Carbs - Carburetors

Team Junk said:
Has anyone tried JB weld to repair floats ?
Click to expand...

if you are talking about brass floats then the best way to repair them is with a soldering iron and some soft solder like silver solder.
JB Weld is going to add weight to the floats and would be a very poor repair solution.
tell us exactly what the fault is with the floats or show us a picture.

If you need to clean brass floats then you can use some Pinesol or pure lemon juice mixed into hot water and let it simmer gently for 20 minutes or so on the stove until the crud lifts off with a soft brush or soft wire wool.

if they are leaking and you need to empty them of water or fuel the use a hair dryer to gently heat the floats and the fluid will come out .
 
Last edited:
Amen, 2M! TJ, IMHO float repair should be avoided except as a last ditch effort; you're sealing a hole that formed because material has been weakened by corrosion, and it's usually only a matter of time before another hole opens up. OE floats are still available. Prices vary widely (Partzilla wants $41 each, Yamatopdog.com lists them for $61), so it pays to shop.
 
Maybe not entirely relevant for most, but anyway: I am super happy with my RS34 pumpers (linked Mikuni TM34 from Topham in Germany, Allens Performance in the UK also sell them) Expensive, but totally Worth it IMHO. Easy starting, dead stable idle, very good throttle response, and very good fuel economy. I just bolted them on as they came, With oval tapered K&Ns, no jetting changes done so far. Easy touring at Norwegian speed limits, between 80 and 100 km/h (50 to 62 mph) returns 4 l/ 100 km, which I think is very good.(62 mpg UK / 59 mpg US)
 
I was going to mention 650Central for floats. He seems to have about the best price on genuine Mikuni floats. Yamaha's price is ridiculous. You can get the same float from Suzuki for about $15 less, but 650Central's price beats that even by $7 or $8.
 
Those are some bad boy carbs.
I really like the 78-79 carbs. the carb syncing is much more civilized. I had good results with my original 750 kit and the BS 38's with 2 into 1 exhaust back in the day. When I get Old Brown running it will have stock rusty 78 special pipes. Once it is inspected and on the road then the stock pipes will go bye bye. I've never ridden a stock 650. I have some VM34's around here somewhere. I don't think I will use them as the only help up near red line and I'm too old for that nonsense.
 
Good call, TJ! I should have checked 650 Central, that's the best price you'll find anywhere for real Mikuni floats. Arctic, you're gonna give these guys a bad case of carb envy. It's too bad the bean counters at Mikuni America won't bring the TM34 mm. flat slide pumpers to this side of the pond. Once upon a time you could pick up a used bank of RS34s cheap and respace them for our 120 mm. centers, but they've gotten harder to find, and when they do surface the prices are usually ridiculous. The Topham kit isn't cheap, but the TM 4-stroke pumpers are manufactured for use on singles, and there's a lot of work involved in modifying throttle shafts, fabricating brackets, tapping and threading mounting bosses, drilling and tapping AP reservoirs for barbs and hoses, and fabricating push-pull throttle cables. The Topham price is actually quite reasonable, considering.
 
Grizld, you are 100% correct on the singles thing. Last year I bought a single project, a Yamaha SRX 600, with a Wiseco 635 cc hi comp piston and a pair of TM/RS34 pumpers with 70 mm spacing. Whenever I get around to work on that one, it may turn ot to be pretty fast for an 80's aircooled single ;)
 
Somewhere, someone wrote up a really good (to me) seat of the pants carb tuning guide. If the motor does this, look at that. Across a number of rev/situations. I saw it a while back but can't find it now. I had my bowls off recently and did not record the pilot jet numbers. I am guessing they might be as incorrect as my mains seem to be and I am looking for information to guide me in the right direction. The seat of the pants (running observation) piece/response was eye opening.
 
Anyone got a link to a suitable 90-degree driver that will squeeze in nicely to turn the synchronizing screw? I found a few online but some of them have larger "driver heads" that might not fit in that small space.... if anyone can share would be great! Thanks!
 
LikeyMeYommy said:
Anyone got a link to a suitable 90-degree driver that will squeeze in nicely to turn the synchronizing screw? I found a few online but some of them have larger "driver heads" that might not fit in that small space.... if anyone can share would be great! Thanks!
Click to expand...
I have used a long straight jeweler's screw driver. No picture now but a #1 or smaller 6-8" will dothe job.
 
Even though I do have those fancy right angle screwdrivers, most of the time I find a long regular screwdriver is easier to use. My screwdriver of choice is a 6" long Stanley with what's called a "cabinet" tip, 3/16" wide .....

StanleyCabinetTip.jpg


StanleyCabinetTip2.jpg


StanleyCabinetTip3.jpg


If you've bench synced the carbs before installing them then the final adjustment to get them perfect shouldn't take much, maybe 1/4 turn of the sync screw in either direction. Coming in from the side with a long regular screwdriver, you can easily do this.
 
It appears the links to the carb guide are no longer valid. Does anyone have a copy on file? I printed it off years ago but cannot seem to find my copies.
 

Similar threads

MountainXS
Carb Boots for Mikuni BS34
Replies
6
Views
717
MountainXS
MountainXS
K
Mikuni Throttle Plate / Butterfly Valve #135 Production Run
Replies
4
Views
563
DogBunny
DogBunny
patentgeek
Carb options for Redline XS650
2
Replies
30
Views
2K
patentgeek
patentgeek
tommytwohands
Intro to Carburetors
Replies
10
Views
2K
tommytwohands
tommytwohands
Sowiuk1
BS38 Mikuni Carb 1977 XS
Replies
15
Views
2K
Niels B
Niels B
Back
Top