delete this

JBM makes replacement diaphragms to fit the stock piston.
craft a hardwood lever to apply some pressure to bottom of piston, slot it so it doesn't hit the needle as you work.
 
kshansen said:
Well I guess you win the prize for the nastiest looking carbs of the week! My only advice is to not try to rush things, a lot of good suggestions already have been made.

Actually you were a bit luckier than my last pair, had to drill out a couple of the screw heads to get the bowls off and even at that one of the bowls cracked around the screw hole before it came off. And that was on a set of carbs that came off a running engine! Well that bike spent over 15 years running year round in New York State so it did see its share of road salt.
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The pin going through the float perches is tiny.I would think push those out,soak the floats until they are clean then resintall.They make brass replacement float assemblies for $15.00 each.I dont want to spend money if these can be salvaged.it is amazing how much cleaner these carbs are already.The burnt toast appearance is nearly gone. I dont think I would want to deal with wasp larvae.
 
yay.got the things out.dollar store hair dryer.patience and a big screwdriver at the last.These pics here.what would you do.Soak in parts cleaner,take the pins out and get floats of,soak them too? This is my only day off.have to make the best of it.
 

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Nasty, lots of brake cleaner. Some people do a soak in Pinesol. I've soaked in LA's Totally Awesome before, it etched the aluminum and turned it blackish. People say that Pinesol does not etch the aluminum, never used it, but if I did I wouldn't trust it to soak for more than a couple hours.

Scott
 
pinesol WILL blacken aluminum if soaked hot anyways........
Check floats very carefully,
cracked float1.JPG
cracked floats (1).JPG
cracked floats (2).JPG
most are cracked. This is real bad but you can often see a series of hairline stress fractures around the perimeter. If they aren't leaking they soon will.

JBM yes all years BS38 are the same. Replace in pairs they are a bit heavier than the stock diaphragms. Note yo9u need to maintain orentation of the piston read AND follow the directions
 
gggGary said:
pinesol WILL blacken aluminum if soaked hot anyways........
Check floats very carefully,View attachment 101213 View attachment 101214 View attachment 101215 most are cracked. This is real bad but you can often see a series of hairline stress fractures around the perimeter. If they aren't leaking they soon will.

JBM yes all years BS38 are the same. Replace in pairs they are a bit heavier than the stock diaphragms. Note yo9u need to maintain orentation of the piston read AND follow the directions
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I am afraid i already did not pay attention to the piston.as in face forward or not? I thought it might be obvious. I did mark right and left.
 
I need a good video or text that shows step by step dissasembly. Also after soaking in dawn dish solution for a couple hours the car bodies look pretty clean.I sprayed with lubricant and penetrating solution but the linkage and butterflies are frozen stiff.will not move at all.I might try a big pair of pliers, make them move,hoping that will get them going and they stay that way.
 
ron bayless said:
I am afraid i already did not pay attention to the piston.as in face forward or not? I thought it might be obvious. I did mark right and left.
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This only matters while installing the JBM rubbers. The diaphragms have a tab that fits a recess in the carb body that sets the piston in the correct orientation. Yeah sometimes it does take a pliers or light rap on the throttle bracket to free the shafts. tap LIGHTLY on shafts from both ends, hit inside and out with rust buster. if they start to move, keep lubing, work the range of motion up slowly, helps reduce burring damage to bushings.
 
mrtwowheel said:
Cheerleading.......Good for you Ron, jumping in to cleaning the carbs at this early stage. Imagine the wasted time that someone would have spent trying to start that bike without going through them.

Scott
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no way that thing could have run.you saw the pictures.the floats looked like burnt toast.The throttle springs are frozen,the butterflies wont move.I havent figured how to get that working yet.Plus I am not sure how to further disassemble,find the jets,remove,clean and replace.As bad as the set looks now its 1000% better than it was a few hours ago_Once i get them cleaned and working right,they go back on.I set up a container of gas,long fuel line to it,take the red white loose from the coils and hook straight red from battery to where coils r/w was. Put in neutral,kick the crap out of it and see what happens.Hopefully it will start.even if it runs rough at least I know I have a runner and can continue on.
 
gggGary said:
This only matters while installing the JBM rubbers. The diaphragms have a tab that fits a recess in the carb body that sets the piston in the correct orientation. Yeah sometimes it does take a pliers or light rap on the throttle bracket to free the shafts. tap LIGHTLY on shafts from both ends, hit inside and out with rust buster. if they start to move, keep lubing, work the range of motion up slowly, helps reduce burring damage to bushings.
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yes.the diaphragm rubbers have a little protruding edge that matches one on the carb if thats what you mean.thank god for engineers.
 
Did you lube the top end, pull the plugs and endlessly kick it through?
If not do that. After that I'm not beyond a bit of gas or carb cleaner thrust etc in the intake and fire it off. No carbs needed to see if it runs without bad noises.
 
You could remove the L / angle iron brace. Then the left side throttle shaft seals. This would create a "cup" to hold diesel, pb blaster, or another lubrication fluid over the shaft and bushing. Heat is your friend when removing the L brace. That and a hand impact.
 
I guess I need to clarify. WARM heat not hot heat. Don't be taking a freaking torch to it.
 
Your jets are mounted in the float bowl, not into the bottom of the main body like most other carbs. The main jet is under the drain bolt on the bottom of the bowl. The pilot jet is on top of the bowl. The gasket will have to be off the bowl (if it happened to stick there) to see it. Your bowl and pilot jet will be the type on the left .....

BS38BowlTypes.jpg


Removing the main jet .....

Stubby2.jpg


..... or if it's really stuck .....

T-Handle.jpg


Perfect fitting screwdrivers are imperative. The jets are just brass and the screwdriver slots in them are easily rounded out or damaged. I've taken to custom grinding 1/4" screwdriver bits to get that perfect fit. The loose fitting bit on the left, the one that's cocked into the jet, has not been "custom" fit .....

JetBits2.jpg
 
gggGary said:
Did you lube the top end, pull the plugs and endlessly kick it through?
If not do that. After that I'm not beyond a bit of gas or carb cleaner thrust etc in the intake and fire it off. No carbs needed to see if it runs without bad noises.
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havent yet.cool idea.I would think gas thrown in wouldnt last more than 10 seconds.Also there is no way to give it throttle.I still have not been able to get the linkage to move which means neither do the butterflies move.
 
5twins said:
Your jets are mounted in the float bowl, not into the bottom of the main body like most other carbs. The main jet is under the drain bolt on the bottom of the bowl. The pilot jet is on top of the bowl. The gasket will have to be off the bowl (if it happened to stick there) to see it. Your bowl and pilot jet will be the type on the left .....

BS38BowlTypes.jpg


Removing the main jet .....

Stubby2.jpg


..... or if it's really stuck .....

T-Handle.jpg


Perfect fitting screwdrivers are imperative. The jets are just brass and the screwdriver slots in them are easily rounded out or damaged. I've taken to custom grinding 1/4" screwdriver bits to get that perfect fit. The loose fitting bit on the left, the one that's cocked into the jet, has not been "custom" fit .....

JetBits2.jpg
Click to expand...
I wisely bought a set of jis screwdrivers.Has saved me from ruining a bunch of screws.
 
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