Carbs

[billwest]

I have all of this heat insulating stuff around my carbs.  Is this stuff really necessay?  Can it be removed to tidy things up?

Thanks,

Bill.

[ccsct203]

I removed mine and went with a larger oil cooler
will I have issues in stop and go highway traffic...maybe, but it looks great!

[Dan Filetti]

Good lookin' motor.  You could eat off that...

Dan

[ccsct203]

Good lookin' motor.  You could eat off that...

Dan

Thanks
I work on it more then I ride is some weeks..lol when I had it apart for the wisecos and the 1200cc block, i redid everything.
I bead blasted the head and the cam cover
I found caliper paint is high temp and wheel paint for the cover.
the mikuni flats need the covers touched up
no one can not believe it's a '85
Keep those Fjs alive

[SkyFive]

Mine was missing when I bought my FJ and I paid around $25.00 for one on eBay. I want to keep my FJ as original and complete as possible besides that, I summized that if it wasn't needed Yamaha wouldn't have gone to the expense and trouble of putting it on the engine but I know for a fact the engine will run without it. I'm sure the heat shield has something to do with fuel vapor lock prevention and cooling the back of the cylinders.

[Pat Conlon]

Hey Bill, where do you live? Do any hot weather riding?
When you say "heat insulating stuff around my carbs", what do you mean?
The insulation on the underside of your gas tank? The heat shield between the motor and carbs? Or both?

In my opinion, yes, you need them. Both. I know that I need them living in the desert. With as much heat as our air cooled motors produce, I could easily envision the fuel boiling dry in the float bowls and gas line. Ever hear of vapor lock? That's what happens. In the old days, that's why folks would wrap their fuel lines.
Depending on the blend, gasoline has a boiling point of between 100*-400*F, so remember that, when you think of the hot air coming off your motor.
http://www.engineeringtoolbox.com/fuels-boiling-point-d_936.html
Also, the added heat has got to play hell with your carb's o rings and electrical components under the seat.

I've had hot summer rides where I've had to keep my knees and thighs away from the steel tank 'cause it was so hot. I shudder to imagine how hot that tank would have been, without the insulation.

YMMV

Cheers!   Pat

[ccsct203]

I have all of this heat insulating stuff around my carbs.  Is this stuff really necessay?  Can it be removed to tidy things up?

Thanks,

Bill.

another option would be to buy some sheet aluminum and use the oem heat shield as a template to make a functional yet attractive heat shield.
and that way the heat will stay clear of the carbs. and as we all know...heat is the enemy of our air cooled bike engines and the carbs.

[VMS]

I don't know if all years had this, but I've seen some where they have a "splatter shield" of sorts coming down from the heatshield to keep the top of the engine clean. I know alot of people cut them off for fear of poor aesthetics

[billwest]

Yep, I have the heat shield between carbs and cylinders, and the insulation under the tank.  That can stay.  I also have an extra sheet of insulation under the carbs, which is what I'm talking about.


I live in Perth, Western Australia, and yes, it does get hot.  I know about vapour lock.  My other big bore bikes (ZRX1200, ZZR1200) don't have these shields, and have no problems.

Cheers,

Bill.

[andyb]

They also aren't air cooled.

I'd replace the shields with something prettier, but I'd definitely keep them in some form or another.

[Harvy]

Yep, I have the heat shield between carbs and cylinders, and the insulation under the tank.  That can stay.  I also have an extra sheet of insulation under the carbs, which is what I'm talking about.


I live in Perth, Western Australia, and yes, it does get hot.  I know about vapour lock.  My other big bore bikes (ZRX1200, ZZR1200) don't have these shields, and have no problems.

Cheers,

Bill.

Bill, do you mean the by now (if its anything like mine) baked almost solid rubbery stuff that is under the air and battery box? I think that's more a dirt shield than anything else?

Harvy