Topic: I'm thinking of rehabbing worn slide bores in my carbs... is it possible?

[grcamna2]

Has anyone heard of fixing worn slide bores in a set of carbs. you'd rather not throw away ?

[BPellerine]

used to get amal carbs resleeved in stainless to stop the wear and make them better than new.bill

[demon78]

I was going to say they do it with Amals all the time
Bill the demon.

[grcamna2]

I'd like to know more about that; any of you here have it done before?
This one has the hard plastic slide 'locating peg' on one side and that will have to be installed too.

[754]

 I dont know any Honda carbs that are not cheaper to replace than get sleeved. the not round opening in the 750 carbs would be real expensive to make a sleeve for.

[grcamna2]

This little Keihin PD carb. is for a Honda CB125 and it's kind of special to me,it's got some corrosion to it that's been cleaned out and the slide is a little loose,want to tighten it up;a couple pics

[754]

 Being one carb is much simpler.. no matching up to each other.. is the bore round ? its not on the 750,s
 i would be looking for a good used regardless.

[grcamna2]

Being one carb is much simpler.. no matching up to each other.. is the bore round ? its not on the 750,s
 i would be looking for a good used regardless.

The slide bore is round for certain but the venturi shape is a type of interesting oval shape..This is a limited production Keihin PD66 and was only used on the 1978' CB125S along w/ an atomizer plate and it was(the Best for oem performance And fuel mileage in my opinion) 'the hot set-up' for a stock carb w/ exh. to match the intake flow.I had another one for a while,bought it used real cheap(the other one)off ebay but someone tightened down the pilot screw SO much on that other one that it messed-up the hole in the carb. body and never was able to lean out the pilot circuit... and it carboned up the cyl. real quick but it Did FLY w/ this style carb. and that's what i wanted on the little CB125S 'mini-cycle'    Well so I found this one also on ebay w/ all good parts except for the corrosion.These are very tough to find,I saw a NOS one going for $295 
I don't mind putting a little more $ into the project now on this carb. because all the other parts to it are nice,even the slide itself is barely smooth from low miles.I found that the aluminum oxide made it 'feel' like it was snug and when i removed that it does rattle from wear when i shake it. I like the idea of a Stainless steel bore  but w/ the shape of the venturi it wouldn't lend itself to being bored inside after the sleeve is installed..
 I need to find a place that will do another way of adding a coating that will fill in the corrosion toward the bottom sides of the slide bore. I'm asking if any of you have heard of a special type of coating I could have sprayed into the slide bore to build it back up again and then they I could lightly 'massage' the slide bore to fit my slide w/ a closer tolerance?
A couple pics of the venturi shape,it works great 

[simon#42]

might be cheaper to bore the carb body then have an oversize slide made

[demon78]

Well I used to Metal spray a/c cylinders but it was external rather than internal and if you had a set up for internal it would be for a much bigger piece You know you might look up an aluminum plating company because they should be able to control the thickness of the deposit I googled plating and up popped Advance Plating Technology and they claim that they can plate alloy with a variety of things so there's a start.
Bill the demon.

[grcamna2]

Well I used to Metal spray a/c cylinders but it was external rather than internal and if you had a set up for internal it would be for a much bigger piece You know you might look up an aluminum plating company because they should be able to control the thickness of the deposit I googled plating and up popped Advance Plating Technology and they claim that they can plate alloy with a variety of things so there's a start.
Bill the demon.

The more I think of it this makes the most sense to me;I could try to think of a durable plating/coating to have someone spray into the bore of the carb. to build it up enough to fill in where corrosion has taken aluminum away.
I don't have a shop right now but would be interested if someone does this.I hate to throw away this carb. body,they are Very Tough to find and the venturi shape works SO well in my engine.
                                            Thanks Bill the demon     Bill H.-grcamna2

[grcamna2]

Well I used to Metal spray a/c cylinders but it was external rather than internal and if you had a set up for internal it would be for a much bigger piece You know you might look up an aluminum plating company because they should be able to control the thickness of the deposit I googled plating and up popped Advance Plating Technology and they claim that they can plate alloy with a variety of things so there's a start.
Bill the demon.

The more I think of it this makes the most sense to me;I could try to think of a durable plating/coating to have someone spray into the bore of the carb. to build it up enough to fill in where corrosion has taken aluminum away.
I don't have a shop right now but would be interested if someone does this.I hate to throw away this carb. body,they are Very Tough to find and the venturi shape works SO well in my engine.
                                            Thanks Bill the demon     Bill H.-grcamna2

Have you heard of someone who's done this type of thing to a carb. and knows how ?

[Don R]

 I wonder if antique carb guru's have a process for this. I met a guy that specializes in old ones (early 1900's) once, he was years behind and had some PO'ed customers all over the world. Said all the local machine shops stopped working for him. That says a little.

[grcamna2]

I wonder if antique carb guru's have a process for this. I met a guy that specializes in old ones (early 1900's) once, he was years behind and had some PO'ed customers all over the world. Said all the local machine shops stopped working for him. That says a little.

I would love to build-up the slide bore Don to give it like new response and I need to find a good source

[754]

I cant imagine anyone setting up to do this for less than a few hundred.. Plus how will you get it clean eough to get a good bond.. Plus any amount of  heat could quickly render it useless.

[grcamna2]

I cant imagine anyone setting up to do this for less than a few hundred.. Plus how will you get it clean eough to get a good bond.. Plus any amount of  heat could quickly render it useless.

think more positive

The reason I said that was because i've already decided to do whatever this little air/fuel 'mixer' needs to keep it alive,the fit inside is a bit loose in the slide-bore especially down bottom w/ general H20 'pitting' on lots of it's surfaces but it's still 'salvageable' and I will do my best to make the performance as good as possible so it can give many more years of service to me.I hate throwing anything away if there's a way it can be saved Frank  ,you should see the crankcases I just recd. w/ the Big cracks on the bottom(all the pieces were there and intact) from hitting a large object in their past that i just gave to the welding instructor over at the Voc-Tech high school in Indiana,PA.  I just couldn't bring myself to throw them toward the junk man;I'll build an engine w/ those..,just 'battle scars'

[754]

I am thinking positive.... Easier to work on outside of stuff , or both sides like cases.
Now working inside a hole.. Difficult..
 Here is an alternate plan.. Bore out the carb slide hole till it cleans up.....absolute easiest/cheapest. Thing you can do to the body....now make a new slide , or keep replating/anodizing the old slide ( ie build it up) till it gets to size to fit the hole.

Metalizing or spray welding is often last resort type work...like the spindle in my Herbert lathe where the bearing fit got loose.. You build it up to avoid downtime (often the case) ....or because the part is unobtanium.. It makes sense to spend 800 bux to fix a shaft, rather. Than lay off a hundred people for a few days waiting for parts.
 But were are talking a carb here..thin fueled fouled cast alloy. That is difficult to build up ( spray welding)..plating maybe ..but still difficult..

[faux fiddy]

I cant imagine anyone setting up to do this for less than a few hundred.. Plus how will you get it clean eough to get a good bond.. Plus any amount of  heat could quickly render it useless.

I think If  interference tolerances with heat or fit within .001 and use certain types of thread locker it would work, but what amount of work, the. I'd look for recommendations on repop carbs  which can be pretty cheap. Ask about ones that work, I hear you can tune them; use the Mikuni kits, I hear  makes them just as good, not sure how it works out cash wise, but I would think a  real  mikuni  only about one beer coupon. 

[grcamna2]

I am thinking positive.... Easier to work on outside of stuff , or both sides like cases.
Now working inside a hole.. Difficult..
 Here is an alternate plan.. Bore out the carb slide hole till it cleans up.....absolute easiest/cheapest. Thing you can do to the body....now make a new slide , or keep replating/anodizing the old slide ( ie build it up) till it gets to size to fit the hole.

Metalizing or spray welding is often last resort type work...like the spindle in my Herbert lathe where the bearing fit got loose.. You build it up to avoid downtime (often the case) ....or because the part is unobtanium.. It makes sense to spend 800 bux to fix a shaft, rather. Than lay off a hundred people for a few days waiting for parts.
 But were are talking a carb here..thin fueled fouled cast alloy. That is difficult to build up ( spray welding)..plating maybe ..but still difficult..

Now you're talking and I 'got it' 
I see your logic w/ boring it's i.d. to make it completely 'round' again and then build-up/plate the slide itself. I'm guessing that "metalizing/spray welding" is not a completely uniform process and could cause more to reside down the bottom and cause me more 'grief' to bore out later if I wanted to think about making it nice and round w/ that process..   ok and then that's the 'plan'. Now I've got the right goal,thanks Frank.
I'd like to have a specialist do the fine honing to the slide-bore and then get their ideas about how to remove and then replace the small oem plastic 'peg' that fits into the one side of the slide to keep it from rotating;that is one Tough plastic piece! and I doubt I could match the quality that Honda originally used to manufacture it and the special glue that keeps it permanently in place. Do you have any ideas about removing and re-setting that piece ?

[grcamna2]

I cant imagine anyone setting up to do this for less than a few hundred.. Plus how will you get it clean eough to get a good bond.. Plus any amount of  heat could quickly render it useless.

I think If  interference tolerances with heat or fit within .001 and use certain types of thread locker it would work, but what amount of work, the. I'd look for recommendations on repop carbs  which can be pretty cheap. Ask about ones that work, I hear you can tune them; use the Mikuni kits, I hear  makes them just as good, not sure how it works out cash wise, but I would think a  real  mikuni  only about one beer coupon.

I hear you faux fiddy,but I'm going to go with Frank's idea

[demon78]

I kind of like what Frank says to about building up the slide to compensate for for the gap I don't suppose you've talked to various carb specialists probably only a few times right.
Bill the demon.

[grcamna2]

I kind of like what Frank says to about building up the slide to compensate for for the gap I don't suppose you've talked to various carb specialists probably only a few times right.
Bill the demon.

Bill,
I'd like to meet a carb. specialist and we could share ideas;I really like Frank's suggestion.

[BPellerine]

sleeve the slide then turn it down,make a brass pin to locate the slide.bill

[grcamna2]

sleeve the slide then turn it down,make a brass pin to locate the slide.bill

That's a good suggestion Bill,have you ever done that on one of your bikes? I think the brass might wear faster than this really tough oem plastic locating 'peg' they use..but I can't say that for sure..
                                                                                     thanks 

[BPellerine]

I have not done it personally,but have seen carbs that were repaired like that,if brass is not strong enough ,then pick a material that is,really easy to set the carb up when it is tight.bill

[grcamna2]

I have not done it personally,but have seen carbs that were repaired like that,if brass is not strong enough ,then pick a material that is,really easy to set the carb up when it is tight.bill