At the drag strip? Yes, you'll most likely notice a difference. Out on the street? Maybe.... but I doubt it.
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BS34 Float Help
- Thread starter bul_racer
- Start date
Yes, I doubt it too. The originals aren't available from Yamaha any more but you can find replacements made by the same company that supplied Yamaha, ARS. I managed to score a couple sets dirt cheap (less than $20 a pair) a few years back.
Even the originals are pretty tight fitting. You'll want to lube them with something to ease the carb install. A rubber lube of some kind would be good but even a smear of white lithium grease is said to work well.
Even the originals are pretty tight fitting. You'll want to lube them with something to ease the carb install. A rubber lube of some kind would be good but even a smear of white lithium grease is said to work well.
hair dryer, silglide and I tend to round off the edge of the intake on the carb.
sharp knife bevel off the inner edge of the boot?
sharp knife bevel off the inner edge of the boot?
bul_racer
XS650 Addict
If you were being fussy a turn a short aluminum collar to match the carb intake ID then bevel back any sharp edge with knife or a rotary cutting tool.
bul_racer
XS650 Addict
If you were being fussy a turn a short aluminum collar to match the carb intake ID then bevel back any sharp edge with knife or a rotary cutting tool.
Thanks Gary but I'm pretty sure that if I mess with it I'll just make things worse. Think I'm gonna just clean up edges and go with what I have.
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bul_racer
XS650 Addict
Ran into a minor problem on carb #2. A couple of problems actually. First, the new float I bought seems to be different & I haven't been able to get a 22mm setting. No matter what I do it seems to come in at just above 24mm. In addition, it did not measure the same level on both sides. I bent it to get it close but that feels really weird. For grins I put in the original leaky float and got 24.7mm. That's what it was set at, I didn't change it. Tomorrow maybe I'll try the clear tube test and see what I get - with the new part, not the leaky one.
The other thing is the float pin. Just doesn't want to go all the way in. I'm afraid to hammer on it because I've seen other threads where people have broken off the posts and I don't want to be doing that. I put the pin in my drill and it makes a nice circle about an eighth inch in diameter. Yep, it's bent! No idea how that happened. Got a few Mikuni parts lying around but no extra float pins so looks like I'll have to order a new one. Found one on ebay, probably not genuine Mikuni, for $5 that I'll probably get but it's another delay. Damn! This is taking forever! Interestingly, saw another pin that was priced at $32. Gotta wonder who is paying so much for these parts.
Well, the adventure continues.
The other thing is the float pin. Just doesn't want to go all the way in. I'm afraid to hammer on it because I've seen other threads where people have broken off the posts and I don't want to be doing that. I put the pin in my drill and it makes a nice circle about an eighth inch in diameter. Yep, it's bent! No idea how that happened. Got a few Mikuni parts lying around but no extra float pins so looks like I'll have to order a new one. Found one on ebay, probably not genuine Mikuni, for $5 that I'll probably get but it's another delay. Damn! This is taking forever! Interestingly, saw another pin that was priced at $32. Gotta wonder who is paying so much for these parts.
Well, the adventure continues.
The float pin is still available from Yamaha and I recommend using it .....
https://www.partzilla.com/product/y...?ref=dbcca4a3eda2a91a3015a16385a35f1bb2c177de
I just got one of those aftermarket replacements and it doesn't fit very well. It's tight going through the float so will probably cause binding. When you install the pin, you don't need or want to drive it all the way in. Just tap it in enough so the other end is flush with the outside of it's post .....
That will leave the end with the head looking something like this, which is fine .....
If you have the brass floats, you're using the wrong setting on them. 22mm is the setting for the plastic floats. The brass float spec is 27.3mm ± .5mm.
https://www.partzilla.com/product/y...?ref=dbcca4a3eda2a91a3015a16385a35f1bb2c177de
I just got one of those aftermarket replacements and it doesn't fit very well. It's tight going through the float so will probably cause binding. When you install the pin, you don't need or want to drive it all the way in. Just tap it in enough so the other end is flush with the outside of it's post .....
That will leave the end with the head looking something like this, which is fine .....
If you have the brass floats, you're using the wrong setting on them. 22mm is the setting for the plastic floats. The brass float spec is 27.3mm ± .5mm.
bul_racer
XS650 Addict
The float pin is still available from Yamaha and I recommend using it .....
https://www.partzilla.com/product/y...?ref=dbcca4a3eda2a91a3015a16385a35f1bb2c177de
I just got one of those aftermarket replacements and it doesn't fit very well. It's tight going through the float so will probably cause binding. When you install the pin, you don't need or want to drive it all the way in. Just tap it in enough so the other end is flush with the outside of it's post .....
That will leave the end with the head looking something like this, which is fine .....
If you have the brass floats, you're using the wrong setting on them. 22mm is the setting for the plastic floats. The brass float spec is 27.3mm ± .5mm.
Thanks Fiver!
Might explain why I'm having so much trouble getting it set to 22mm except that I did get carb #1 set. Guess I'll have to revisit that one. Good about the pin not going in all the way. Doesn't really matter since it can't really get out with the wall of the float bowl restricting it's lateral movement. And thanks for the link. You're a lifesaver!
I don't have a bowl lying around to check, but I believe the bowl was designed so the pin won't come out of the towers with it in place.
bul_racer
XS650 Addict
bul_racer
XS650 Addict
Yeah, I'm gonna change that. Clearly I'm out of my element here. All my experience is with single cylinder 2 strokes. With the help of you folks on this forum maybe I've got a 1 in 10 chance of getting this bike running...
I'd say your chances are more than a little bit better than 1 in 10 .
For one thing this group will not quit if you don't .
For another thing you'll find that for every question answered another appears.
It's a process, a true mindfuck.
In the end it's all about the ride (and how you got there)
Teach what you learn
bul_racer
XS650 Addict
I'd say your chances are more than a little bit better than 1 in 10 .
For one thing this group will not quit if you don't .
For another thing you'll find that for every question answered another appears.
It's a process, a true mindfuck.
In the end it's all about the ride (and how you got there)
Teach what you learn
Thanks Kop!
Well, I'm still learning. When I took these carbs apart I didn't think much about the butterfly's, other than just to get them out. Now I'm putting them back but they don't feel right. Is it important to have a tight fit? I have 1 in but if I shine a light behind it I can see if behind the butterfly. Is this OK or should I be trying to get a better fit? I can take a picture if that helps.
On butterflies with everything assembled on the throttle shafts (in correct order 
) leave the butterfly screws slightly loose. idle screw backed off. open throttle a bit, and allow to snap shut a few times (it should move freely and "snap" shut, this should get everything into correct position now tighten screws, repeat open, snap, making sure butterflies close fully and smartly.
Easy enough to mix up assembly order, several similar but not identical parts between the two carbs.
Bent throttle shafts can happen, they are just chrome plated brass, and softer than you might expect.
The butterflies are kinda fragile being brass, the edges are sharp, precisely angled, and need to stay that way. Never polish a butterfly on a buffing wheel.
) leave the butterfly screws slightly loose. idle screw backed off. open throttle a bit, and allow to snap shut a few times (it should move freely and "snap" shut, this should get everything into correct position now tighten screws, repeat open, snap, making sure butterflies close fully and smartly.Easy enough to mix up assembly order, several similar but not identical parts between the two carbs.
Bent throttle shafts can happen, they are just chrome plated brass, and softer than you might expect.
The butterflies are kinda fragile being brass, the edges are sharp, precisely angled, and need to stay that way. Never polish a butterfly on a buffing wheel.
bul_racer
XS650 Addict
[QUOTE="kopcicle, post: 705537, member:
It's a process, a true mindfuck.[/QUOTE]
Kop, I think you just described my entire life...
It's a process, a true mindfuck.
[/QUOTE]Kop, I think you just described my entire life...
bul_racer
XS650 Addict
On butterflies with everything assembled on the throttle shafts (in correct order
Easy enough to mix up assembly order, several similar but not identical parts between the two carbs.
Bent throttle shafts can happen, they are just chrome plated brass, and softer than you might expect.
The butterflies are kinda fragile being brass, the edges are sharp, precisely angled, and need to stay that way. Never polish a butterfly on a buffing wheel.
Thanks Gary.
Yes, I just lightly polish the butterfly plates by hand with Mothers or Blue Magic, and only lightly clean/polish the edges. Since the plates aren't completely vertical when closed, the top and bottom edges are beveled slightly to form-fit into the bore better. Make sure you install them oriented correctly. You want to see the number on the plate upright and below the butterfly shaft .....
bul_racer
XS650 Addict
Yes, I just lightly polish the butterfly plates by hand with Mothers or Blue Magic, and only lightly clean/polish the edges. Since the plates aren't completely vertical when closed, the top and bottom edges are beveled slightly to form-fit into the bore better. Make sure you install them oriented correctly. You want to see the number on the plate upright and below the butterfly shaft .....
I figured out the orientation the hard way. Didn't know I was supposed to just 'Gently Polish' the butterfly. Hoping I didn't do too much. Don't seem to be a lot of sources for replacement butterfly valves. At least not just the butterfly. Seems you might have to buy a throttle shaft in order to get the valve.
Sorta looks like the butterfly should go in before the slide & diaphragm to allow good access to the butterfly from behind. Saw on one post that there's an accepted sequence for assembly but not sure where that is documented.
On a different note: does anyone know specific measurement for the 3 tiny screws that hold the gas cap seal ring on? I'm sure I put them 'Somewhere Safe' and when I find them I'm sure they will be among a large group of miscellaneous stuff that I haven't seen in years.
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