Hello guys,
My early B33 (1947) which I'm in the process of restoring is in need of a carburetor. As I understand it, the O.E. fitment was an Amal type 289G. I suppose I could repair the one I have if I could source the parts but that might work out more expensive than getting a replacement. Does anybody have a decent used one of this type, or any good spares for sale? Alternatively, what's the view on moving to a more-readily available and seemingly cheaper Monoblock? Any tips/advice would be greatly appreciated. Cheers.
Well if you can repair your original, you would save over £400 on buying a new one. The only thing which might be worn is the slide, which again can cost £65 or more. https://amalcarb.co.uk/pre-monobloc.html stock some of the parts.
If all else fails, just measure the carb's diameter, and fit a cheaper newer carb, which has been jetted correctly. I think the flange bolt spacing is pretty much standard for those inlet diameters.
Hello Scifi, thanks for advice.
Having measured it with the vernier I'm fairly confident a new slide will do the trick. However, my restoration, whilst not concours, is pretty extensive and the body of the existing carb is completely worn through to the brass and would look right out of place with the rest of the bike. I'm not too fussy about replacing the carb with the same as the original (as you say, very expensive) and I'm not concerned about criticism from the tyre kickers either! So I'm feeling the best route would be a different, less expensive carb. Monoblocks appear to be much more readily available, would you advise going for one of those?
A few of my older bikes have the Concentric Carb replacements, which are cheaper than the monobloc. Also my 350 RE Bullet has a Mikuni, which is most modern and cheaper still, also it has a great cold starting device, which gives first kick starting. The Mikunis do have a different main jet numbering scheme, so best of luck with that..!
Thanks again Scifi, looks like I could be going for a concentric. Cheers.
If going for a new concentric the wass⁰el equivalent is good value. I might have a good used amal concentric.
Hi cds, thanks for the note.
I looked at the Wassel and was considering it. Having said that, if your used concentric is good and useable without any issues, I could be interested in that. Also, to say I'm not particularly technical is an understatement! So assuming the flange measurements marry up, if I used a concentric or Wassel in place of the O.E. type, is it simply a case of ensuring the jet sizes in the replacement correspond to the to originals?
As far as I know, jetting will be different on pre monobloc, Monobloc and Concentric. Guess partially due to different fuel level.
Only problem I've had with old pre monoblocs is leaking float valves. Leaking carbs can cause fires. So why not try the old one you have first?
Morning Mike, thanks for your advice, I wholeheartedly agree a fire is to be avoided at all costs! And I appreciate I can easily use the original carb effectively simply be buying a new slide. The reason I'm hesitant to do so is that the body of the old carb is in a very poor state and in my opinion, will significantly detract from the overall appearance of the finished restoration. That's why I'm leaning towards an Amal concentric. Member, Cdsdorset implied in a post earlier this week that he might have a decent concentric for sale, but I've not heard anymore from him since 28th February.
Hi. Sorry been a bit manic here. Afraid i only have a spare monobloc.
Morning cds, Thanks for letting me know; and no need to apologise, we all get busy from time to time. I think I'd prefer to use a concentric. However, if I can't find a suitable one, I might have to consider a monobloc. If that turns out to be the case, can you confirm your monobloc is in good useable condition? And if so, how much would you want for it? I hope to hear from you soon. Thanks.
Geoff. An old carb is worn. Don't mess about with old carbs. Buy a new one.
Hi Stevegayler, On reflection, I think you're right. On the subject of Wassell carburetors, I've heard conflicting reports on the quality of these. But bearing in mind it'll be fitted to a very early B33 (1947 rigid), so we're not looking for high-spec/super-duper performance, just something that functions properly. Do you have an opinion?
have you tried ringing BURLEN in Salisbury ??
very helpful carb people
https://amalcarb.co.uk/catalogsearch/result/index?p=4&q=289
From what I've read part of your reason for changing the carb rather than repairing the old one is the look of the thing. I reckon if that's the case then a (new) Monobloc would look better (more in keeping) than a Concentric, the Concentric might look just a tad too modern?
Just a thought.
If your not bothered about originality and appearance an Indian VM24 carburettor as fitted to the basic 350 Indian Enfield works a treat without any jet changes. I have one fitted to my 1949 B31. £45 off Ebay.
Hi Yellow B31... Is the VM24 a 24 mm carb, i.e. less than 1 inch..? Hitchcocks list a VM28 (out of stock.) for their Enfields , which may be the size for the B33 500cc machine. A 26mm carb might be what is required however.
Hi The VM24 is a flange mounted carb of 24mm choke so yes just under an inch. The VM28 is a stub mounting so would require a flange adaptor to fit. £53 on Ebay
Allens Performanec lis a Mikuni kit for the B33
https://www.allensperformance.co.uk/carb-kit/carb-kit-listings/
Morning guys, apologies for the delay in responding but thanks for your suggestions rhyatt and Stubaker58.
I'll try the people in Salisbury, it'll be interesting to see what they say and at the very least it's another useful contact. However, since my last post, I've spoken to a pal who's suggested (as you have Stubaker) that the monobloc is the way to go as it's more in keeping. So I'm sure we'll get there in the end.
Thanks again to everyone for their very helpful contributions. What a great forum this is!
Hi Yellow b31, will the Indian VM 24 carb you referred to on your B31 do the same job on the B33?
It will certainly run ok on part throttle but if you want to ride flat out every where it will no doubt be lacking. The B33 carb is 1 1/16 (27mm) choke so using the VM24 your 3mm smaller but in numbers I can visualise 1/8 inch smaller on diameter (1/16 per side). If I had a B33 I would consider it worth a try at £45.
Have used these cheapo carbs on a Norton single and a 350 Russian 2 stroke with good results. I run my B31 at 50mph and responds well to the throttle, cannot fault the VM24.
It's worth remembering that although 3mm difference doesn't sound much it works out as a 25% increase in area.
Do you think you would notice the difference in general riding? Whenever I see old Brit singles on the road and I include myself in this category no one is rushing about.
That's very true!😁
That is all very well using a smaller carb until the day comes when you need a bit more get up and go in an emergency.The manufacturer knew what they were doing when they specified a carb of a certain size.
Yes your quite right idie the correct carb is the way to go, just offering an option as £480 for a new 276 would hurt my pocket.
Hi,
I suppose it comes down to what you are going to do with this bike. A 'restoration' to original will require the original type carb. especially for showing. For regular use and with an eye to something a bit more in keeping the monobloc could be the next choice. If all you want is a some reliable practicality then a concentric could be the best choice. Clean up the original carb and keep it as an ornament and have a picture on your phone to show any critics that you have it. In the mean time search a few jumbles for the bits you need for the original.
Dave.
Morning guys, Thanks again for all of the very useful observations and informed suggestions, I now have plenty to go on. Since I'm reluctant to spend a fortune on a new carb, I'm probably in for several hours scoring the autojumbles. Unless anybody out there has a good useable body of the original type - mine's reusable (it's the slide that's defective) but has lost it's coating and looks lousy! Thanks again everybody.