I fitted a new Burlen 289 to my M33 a couple of years back when they first introduced them again. Easy to set up and responsive to the mixture screw. Done a lot of miles on it now and it has never been a problem, it has a steady tick over and is very responsive to the throttle. Only thing i changed was the bell mouth the new one looked naff so i fitted a original one i had.
Hi John, that\\\'s interesting re the concentric float height, would I be right to assume it was too low? Only thinking that on the basis that there isnt much space for it to be too high on a concentric before the float hits the body.
I\\\'ve fitted a new concentric 626 to both my M20\\\'s and on one the tickover isn\\\'t as smooth as I\\\'d like, and there is not as much effect on that from pilot screw adjustment as I\\\'m used to finding with these instruments. Any thoughts on that would be appreciated please.
Another carb issue I\\\'ve been aware of for a long time when comparing original Amal and modern reproductions regards monoblocs -
The originals had no sealing washer of any sort between the float needle housing (under the banjo) and the body. All the replacement carbs I\\\'ve seen have a fibre washer there. Surely that is going to raise the float/fuel height?
Old carb lore says the correct fuel level on a monobloc is indicated by the \\\'pip\\\' near the middle of the float chamber cover. But the only way to see the level of fuel with the lid on is to run a stand-pipe from the main jet cover nut...
Rupert.
There are two versions of monobloc carbs - one with and one without the fiber washer. As I discovered after much tinkering, the needle seats are different and they don't seem to like being mixed up. I also suspect it is possible that the body is machined differently there too. as for float levels, there are a number of tools that can be used to check this. the one I like is this one:
Hi Cas, thanks for clarifying that re monoblocs with or without the fibre washer. I never saw one with the fibre washer before the post-Amal replacements appeared in the '90's?
Concur re not mixing Old and new parts in that area.
Rupert.
Hi All
Very interested in Mikes view of the concentric conversion on his TRW. Mine is generally a pig to get started despite using various different choke routines etc. When its going it is really nice to ride, idles very well, just except for what feels like a bit of a flat spot on mid throttle openings. Carb has been off, cleaned, re gasket with my last set of gaskets!!No change.
Is this a common fault, would a carb change help. Its a real shame as if I can't improve things I think it will have to go.
Any help would be great.
John
Hi John..It was my TRW with the concentric fitted...My bike was an early version of the TRW with the BTH mag fitted as standard....To get the concentric to clear the mag I had to machine an adapter that fitted between the barrel and the carb to provide the needed clearance...
If you have a later TRW with coil ignition fitted that will be something that needs to be looked at...I've since sold the bike and I think the new owner has removed the carb and adapter and fitted an original...Personally I didn't even try the original carb as I spent more than a day trying to get a friends TRW to run well on one without a lot of success...
So, I replaced the original carb shortly after I bought the bike...The Concentric and adapter MAY be available as I don't think the owner has any plans to use them...He doesn't ride the bike much and would rather have it looking original I think....Ian
Hi Ian
Thanks very much for the reply. I may get back to you on the adaptor. My bike is a later one with the coil ignition set up and I need to pull it out of the shed to see how much room there is around the carb.
Has anybody tried a Mono bloc on these bikes?
R
John
