Hitchcocks Forum

put an amal on my 2001 350 and noticed significant improvement. the stock carb on my 2007 500 seems to work better than the stock carb that was on my 350. will I see significant gains with the amal on my 500 or should I just leave well enough alone

Hi DEAN------- You (and your wallet) know the answer to that one !!.......... Myself, RIGGERS and many others can tell you that the VM28 on a std. road bike is more than capable of providing for the needs of the Classic 500 engine etc....Assuming you've done all the other mods eg}--- dump the PAV, air filter, de-restrict the silencer etc then a 19T output sprocket will be all you need...Works for me, that's for sure-----

I have an amal Mk1 concentric on my '89 350. I started off with a mikarb, replaced it with the Amal, tuned it and got it running satisfactorily. I ran it like this for some time. Then I needed to change the cable and I didn't have the right one, so I put the Mikarb back and, guess what, it was faster!
I have since put the Amal back and I am quite satisfied with the performance, plus it looks pukka.
My opinion is that both carbs work in pretty much the same way and are both very serviceable. Performance depends on how well tuned your carb is as well as timing etc. I doubt if either has a significant advantage in terms of performance but I do think that being able to tickle the Amal gives it the edge in terms of cold starting.

gentleman can 1 ask what slide and main jet settings you used

Only thing wrong with Mikarb on the 350 is that it's a bit small for the job. 26mm would be better but you would really need to open up the inlet tract to suit it. Mr H's tuned head is opened to 28mm which seems a touch too big to me and I suspect you would start to spoil that nice "softness" that the 350 has. Tollgate recommend 26mm for optimum and 28mm for maximum power at the top end.

I noticed quite an increase in midrange with the amal on my 350 - which is where I do most of my riding, as the bike is a bit small for US highways. It also looks cool compared to the micarb. will hang onto my $ and keep the stock carb on my 500 for the time being. Live in the high desert of Nevada and hate to admit it, but the best bike for the mountains around here is my 500 EFI

Dean, was it a 26mm Amal and did you do any work on the inlet? I'd also be I interested in what jet sizes you used.

Pete, it is a 26 - the folks at Hitchcocks "jetted to suit" for my elevation of 5000ft and apparently the were dead on. they used 160 main, 106 needle and 3.5 slide. They said they had used similar jetting for the high country in India.

Carbs of any type are a mystery to me. The flange on the correct 15/16ths 376 on my bike was damaged so I put the jets into a 1+1/8th 389 that was laying about my garage and the bike ran beautifully and as economically as my mates EFI. I subsequently bought a new old stock (not a spanish one)376, jetted correctly for my bike and the loss of performance was immediately noticable. There is nothing wrong with the new carb, it was set up perfectly well, I've had it apart, cleaned and checked it and am now seriously considering putting back on the oversized 389. What exactly is the difference between the 376 and 389 carbs?

Hi Eddie, I agree amal numbering is something of an enigma to me as well, but i think the 376 series go up to 1-1/16" internal bore..

The 389 starts at 1-5/32" bore.. Sure somebody knows better... gwilly