Topic: Heat shrink tubing over carb rubbers?

[Alan F.]

I just watched a video from Brick House Builds where he used a double walled Marine heatshrink tubing to reseal cracked carb rubbers on a water cooled Honda GL500. He's worked on several CB750s, so he may be familiar.

Link to the heat shrink he used:
https://www.amazon.com/Chanzon-Waterproof-Adhesive-Polyolefin-Shrinking/dp/B0B619131P?crid=2BKKB6YJ94MFI&dib=eyJ2IjoiMSJ9.-XfNRIalkC962PXE70K8t3NbOeNPOY5169ZBr50cVyCyONl6BP7RZFVKTPAZ9DXbDigILlnLs6meQdPbN9BmM2jyhaxvRqxe_AwdAKE0MT2uhGVW-ETPor4A-liSdFu6rztd55qkCyzJBvhDXWfftYneMOZEgvxNFFeIvBE4ANvBmwKyN4SB6P_kDDfdhGOgXCCk6MiLdij9QH2Ijj1I_1daq7QmL9OanL4mqcpQ350.w1pbsI1NRcbNKiZbHRqgWbGGSZaTyc9pZWwb8aDKNQo&dib_tag=se&keywords=2.5%2Binch%2Bheat%2Bshrink&qid=1754655837&sprefix=2.5%2Binch%2Bheat%2Bshrink,aps,100&sr=8-3&th=1&linkCode=sl1&tag=brickhousebui-20&linkId=b18c00aeb51220539cfedcca5fcdd569&language=en_US&ref_=as_li_ss_tl

Working temperature is listed as 125°C or 257°F
I wonder if this would be useful for the Fours?
Will temps be too high, especially at the middle cylinders?

[newday777]

I saw that over the weekend

[Kelly E]

My Carquest in town stocks that stuff in 4' lengths. It has a million uses. Just the other day I used some to fix the black plastic 90° fitting that plugs the valve cover vent line into the bottom of the airbox on my 74' CB 550 K0. It's made from the same plastic as the airbox and is cracked to the elbow on one end.

[seanbarney41]

BHB knows his stuff and is/was a member of this forum.  But still, they call it heat shrink for a reason.  I would expect that heat will continue to shrink it in that application until it tears and fails...but if all you got is torn boots, it ain't gonna hurt to try...

[newday777]

BHB knows his stuff and is/was a member of this forum.  But still, they call it heat shrink for a reason.  I would expect that heat will continue to shrink it in that application until it tears and fails...but if all you got is torn boots, it ain't gonna hurt to try...

I think he said in the video that the marine grade has a layer of glue inside to adhere to the surface.

[seanbarney41]

BHB knows his stuff and is/was a member of this forum.  But still, they call it heat shrink for a reason.  I would expect that heat will continue to shrink it in that application until it tears and fails...but if all you got is torn boots, it ain't gonna hurt to try...

I think he said in the video that the marine grade has a layer of glue inside to adhere to the surface.

yeah, I have used the stuff extensively.  If you need to remove it, you just re-heat and it just gets soft again and can be pulled right off.  The glue is like rtv, or hot glue gun glue...designed to be strong but can be cleaned up.  It is fantastic for building harnesses...like what it was intended to do.  Was not meant to repair hoses of any kind.  Could it work?  Maybe?  I am skepticle it will work for any long term on carb boots.

[Kelly E]

BHB knows his stuff and is/was a member of this forum.  But still, they call it heat shrink for a reason.  I would expect that heat will continue to shrink it in that application until it tears and fails...but if all you got is torn boots, it ain't gonna hurt to try...

I have been using it for years. It only shrinks so far, it has a shrinkage rating on the label.

[simon#42]

i dont see that as a permanent solution to cracked inlet rubbers . just fit new ones and be done with it . 

[HondaMan]

i dont see that as a permanent solution to cracked inlet rubbers . just fit new ones and be done with it . 

What he said?  ^^

[seanbarney41]

Yeah, agreed...but there ares so many bikes where new rubbers is not a viable option because no one makes them.

[HondaMan]

Yeah, agreed...but there ares so many bikes where new rubbers is not a viable option because no one makes them.

Kinda makes one want to start up rubber molding, no?
I've been in a rubber molding plant before: it takes some stamina to get used to the aroma.

[MRieck]

But..but......but.....if you soak in a mixture of acetone, Oil of Wintergreen, nitromethane, baking soda and Betty Crocker frosting in a can (Milk Chocolate, NOT Vanilla) they will be better than new.

[spotty]

i dont see that as a permanent solution to cracked inlet rubbers . just fit new ones and be done with it .

he specifically said he was using that method as new carb rubbers for CX/GL500's are no longer available, which is as good a reason for setting fire to them as i can think of but he seems to like them, but as with all things motorcycle related there are people out there with a soft spot for them. Rode one once and couldn't wait to get back on my XS250....

[BenelliSEI]

I did something similar to repair a “no longer available” air filter connector tube on an old Honda single a few years ago. Pulled it gently over a piece of of pipe with the correct OD and applied the shrink tube. Looks nice and still in one piece……

Not a best practice, but useful when the options are limited.

[MauiK3]

Agreed, do it when needed, it's a method of last resort.

[CycleRanger]

But..but......but.....if you soak in a mixture of acetone, Oil of Wintergreen, nitromethane, baking soda and Betty Crocker frosting in a can (Milk Chocolate, NOT Vanilla) they will be better than new.

Yeah but in what proportions? That's the real secret! 

[Kelly E]

But..but......but.....if you soak in a mixture of acetone, Oil of Wintergreen, nitromethane, baking soda and Betty Crocker frosting in a can (Milk Chocolate, NOT Vanilla) they will be better than new.

Yeah but in what proportions? That's the real secret! 

Without the 99% alcohol/oil of wintergreen mix I would have never gotten the carbs back on my 84' Honda Sabre 700S V4.

[MRieck]

But..but......but.....if you soak in a mixture of acetone, Oil of Wintergreen, nitromethane, baking soda and Betty Crocker frosting in a can (Milk Chocolate, NOT Vanilla) they will be better than new.

Yeah but in what proportions? That's the real secret! 

Without the 99% alcohol/oil of wintergreen mix I would have never gotten the carbs back on my 84' Honda Sabre 700S V4.

You haven't lived until you try to reinstall any Honda V4 carbs. I use to replace the insulators as they were actually pretty cheap. I rebuilt 1 Magna 1100 engine.....swore to never do it again and have been true to my word.
I think Honda engineers were heavily into crack during that design period. The gear driven cam designs were much better but the number of special tools and general bull$hit associated with them makes them something to avoid.

[Leino]

But..but......but.....if you soak in a mixture of acetone, Oil of Wintergreen, nitromethane, baking soda and Betty Crocker frosting in a can (Milk Chocolate, NOT Vanilla) they will be better than new.

Yeah but in what proportions? That's the real secret! 

Without the 99% alcohol/oil of wintergreen mix I would have never gotten the carbs back on my 84' Honda Sabre 700S V4.

You haven't lived until you try to reinstall any Honda V4 carbs. I use to replace the insulators as they were actually pretty cheap. I rebuilt 1 Magna 1100 engine.....swore to never do it again and have been true to my word.
I think Honda engineers were heavily into crack during that design period. The gear driven cam designs were much better but the number of special tools and general bull$hit associated with them makes them something to avoid.

[simon#42]

 i used to think rc30 carbs were hard to fit until i did a set on a rvf400  , never again.

[Kelly E]

I've done Sabre carbs 3 or 4 times and that's why I make sure to run it in the winter to keep the carbs clean. A heated shop helps a lot. The 84' VF 1000 Interceptor is much better. The perimeter frame lets the carbs come out the top, it's much easier to do.

[seanbarney41]

yeah, I have worked on a 500 interceptor, it was several years ago and brand new OEM boots made it pretty easy to put the carbs back...then I put 12,000 miles on it and it dropped a valve and shattered one piston.  Can't even get aftermarket head gaskets for that engine even if I wanted to dive into the complexity and expense.  Honda engineers were surely smoking crack in 1986.  The bike was fantastic to ride but I can't have my motorcycle heart broken like that again.

[Kelly E]

yeah, I have worked on a 500 interceptor, it was several years ago and brand new OEM boots made it pretty easy to put the carbs back...then I put 12,000 miles on it and it dropped a valve and shattered one piston.  Can't even get aftermarket head gaskets for that engine even if I wanted to dive into the complexity and expense.  Honda engineers were surely smoking crack in 1986.  The bike was fantastic to ride but I can't have my motorcycle heart broken like that again.

I have two spare motors for the Sabre and the Interceptor 1000 only has 18k miles on it and both bikes run great. The aftermarket rebuild parts were minimal and not only are head gaskets rare so are engine bearings. With the V4 Honda's you take care of them the best way you can. I put 150k miles on my first Sabre so they can last.

[MRieck]

yeah, I have worked on a 500 interceptor, it was several years ago and brand new OEM boots made it pretty easy to put the carbs back...then I put 12,000 miles on it and it dropped a valve and shattered one piston.  Can't even get aftermarket head gaskets for that engine even if I wanted to dive into the complexity and expense.  Honda engineers were surely smoking crack in 1986.  The bike was fantastic to ride but I can't have my motorcycle heart broken like that again.

Almost spit out my coffee.....I'm glad you concur.

[MRieck]

i used to think rc30 carbs were hard to fit until i did a set on a rvf400  , never again.

Off subject Simon but did you know or have dealings with Tony Scott? I always enjoyed reading about him in Performance Bikes etc and felt he was a pretty smart fella given his work with the RC-30 and especially the RC-45.

[simon#42]

i did mike and your feelings are right he was very good , very good indeed . he built lots of different race engines but is best known for getting the best out of rc30s . not an easy feat .

[MRieck]

i did mike and your feelings are right he was very good , very good indeed . he built lots of different race engines but is best known for getting the best out of rc30s . not an easy feat .

I had a feeling you did and I'm a bit jealous Simon. Tony's rebuilding methods weren't very exotic just great attention to every detail when blue printing engines. While I say not "exotic" his solution to raising CR in the RC-45 was one off. The RC-30 gear driven cams rode on carriers which could be shimmed after removing material to increase CR. The RC-45  gear driven cams rode directly on saddles which were part of the heads. Tony developed eccentric small end rod bushings to compensate for material removed. Simple and brilliant. All this from a fellow that started his working career....if memory serves correct.... running a KFC franchise in Great Britain.
 I apologize for going sideways on the thread but when Simon mentioned the RC-30 and, given his racing heritage, I had to go down the rabbit hole and ask.

[simon#42]

Not sure where his career started but I think you might be getting mixed up with Fred walmsley the Manx norton man , he had a couple of KFC’s