CBR250RR doesn't heat up

[DuCKy!]

Hi all!

I searched the whole internet for my problem!!
New to bikes, just got a 1990 MC22 done 28,000k's. Everything's mint apart from some cracked fairings.

Anyways, when I started it and let it idle for 5 mins, nothing happens on the temperature gauge. So I decided to take it for a slow ride.
Another 10 minutes later, the temperature goes to just past the big thick bar by the "C" symbol on the gauge. Decided to get the revs up to around 11k or so.
Another 5 minutes later it's gone up just a tad and that's about it.

From my car knowledge, this points to a rooted thermostat.
Am I correct to assume so?

Cheers
Nicholas

[Rhys]

I think you will find that it is at the right temp, the gauge should be on about 1/4

[Big Dog]

Hi all!

I searched the whole internet for my problem!!
New to bikes, just got a 1990 MC22 done 28,000k's. Everything's mint apart from some cracked fairings.

Anyways, when I started it and let it idle for 5 mins, nothing happens on the temperature gauge. So I decided to take it for a slow ride.
Another 10 minutes later, the temperature goes to just past the big thick bar by the "C" symbol on the gauge. Decided to get the revs up to around 11k or so.
Another 5 minutes later it's gone up just a tad and that's about it.

From my car knowledge, this points to a rooted thermostat.
Am I correct to assume so?

Cheers
Nicholas
The delay in temp increase is that you are measuring the temp of the water on the cold side of the thermostat.
That this goes up after a period indicates your thermostat is working.

Unless you can feel heat coming out from the fairings I wouldn't panic.

Most bikes of this era barely register on the temp gauge unless in stop start traffic( no air flow), you thrash it or there is a problem.



Stupid phone / Tapatalk, apologies in advance.

[The Pastor]

does the fan kick in?

Check the thermostat is still in there, some people take them out.

[DuCKy!]

The Pastor: I didn't notice if the fan kicked in or not. From what I've read around, the fan only kicks in when the gauge is at 3/4 to Hot.

Big Dog: I didn't realise that the thermosensor is on the cool side of the thermostat! That makes sense in regards to the huge delay in temperature increase, although I don't know why they designed it like this, unlike motorcars?

I'll warm it up, and take it for a longer ride. Will keep note of the time I've rode, as well as snap a pic of the gauge when I park up.

[AllanB]

1. don't idle the thing for 5 minutes. That is not good for your engine. Fire it up chuck on the helmet and gloves (I'm presuming you have your other riding gear on) and ride. just take it easy for the first few kms while the engine warms it's self up.


At normal operating temp the Honda's tend to read at the low end of the temp gauge - you'll notice it rise when idling at a traffic light for a long duration or when stuck behind traffic heading up hills.

[DuCKy!]

1. don't idle the thing for 5 minutes. That is not good for your engine. Fire it up chuck on the helmet and gloves (I'm presuming you have your other riding gear on) and ride. just take it easy for the first few kms while the engine warms it's self up.


I never let my cars idle to warm up. However I've seen people religiously suggesting to warm up at idle for 5 mins as the older engines "need" that warm up phase.

I'll go with your instructions :)

[Big Dog]

I warm to a smooth idle. Usually as long as helmet and gloves plus reversing to where I usually put it in gear on a cold morning.


Stupid phone / Tapatalk, apologies in advance.

[neels]

I never let my cars idle to warm up. However I've seen people religiously suggesting to warm up at idle for 5 mins as the older engines "need" that warm up phase.

I'll go with your instructions :)
Idling warms your engine very slowly, while the oil is still finding it's way around and nothing is up to it's designed operating temperature. Just remember it's not a 1950's Morris that needs warming up so the poxy old carb works properly.

[Erelyes]

Idling warms your engine very slowly, while the oil is still finding it's way around and nothing is up to it's designed operating temperature. Just remember it's not a 1950's Morris that needs warming up so the poxy old carb works properly.

1 out of 3 it's. I'll take that.

Seriously though, the increased wear you get from 5 minutes worth of idling is going to be far and above any wear you get because the thing's still 'warming up' as you ride.

[AllanB]

the 'old' 5 minute warm up comes from absolute decades back - heavy weight single rate oil, poorer machining tolerances etc. Your modern water cooled car manual will tell you NOT to do a lengthy warm up. Same applies to the bike. Just take it easy through the revs until it reaches temp.

Good question though.

[hayd3n]

what ???? ive been cranking and thrashing my bike for almost 4 years now , now you say i should warm it up??
i guess 117,000 kms is almost run in lol,
seriously tho leaving you bike on its sidestand and warming up is not good for it think about how the oil is flowing around your engine on its side and barely pumping over the cams

[nzspokes]

All this talk of warming up. Meh.

Neighbors have a prem baby, If I start it and warm it up I would wake the kid. I roll down the drive and start it on the street and away I go.

My bike is not subtle.

[DuCKy!]

Alrighty, point taken! No "warming up for 5 mins".

300628

Does this look alright? This was after a good amount of riding.

[nzspokes]

Yup, thats fine.

[Ender EnZed]

Most bikes of this era barely register on the temp gauge unless in stop start traffic( no air flow), you thrash it or there is a problem.


This.^^

From your description (getting just past the "C" symbol, then little further) it sounds like it's behaving normally.

If you really want to see the needle go up and check that the fan works then go for a decent ride and leave it running when you stop. That'll get it hot.

[DuCKy!]

Cheers guys!
Great fun to ride... definitely different to the 9krpm on my S2k :laugh:

[avgas]

seriously tho leaving you bike on its sidestand and warming up is not good for it think about how the oil is flowing around your engine on its side and barely pumping over the cams
Come again? Wet sump and a mechanical pump. You should have the correct amount of oil through the engine at the complete rev range. You need less oil at lower revs - so a mechanical pump will run slower. Likewise because its a wet sump - you should have the oil intakes complete covered at all times, so pump doesn't run dry. This means that even with half (or worse) a tank/sump of oil - the intake should still be saturated.

[hayd3n]

Come again? Wet sump and a mechanical pump. You should have the correct amount of oil through the engine at the complete rev range. You need less oil at lower revs - so a mechanical pump will run slower. Likewise because its a wet sump - you should have the oil intakes complete covered at all times, so pump doesn't run dry. This means that even with half (or worse) a tank/sump of oil - the intake should still be saturated.

think how liquids flow, it will always take the easiest path so the high side will receive less lubrication up top whilst idling on its side-stand

[The Reibz]

think how liquids flow, it will always take the easiest path so the high side will receive less lubrication up top whilst idling on its side-stand

The oil (fed to the head) is inside a constant pressure fed system usually fed by a gear driven pump. All parts should be equally lubricated unless the oil pump pickup is not submerged in oil. :)
Having the engine on a incline will take slightly longer for the pressure to build up but it is nothing to be worried about. My falcon has noisy tappets until about 10 seconds after startup which is when the oil pressure is built up. Busa also has a light tap from the head on the first couple of engine cycles on startup.

As for the CBR temperature issue, I won't worry unless that needle was on the other end of the gauge

[avgas]

think how liquids flow, it will always take the easiest path so the high side will receive less lubrication up top whilst idling on its side-stand
To add what Reibz has already said. The oil loop is designed to coat every part of the engine with the bare minimum amount of oil. So provided you don't leave it on the side stand idling for a good 3-4 hours you should be fine, as the minimum amount of oil will cover what it needs to cover. After 4 hours idling on the side stand, it might start getting a bit dry. But even then I would be a little surprised.

They got pretty smart with engine design over the last 50 or so years. Even see a nissan motor running sideways to operate some crazy belt driven thing. So while they core of how a piston engine hasn't really changed - oil distribution and other funky elements certainly have.

[ducatilover]

Always warm one up, you cannot ride a tiny 4 cyl without revving fuck off it (try keep one under 3000rpm, even in town). Seriously. Why do you think the bastards explode so much? Cold riding eats them.

It will fuel like poo until it has a wee bit of heat any way

The oil does get to the cams, don't be silly, it is force fed to the journals. I can have my Kawasaki sitting for a year on the side stand, pull the rocker cover and it still has oil on the lobes/lifters on number four. :rolleyes:



The temp gauge on an MC22 should sit around a quarter. Buy a new fan switch too, because it's easier than having a 20+ year old switch shit itself, and in turn your engine.

[ducatilover]

My falcon has noisy tappets until about 10 seconds after startup which is when the oil pressure is built up.

That, good chap, is because Coons glaze the lifter feeds and it takes longer to get the right volume of oil in the bastards.
:first: