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Gixxer 4 ever
17th July 2004, 09:41
Two weeks ago I went from Napier to Taupo and back. I left Napier at 8.30 and it was cold. The bike ran well but.......From the Mohaka bridge on, there was a lot of ice and the air temp was very cold. The bike temp gauge dropped to 48 beg in the hills. When I got to the long plains it dropped to 42 deg. Now it was a very cold morning and the road was frozen solid. It took one and a half hours to go from Napier to Taupo. I could go on for ever about the ride but my question is... Could it have been so cold that the engine case and radiator etc lost so much heat that it could not retain a normal operating temp or would the Thermostat be allowing water to circulate through the radiator and not allowing the temp to build up? As soon as I got to the turn in to Taupo the temp returned to 57. No problems on the trip home or since. This is a 1997 GSX-R 750V

merv
17th July 2004, 10:08
Sounds like your thermostat needs replacing because they should hold the engine temp at or above the temp the thermostat opens at - i.e. if the air gets colder it should close down and prevent so much water circulation to the radiator.

As a comparo, my wife's Honda car did this last year and she hadn't noticed - I drove it one night and thought jeez the temp gauge damn near dropped to zip as we headed down the Nguaranga Gorge. Other problem was it meant the engine wasn't warming up as quick and the fuel injection was forever compensating by pouring in more fuel. One new thermostat and all fixed - it warms up quick and stays at that temperature.

It is not good for a motor to run too cold.

MikeL
17th July 2004, 21:27
Can't speak from recent experience but in the past I have found thermostats to be a bit unreliable. Once they get a bit old they tend to stick in the open position (better than staying closed, I suppose).
Having said that, I have found that on my Honda where I'm pretty certain the thermostat is working properly the temperature on the open road in winter is always well below the half-way mark. But 57 deg seems very low for "normal"...

DEATH_INC.
17th July 2004, 21:46
My 'X' normally runs 77deg,so 57 seems awfully low,and yeah,I'd look at the thermostat.

scumdog
18th July 2004, 05:29
My 'X' normally runs 77deg,so 57 seems awfully low,and yeah,I'd look at the thermostat.

Especially when most water cooled vehicles run at 80 -90 degrees

Kickaha
18th July 2004, 09:01
My 'X' normally runs 77deg,so 57 seems awfully low,and yeah,I'd look at the thermostat.


Would that not depend on where the sender unit is and where it's being measured from?

With the TZ250 superkart we go for 55deg measured at the top of the radiator,or do two strokes like a different temp range than the four strokes?

merv
18th July 2004, 09:12
Would that not depend on where the sender unit is and where it's being measured from?

With the TZ250 superkart we go for 55deg measured at the top of the radiator,or do two strokes like a different temp range than the four strokes?

Yeah 2 strokes seem to be cooler where they measure it as per our discussions about Mr Melon's bike a few months back.

4 Strokes tend to have the sender near the thermostat on the cylinder head and typically 80+ is the temp. Basically to know the answer to what it should be you need to check your manual if you have one as to what temp the thermostat should open at as thermostats are sold as say an 82 deg or whatever. The radiator cap then has a specified pressure rating as well which allows the engine to go above normal boiling point typically 10 - 20 deg more than 100 when working hard without losing water.

Motu
18th July 2004, 09:36
42deg sounds totaly wrong,I don't think a motor would even run at those temps - even with the thermostat removed most motors will get up to 80deg under normal running.Where is the sender unit located?

jimbo600
18th July 2004, 16:38
My 'X' normally runs 77deg,so 57 seems awfully low,and yeah,I'd look at the thermostat.

The new K3 750 runs at 76degrees. So 57 is way too low mate. However, as I know fuck all about mechanics I can offer no solution, so I'll go with Death on this one, it must be the thermostat.

Gixxer 4 ever
18th July 2004, 18:21
42deg sounds totaly wrong,I don't think a motor would even run at those temps - even with the thermostat removed most motors will get up to 80deg under normal running.Where is the sender unit located? It ran at that ok but as we all know it is way to cold. Found the problem see message below.

Gixxer 4 ever
18th July 2004, 18:23
Would that not depend on where the sender unit is and where it's being measured from?

With the TZ250 superkart we go for 55deg measured at the top of the radiator,or do two strokes like a different temp range than the four strokes?
Yes and it is in the back of the thermostat case. That is attached to the back of the head. Problem solved see note later in this thread.

Gixxer 4 ever
18th July 2004, 18:28
Pulled the thermostat out yesterday to find some one has gutted it. Left the frame in to seal the cap when screwed back on. SO have replaced it. Many thanks for the feed back. It is good to know what other bikes run at. I am a touch worried as to why the previous owner removed it in such a fashion. I note the temp stamped on the old one and the new one is 76.5. So I am happy to get that sorted. Lets see what happens in the summer. Thanks people for your help.

merv
18th July 2004, 18:59
The dork probably thought he was gonna make it go better contrary to what really happens. The real guts with keeping an engine from getting too hot is the size of the radiator, air flow across it and the pump capacity and the electric fan. Once the engine reaches the temp of the thermostat anything above that the thermostat has no effect so it won't help overheating to put a cooler thermostat in or to have it jammed open or holes cut in it or whatever. However on the cool side is where they control as they act like a regulator to control the amount of water that flows to the radiator.

What you said Motu about normal running, the example I gave of our Honda car they won't hold temp if you are running downhill on a cold night, the radiator capacity is just too great for that and it overcools the engine badly if the thermostat is stuck open.

Kwaka-Kid
18th July 2004, 20:40
just to give another reference my VFR400 runs @ 85degrees on m/way @ 100kmph and generally everywhere, all rides i go on, unless it gets tight and twisty and im ringing her balls (then she goes to 90degrees).. or sitting in traffic/thru auck city she runs up passed 90degrees (say, 95, even up to around 100 - this is apparently normal for a viffer)
So yeah, only on VERY cold mornings going to work does my bike sit @ like 70 degrees - so i just dont revv her hard etc, take it easy/

Motu
18th July 2004, 20:55
Over run down hill cools a motor down real fast alright Merv - on an engine transplant I did years ago I didn't fit a thermostat as I wasn't too sure about how it would go,I had a super acurate Smiths capilary tube gauge on it.I could see a temp drop as I went past the shade of some trees - on a down hill you could just watch the gauge unwind like the second hand of a watch in reverse.

Gixxer 4 ever
18th July 2004, 20:56
So yeah, only on VERY cold mornings going to work does my bike sit @ like 70 degrees - so i just dont revv her hard etc, take it easy/
Last time we had the gixxer in Auckland city it got up to 118. March 04 As soon as we left the city and headed out in to the open country she came down again. I will have to check the radiator air flow for the summer. Even with the fan on she did not loose heat. We had to get moving forward on the open road. So I suspect I have fixed the winter cool thing now I will have to work on the summer heat. Can these radiators be recored? Remember it is a curved core...

LB
19th July 2004, 05:41
Interesting thread. My bikes are air/oil cooled, and they normally run around 77-80 on the open road. One day on the 800 over Christmas in Taupo in stopped traffic it got to 109, and going up Takaka hill when stuck behind a caravan got to 112. Once out into normal running you can see the temperature drop very quickly.

It's interesting how much longer they take to get up to operating temperature in this colder weather.

Gixxer 4 ever
20th July 2004, 07:16
With the new thermostat it is running at 66-70 on the open road. Cold days but with the thermostat it is regulated and stays warm. In town it is around 75-80. So It is still cooler than most on the open road but as this is a "genuine part from Suzuki" it must be good. Happy riding out there and again thanks for the help. :calm:

F5 Dave
26th July 2004, 17:41
Just to bang on about this again as I have with My RF & YZF. Suzi seem to have a penchant for running very cold thermostats in their bikes & in the RF had 4 holes drilled in the main bending part of the unit. This is dumb as it means the engine takes ages to get up to temp. Reading the Factory website info he reckons they will have trouble carburetting properly at those low temps & suggests ~ 90 deg thermostat. Worked well on my RF (See other thread).

While you have it apart flush the coolant in both directions with a hose to clean out the rad & any backwaters. Use new coolant & Redline Water wetter if you are keen (reduces surface tension). You can replace the temp fan switch with a lower activating switch to turn the fan on earlier. Usually lives in rad, small one will be for the guage & the bigger one the switch. Take it to an auto electrician supply store & see if you can match it up.

MikeL
26th July 2004, 21:25
It must be difficult to design a cooling system that will cater for the extremes of operating conditions that are likely to be encountered. In summer my CB-1 temperature gauge shows what I would consider to be a fairly efficient operating temperature: on the open road the needle is just below the half-way point and falls lower on a steep descent. When stuck in city traffic the needle goes above the half-way mark and the fan cuts in. It never reaches the red zone. However on these cold winter days the gauge rarely rises above the bottom mark of the normal range unless I am stuck in a traffic jam. The fact that in summer it reaches normal operating temperature fairly quickly leads me to assume that the thermostat is operating correctly. In winter however the engine must be running most of the time at less than the optimum temperature. I know that on cars in very cold climates radiator blinds have been used and I wonder whether something like that on bikes would improve efficiency.

Kwaka-Kid
26th July 2004, 22:09
yeah mike, Duct tape! just tape half of her up for winter then tear it off for summer!

s'all good! or if you gotta VFR like me you can just plug up one of hte 2 radiators, i.e only getting half the cooling.

merv
27th July 2004, 08:09
yeah mike, Duct tape! just tape half of her up for winter then tear it off for summer!

s'all good! or if you gotta VFR like me you can just plug up one of hte 2 radiators, i.e only getting half the cooling.

If the thermostat was doing its job properly you shouldn't have to do this.

Gixxer 4 ever
27th July 2004, 09:22
If the thermostat was doing its job properly you shouldn't have to do this.
Yes I agree with that comment. I think I will also flush the system and replace water and antifreeze.

Gixxer 4 ever
27th July 2004, 09:29
Suzi seem to have a penchant for running very cold thermostats in their bikes & in the RF had 4 holes drilled in the main bending part of the unit. This is dumb as it means the engine takes ages to get up to temp. Reading the Factory website info he reckons they will have trouble carburetting properly at those low temps & suggests ~ 90 deg thermostat. Worked well on my RF (See other thread).
.
From what I can see this is true. Suzuki do seem to run them cold. Not the best option in my book. I know heat kills engines but so does friction and oils need to be warm to work at their Optimine. But in saying this the Gixxer has done 50,000+ ks and is running well and uses no oil so buggered if I know.

DEATH_INC.
29th July 2004, 14:55
Yep,mines over 40k now and still going strong,so it can't be to big of a deal.I've seen mine go up to about 106(the fan comes on at 105)then drops back down within a couple of minutes of the fan running....
(this should be fairly relevant,the X and V are quite similar)

MikeL
29th July 2004, 20:42
Interesting thread. My bikes are air/oil cooled, and they normally run around 77-80 on the open road. One day on the 800 over Christmas in Taupo in stopped traffic it got to 109, and going up Takaka hill when stuck behind a caravan got to 112. Once out into normal running you can see the temperature drop very quickly.

.

Is it common for air/oil cooled bikes to have a temp gauge? Neither my GSX nor the XJR has one.

Kwaka-Kid
29th July 2004, 21:23
nope, infact rare.

DEATH_INC.
29th July 2004, 21:26
My old turbo (aircooled)runs about 105-110 deg on the link module....

Gixxer 4 ever
31st July 2004, 10:22
Is it common for air/oil cooled bikes to have a temp gauge? Neither my GSX nor the XJR has one.
No. My 85 oil cooled had no temp gauge. I think it would be a worry to see just how hot they run in the middle of summer in traffic. :confused:

Morepower
1st August 2004, 23:24
Dont panic yet , often an engine will run hotter without a thermostat as the water circulates through the radiator to quickly without any restriction and it does not loose as much heat as its should.
My TL runs late 60's to early 70's now since I changed thermostat location and put in a new 78.5 degree thermostat. I need 80 plus as at under 80 it still runs the cold fuel map . but getting there.

Dave

LB
2nd August 2004, 06:15
Is it common for air/oil cooled bikes to have a temp gauge? Neither my GSX nor the XJR has one.



No, I don't think many have. Mine is digital and doubles as a clock - you have it showing as either the temperature, or press a button and change it to the clock. Both my bikes have them (same instrument clusters).

I had three air/oil cooled BMW's and none of them had tem gauges. Italian engineering triumphs over German. :rolleyes:

Gixxer 4 ever
2nd August 2004, 11:59
Dont panic yet , often an engine will run hotter without a thermostat as the water circulates through the radiator to quickly without any restriction and it does not loose as much heat as its should.
My TL runs late 60's to early 70's now since I changed thermostat location and put in a new 78.5 degree thermostat. I need 80 plus as at under 80 it still runs the cold fuel map . but getting there.

Dave

Hmmmm Now that's helpful. I had not consider that the water needs to be slowed down. Wish I had read this before the ride on the weekend i would have asked you about it. Was a good ride never the less. You gave me a fright when you did not appear after the fast corners. I new you would not have had a problem but was wondering if the 1100 had gone down. I assume it was a helmet strap or something? Happy riding and will see you in a month or so.

Morepower
3rd August 2004, 12:37
You gave me a fright when you did not appear after the fast corners. I new you would not have had a problem but was wondering if the 1100 had gone down. I assume it was a helmet strap or something? Happy riding and will see you in a month or so.

No the road must have been slippery going down to that bridge and I was fishtailing. Just stopped to check my tyre wasnt going flat.

Dave

Gixxer 4 ever
3rd August 2004, 13:00
No the road must have been slippery going down to that bridge and I was fishtailing. Just stopped to check my tyre wasnt going flat.

Dave
That's what happens when you have a big twin. To much engine braking. You would have had a lot more problems than me if you had come to Taupo that morning that started this thread. I did think of the big twins as I cruised along on the ice that morning. :calm: Not :eek: