Single Mikuni Conversion?

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Aug 16, 2004
I'm considering converting my '74 to a single mikuni. My motivation to do so stems from the disire for maximum reliablity with out a performance sacrafice. My expectation is easier tuning, starting, similar or greater lower end torque, sacrafice of some top end power.
Any input on whether my expectations will be met?
Any input on bore size? (motor is bone stock)
Any recomendations on kit supplier? I'm considering MAP after reading the thread on someones experience with throttle cable wieght - apparently they include a "special " throttle cable.
In the same light I'm considering a boyer or rita electronic ignition.
My consternation comes from appreciating the stock set up for what it is yet at the same time desiring the best set up. - I suppose I could always put it back to stock though.

Hi Rich,

It sounds like you did a search for "Mikuni" on the forum? There have been several threads talking about Mikuni versus Amal lately. From you expectation you should be able to achieve this with a single Mikuni. Fit and top end performance are the negetives although my experience was twin Mikuni's were very hard to tune properly. Sleeved 932 Amals have served me very well for the passed several years.

Do a search also for Lucas RITA. DynoDave posted a thread several weeks ago indicating this ignition is no longer in production, recommending sources to get the last of the inventory. I went with Dave's opinion that the RITA is superior to Boyer for the combat. With a Boyer I was getting engine pinging. Replacing it with the RITA cured this. I put the Boyer on my '74 JPN and it worked fine. Watch out for the low tension wires coming from the inductor coils..these break inside the insultation due to vibration causing the engine to misfire at midrange.
Two types of MIC's 34 and 36. 34mm is the best bolt on easy fit. (smaller)Two types Boyer digital and anolog. Anolog bolts right up good for stock engine. Digital (red box) can be ordered with any advance curve you like for an up charge. If you ride side roads with your bike and consider 70MPH speeding than go with the bolt up stuff. If you like working on your bike as much as riding it and like wearing thru rear tires spent another 200.00 and a lot more time just for fun. norbsa
Hi darkroast,

In my mind the "best setup" is one that not only performs the best but LOOKS the best.

The appearance of an AMAL concentric stirs my primal instincts whereas a Mikuni just looks flat and bland like and over-cooked noodle. Moreover, a single Mikuni will not out perform twin AMALs.

However, if you are frustrated with trying to tune your AMALs, then go for the Mikuni setup; many people swear by em!


Thanks for all of the feed back - I'm still new to the forum but appreciate all the rich content. I'm psyched to be back into the fold of vintage bike ownership!. It so rewarding and challenging at the same time. After riding my 99 honda vtr1000 for five years its a refreshing change to kick a bike and build a relationship that goes beyond just riding, one that brings feelings off the bike as well as on.
Thanks again for the feed back - but I'm still undecided!
I think the Mikuni would be much less troublesome than the amals once you got it set up properly. The people who use the kits from Rocky Point Cycle seem to be quite happy with them.

I still have amals on my bike though. I've had a lot of issues to work through with them but at the moment they seem to be in good shape. Not sure what I'll do when they wear out.

Made the switch to a 34mm Mikuni this year after 16+ years with the stock Amals. Did the resleeving by AMR quite a few years ago. The Amals ran ok but erratic idling and the ability to stall in traffic convinced me it was time to change. The Mikuni has run great so far. Starts on 1st or 2nd kick and purrs like a kitten...when warm. Cold starts with full choke needs a bit of sorting; my fall project. It's probably a bit slower on top and it seems to run up a bit slower also but I don't ride her fast enough for it to make a big difference. Took my 10 year old son for a 50+ mile ride this weekend. It was great fun cruising the back roads. I'd rather be there than in the garage. :D
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