Hi all,

I am new to the world of the 'cane and have just put an 87 back together that I bought 18m ago from a friend.

Having taken it for a test ride last night, I found that the bike is running hot - very close to the 'engine about to explode red line'.

After lots of searching the forums here (what a great resource - without the usual forum bs!) I have found the following out.

I put car oil in - cardinal sin. Will fix today. Tho that shouldn't result in overheating.

Thermo fan in manual only and was running as soon as I noticed the temps.

New coolant already done with a flush.

I my mind this leaves one of three possibilities, blocked radiator, bad thermostat or buggered pump. As the is no water oil present in the exhaust.

Looking for a little help to find and check these items as I wasn't able to find anything on the forums.

Cheers
Mike

 

After you turned on the manual fan, did the temps come back down?
My fan runs normally (all the time while sitting), but the bike gets about 3/4 of the way up the gauge on a normal day if I'm sitting at ALL.

As for car oil.... which oil did you use? You may be absolutely fine with what you put in it.

 

as per experience few thing too check;

in this order.

check if your bike is spewing up coolant, the tube in the overflow if original, is too long, and it spewing coolant as soon as the bike is spewing it in the reserve. if it goes to the bottom cut in halfway to stop the coolant to be send in overflow mode.

check your radiator cap under the tank, if it is too hold it might not keep the right pressure, causing the coolant to boil t a lower temperature and loosing the ability to coll the motor correctly.

last if this fails, check the thermostat. if that fail again then, d a flush of your rad with a mixture of 50/50 of vinegar and distilled water.

try these first.

Have a good day

 

Dragon's on the money with the vinegar - I have always soaked sticking thermostats in
vinegar over night - quick fix

 

First things first, I say.

I just take them out and put a new one in.

 

nah I save that what is still serviceable - ooops almost forgot the

 

Re oil - it was 20/50 castrol mineral oil. I'm not a believer of using synth oils on old motors! (not to incite another oil war - each to their own).

Re with fan, I'd say it stabilised at about 7/8ths before red line.

I'll work through dragons tips (thanks mate!) and see how I go.

Interestingly, I checked the oil level this morning and it was extremely low, this bike was sitting with the oil pan off for 6m due to a crack in the pan, so perhaps I didn't put enough in to fill it properly, tho when filling I put 3l in, the let it idle for a few minutes before adding another liter - it was on the high mark before setting out on the road.

It's draining now, so I'll refill today and go for another ride to see how we go.

Thanks all for the quick responses!

 

Welcome to the forum rolli,

While searching the forum did you see where it is very common for the temp gauge to read 3/4 scale before the fan kicks in. Without a regular temp gauge reading temperatures in degrees, I have little faith in what red means on the ones on these bikes.

What's 3/4 scale on these things? 195, 200 ,212, 250 degrees????

It seams like that little temp gauge may have a bigger bark than a bite.

You know what...you know what...I may buy one of those hand held IR temp readers when I get home. It should give me the actual temp if I aim it at the radiator.

Unless you put a candy thermometer in the coolant, or use an IR reader, you won't know if you have a false alarm.


When measuring the oil, the bike should be level, center stand, not on the side stand.
You should be using Motorcycle oil or oil made to work in motorcycles. As suggested by members in this forum, I use Shell Rotella T6 now.

 

BTW some additives like Water Wetter & Engine Ice can help a lot too.

Generally lowers temps by 15 to 20 degrees F

 

Dragon - thanks for the advice, after refilling the oil I let it idle = same temp issue....

Checked the expansion tank and it was empty so after letting it cool I opened up the cap and the cooling system took about a liter of distilled water.

I've since topped up the expansion tank to the upper level and cut the overflow hose about 20mm above the upper level.

After about 15m of idling, I let the temp hit the upper normal before turning on the thermo fan, which brought the temp back to a little over half way.

After a test ride I'll consider it fixed!

Cheers again for the advice, I will still give the vinegar clean a shot, cooling systems can't work too well!

Having used vinegar on kettles to clean, I know this will lower the BP, how long do you idle it for?? Or do you go for as long as it takes to hit the boiling point the drain and flush??