Just another first build.

[Rd51]

Plastic straw? Eeooww! Double check the screw pitch, isn't it 5mm x 0.5 ? This tap is available, but may not solve this problem if the aluminum threads are severely stripped, and if not run precisely over the old threads, may strip it even more. If the aluminum threads are still halfway there, new mix screws may have enough external diameter to sufficiently grab.

This would be a good project for a budding lathe student. Make replacement screws with a slightly larger (.005") diameter, same pitch.

Caswell offers an electroless nickle-plating kit, easy to do at home, could add .001" to .002" plating to the threads to improve purchase (thread engagement).

The mix screws handle a fuel/air mix, they aren't air screws.

Right when I thought this was an easy fix!
Thank you for all the info.

Yes the tap is 5mm by .05 pitch, I found a site online that carries every tap known to mankind. I have yet to pull the old mixture screw that is being held with a straw, so I'm not sure at the moment how bad the threads are in the housing.

I'll be sure to be extremely careful while threading in the tap. I figure I might as well try a tap first, and if no luck I will proceed with your other recommendations.

I understand it technically isn't a screw. It sounds like you're saying the mixture screw controls both fuel and air simultaneously? I was always under the impression that if it's fuel screw, any adjustments made would only affect fuel flow (I.e. Turn the screw in, less fuel, leaner. Turn the screw out, more fuel, richer) And conversely if it's an air screw (turning in richer. Turning out- leaner)

^if that is the case I was asking if it is the latter of the two, is it that crucial the threads are perfect? Will the threads be responsible for sealing as well? Or does the o-ring take care of the sealing, and the threads are just responsible for adjusting the screw?

Hopefully I made some sense in what I'm trying to ask. Thank you again!

 

[TwoManyXS1Bs]

Oh, yeah, what you're asking makes sense. On these bikes, like many other vintage bikes, the idle fuel is metered thru the pilot jet, and intermix air is metered thru a bleed-air jet, the two are mixed (emulsified) within either the pilot jet body (early models) or above the pilot jet within the idle fuel passage (later model EPA carbs), and this frothy mix travels to the transition/off-idle and idle ports. So, this screw actually meters an emulsified/frothy fuel/air mix to the idle port. The o-ring would seal this. Other bikes, like Honda, elected to make this screw meter the amount of bleed air when the EPA regs came out, different system.

Again, double-check your thread pitch. 0.5mm is about 0.020", about 50 tpi, a standard pitch for 5mm threads. .05mm is 50 microns, about .002", about 500 tpi, micro-machine territory.

My first thoughts on stripped threads in soft aluminum are to avoid removing material from an area that is already missing material, like trying to tap the aluminum carb body threads. This is a real challenge, requiring swiss watchmaker finesse, usually ends up with carb body replacement.

A variety of techniques can be tried, each in an increasing order of severity.

First, I would try to first gently 'swage, the threads back to usefulness by carefully threading a very clean/sharp/lubed screw in there, in/out a little at a time, hoping to displace the material enuff to regain thread purchase. Not a store-bought screw, but a machinist's reference go/nogo screw, or a custom cut swaging screw.

Some would advocate building up the threads by using epoxy, threading in a screw coated with release agent, let it cure, then carefully backing out the screw, followed with brain-surgeon surgury to clean out unwanted residual. Limited success here, depends on skill and material.

Next would try oversized screw, built-up or machined.

Then, the more severe/irreversible options. Threaded inserts, pressed-in inserts, threaded next size up with custom made screw, ...etc.

This project is ideal for a meticulous restorer and model machinist.

The plastic straw trick is novel and interesting. Out of desperation, might actually work for awhile...

 

[Rd51]

Oh, yeah, what you're asking makes sense. On these bikes, like many other vintage bikes, the idle fuel is metered thru the pilot jet, and intermix air is metered thru a bleed-air jet, the two are mixed (emulsified) within either the pilot jet body (early models) or above the pilot jet within the idle fuel passage (later model EPA carbs), and this frothy mix travels to the transition/off-idle and idle ports. So, this screw actually meters an emulsified/frothy fuel/air mix to the idle port. The o-ring would seal this. Other bikes, like Honda, elected to make this screw meter the amount of bleed air when the EPA regs came out, different system.

Again, double-check your thread pitch. 0.5mm is about 0.020", about 50 tpi, a standard pitch for 5mm threads. .05mm is 50 microns, about .002", about 500 tpi, micro-machine territory.

My first thoughts on stripped threads in soft aluminum are to avoid removing material from an area that is already missing material, like trying to tap the aluminum carb body threads. This is a real challenge, requiring swiss watchmaker finesse, usually ends up with carb body replacement.

A variety of techniques can be tried, each in an increasing order of severity.

First, I would try to first gently 'swage, the threads back to usefulness by carefully threading a very clean/sharp/lubed screw in there, in/out a little at a time, hoping to displace the material enuff to regain thread purchase. Not a store-bought screw, but a machinist's reference go/nogo screw, or a custom cut swaging screw.

Some would advocate building up the threads by using epoxy, threading in a screw coated with release agent, let it cure, then carefully backing out the screw, followed with brain-surgeon surgury to clean out unwanted residual. Limited success here, depends on skill and material.

Next would try oversized screw, built-up or machined.

Then, the more severe/irreversible options. Threaded inserts, pressed-in inserts, threaded next size up with custom made screw, ...etc.

This project is ideal for a meticulous restorer and model machinist.

The plastic straw trick is novel and interesting. Out of desperation, might actually work for awhile...

Ahh that makes sense. Thank you for clarifying.

Your logic for not running a tap through there makes sense as well. This afternoon after I got home from work I decided to pull out the mixture screw to see exactly what it is I'm dealing with.

Here is the housing that had the plastic straw inserted with the mixture screw.

Here is the good housing on the other side.

The bad side has threads running down the full length of the sidewall, while the good side the threads don't start until a portion of the way down. Hmm... I wonder if the previous owner tried running the wrong size tap through there? Or even worse; the person who I had rebuild the carburetors?!

At the moment I feel like I'm going to be purchasing a set of carbs. Sigh.

 

[TwoManyXS1Bs]

Well, looks like you have a 'frankenbike', mix/match of components from different models/years. Looking again at your 'freshly rebuilt' carb pics, you can see they have different bleed air ports, two different carbs here. Might want to check the 'Tech' section and find the carb rebuild and ID guides. Then you'll know what you have, and what your options are. I wonder (hopefully) that your carb rebuilder inadvertently gave you the wrong carb, in a production mixup, and that bad carb isn't yours...

 

[Rd51]

Well, looks like you have a 'frankenbike', mix/match of components from different models/years. Looking again at your 'freshly rebuilt' carb pics, you can see they have different bleed air ports, two different carbs here. Might want to check the 'Tech' section and find the carb rebuild and ID guides. Then you'll know what you have, and what your options are. I wonder (hopefully) that your carb rebuilder inadvertently gave you the wrong carb, in a production mixup, and that bad carb isn't yours...

Very impressive attention to detail. I have a picture of the carbs before I sent them out to be rebuilt. This is the same carburetor that I'm having the issue with; you can see all the dirty fuel/etc right next to the mixture screw. The other carburetor is spotless in this area.

So I'm going to eliminate the possibility of the carb rebuilder giving me the wrong carb. But I definitely think I had two different carbs to start out with.

I found a set on ebay. but they came off a TX650. Here is the link. http://www.ebay.com/itm/Yamaha-TX75...Parts_Accessories&hash=item58a4dbc373&vxp=mtr

Will these still work? I imagine the only differences would be jetting? Maybe I'm far off. Thanks again

 

[TwoManyXS1Bs]

Those are TX-750 carbs, different bike, use dual throttle cables, not a direct swap. If you peruse the 'Tech' section, under carburation, you'll come up-to-speed on these things. Don't want you to burn yourself before having a working knowledge of the carb setups. There are many threads here on suitable carb possibilities, try forum search 'carbs'. These things pop-up frequently on eBay, welcome to the wait-and-find world of the XS!

 

[Rd51]

Those are TX-750 carbs, different bike, use dual throttle cables, not a direct swap. If you peruse the 'Tech' section, under carburation, you'll come up-to-speed on these things. Don't want you to burn yourself before having a working knowledge of the carb setups. There are many threads here on suitable carb possibilities, try forum search 'carbs'. These things pop-up frequently on eBay, welcome to the wait-and-find world of the XS!

Ahh I see. I will do that. Thank you for all your help!

 

[Rd51]

I've decided (sadly) that I'm going to purchase a new set of carbs. I found this set on ebay. I determined these are the correct carbs based off of the following factors

1.) vertical pull choke
2.) linked, not solex
3.) single throttle
4.) mixture screw outside of the housing, not in

Here's the link to the listing

http://www.ebay.com/itm/271289295059...S:1123&vxp=mtr

Here's the link to the PDF I used to determine the different carbs.

http://www.mikesxs.net/pdf/XS_Model_ID_Chart.pdf

Am I on the right track?

 

[Rd51]

Shorai battery showed up today. Tackling the battery box within the next few weeks. I plan on running the battery on its side, and having a box/pan run underneath the seat.

 

[Rd51]

Today I prepped the forks for reassembly tomorrow. (fork seals came in this morning) When I pulled the fork seal out of one of the fork tubes my seal puller slightly bent in the ridge that holds the cir-clip. I used a mini cutting wheel to slightly cut the groove so the cir- clip could snap in again. It worked out great.

I cleaned up the other parts, and installed the 1" fork lowering kit from HHB. I was under the assumption that the spacer would slide to the very bottom of the dampening rod, but apparently it does not. The "how to" I looked at showed the spacer sitting at the very bottom of the dampening rod, but it looks like the "how to" was using a longer spacer.

Hole is lined up, tightened the set screw in snug. Am I missing something?

 

[Rd51]

The batch of parts that showed up today. Fork seals, swingarm bushings and seals, upgraded bearing set for the steering stem, drag bars, and 13 3/16" Monza sport shocks.

 

[Rd51]

So I went to install the fork seals today, only to watch them fall right into place. At first I thought I somehow had late style forks with early style fork tubes (franken bike pt 2) but I looked on my order to find I ordered the 35mm seals, but Mikes felt like sending me the 34mm ones. Yay.

I thought I'd try my local motorcycle shop, they said Yamaha has the 35mm seals in stock. I ordered them and will receive them tomorrow. Forks will just have to wait another day.

I did manage to find some progress for the bike and installed the swingarm bushings. Those went it really smoothly.

Thought I'd compare and contrast the two bars I have. I love the drag bars. Winner winner.

 

[TwoManyXS1Bs]

This might help with the swingarm bushing install:

http://www.xs650.com/forum/showthread.php?t=28637

 

[Rd51]

This might help with the swingarm bushing install:

http://www.xs650.com/forum/showthread.php?t=28637

Twomanyxs1bs to the rescue! Haha I went out and looked at them right now. This is what I found.

This side the pivot tube is slightly protruding.

Annddd you can already guess. This side has nothing protruding, it is actually retracted in a hair. So it looks like even though they went in smoothly, I will be following the similar process to the thread you showed me. Thank you!

 

[Rd51]

The new carburetors I ordered showed up today. Both sides are the same on this set. New K & N pod filters.

I installed the fork seals at the shop today, but that's all I really got to in regards to the forks. Plan on finishing them up next week.

Excited to check out the progress on my frame this Sunday!

 

[TwoManyXS1Bs]

Those carbs look good, hope they're worth the price. There's multiple posts in this forum cautioning members about those air filters, restriction/turbulence issues, filter flange blocking inlet ports, preferring uni-filters instead. Some folks have trimmed the flanges to prevent the blockages.

Another good forum search exercise...

 

[RockingThePartyDJ]

Those carbs look good, hope they're worth the price. There's multiple posts in this forum cautioning members about those air filters, restriction/turbulence issues, filter flange blocking inlet ports, preferring uni-filters instead. Some folks have trimmed the flanges to prevent the blockages.

Another good forum search exercise...

Even though I understand the positives and negatives of these filters, don't they look better than the, what I consider ugly foam filters! Isn't there a better solution out there that looks good and functions good? I'm just curious, because for many builders appearance is important over function (at times). Look at a sport bike, I love the look, but the ride position is murder on the lower back on a long haul as well as a Hardtailed bike, they look great but are murder on the spine on long bumpy rides. But so many do it anyways. I personally want a better solution, but until then I personally like the look of the Pods. IMHO

 

[TwoManyXS1Bs]

Even though I understand the positives and negatives of these filters, don't they look better than the, what I consider ugly foam filters! Isn't there a better solution out there that looks good and functions good? I'm just curious, because for many builders appearance is important over function (at times). Look at a sport bike, I love the look, but the ride position is murder on the lower back on a long haul as well as a Hardtailed bike, they look great but are murder on the spine on long bumpy rides. But so many do it anyways. I personally want a better solution, but until then I personally like the look of the Pods. IMHO

I agree, I like the look of the pods, but have ZERO experience with either. The hi-tier members here have posted cautions with solid evidence, but the non-performance crowd can modify and tune to an acceptable or tolerable level. To reduce the reported turbulence, one member advocated mounting a flow smoothing funnel-shape cone inside the pod, attached to the end plate, as used on snowmobiles.

 

[Rd51]

Those carbs look good, hope they're worth the price. There's multiple posts in this forum cautioning members about those air filters, restriction/turbulence issues, filter flange blocking inlet ports, preferring uni-filters instead. Some folks have trimmed the flanges to prevent the blockages.

Another good forum search exercise...

Live and learn.

 

[Rd51]

Didn't get to stop by S.S. metal fabricators to check out the progress on my frame today. I did however spend some time in the shop hooking the engine up to its stand and started tearing it down.

My plan for the engine at this point in time is to do a valve job, piston and rings, and clutch. I'd prefer not to split the cases; unless it is advised that I do so? The few weeks I did ride the bike I did not notice any issues with shifting, etc.

Exhaust

Intake