Looking at a new 26mm vm round slide carb for a 74 Berkshire.Would this be a good choice.Or maybe a 28mm.Is this carb legal for vintage racing.If so would it mount corect or does it require a different boot to mount on cylinder?
Mickey Sergeant
74 Berkshire
Actually a great choice for that bike.
Sometimes the MIKUNI type carbs must be mounted to the Sachs cylinder by using a rubber hose which looks like a short radiator hose, using two radiator clamps. I think this is an idea set-up for several reasons. The rubber insulates the carb from heat and vibration, it lengthens the plenum (is this the correct word and spelling?). I think either size carb will work, depending upon what type of riding you intend to do. The smaller carb (26) will be more of a stock replacement, and work better for low and mid-range power. The larger carb will be a performance improvement. I ran a larger BIG carb on my 1974 Penton Berkshire and it worked great, but the engine had quite a bit of port "cleaning", and an internal Moto-Plat which enhanced the upper end of the power band. Either carb must be jetted correctly! Just be sure the carb is sealed well so dirt does not get in... and check the spark plug for color which shound be a light chocolate brown.
If you intend to race AHRMA, 28mm is the maximum allowed in the rules for a 100. Mikuni made a 28mm but it has been discontinued. The 28mm can still be found, but right now Mikuni makes either a 26 or a 30 and the 30 is a larger body size than the 26-28 which makes it harder to mount. I love Mikunis, and generally prefer them to Bings, but I would recommend you find a 28mm Model 84 Bing, it will make noticeably more power than the Mikuni and it mounts like stock.
Brian
'72 Berkshire
Are you talking about radiator hose that can be purchased at any automotive store.I'm guessing no one makes a rubber boot for this aplication.
(http://i250.photobucket.com/albums/gg276/ernie7711/penton44u100cc062-1-1.jpg)
Photo shows small body 28mm Mikuni mounted with radiator hose and hose clamps. Note how you have to squish the air box boot to get it to fit. We mounted the Mikuni becaude Christopher was having a hard time after a spill with the Bing loading up. Now that he is a better rider, if we race this Berkie, it will have a Bing.
As a side note, last weekend at New Blaine I watched several Husky riders with Mikuni's kick-kick-kick ... if they only knew how to tune a Bing;)
Ernie P.
Chattanooga, TN
Ernie P, is correct with respect, with the mounting of a 28mm Mikuni. I have an article "Super Sach's Secrets" which describes modifications......Authored by "Bill Wright", so like, who was this guy? was he privy, to the ISDT, and tuners of a place in Penton History. The article is pure, I will send it , just ask.......
Never seen a 28mm Bing, is there such a thing?
Tom Brosius
I definitely have a 28mm Bing Model 84 on my 100, dont know what it was originally for because it is not stock and was on the bike when I got it. The number on the carb is 1/28/511, I know Bing can tell what it was for with that number but I've not called them to find out. Bultaco Sherpas and Alpinas also came with 28mm Bings, which have the choke circuit along with the tickler, but they were the "male" flange where mine is the standard "female" like on a Penton.
Brian
'72 Berkshire
Seems to me that you might as well spend the extra money for a bing.They mount without any modifications.Am I wrong or am I missing something?
The trick is if you plan to race AHRMA you are limited to 28mm and the one on my bike is the only one I have ever see with the female flange. Victor Monz says he has some, but I've only seen mine in person. The Bultaco 28mm Bing would be just as difficult to mount as a Mikuni since the flange is the same type. If you do not have to worry about AHRMA rules I would put a 30mm off a Jackpiner since they are very easy to find.
Brian
'72 Berkshire
Does anyone out there have a good used type 84 bing 28 mm carb to save me some $ from getting a new one.
74 berkshire
I think the 84 is only available new in 32mm for ultralights so you will have to find a good used one.
Brian
'72 Berkshire
Seems this bing vs mikuni thing is always good for an uproar.I first did the swap in 72 on a 72 six days.And most recently last summer on a 72 six days.Again the same results.It's a three kick starter cold,one at operating temp.parts are cheap as are the carbs.I prefer to use the automotive hose that goes between the filler neck and gas tank.Holds up better being it's intended to come in contact w/fuel.I buy mine at napa.Last carb came from sutco,installed it and ran right out of the box.I myself just like to ride and working on the bike is part of why I do it but the Bing thing for me has been an easy fix since the seventies,I don't run them.
Dave
Great tip on using gas tank filler neck hose to adapt the Mikuni carb to the Sachs cylinder. What is the general size hose which is used. I assume it would be an inside diameter, right? Do you mount the carb right against the Sachs intake extension, or leave a space?
Mickey.
I have been soaking up some Florida sunshine for a week or so and will check on my supply of 28 Bings when I return home, what cylinder do you have...female or male carb fitting....have you tried the 27 Bing, I think, if I am not correct 27.5 actually, but it is a 53 series Bing. I have been using the 28 on my 125's and also the 100, when I get back and install my fresh 100 motor, I have rebuilt a 27 Bing for the 100....kinda thought the 28 was too much for the 100 when it was running, although now it should be a "rocket ship" with the 'secret work" my R&D Department has performed, probably "blow" the head off with the first start up...the 84 series looks more mechanical/beefy, but the 27 mm 53 series, tuned properly, I emphasise TUNED PROPERLY, for me anyway, has been a good runner, on either bike and easy to find. Jetting and float management, vital, yet simple to do. I believe in the Bings performance and I have just gotten to where I can shut my eyes and rebuild, tune and dial it in....most times with some patience.
I will check back in towards the weekend, when I return to California.
Victor
Mickey,
The type 53 stock Bing that came on the Penton would work well.
Its only .5 mm smaller than the 28 mm type 84 and fits. The max size you can go on the standard cylinder would be 28 mm because the intake spigot can only be opened up to 28 with out becoming weakened. Thinning out the spigot to take larger than 28 mm is not a good idea.
Do you have the stock carb that came on your bike in hand?
New slides are about $20 from one of out parts suppliers.
http://cgi.ebay.com/ebaymotors/BING-NOS-Carb-Slide-Penton-Sachs-Hercules-Tempo-DKW_W0QQitemZ110376231433QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item19b2efa209
You can get a New 26 mm body from the same supplier ( call Tom at 608-295-3839 ) if yours is damaged beyond repair , use the parts from your carb with a new needle jet and float needle to fix what you have. Forest or JP should be able to ream out the 26 to 27.5 if you ride it and think the 26 is too small.
hope this helps ,
john d.
Quotequote:Originally posted by Mickey Sergeant
I just finished a 74 berkshire.I'm having the same problem your experiancing.Replaced needle and jets that someone recomended to me.Helped a little.Wont Idle wants to die.Checked plug shows signs of being rich.One thing I noticed was when checking float level was that float tab would push float needle down.Am I wrong or should floats be resting on float needle without pushing it down?If this is the case could this be my problem?All feedback needed.
When you had the carb apart, do you happen to notice if the rubber seal on the bottom of the choke plunger is either deteriorated or missing?
Thank you to all those who added interesting information on Sachs carburation; both Bing and Mikuni. But what about that other carb; Keihin? How well do they work? I would like to add that my Bing 53 ran great on my Penton 100, but the Bing 84 (28 mm) ran better. I also prefer the Bing 84 (28mm) because it has a brass fitting for fuel overflow, like the tickler, which dumps the fuel into a plastic fuel line. The Bing 53 has an open slot on the side of the carb which the fuel dumps onto the side of the carb. I do not like any openings which may allow dirt or debris to enter the carb. Joe
Remember when a 30mm Amal was the hot set up on a Six-Day ?
I have taken all the info in from everyone.Purchased a new 26mm mikuni.Should work well for what I need. Will be here in a few days.Bike is all stock,no modifications.Called bing they have a exact replacement.Well over $300.To much out of the budget for me.Still Need to purchase progressive shocks. Will check out hoses at napa for mounting.Again thanks for all the help,Didn't think that mounting a new carb could be so complicated.
Mickey Sergeant
74 Berkshire
Joe,Thats the first thing I learned.It was missing.Filled up With good silicone level.Made a small improvement.Started a little easier,Still would't idle at all.Decided to just purchase new carb,Rather than keep messing with the old carb. Want to be at the races this month.
Just my opinion, but progressive shocks are not worth it. They work very well, I actually prefer the performance of Progressives to Works or Ohlins, but the Progressives are not durable enough. They are 2/3 the cost of Works and not nearly as durable. IF Progressives would not blow seals I would use them, but I think you are throwing money away on them unless you are just going to do mild trail riding.
Brian
'72 Berkshire
Brian, I would agree with you, the Progressives work well but I have also blown seals on them. The last time was about a year ago, one side blew out on a drop off at Glen Helen, caused a huge tank slap and oil everywhere. I dented the top of a new metal coffin tank on my CZ I just got from CR Products. (Yes that is right, I dented the top of the steel tank at the top crease when I came down on it.) I now talk 2 octaves higher. They work well but the seal thing is an issue.
Lloyd
I strongly suggest going with the Mikuni vs. a Bing. For mounting it, I used clear hose that I purchased at Home Depot (for way less than auto filler spout hose). It worked well in the day and still does today. It gets hard after about a year so you have to change it out from time to time but no problems with deterioration. Regarding the fuel line, I used a very short piece of fuel line from the carb to a hand formed hard line (used brake line) to go under the pipe and upward on the right side of the bike. The fuel tank spigots are connected to it with fuel lines and a "T" fitting. This eliminates the risk of burning the fuel line on the pipe, etc.