What are these screws for? And should they be removed for a carb cleaning? It’s pretty tight coming out so would rather leave it if it doesn’t need to come out.
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Kevin's 1980 XS650-G "Restoration" Thread
- Thread starter Kevin Kruse
- Start date
Vacuum taps only needed when you sync if you don't have intake manifold vacuum barbs.
The holes are blocked off/not drilled through, so they don't see any vacuum.
They're for the butterfly return spring. There's a nub cast into the body for the springs. Apparently Mikuni decided it needed the extra screw to prevent the spring sliding off.
They're for the butterfly return spring. There's a nub cast into the body for the springs. Apparently Mikuni decided it needed the extra screw to prevent the spring sliding off.
Yes, no need to remove those screws on the BS34s. The late model BS38s have similar looking screws mounted a bit higher up that are vacuum take-off ports ......
The one on the right carb is mounted in the choke housing, so if they are removed, don't mix them up, lol. Personally, I rarely remove the choke housings, I just pull the plungers out of them .....
The one on the right carb is mounted in the choke housing, so if they are removed, don't mix them up, lol. Personally, I rarely remove the choke housings, I just pull the plungers out of them .....
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That’s good it doesn’t need to be removed because it’s in there.. even tried heating it and won’t budge.
Made a needle valve seat removal tool as recommended around here, very cool.
And the throttle plate screws came out nicely with the help of that wooden shaft holder, and after filing the staked threads.
Also noticed that the throttle shafts seem like they’re made of steel, I thought I read that they’re chrome plated brass. They’re magnetic and feel a little heftier than brass.
Made a needle valve seat removal tool as recommended around here, very cool.
And the throttle plate screws came out nicely with the help of that wooden shaft holder, and after filing the staked threads.
Also noticed that the throttle shafts seem like they’re made of steel, I thought I read that they’re chrome plated brass. They’re magnetic and feel a little heftier than brass.
mebby changed on BS34s? earlier are brass.
Yup they changed.
Good catch!
Yup they changed.
Good catch!
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Made a fixture to drill the ends of the throttle shaft screws to help restake the ends as per this 2M post,
https://www.xs650.com/threads/carb-...aft-butterfly-screw-removal.46423/post-486649
Then I decided to check the countersink angle of the new MikesXS screws to the originals on our optical comparator at work, and found the originals to be 90 degrees and Mikes 82 degrees.
I’m guessing that’s why 2M recut the shaft countersinks? Why 92 degrees though, why not 90?
I think I’m going to do the same.
https://www.xs650.com/threads/carb-...aft-butterfly-screw-removal.46423/post-486649
Then I decided to check the countersink angle of the new MikesXS screws to the originals on our optical comparator at work, and found the originals to be 90 degrees and Mikes 82 degrees.
I’m guessing that’s why 2M recut the shaft countersinks? Why 92 degrees though, why not 90?
I think I’m going to do the same.
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I decided to cut the screw angle to 90 instead of modifying the throttle shaft countersink, I think that’s what 2M meant anyways..
Redid my cam chain master link.
This time I modified my cheap chain tool so that the anvil has a slot for the riveted pin on the back deep enough to hold it bottomed out but close to the plate without pushing on it so the tool doesn't wobble, and then turned the pin with a little nub that keeps it from walking off when riveting. I seat the pin nub in the rivet end then snug the pin guide against the plate so there's no wobble, then torque the pin, worked out perfectly.
Now I can sleep at night
This time I modified my cheap chain tool so that the anvil has a slot for the riveted pin on the back deep enough to hold it bottomed out but close to the plate without pushing on it so the tool doesn't wobble, and then turned the pin with a little nub that keeps it from walking off when riveting. I seat the pin nub in the rivet end then snug the pin guide against the plate so there's no wobble, then torque the pin, worked out perfectly.
Now I can sleep at night
just found your topic, like it!
Also like the machining, what kind of machine do you have?
Also like the machining, what kind of machine do you have?
Thanks! The lathe isn’t mine, it’s a Hardinge and it’s at the shop where I work. We also have a Bridgeport mill.
Someday I’ll have my own workshop with my own machines..
Someday I’ll have my own workshop with my own machines..
Ooeh that's a nice lathe! I've never seen one here in the Netherlands, but I know they are nice and solid
I’m back in business
Sounds good, valves are noticeably quieter.
But I’ve acquired a nasty leak in the clutch pushrod seal, funny how the old one in its condition was sealing better..
Let’s see how many more leaks spring up..
Sounds good, valves are noticeably quieter.
But I’ve acquired a nasty leak in the clutch pushrod seal, funny how the old one in its condition was sealing better..
Let’s see how many more leaks spring up..
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Happy dance!! 
Some other things I’ve done,
Polished the forks, top tree, risers, and powder coated the instrument bracket “Honda Silver Cloud” (don’t hate)
Powder coated the top motor mounts
Bought a Kawasaki KZ305 clutch lever, the pivot hole was pretty worn out so I bored it and pressed in a bronze bushing, perfect fit.
Got some safety wire bolts for my caliper.
New OEM intake manifolds.
Ultrasonic cleaned carbs 5 times lol, I’m 99% sure they are clean. Replaced throttle shaft seals and went up a step on the major and pilot jets to 135 and 45. Also replaced floats with Suzuki floats, didn’t even need to adjust.
Modified some locking pliers to crimp the throttle shaft screws, worked out pretty good.
So I noticed the CB Performance elephant foot adjusters had very loose threads, so I ordered some different ones off eBay that I think are EMPI brand, talking with 5twins they seem to look slightly different than his EMPI adjusters, maybe they updated them or maybe a different brand? But they fit MUCH better, only thing was the foot was slightly taller so I had to cut into the rocker a tad more, I’m hoping there’s enough threads left
Polished up the rocker faces while they were out, and replaced the seals.
Trying out this cheap Amazon windshield, I like how it looks but I have a feeling those plastic handlebar clamps aren’t going to last.. Also going back to the stock pull backs for a bit to feel them out.
Placed a voltmeter in the dash, had to very carefully dremel out the round lens behind the top lens, which I found out is a very tedious job, but worked out pretty nicely. I got the idea from a @Mike G post, and he gave me some advice on how he did it.
https://www.xs650.com/threads/1980-sg-back-from-the-dead-–-aka-dad’s-bike.54325/post-651883
And bought a candlepower headlight lens so I can change out a bulb if it pops.
Polished the forks, top tree, risers, and powder coated the instrument bracket “Honda Silver Cloud” (don’t hate)
Powder coated the top motor mounts
Bought a Kawasaki KZ305 clutch lever, the pivot hole was pretty worn out so I bored it and pressed in a bronze bushing, perfect fit.
Got some safety wire bolts for my caliper.
New OEM intake manifolds.
Ultrasonic cleaned carbs 5 times lol, I’m 99% sure they are clean. Replaced throttle shaft seals and went up a step on the major and pilot jets to 135 and 45. Also replaced floats with Suzuki floats, didn’t even need to adjust.
Modified some locking pliers to crimp the throttle shaft screws, worked out pretty good.
So I noticed the CB Performance elephant foot adjusters had very loose threads, so I ordered some different ones off eBay that I think are EMPI brand, talking with 5twins they seem to look slightly different than his EMPI adjusters, maybe they updated them or maybe a different brand? But they fit MUCH better, only thing was the foot was slightly taller so I had to cut into the rocker a tad more, I’m hoping there’s enough threads left
Polished up the rocker faces while they were out, and replaced the seals.
Trying out this cheap Amazon windshield, I like how it looks but I have a feeling those plastic handlebar clamps aren’t going to last.. Also going back to the stock pull backs for a bit to feel them out.
Placed a voltmeter in the dash, had to very carefully dremel out the round lens behind the top lens, which I found out is a very tedious job, but worked out pretty nicely. I got the idea from a @Mike G post, and he gave me some advice on how he did it.
https://www.xs650.com/threads/1980-sg-back-from-the-dead-–-aka-dad’s-bike.54325/post-651883
And bought a candlepower headlight lens so I can change out a bulb if it pops.
I've got an extra Givi 603 windshield if you're interested. Pretty good shape... a few minor scratches and some marks at the bottom where engine vibes rubbed it against something. PM me if you're interested.
Here's the one on my SG. Been on there about 4yrs now...
Very solid, good quality mounting (also plastic). Numerous blasts out past 80mph have failed to dislodge it. At least it doesn't have the butt ugly mounting system your Amazon special does. Hard to shoot defects in glass. Camera wants to focus past 'em.
Revzilla wants about $120 for one. I'll let it go for much less than that.
I wish you showed me that before I bought mine, just passed the return window. I’m gona give these a shot and see how they do. I’ll let you know, thanks!
So im having an electrical issue, no turn signals, no speedometer back light, and brake light failure light is on. I replaced the brake light and all the small instrument bulbs with leds, I put the old original bulbs back in but same problem.
Before tearing down the bike I’ve always had the problem with the speedo back light not working, just figured it was a burnt bulb but it wasn’t. And also my front left and rear right turn signals wouldn’t work, checked bulbs and grounds still wouldn’t work.
I did go through my turn signals housing assembly when I got the bike and cleaned and greased the mechanism with dielectric grease and had to resolder a connection. I want to say all signals were working for a bit, sorry memory is fuzzy.
And I have done the reserve lighting unit delete.
I’ve got some digging to do..
Before tearing down the bike I’ve always had the problem with the speedo back light not working, just figured it was a burnt bulb but it wasn’t. And also my front left and rear right turn signals wouldn’t work, checked bulbs and grounds still wouldn’t work.
I did go through my turn signals housing assembly when I got the bike and cleaned and greased the mechanism with dielectric grease and had to resolder a connection. I want to say all signals were working for a bit, sorry memory is fuzzy.
And I have done the reserve lighting unit delete.
I’ve got some digging to do..
I figured out my issues.
I removed the speedo bulb and inspected it, no issues, put it back together and now it works
And I had the flasher connector plugged in wrong lol, it’s a 2 prong and didn’t think about it when I plugged it in, all signals working.
And I removed my light checker unit, no more break failure dash light.
Now to order another pushrod seal…
I removed the speedo bulb and inspected it, no issues, put it back together and now it works
And I had the flasher connector plugged in wrong lol, it’s a 2 prong and didn’t think about it when I plugged it in, all signals working.
And I removed my light checker unit, no more break failure dash light.
Now to order another pushrod seal…
You replaced the push rod guide bush behind the seal? If not, highly recommend you do so. It's only a few minutes to collapse the one in there, pull it out and push a new one into place.
