?? What are the rubber buppers on the side of the cylinder head for??

[Guest]

My 82 GS 750 E is missing one and I also noticed that they have arrows as well but I don't what they do? Sorry if this is dumb question but I really have no clue. Please let me know what they for and what position they should point. and if they are needed?

[tkent02]

Back in the day they were installed on air cooled two strokes to reduce noise. Not sure why they were carried over into the GSes, probably because "that's the way we've always done it."

[gsrick]

Back in the day they were installed on air cooled two strokes to reduce noise. Not sure why they were carried over into the GSes, probably because "that's the way we've always done it."

That's bunk, "the man" made the foreigners put them on their bikes to slow them down, because even the little 450's were blowing away the Harleys.

[tkent02]

No, that's bunk. When I took them out it didn't get any faster. Maybe I should have installed red ones.

[recycled64]

All finned cylinders radiate internal engine noise to some degree or another, was just more apparent on the 'ring-dinger' 2-strokes. Suzukis' famous X-6, (T20), actually had fins that were 'bridged', as a cast-in part between the fins, for example. But all in the interest in reducing harmonic 'ringing' noises from air-cooled engines, hence the little rubber squares, even in 4-strokes.

[Fancool]

Ok I like the answers, very informative and clever. Still not sure if I should just take them out or leave them in? What is the protocol on these rubber inserts? In or out? Don't see any old bikes like these to make up my mind and like I said I'm missing one anyways.

[Fancool]

BTW not wanting to hijack my own thread but is there any tricks or tips on get a few more HP out of her? Has nice header and air filters but all 1500 CC bikes are pulling away from me even if its just for a second, And No I don't want a 1000cc or bigger I like 750CC.

[bonanzadave]

And No I don't want a 1000cc or bigger I like 750CC.

711. Put an 1100cc motor in your 750. Easier yet....go get an 1100 and put your 750 side covers on it.

[storm 64]

BTW not wanting to hijack my own thread but is there any tricks or tips on get a few more HP out of her? Has nice header and air filters but all 1500 CC bikes are pulling away from me even if its just for a second, And No I don't want a 1000cc or bigger I like 750CC.

Adding aTurbocharger, they are usually good for a few more horsepower...

[tkent02]

Pull the little rubber things out, I can't tell any increased noise. As far as outrunning the 1500cc bikes, find smaller windier roads to race them on.

[Fancool]

Too funny. I'll put a V8 in it. But good call on the windy roads those big monsters get in the way so I just stay in front and don't have to smell their exhaust. Rubbers are coming out and maybe racing stripes will make it faster.

[Grimly]

BTW not wanting to hijack my own thread but is there any tricks or tips on get a few more HP out of her? Has nice header and air filters but all 1500 CC bikes are pulling away from me even if its just for a second, And No I don't want a 1000cc or bigger I like 750CC.

850 barrels and pistons for the 8-valve 750, but is yours a 16-valver?

[Fancool]

Yeah 16 valve, Guess I'll start looking for an 1100. Or maybe I'll just try and keep my drivers lic. I really like the way the smaller bikes handle.

[Hayabuser]

Bandit 1200 engine... 7/12 has a nice ring to it!

[bwringer]

No one rational has ever noticed the slightest difference with or without these rubber bumpers. (I do remember one nutbar on this forum a long while back who had an elaborate and exotic "sonic cooling" theory, and was firmly convinced that leaving the rubbers out would lead to drastic overheating.)

Most of us just yank 'em out and toss 'em, since they quickly turn to hardened lumps resembling charcoal. Whatever they originally did, they never last long. Shine a light into the fins on your cylinder head, and you'll likely find a few that have fallen into the depths. Extract them with long thin needle-nose pliers.