gt750 fan

[chance johns]

im reworking some bad electrical descions from the previous owner. i hooked up the fan switch according to the diagram, previous owner had it wired to a toggle. i took it out for a test ride and i noticed that the fan would only operate when i accelerated. i came to the conclussion that the battery wasnt charging great and only had enough juice to spin the fan, only with higher rpms. but then i was thinking, the fan would pull from the battery regardless and just kill the battery eventually. regardless i checked the batt and it wasnt charging very well, 11.5 at idle 12.5 with 5k rpms so i played with the adjustment and got it a little better, then the fan wasnt working at all. i unplugged the ground to the switch so it consistantly would run. it was barely putring any load on the battery, and didnt seem to be cooling the bike. where as when it had the toggle switch it did cool the motor and put a big draw on the battery. i am assuming this switch is bad , and thats why the previous owner had a toggle on it. how can i check this switch or be sure it is bad? its possible there is screwy wiring in there aomewhere, ive been going through it and fixing all sorts of things but im not rulling out that i may have missed something. explain the thermostat and fan switch .

[tz375]

It's possible that the PO used a sender that changes resistance as temperature rises which is what the gauge sensor does. The switch should go from open to closed at a certain temperature. You could hook it up to a multimeter and measure resistance as the bike runs. It should stay the same until the bike gets hot and then it basically switches - contacts open or close as temp changes.

[Alan H]

The fan wasn't used after the J model. Just not necessary.

[Coyote]

The fan wasn't used after the J model. Just not necessary

.
+1 The best cure for the fan is to remove it and place it on the shelf. Suzuki omitted the fan after the J as it never ran anyway. Looks trick, but all it does is add weight.

[GT750Battleship]

Hi,the story goes that Suzuki took six 750J's to Death Valley (Southern California) for testing at the height of summer,& could only get one bike to start its fan during testing....hence the fan not fitted in later model production ! Fan could be bought as an accessory I think I read this back in the day in Cycle World Magazine ?
Cheers,

[chance johns]

wow really?! how did it get passed the prototype phase? anyways why is the damn thing over heating then? how come when i had the toggle hooked up it seemed to keep my bike at proper temperature when the motor was hot and i switched the fan on? i checked for airleaks? it is jetted properly. waterpump failure? how do i check that? the radiator does get hot when my gauge reads hot.

[tz375]

First rule is if a gauge reads out of spec, suspect the gauge.

[Suzukidave]

Its not possible the thermostat was left out as that will cause the engine to over heat ?

[chance johns]

dave,what?

[Suzukidave]

I was just asking if the thermostat is still installed as running these engines without one can cause them to over heat .

[GT750Battleship]

yes designed to fail "open",as mine did a month ago.....temp gauge stayed firmly in the blue zone...day time temp was 30c !!!
Cheers,
Roger.

[tz375]

And strangely enough I was sorting through piles of GT750 electrical components last night and came across a fan relay. It took me a while to work out what it was though

[Suzukidave]

Its just if the lower " bypass " action of the thermostat does work some of the coolant will not go through the radiator and this can cause the engine temp to run higher http://www.oldjapanesebikes.com/mraxl_G ... /sr57.html" onclick="window.open(this.href);return false; .

[Suzsmokeyallan]

Hey Richard, do you have plans for using that fan relay???

[tz375]

Allan,

Those are ultra rare and desirable I hear.

Good question. I have accumulated so much GT electrical stuff that I am sorting through it to see what's worth selling for parts and what belongs in the recycling pile. I should test the relay before I say anything rash I guess.