rubber circles inbetween cooling fins??

[WMarshy]

the rubbers are there to dampen the sound of
vibrating fins, the fins are designed on an air cooled
engine to vibrate to assist in cooling.

upto yourself if you want to have them in or not, no damage
will occure if there not fitted,

The fins are there to increase heat dissipation, the rubbers are there to decrease any transient vibration from the motor that will ultimately lead to fatigue and cause them to break off. The vibration of the fin is undesired and will not necessarly increase or decrease the cooling ability of the engine.

[b.walker5]

The fins are simply a heat sink, designed to increase the surface area to dissapate the heat from the cylinder. The rubbers are there to dampen vibration and deaden noises from the fins and engine. The longer the fin the greater the need. Short fin engines are generally happy without them, longer fin engines, in particular 2 smokes, can be horrendously noisy without them. I've had engines in the past without them with no noticeable difference, OTH i've had other engines where it's been very noticable. I've never seen a fin break without them due to vibration but I guess it's entirely possible.

[Guy_b_g]

Yeah I agree that the fins are safe on the XS11 without the dampers, but I have seen 2 strokes lose fins to stress cracks created by vibration.

Yamaha KT100 Kart engines are notorious for it, and you have to be fairly diligent in looking for them and drilling the end point of the crack to prevent it continuing. They also tend to start at the intake and exhaust where the fins are often squared off and have right angles which tend to lead to cracks more than the rounded edges everywhere else.

[petejw]

i probably could of put it better,
in that the fins are there to dissipate
heat away from the cylinders,

"The vibration of the fin is undesired and will not necessarly increase or decrease the cooling ability of the engine."
sorry i dnt know how to quote,
but i dont agree with this, -

When an air cooled engine is stationary and running the vibration of the
fins assist air flow preventing the engine from overheating.

the best way i could describe it, would be like moving your hand up and down really fast, try it and youll feel the air move around your hand.

[WMarshy]

...
"The vibration of the fin is undesired and will not necessarly increase or decrease the cooling ability of the engine."
sorry i dnt know how to quote,
but i dont agree with this, -

When an air cooled engine is stationary and running the vibration of the
fins assist air flow preventing the engine from overheating.

the best way i could describe it, would be like moving your hand up and down really fast, try it and youll feel the air move around your hand.

The air movement due to the slight vibration of the fins isnt even quantifiable when stationary in comparison to the rising warmer air due to density differences... They dont act like bird wings or your hand and pump air. lol, b.walker5 nailed it on the head about increasing the surface area...

[motoman]

+1 what WMarshy said! Vibration for improved cooling......now that's funny, don't care who you are!

[alaskey2]

anybody have a video of the bike without the dampers? Mine look half melted and I want to hear what it's like with the "ringing" before I pull them out.

[motoman]

Don't chuck them. They dampen sound and prevent fin vibration caused by the air that is forced through the fines at highway speeds. Take a photo of their location and remove them. They are just wedged in place but do pay attention to them so they go back into their original positions. They are of DIFFERENT thicknesses and will not wedge back into place as intended if you mix them up. Try removing all the top ones and bag & label them followed by each set going downward.
Rob

Fast moving air?.........lol.....now that's funny, don't care who you are ....has absolutely nothing to do with there purpose! They are there to absorb the harmonics from the vibration ONLY.

[MattWood]

Harmonics can kill a perfectly good piece of metal. If the engineers bothered to waste their time designing some pieces of rubber in the heads, there must have been a really good reason for it.

[motoman]

Harmonics can kill a perfectly good piece of metal. If the engineers bothered to waste their time designing some pieces of rubber in the heads, there must have been a really good reason for it.

.....and passenger car tire chain rubber Tighteners cut in pieces slightly taller than space between the fins work as replacements ....but those could be 'unobtanium' in some parts of the country.....

[rdmcguy]

another 2cents

Does the term "fin ringing"mean anything to you?
As previously mentioned...The longer the fins for cooling purposes,more sound is transferred to those fins ....Hence the term "dampers"as they are known by.

[mharrington]

I would think they dampen the resonation from all the goings on inside an engine. You must remember engineers are under the gun not only to keep emissions low- but sound levels too.

[mack]

dampeners

I've removed them from all my bikes, makes no difference at all in sound or vibration. No fins have cracked in the time I've been riding them. If anyone need some PM me I have five sets here.

[James England]

I pulled mine out for the recent engine work, didn't bag them up (except in one bag) and have been fiddling about trying to get the right ones in up right places!

I'd keep them. They are there for a reason and the Japanese usually were pretty thorough design-wise. I intend sorting mine out and putting them all back. I'm trying to find a closeup engine shot of how they were arranged as I do remember it looked kinda nice in a curve downwards, each side of huge plug...

Also, I'm obsessed by trying to keep them at leastlooking as standard as possible but improved...if you see what I mean.


Ps does anyone have a closeup pic of the head from the side, complete with rubber bits? I can't find mine in the thousands of pix I have!!

[motoman]

I pulled mine out for the recent engine work, didn't bag them up (except in one bag) and have been fiddling about trying to get the right ones in up right places!

I'd keep them. They are there for a reason and the Japanese usually were pretty thorough design-wise. I intend sorting mine out and putting them all back. I'm trying to find a closeup engine shot of how they were arranged as I do remember it looked kinda nice in a curve downwards, each side of huge plug...

Also, I'm obsessed by trying to keep them at leastlooking as standard as possible but improved...if you see what I mean.


Ps does anyone have a closeup pic of the head from the side, complete with rubber bits? I can't find mine in the thousands of pix I have!!

Obviously not home being in Georgia, but they just follow a straight top to bottom, front and rear of plug James.