softening hard carburetor boots

[triton28]

I figured there must be a way to soften my rock hard cylinder head to carburetor holders so I googled it. The most popular method was to use methyl Salicylate, ( Wintergreen oil ), and Isopropyl alcohol in a 1 part oil to 3 parts alcohol solution. I kept 4 rock hard holders as control units and immersed 4 into the solution. 24 hours later I removed the holders from the solution and without any exaggeration they were almost as soft and pliable as my good ones.
I think 48 hours may be the right timing so I am going to put them back in for another 24 hours, right after I remove 3 lower airbox to carburetor ducts/boots later this afternoon after their 24 hour bath.
One thing to note is that there is a certain amount of swelling associated with this procedure but in testing the fit on the cylinder head stub and on the carburetor flange the fit is still good on both sides of the holders. I suspect that when the rubber hardens it shrinks with the loss of plasticizer and it is not really swelling but rather it is returning to it's original size.
I am truly impressed with the results so far but being cautious I will be checking the pliability and size of the first 4 over the next week or so just to see if it remains as pliable as when I first removed it from the solution.
I will post results as I determine them but if this method holds true it could make the fight to fit the ducts from the lower airbox onto a set of replaced carbs much easier than if they are rock hard as were mine.
Dave

[triton28]

Well the holders worked out fine after a 24 hour immersion BUT after a 48 hour immersion there was no noticeable increase in pliability. There was however an additional amount of swelling on one of the 4 holders to the point that I wondered if it was still usable. In place without a clamp it appears too loose a fit, however with the clamp tightened to it's normal amount of torque the fit is compressed and there does not appear to be a problem. However I will be leak testing the fit with some petrol in the near future and will report.
Two of the 4 ducts after a 24 hour immersion exhibited a greater degree of swelling than the other 2 ducts, probably due to prior exposure to UV rays when they were in service, I can't say scientifically so that is just an observation. Those 2 are noticeably looser on the carburetor so I installed the OEM roll up spring where the duct sits on the carb and the compression of the spring produced a tight fit, even with the swelling. The 2 ducts which did not swell as much are OK even without the compression spring installed.
So now I will conduct the same test with the control, hard holders and control, hard ducts but this time I will only immerse the holders for 24 hours and the ducts will be immersed for only 12 hours. I will report the results but to sum up so far, even with dimension changes, I will be using this method for any future rock hard rubber items.
Having said that though, this procedure is NOT for the faint of heart as without careful timing and due consideration to the degree of stiffness to start with, and the OEM dimensional thicknesses involved, I can see problems for the casual user.
I will post again after the 2nd batch are done.
Dave

[ekap1200]

Hello from New Jersey. Here is a Co. that may have new replacements .
/www.murphskits.com/product_info.php?cPathducts_id=220
I will try to research this a bit more and find more companies that may have some.
Partzilla lists them 16065-1140 but lists for 21.02 each, a bit pricey but if you need them , be ready to drop some cash
Gene Kap.

[triton28]

Hello Gene;
my experiment is not out of necessity as I have lots of good holders/ducts, but rather out of interest as I was going to throw these out but thought "There must be a way to soften these". And not being one to waste anything which may possibly be resurrected, I decided to start on this experiment. The results are very promising so far.
Yes I saw that suggested price so that helped prompt me to action as well.
Hopefully between your research into Murphs and my layman mad scientific experimenting no one will have to use rock hard holders/ducts ever again.
As a footnote, my shop has the freshest smell of wintergreen of any shop around here, reminds me of those little round white Lifesaver candies I used to get as a kid. The scent/odor/smell hits me in the face everytime I go in the shop, and it is a little heavy but still, it's not as offensive as Kleen-Flo 651 Carb and Metal Parts Cleaner. Man that stuff is killer!
Regards,
Dave

[triton28]

The results are in! I started with 8 hard holders and 8 hard deformed ducts and did 2 batches of testing. The first batch of 4 holders and 4 ducts were soaked for 24 hours, removed, soaped clean, rinsed and evaluated for pliability and swelling. Then the holders were immersed for a further 24 hours whereupon they were soaped, rinsed and evaluated again. The ducts only remained in the solution for a further 12 hours as opposed to the additional 24 hours for the holders. The results for the holders are given in my post of Thursday May 21st. As mentioned the ducts of the first batch were immersed for a further 12 hours due to the relative thinner cross section versus the holders. This gave the ducts a total immersion time of 36 hours. At this point the 36 hour ducts did not show any increase in pliability nor swelling as compared to the 24 hour immersion time. On to test batch #2.
For the 2nd test batch I immersed the remaining 4 control, hard holders for a total time of 24 hours only and found the results to be similar to the 48 hour immersion time: very pliable but with less swelling than the 48 hour holders. This seems to be the "Sweet spot" in so far as timing goes for the holders.
The remaining 4 control ducts were immersed and after 6 hours I removed 2 of the 4 for observation. They were very pliable and did not exhibit any noticeable swelling. After an additional 6 hours I removed the remaining 2 ducts and found no increase in pliability versus the 6 hour ducts, nor was there any additional swelling evident. So for the ducts 6-12 hours seems to be the ideal amount of time.
I have included some photos which show the holders/ducts after completion of this experiment. As well several of the photos show my"Drop test" for the ducts. One will notice that the ducts still hold onto the flange of the carburetor without the aid of the roll-up spring.
The holder photo can't show the fit onto the carb due to the external shoulder on the carb and corresponding internal divet of the holder interior passage. You will have to take my word for the fit: it was snug with all of the holders except for the one from the 1st batch.
The fit of the holders onto the cylinder head stubs was also checked and in all cases it was still snug, even with the holder from the first batch which was loose on the carburetor mouth flange.
So to sum up, the ideal time for holders is 24 hours and the ducts 6-12 hours depending on degree of hardness at the start. Anymore time than these suggested timelines is risky in so far as swelling is concerned, and there does not seem to be a corresponding increase in pliability. The one minor irritant in this has been the smell of wintergreen: it has penetrated the holders and ducts and I have had them outdoors to try and eliminate the scent. I'm sure it will dissipate with time.
So that's it for the softening experiment, now it's time for a CLR (calcium/lime/rust) flush of a radiator to see how that works out. I will post results of that as they become available.
Dave

[triton28]

Well it is now 1 year since I tried the softening experiment outlined in the previous posts and I can report that the ducts/holders have remained soft and very pliable. I retrieved them from my secret stash of unused but valuable parts and compared them today. I was pleased with the one year comparison results.
The noticed swelling previously mentioned does seem to have decreased to a size closer to stock than they had been after the experiment was first completed.
Overall I would have to say that a solution comprised of oil of wintergreen and isopropyl alcohol does in fact work to soften hard brittle rubber parts. I would recommend this procedure to anyone whose rubber parts have become hard and difficult to install.
Dave

[SgtSlag]

I have used a product called AT-205 Re-seal, with great success. I used it on my 1979 Honda CB750K, and my 1993 Voyager XII, as a preventative measure: I added some to the crankcase, to soften rubber seals within the oil systems. I sold the Honda back in 2012, but there were no apparent issues caused by the treatment, in the 3+ years I rode it after treating it. In 2009, we circled Lake Superior on the Honda, two up, after the engine was treated with the product: eight days of riding, 1,935 mile trip, without issue. On the Voyager, well, that was 20,000 miles ago, mostly long distance touring two up, and no issues yet.

The AT-205 Re-Seal product does not smell of Wintergreen. It has minimal odor, actually. It claims that it will not dissolve rubber, over time, after treatment. That is something I would be wary of, with your home-brewed formula. Still, after one year, I would think that would have manifested by now, it it were an issue. Cheers!

[triton28]

SgtSlag;
I forgot to mention that the smell of wintergreen has completely dissipated from the parts, thank heavens.
The AT-205 looks like an interesting product, thanks for the info,
regards,
Dave