Hitchcocks Forum

Our hosts do a kit which are designed for the EFI models and state "These are the rubbers fitted to the EFI models as standard and can be trimmed to be used on the cylinder barrels of the older Bullets."

https://accessories.hitchcocksmotorcycl ... head/21023

My 612 bullet makes a terrible clattering noise like there's a ducati clutch stuck in the valvegear and the old trick of shoving some slices of fuel hose in there quietened it considerably. it seems the alloy barrel is a bit known for this. I've bought one of these kits because it should look a lot less Heath Robinsonthan bits of fuel line but I'm not sure where to put them/trim them. It's relatively expensive for what it is so I don't want to wreck it.

I was wondering if anyone has any experience of fitting these to a pre-unit bullet?

They have a number embossed on them and this is where the different number are meant to go, on an efi.

Yeah, they all seem to go on the head on an EFI rather than the barrel.

If the efi ones don't fit, try MZ TS 250 cylinder rubbers.

Why not try the ones fitted to the AVL engine, about a quid each (AVL engine uses 14)
https://accessories.hitchcocksmotorcycl ... ges%2F2355

But just looked on mine and seem to have 3 so looks like they fall off, not sure how you stick them on?

Parts 38 and 39 fit on the barrel of the efi.

Allanfox wrote: ↑

Wed Sep 08, 2021 8:00 am

But just looked on mine and seem to have 3 so looks like they fall off, not sure how you stick them on?

I was considering this myself, I reckon a good bet would be silicone sealant. It'll take the heat, just not sure how well it'll bond to the rubber.

Got a reply from our hosts on this subject:

"The smaller identical rubbers as you mention go on the barrel, the two longer angled rubbers (the two on the EFI cylinder head as in the picture on the website) will fit on the drive side of the older bullet head, but turn them upside down to match the profile of the fins as they taper in towards the rocker covers. Fit one in front of the spark plug and one behind, you may need to trim one of the longer ‘fingers’ so they push fully in between the fins."

For positioning of the smaller ones, I ran a fingernail across the fins and put a rubber where the sound was most resonant. I also added a couple of bits of fuel line on the head where it was still seeming to "ring".

The long ones aren't a perfect fit but close enough once a couple of the over-fat fingers were shaved down. A stanley knife blade was perfect for this, they cut very easily.