O.K. I am considering shelling out the money for a set of Mikuni Carbs for my 66' A65L. It is currently fitted with AMAL 369/389 Monoblocs. I know that I can go to several Brit Bike Suppliers and browse. Most of them do list something like "Mikuni Set For BSA A65". I do not need anything fancy or expensive - just reliable. I live in South Texas where it is Hot and Humid so I would like to get the jetting right the first time. And I would like a model if possible that will be compatible with my original pancake filters. I have been fighting with my Amals - loose slides etc. I am loosing my patience. Any input would be greatly appreciated. Thanks in advance....
Rink, Don't give up on the Amals quite yet. I was having similar frustrations when I was setting up my 389/689's for the 64 Hornet/Lightning. A friend gave me a copy of instructions from a seminar given at Daytona in 2001 by Coventry Spares, John Healy. I went through the process of installing new guts inside those carbs and then followed those directions to the tee, using 3/16 drills etc. I only had to follow the directions on page one that said "Please Read". Bang, it started on the first kick and actually idled. I don't regret one bit spending the extra money to rebuild them right . Furthermore, it goes like stink, which again I attribute to setting up those things right the first time around. We know you can do it. Skeet
Skeet Enjoy life....it has an expiration date.. 1964 Hornet 1970 TR6R 1971 Norton 1972 XLH
Rhett: Are the Mikunis cheaper than a pair of the new AMAL 930s? I've not touched a Mikuni for years, but from my reading have gotten the impression they might need considerable tweaking unless you get lucky out of the box. If I was buying them I'd also probably buy panic's book at the same time.
I ran a pair of Mikunis on my 1966 BSA Lightning while in graduate school at Texas A&M. I bought them from http://www.sportingforless.com and I ran them straight out of the box with prejetted settings.
The bike ran very well and started effortlessly, but they are a tight fit between the head and the frame. Some trimming of the carb holders is necessary and the side panels will rub on the air filters. see:http://i170.photobucket.com/albums/u272/66triton/_MG_3746.jpg
I sold the bike last year to bills and have regreted it every day since...
1966 Triton 1962 BSA DBD34 Gold Star 1966 Triumph Bonneville
Re: Mikuni Carb Model - Recommendations - 66' A65L#29067 09/11/073:18 am09/11/073:18 am
Hey thanks for the responses and input from everyone. Skeeter - I really don't want the Amals to get the better of me. It's just that I am so close to getting this 2 plus year project on the road - and not to mention the $$$ spent. And now to be delayed by this!!! Yes, at times I have a very short patience level. I really don't want to spend another $400.00 or more on carbs - I'd rather it go to rebuilding the Smith's instruments. It's just that I have taken these suckers apart at least 3 times now. I am just going to have to ponder for a day or two. Mr. Smith - thanks for the reminding me about MAP. Swan - thanks for the link. Leon-Bee - thanks for correct name calling.. And I'll look into the 930's...
Rkade, I cannot speak for your Monoblocks. My 66 A65L came with clapped out 930 concentrics and I could never get them right. I finally put new 930's and the bike will idle at 500 rpms if I want it there. I prefer about 800. I have no hitches in acceleration and it is smooth thru the entire range. I paid about $150 each for them with the jetting I specified. The setup is 2 1/2 slide, .106 needle jet, needle jet in lowest position (leaner), main jet 190. Idle mixture scres out 1 1/2 to 1 3/4. That is the same as the 68 factory setup for 930 amals except for needle position. Some will tell you to run a #3 slide, but I like the comfort of being a little richer. Plugs are dark brown and I have never fouled one. I am in coastal North Carolina where it also is hot and humid during the summer and early fall.
I'll add my input to stay with the Amals for your BSA; they work good when new, they look right, and they don't change.
I suppose Mikunis will work if you get them jetted right, but for every person who I've heard say "They came jetted right when I got them", I've heard five say "It was a pitched battle lasting all season trying to get these *&^%$ to run right ..."
I'm like super lazy today. It's like normal lazy, but I'm wearing a cape.
Re: Mikuni Carb Model - Recommendations - 66' A65L#29070 09/12/073:07 am09/12/073:07 am
I have Mikunis on my A65, and I think they're very fine carburators, but when I bought them (1983), they were $150 for the whole kit, including manifold adapters and cables. Today the whole setup is more than twice that amount, while brand new AMAL Concentrics can be had for about $130 each. Also, as was mentioned above, the Miks come so close to the frame on a dry-frame A65 that you cannot mount any manufactured air filter that I know of, unless you cut the manifold adapters short and weld them to the carbs. Jetting was also a PITA, but you would have the benefit there of those of us who have gone before, and at least one very good publication on the subject that I know of.
I'm also a fan of the Monoblocs; they were the original carbs on my '67 A65L, and the bike ran very well with those before the bodies got distorted from frequent dismounting and overtightening the flange nuts. They're also very attractive carbs, IMO. If you're into that, or into originality, you might want to give the Monoblocs a go, but you may find that you'll have to have them rebuilt (bored and sleeved) - there are a couple of places that do that, for less than the cost of new carbs.
If you do buy Mikunis, I'd recommend 30mm rather than 32s for a street bike in stock tune. The 32s may be better at the top end, but it's easier to get that low-to-midrange pull with 30s.
Gentlemen - thanks for the valuable input, recommendations, and personal experiences. Now that I have chilled for a day or so I guess I am going to give it another go with the Amals. I agree they are great looking carbs and original. Mr. Mike - thanks for the detailed specs on how you set up your 930's. - it was very helpful. Tomorrow I will be ordering some internals for the Amals. Re-sleeving will be a last resort of course. Thanks again guys. I will keep you posted...
1966 BSA 650 Lightening
Re: Mikuni Carb Model - Recommendations - 66' A65L#29072 09/12/076:46 am09/12/076:46 am
I have a 389/689 pair on a 66 and they really work well. Also got a 376 on a T100 and its just about perfect.
I know you've been having trouble with yours. Have you ever seen a post here about bogus brand new needle jets for these? I and at least one other have gotten them. Maybe 3 years ago I was having trouble getting mine to cruise nice at 3500-4500 rpm. New needle jets were suggested. I got some, marked AMAL 106......correct for Monobloc. Put em in, bike wouldn't run at all! Put old ones back in. When I finally got some more from britcycle it was a significant overall improvement.
So, needle jets do wear out and should be replaced sometimes. I don't know how you could check yours. But, there have been some bad new ones floating around.
Do you have the gasket under the jet blocks on yours? I read somewhere that needs to be there.
You mention spending the money on instrument rebuild instead , another area approaching $500 per pair with some questionable results I bought a knock off Oriental clone set (identical except for lettering on the face) and the seem as accurate as the rebuilt Smiths ones on my Triumph and cost $150 . for the pair .No worse than oriental carb set up . If you are just tired of trying to tune carbs i picked up a single carb head for my Triumph Bonneville in Mid Ohio looked really clean bolted right on Thru a new AMAL on it and Im and the bike is transformed Ill put the twin head away for when I sell and Im now looking for a single carb head for my Lightening Peter
Re: Mikuni Carb Model - Recommendations - 66' A65L#29074 09/13/072:46 am09/13/072:46 am
Leon Bee - I do have the gaskets under the jet blocks. I will definitely be careful when I order the carb parts to try and stay away from the sub-standard stuff if possible. Peter Berry - I came very close to ordering these aftermarket instruments but the BSA's have a 3:1 tach ratio and these where 2:1. Althought the ad stated they would work for a BSA. Thanks for the input gentlemen...