Hitchcocks Forum

Hello everyone.

Has anyone removed the rubber grip strips from the fins of their EFI engine?

I presume these are just to reduce noise but I wondered how effective they were and what effect it had taking them off.

Thanks. Happy summer riding.

Rich

Reduce noise, but more to reduce vibration too... not taken mine off

Why take them off? I made some and fitted them to the Bullet. Then again, maybe it`s all in the mind?

Think back 30 years and many strokers had these rubbers.The idea is not to prevent engine noise per se, but the sound of the high frequency resonance/vibrations in the cylinder fins. I can see this could be a problem in a stroker reving to 10 or 11,000 rpm but not many Enfields manage that more than once!

Eddie, it depends what else resonates at that frequency. For example, at about 2/3rds revs, the resonance of the engine matches that of the heat shield for the silencer... which is why it sounds horrific at that engine speed as the heat shield starts to vibrate at an awful pitch, eventually cracking. Remove the rubbers and you risk bits falling off!!

I wonder if there is a risk of vibration causing the fins to break if the strips are removed?

The resonances that make fins ‘ring’ aren’t necessarily high frequency. Nor do they ring only at very high revs – MZ fitted them and they weren’t high revving. They are there I guess not for looks but for a purpose. Why anyone would want to remove them to make their engine more mechanically noisy than it is already is beyond me! On the other hand, removing them is very unlikely to cause the fins to crack.

My EFI was delivered to me from Germany in 2011, without the fin rubbers. I never heard any sign of the fins resonating and after 8,500km there were no visible cracks in the fins. I did however find that the exhaust clamp ring was cracked but it did not affect the clamping action. TrevorCH.

Did any British bike end up with cracked fins,of course not!They are apparantly fitted
for a slight noise reduction for modern laws.Comments from other forums is remove them
and notice no difference and motor looks a bit more attractive,if that's the right word!

Took mine off about 12,000 miles ago. I think the bike looks better without them, and they make not a jot of difference to sound or vibration. Instinct tells me they can't be beneficial to cooling...