oil cooler rubber flap

[jetta90]

Hello - can someone tell me how the rubber flap that attaches to the top of the oil cooler on a 93 Katana 750 mount once installed?
Does it hang down and fit in between the cooler and the cylinder head or is it meant to reach back above the cam cover?

The project bike I'm working on had this flap basically hanging from the top of the oil cooler (which looks correct), folded in half and hanging down in between the cooler and in front of the cylinder head and above the exhaust ports.

What does this flap do?

Your help is appreciated.

[Black_peter]

That flap is currently in the Travis County Landfill..
No one, not even Cyberpoet knew what that think really did..

[arsenic]

It does absolutely nothing. It's supposed to cut down on noise, but it doesn't. It lays over the valve cover.

[Black_peter]

It's supposed to cut down on noise, but it doesn't.

Mystery solved, it still looks better in the landfill than on my bike..

[jetta90]

Thanks for the responses. The way it was installed on the project bike I bought it would appear to me to limit the cooling air flow through the upper portion of the oil cooler and the upper area of the cylinder head.
Doesn't sound like a very healthy thing on a oil and air cooled motor.
I'll probably pull it off for good.
Intended to muffle some the engine noise, really??

[arsenic]

indeed.

[hardlydangerous]

it actually is important.

it is there to deflect and direct air flow through the oil cooler down onto the cylinder/head/headers and away from the bottom of the fuel tank. this way air goes around the cylinders and out the vents instead of over top of the engine heating the fuel tank and the air box/carbs/seat etc.

Some other bikes that use a rubber plastic or metal deflectors like the ST, goldwings, contours etc have problems with cooling, overheating the fuel tank, and making the rider uncomfortable by removing them.

I recommend you use it and dont throw it away. I know its ugly but its there for a reason. it attaches with the wire tabs on the sides and slips over the front of the cooler mounts... pretty basic

[arsenic]

I got to disagree there HD. It's really not there for a reason. In "theory" you could say it is important, but it's really not.

[rexazz2]

For those of us that dont get scared off by rain
I think it helps keep some of the water from getting in there

[Black_peter]

I gotta say CP knew more about the Kat than anyone.
Maybe not the nuts and bolts of carb like Chris, or such.
But for him to be clueless, not that we didn't have theories that we debated/considered, but for him to be clueless about why it was there, what it did and why only the 750 had it.
Tells me it wasn't really important..

And the rain theory doesn't hold water (see what I did there?) because few kats get as wet as mine, and I have zero issues with the bike in the rain.. I once poured water out of my boots, but the bike was fine.

[Kreylyn]

I'll make no claims to if it is a nessasity, or that it will cause problems if not there but...

The Pre 750 had both the rubber cover over the engine AND heat reflective material stuck to the bottom of the gas tank.

It would be pretty obvious to me they though there was a heat issue for that CC bike comparatively, but it's pure conjecture on my part. I don't know why else the differences between the 600 and 750 in that aspect if it wasn't a heat issue.

Perhaps they expected it, but it didn't really turn out to be an issue?...

Krey

[arsenic]

I'm with Krey. I have no idea WHY it was there. I don't know 100% sure, I mean I have theories and stuff I've heard. I just do know 100% that it doesn't NEED to be there.

[Tmod]

it actually is important.

it is there to deflect and direct air flow through the oil cooler down onto the cylinder/head/headers and away from the bottom of the fuel tank. this way air goes around the cylinders and out the vents instead of over top of the engine heating the fuel tank and the air box/carbs/seat etc.

Some other bikes that use a rubber plastic or metal deflectors like the ST, goldwings, contours etc have problems with cooling, overheating the fuel tank, and making the rider uncomfortable by removing them.

I recommend you use it and dont throw it away. I know its ugly but its there for a reason. it attaches with the wire tabs on the sides and slips over the front of the cooler mounts... pretty basic

My original thought was the same as yours hardlydangerous. Left mine in place and all is fine.

Tmod

[Wild-Bill]

I've seen engines where directed airflow made a tremendous difference (classic VWs). It seems possible that Suzuki thought the 750 made enough heat to need some control of the airflow in order to run its best. The other thing that rubber mat does is provide some insulation for the wiring above the head cover.

You've got the part. The factory engineers thought it needed to be there and managed to make a strong enough case for that to the penny pinchers that it's there. Keep it.

[jetta90]

Having spent a little more time again on the 750 Katana project I would think that pretty much all the comments made regarding the "rubber flap" make a lot of sense.
While reinstalling the ignition coils on the bike today, I realized that they live just above the engine, mounted on the frame. With the rubber flap installed I can see how the flap would have a very serious role in keeping the coils cooler by insulating them from engine heat.
Just a thought......