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+--- Thread: SU 1' OM type damper cap type (/showthread.php?tid=2719)
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SU 1' OM type damper cap type - Robin Gooders - 29-04-2019
Hi all,
after a successful Drive It Day outing yesterday I was checking the old girl over and I've lost the damper cap from my OM type carb.
Looking on Burlen's site it's not clear whether I should have a vented or un-vented cap, and I can't remember which type was fitted to mine. I can't remember seeing a vent hole in the cap, but not sure. Is anyone on the forum running a pre-war type 1" OM? If so, would you be kind enough to see if yours has the little vent hole, or not, in the brass damper cap and post a reply.
Also, anyone got any cunning ideas for stopping these things vibrating loose other than loctite?
Best wishes and thanks for any advice.
Robin
RE: SU 1' OM type damper cap type - Alan - 29-04-2019
Get an unvented one. If it doesn’t run properly you could always drill a hole in it.
RE: SU 1' OM type damper cap type - Steve Jones - 29-04-2019
Yes, as Alan says. Don't Loctite. Give it a slight nip up with water pump pliers or similar.
Steve
RE: SU 1' OM type damper cap type - Robert Leigh - 29-04-2019
I am not good on SU type letters, but does the OM have a damper? If it has I think there won't be a hole.
Robert Leigh
RE: SU 1' OM type damper cap type - Bob Culver - 29-04-2019
Without hunting out my hoard, surely whether a dashpot or not, now or originally, must be a vent of some sort. Unless of the 1960s type with diagonal vent to air cleaner formed into the round body.
RE: SU 1' OM type damper cap type - Robin Gooders - 29-04-2019
Thanks for the advice folks.
I like Alan's idea regarding the vent hole. Why didn't I think of that!
To answer Robert's question. The OM has no damper/ dashpot. The cap on these carbs is just a cap.
(I.e. no attached damper as in the later post-war SUs on minis etc).
Best wishes
Robin
RE: SU 1' OM type damper cap type - stuartu - 29-04-2019
One of my cars is prone to having its SU cap unwind. Fixed by cutting a short length of cycle inner tube and slipping it over the neck of the dashpot.
If your bicycle tyres are the wrong size I would think the finger from a redundant rubber glove might work.
Regards,
Stuart
RE: SU 1' OM type damper cap type - Ian McGowan - 29-04-2019
I run with an OM carb, no damper, I believe that the correct circular brass cap has a vent hole, a coin slot, a knurled edge, and is engraved "use bicycle oil". Burlen part No. AUC 2144SBO. (don't forget a fibre washer to suit AUC 4900)
I lost a couple before, as Steve Jones suggests, I nipped them up with water pump pliers every installation, since then no problems.
RE: SU 1' OM type damper cap type - jansens - 29-04-2019
It's great these old SU bits are still available and the cost of the parts is reasonable but their international postage rates are terrible! I just bought a couple of ball ends, a 6 inch rod, two throttle shaft levers and a couple of new dashpot screws and postage to New Zealand was 25 quid!
I looked at using one of the UK forwarding services but it worked out to be much the same since if you post to a UK address you get charged the VAT. That offset any postage savings.
Simon
RE: SU 1' OM type damper cap type - Nick Lettington - 29-04-2019
Which just goes to show that you should never throw anything away... Found this in a box of toot from my dad's man tin. No idea what it was!