There appears to be two readily available options, and I would like to hear back from any members who have used either of the above company products, is one better than the other - say - from porting perspective or is there anything else out there?
Has anyone got one they'd like to sell?
Thank you all!
I fitted a RGM manifold for a single carb and it fitted perfectly. The performance seems fine for me.
You'll need a new throttle cable that has a 45 degree bend to bring the cable to one side to miss the top frame member, which is directly above the top of the carburetor. Also, I fitted a K&N filter onto my Amal Concentric. Both of these are available from RGM.
Thank you Philip.
Hi Philp - I am considering the change to the MK2 Amal as I have been promised a new old stock unit that has been sitting in a friends shed! I understand its a 2034(?) - which I think will work. My MK1 carbs are worn so from a cost point of view buying a manifold and using the MK2 seems a sensible path however, - from your experience, are they relatively easy to set-up - I have read a lot about the issues people have trying to set them up....choke being a particular problem(?)
Many thanks Graham
I have the RGM 2:1 and an Amal MkII. This is on an 850 MkIII.
Initially I had a 34mm but have now changed to a 32mm (2932/301) which is much better. Easier starting, smooth tickover. The 34mm was always lumpy at tickover whatever I did.
Happy with the performance, all fitted easily. Easy setup and no more faffing about trying to balance the carbs.
I fitted an RGM type to my Atlas many years ago and concur with all the above posts. If you go with the RGM manifold I suggest you apply thread lock to the two inner mounting bolts as a precaution in case they come out and are digested by your motor.
From memory I think the jets I used were 260 main jet and 106 needle jet. These jets sizes were published many years ago in RH mag by a member who tried many different jets and settled on these as the best for all round performance.
Thank you everyone. I am doubting the suitability of the 34mm.
Philip, is yours a 34mm? I know about the recommended jets; 260 main and 106 needle but these were for the 32mm. The 34mm suggested sizes are 290 main and 107 needle. Many thanks Graham
I used one of the existing 32mm Mk 1 Concentrics that was on my Mk3 as a starting point, with the intention of fitting a 34mm Mk 2. But it went well enough for my needs on the 32mm carb, so have left well alone.
A good friend helped me with the change to single carb as I had no experience of Commandos at that time, so didn't see what jets were used. I'll have a look later today.
Thank you Philip.
Graham, I forgot to mention that the jet sizes I mentioned were for a 32 mm Amal. I also fitted a brass slide as the carb i used had little wear.
Thank you Andrew,
Do you think the 34 would work with appropriate jets?
If you do proceed on going up the 2 into 1 inlet manifold route, please consider lockwiring the two nuts (or allen cap bolts) that are done up on the inside of the manifold.
I have heard of several people that have had issues with these working loose and wedging the inlet valve open.
The main jet in my 32mm Concentric (Mk1) was increased from 250 to 270. There was no evidence of the needle being changed, so I expect it is the standard size i.e. 0.106.
I looked at the other carb that was removed and the needle in that one doesn't have any markings on, so the one fitted to the machine probably isn't marked either. To inspect the on in the bike means removing the tank, and I don't fancy doing that at the moment!
Thanks again, - please don't pull anything apart! regards Graham
Thanks Mike , will do!