resolve it or just move the bike on now.

I will take it for a run and keep an eye on levels.

thanks for your help

 

Aaarrrrggghhhhh !!!!

Just did coolant flush and looked like a bit I oil was on the surface of the water. Stay calm I told myself, it may be the pump or oil cooler o rings. Decided to run it for a bit and there are now bubbles in the expansion tank !!!.
Well that's the head gasket then ( tell me if there is any other straws I can clutch at). I will have to keep my fingers crossed it isn't warped or cracked but knowing my luck.
Oh and it's also loosing oil which I think is another sign. Nothing showing in oil yet and the coolant isn't milky.
Today is the first day without rain where I live in the uk. I'm off to find some beer.

 

out of interest and because it may be cheaper to do given my other problems can I drop an F3 engine in as long as it is a 95,96 or 97 ?.

thanks