Engine not warming up fully

[Rainman]

My engine doesn't warm up correctly. I think that the guage works because if I sit in traffic long enough on a hot day it will eventually creep up to normal. I've already tried fitting a new thermostat, which made no difference. Even keeping the revs up only gets the reading to show cold. Apart from that the engine runs really well.

Has anyone else experienced this or have any ideas what may be causing it?

[amorti]

My engine doesn't warm up correctly. I think that the guage works because if I sit in traffic long enough on a hot day it will eventually creep up to normal. I've already tried fitting a new thermostat, which made no difference. Even keeping the revs up only gets the reading to show cold. Apart from that the engine runs really well.

Has anyone else experienced this or have any ideas what may be causing it?

Is your bike restricted? They seem to run cold with 33hp.

[Rainman]

I don't know. It seems to go fairly well and revs freely. Is there an easy way to check for a restriction kit? I was given this bike as "fixer upper",by a girl that I know. She's not mentioned anything like that being fitted.

When I'm riding it I don't rev the engine much. I'm used to riding a big twin and a triple, both of which have loads of low rev grunt so I'm not used to taking it round the dial. I've done the odd overtake where it's revved to about 11,000 rpm. without any problems.

The thing that puzzles me about this problem is that the engine won't come up to temperature even when left running in the driveway for ages. Is it possible to fit the thermostat incorrectly? I just fitted the new on in the same way as the old one.

[amorti]

If it has a restrictor fitted then it won't make much difference until the far side of about 80mph anyway.

You can only tell by removing the airbox and either removing the carbs or opening the butterflies and looking through, then you would notice the diameter is reduced by around 50% by a metal disc / washer.

Could be anything else but this seems to make sense to me, if the previous owner was a new rider.

[ONDA SF]

Check the temp sender unit, you will probably find that it is getting up to temp just that your getting a false reading.
Colin

[nampus]

The temp guage on my super four almost never moved more than 1 of 2 mm above minimum.
I once had it halfway up the scale, but that was in very bad traffic at 31 degrees celcius.
I just took it easy the first 10 minutes of every ride, and then I just opened her up

[Mansie]

Check the temp sender unit, you will probably find that it is getting up to temp just that your getting a false reading.
Colin

That's probably it. What is your temperature gauge really measuring? The water temperature? Where is it located? Perhaps you take the sensor out and calibrate in warm or boiling water of known temperature. The manual I have a temperature probe for my multimeter and I remember that some years ago I measured the oil temperature after a ride, something between 45° and 50°.
Hope this helps.
Groetjes, Mansie

[Rainman]

Thanks for the advice. I'll be checking the carbs for a restriction and also testing the sensor. Once I've done that I'll post again to say what I've found.

[Rainman]

Is there a knack for getting the airbox off ? Had a go at it and eventually gave up. I removed the tank and the 2 bolts at the rear of the airbox, then disconnected it from the carbs but there doesnt seem to be any room to do much more than move it back an inch or so. With it still in the way I couldn't see into the carbs so I still don't know if it's restricted. All 4 spark plugs looked quite fouled so they've been cleaned up. Maybe a sign that it is running cold? Also noticed that the radiator gets warm almost as soon as I start the bike up, don't think that can be right.

[amorti]

Is there a knack for getting the airbox off ? Had a go at it and eventually gave up. I removed the tank and the 2 bolts at the rear of the airbox, then disconnected it from the carbs but there doesnt seem to be any room to do much more than move it back an inch or so. With it still in the way I couldn't see into the carbs so I still don't know if it's restricted. All 4 spark plugs looked quite fouled so they've been cleaned up. Maybe a sign that it is running cold? Also noticed that the radiator gets warm almost as soon as I start the bike up, don't think that can be right.

Could the choke be jammed?