Mikuni's on my R-65

[bubby-joe]

My bings were so bad and the bike ran so poorly it would only start on full choke even warm very poor milage and other fuel related problems, the throttle shafts were worn so bad w-40 on the shaft picked up RPM a lot.  Thirty two years of neglect and abuse with todays fuels and ethanol..and foam floats.

Put a 32mm mikuni setup from dare I say Bill Blake the MIKUNI GURU at rocky point cycle.  Kit fit perfectly new cables were a snap to install all new rubbers and clamps in the kit and cost less than 1/2 of what the Bing replacements would have cost.  Only had to set the syncro and idle speed scews thats how close the jetting was.  Idles perfectly at 1000 RPM it's never done that in the four years I've owned it

But the differnce to the performance WOW, 255km yesterday on less than 1/2 tank of fuel (Double WOW), staying ahead of a Buddy and his Harley priceless way to go Bill if any of you are close to Rocky Point Cycle NH stop and say thanks for me, tell him I said (THANKS BIG TIME)  From   to   in minutes.

Another perk is I can see out the rear view with no buzz at speed now and some bar vibration at 4000 is gone as well ( SOME not all)

[montmil]

A few snaps of the install would certainly be appreciated. Just saying...

[bubby-joe]

A few snaps of the install would certainly be appreciated. Just saying...

On the way

[bubby-joe]

Here's 2 quick picks both sides fuel filter not included in kit just a precaution.  Throttle cables are new and old choke cables hang free, there is a kit to use the original choke lever if you desire.

AGAIN THANKS BILL

[montmil]

Your install looks pretty sanitary.

Is the fuel line connected to the right-side Mikuni? I can't see it.

Did notice that both carbs are identical rather than being "handed" -with left-side and right-side units. Choke linkage and carb fuel inlet is the same on both. No biggie, really.

Is the kit developed as an upgrade through an ultralight aircraft vendor and resold through Rocky Point? I also noticed the sticker on the right-side float bowl even says aircraft. These carbs are either very similar or identical to those I've seen on Rotax-powered aircraft.

But then again, I have also seen an ultralight powered by an Airhead engine flying with the gear box forward -using that gear box as a prop speed reduction unit for the long, "toothpick" propeller! Pretty neat idea.

[bubby-joe]

The label actually says not for use on aircraft.  ( I don't fly inverted anymore and neither should you) The kit is from ROCKY POINT CYCLES, NH  for older ailing BEEMERS and OTHERS and BILL the WIZARD did the jetting from my altitude 0 to 2500ft and extra jets for up to 5000ft included along with some new fuel line, all rubber conectors I cut 1 old airbox conector in 1/2 to fill the gap but all in all a great kit.  

The way mine went together Bill's been doing this for a very long time and knows his stuff they also offer kits for LIMEY stuff to replace failing AMALS and such. There is a kit for the chokes that use the handle bar lever 2 cables from carbs into 1 at the bar, maybe later for now the old choke cables are tied up in the frame.  Never just toss a BMW part someone WILL need it.  

With the kit left right handed makes no difference.  The right carb uses the stock fuel hose thru the airbox and the left I inverted the "T" and came back over the top was the easiest sort for that side.


Update
Went to lake without filling up and back, 320KM to the reserve 345KM to the layover split and 355 to the pump 21.44 ltr to fill and that's why you always use a filter.  For all that still do MPG that's 46.71MPG

[Session101]

http://www.rockypointcycle.com/c-bmw12_mikuni_carb_kits.html

i think this is what he means

[bubby-joe]

http://www.rockypointcycle.com/c-bmw12_mikuni_carb_kits.html

i think this is what he means

That's the place all right

[steven m]

So is there an inherent performance advantage to the Mikunis not being CV or does the improvement just reflect the condition of your and a lot of our well used Bings?  Would rebuilt Bings do the same thing?  

Nice install.  Just curious.

Steve

[Barry]

Slide carbs tend to give a sharper throttle response than CV's particularly if they have accelerator pumps but they are inherently less forgiving if the throttle is whacked open at the wrong time. I can't see how full throttle power could be any different except that Slide carbs don't have a throttle plate which will cause some restriction even when wide open.

There shouldn't be a significant "new being better than old" issue as Bings don't seem to wear out other than needle/jet wear.  And even then the old Amal slide carbs would be worn out before a Bing needs new needles/jets. Mikuni's are a lot better though. Never had a problem with them on Jap bikes. There's nothing wrong with slide carbs given a sensitive right hand but in the end you have to consider that for normal road use most Japanesemanufacturers overwhelmingly voted for CV carbs even though they are more complex and more expensive.

[bubby-joe]

So is there an inherent performance advantage to the Mikunis not being CV or does the improvement just reflect the condition of your and a lot of our well used Bings?  Would rebuilt Bings do the same thing?  

Nice install.  Just curious.

Steve

Better ridability, shorter warm up, smoother idle and mid range, better fuel milage 46.71 up from 39.5, goes like never before pulls all gears right to the red line including 5 gear OD.  I slowed down at well over 90 sunday, plenty fast enough for me.  To think back to other rides with CV's I can't remember any pulling red line in high gear, likely because the vacumn drops off to near zero at W.O.T. and slides slam shut.  More power on less throttle on long hill climbs.  These are some of what I've observed in the last 400km.  I put this off for a long time before biting the bullet cost delivered was about the same cost as 1 new Bing without taxes and freight. For me I see better milage for the rest of the life of the bike eventually paying for the carbs at todays prices for fuel sooner than later.  WIN WIN comes to mind.

I really don't agree that the OEM Bings don't wear out, my butterfly throttle shafts leak so bad it's almost impossible to balance the old carbs and the rubber parts all leak extra air into the mix making a very lean engine tuned to the very rich side to even run and my R-65 hasn't idled for the last 3 years.  Enricheners quit working starting was not possible when I decided to order the kit.   Driving had become almost impossible even if I could even get it started in the last 3 months.  Milage dropped from 39.5 MPG 2 years ago to 34-35 at best.

My opinion the Bing's when in fine working order and very well tuned would still miss the mark specially on power and milage.  I kept the Bing's but will probably never run them again.  Same as the brown seat cover...........

[steve hawkins]

I think the most important point here is that you have managed to get a set of carbs that seem to run well 'out of the box' with no expensive set-up/tuning.  This makes the replacement of old worn out Bings a far more attractive/viable option than attempting to rebuild them.

Any performance advantages are a bonus.

Who is next then?

Cheers

Rev Light.

[Barry]

Agree that the enrichers are not wonderful on Bings. That's one thing I wouldn't miss for sure.

Maybe your carbs were abused by a PO. Puzzled though as to why Bings can't be re-built to as new condition for less than the cost of buying new slide carbs. Also if slide carbs are that good puzzled why BMW didn't save some money and fit them to the bikes when they were new. Never had experience with Bing slide carbs though. Perhaps they weren't as good as Mikuni's. I guess back then BMW wouldn't have fitted Jap carbs to their bikes even if they were cheaper and better Got to admit my opinion of slide carbs is coloured with years of old Amals and they most definitely didn't last the distance without wear.

My Bings have only done 16,000 miles so they are like still like new. My average is 65 MPG (Imp) over 6 years summer and winter. Average this last summer 72 MPG (Imp). If the enrichers worked better I'd be more than happy with Bings.

Brown seat cover was the first thing to go on my bike.  

[nhmaf]

I don't know about Bings being less efficient with fuel mileage - my recent weekend trip of a little over 300 miles yielded an average 48.5 MPG, and I got over 50 MPG on one tankful (these are US gallons, not Imperial).    This wasn't riding over 60-65MPH, but it did involve going up and down alot of mountains.  My bike is ready to roll in short order from starting up, even at 32F temps.

I'm glad that you like the Mikunis - but it really sounds like your Bings were in serious need of serious attention to begin with.

[bubby-joe]

I've never seen throttle shaft bushings to repair worn throttle shafts for the Bings short of making my own they just don't seem to exist and I know they can be built quite reasonably.  I know someone will now point out I could have gotten them from here or there.  The Bings on my bike were a pair of the most worn I've seen and I was done with that pair.  No dought others are very worn as well and just cleaning and repalacing the rubber parts as the major part of a rebuild will not address just plain wore out for very long.  

The main reason for the kit was the local dealer where I get my parts can get new Bing's but 2 carbs no extras were more than the to date cost of the bike and the new carb kit and yes the kit was one of the best no fiddle part replacements of my 55 year old riding history.  
I'm not sure of the whole 32 year history of the bike but neglect and abuse were on the menu for at least part of it's life history.  Old cold wet lean-to for at least 5 years in the pacific northwest.

My reviving has been either good older parts some unconventional hand made parts rotted cross over made from a (BUD) satellite dish, a clutch cable made from a scooter brake inner cable to get me through until the new OEM one got here  it's in place ready to go again if I need it as well as some fresh made from scratch bags from beer backpacks, my sidecar when complete will also fall in here.  Experience gathered through years of the low end of the money pit has made me look at things diffferent than don't like the color pay someone to change it or just replace a broken part but I will not make my own carb.  

To be honest a posa fuel injector is within my capability and I have a pattern part with the adjustment tools for setting it up but I lost the setup instructions. At this point it's just not worth my time at this stage in life.  

I bought the bike to ride and enjoy not be frustrated every time it wouldn't start when it was cool or something breaks and then just throw money at it.  If I wanted that I'd have kept the BOAT. there was a hole for eating money.  I beleive the old designers had meant for it to be repaired with ingenuity by farmers and everyday people and not to always just toss a hand full of money at it.

For the most part this OLD odd ball (Red Headed Step Child) of BMW'S has and will continue to do just that, I really can't figure out why I passed on a brand new R-model I test drove in 1968 from Philip Funnell's in Vancouver but such is life.  Maybe the earles fork dive on acceleration and rise on breaking i'm just not sure.