Has anybody on here fitted a mikuni carb onto an A65?
Hi and yes, to a T-bolt, but it was around 25-years ago. I bought a Mikuni VM28 from Allens Performance and seem to recall all-round improvement compared to the Amal 928. I didn't run with it for more than a few months though as I was troubled by the inability to accommodate an air filter. I always had a paranoia about spitting back through the carb, although it never did, but it created a discolouration in the paint on the front of the oil tank.
I always fit new Amal Premiers and found the performance and smoothness compared to the old concentrics was major.
Basically I think it's down to the pilot system. As most of the time we are tootling along on low throttle at the twistgrip a blocked or restricted pilot jet makes the engine dog rough.
I like Premiers too.
Relatively cheap and easy to tune, and perform well.
Never understood the attraction of Miks...seem to require a lot of fine tuning and look too Japanese.
If the bike so fitted then did 100MPH at a 100MPG I could see the attraction, but as the performance gain is from nil to imaginary, what's the point?
Hi,
Before they made the Amal Premiers I fitted a 30mm Mikuni to a Thunderbolt. Iyt came jetted to suit and 2 spare pilot and main jets a size either side of those fitted.
It worked straight put of the box and I found that is was very smooth on pick up with no flat spots and the engine would pull smoothly to well over 70mph and mid range torques also seemed to be better.
Why a 30mm? Well I had read that the Thunderbolt ran better with a 30mm carb. and the bike was fitted with one when I got it. One probable advantage over the Amals at the time was the better built quality and even today after many thousands of miles on the 650 and now on a long stroke 750 the carb. feels and sounds like new. The 650 now wears a 28 Premier and runs well.
As mentioned, unless using wide throttle openings, it the pilot circuit and the transition to the needle jet that we use most hence the return to a 28mm which is opened that bit more than the 30mm which was barely open for the same performance.
The 30mm Mikuni replaced a 32mm Concentric MkII on the 750 which was less than half open 70mph. The 30mm Mikuni which is, I believe an Amal design made under licence, is quite similar to the MkII Concentric.
Today, as the Amal premier is available, I would opt for that mostly on price and to some extent, unless using the full performance of the bike, the Mikuni is possibly wasted if only.
Dave.