Topic: CB750 carb bushings

[lucky]

Replacing throttle shaft bushings in CB750 carbs.

I was rebuilding some CB750 carbs and i need to replace the throttle shaft bushings.
The originals were some kind of sintered bronze and had deteriorated.

Lots of corrosion potential A steel shaft in a bronze bushing inside of an aluminum casting.

So I replaced them with PTFE sleeve bushings,.
They can with withstand 547º and need no lubrication and will not corrode.
I bought them in New York from Quality Bearings& Components
2101 Jerico Turnpike,New Hyde Park.
Sales 516-616-0043

They are PTFE Sleeve Bushings 10mm x13mm x 10mm wide.
It take s 2 for each side of the casting so you need 4 bushings.
There is a minimum order so it is best to order 8 and then you have enough for two sets of carbs.

They are about $5 something each.
P/N is BSPPLNM101310T

Just clean and sand the casting hole and tap them into place.
Support the casting on the edge of a table so you do not break the casting.

[Retro Rocket]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

[lucky]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

Homade fiX?   Can't you think of something more derogatory?

[754]

 If they were sintered they may have been OILITE..in which case, a drop of oil every 3 years should keep them going for like.. hmm the ones on the bike outside are 38 years old. Benn riding it 2.5 years plus.. time to oil them..

[lucky]

If they were sintered they may have been OILITE..in which case, a drop of oil every 3 years should keep them going for like.. hmm the ones on the bike outside are 38 years old. Benn riding it 2.5 years plus.. time to oil them..

I have encountered a set that were coming apart.
Another person rebuilding a set of cabs discovered the same problem and I was able to help that person too.

Since you doubt me I will now post a photo of what that bushing looked like upon tear down.

Here is a bushing that has come apart from corrosion.
The problem is caused by a bronze bushing inside of an aluminum casting. There is also a pin inserted into the bushing and that is a steel pin. Fortunately the steel pin usually gets completely corroded and it makes it easier to get apart.
Also the steel throttle shaft gets a lot of pitting corrosion in the area between the sets of bushings. Otherwise between lifter arm A and lifter arm B.

[Retro Rocket]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

Homade fiX?   Can't you think of something more derogatory?

Only you could find something derogatory out of something positive...........

[lucky]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

Homade fiX?   Can't you think of something more derogatory?

Only you could find something derogatory out of something positive.......Fool....

Sorry RETRO....I thought you were knocking down my repair solution.
My apology.

[Retro Rocket]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

Homade fiX?   Can't you think of something more derogatory?

Only you could find something derogatory out of something positive.......Fool....

Sorry RETRO....I thought you were knocking down my repair solution.
My apology.

Thats ok, i was saying that i thought it should stay in the tricks and tips section because it is a great fix , its things like this that make this forum a great place.

[lucky]

Thanks Retro Rocket.

You are a good guy.
When I posted my repair solution I really try to be accurate and make sure it is a safe and secure solution. I would not want anyone to get hurt.
I checked all of the material parameters for heat etc.,.

TEFLON® PTFE fluoropolymer fiber is stable over a wide range of temperatures. The fiber becomes less ductile at extremely low temperatures and softens at extremely high temperatures. Experi­ence shows that adequate toughness and strength are available for selected uses at temperatures as low as -450°F (-268°C) and as high as 550°F (288°C).
 PTFE can withstand 550ºF for 1 hour.

[brandEn]

Bumping this thread, I need the part number. Thanks Lucky!

[lucky]

Hey Bob, seeings though these are non stock bushings and a home made fix, shouldn't it stay in tricks and tips..?

I believe it is already in the tips section.

[lucky]

If they were sintered they may have been OILITE..in which case, a drop of oil every 3 years should keep them going for like.. hmm the ones on the bike outside are 38 years old. Benn riding it 2.5 years plus.. time to oil them..

The problem is that on some bikes (different geographic locations) there is a great potential for corrosion to take place.  It is a bronze bushing inside of a aluminum casting with a steel roll pin holding it from spinning. Lots of corrosion potential under certain conditions.

With a plastic PTFE bushing all of that corrosion potential is eliminated.