Installing a Carb Cap Kit

[cfairweather]

I decided to make the sealing rings on my Lulzbot Mini 2 3D printer using a soft TPU filament. I pressed a button into a cap using one of these seals without any sealant to see if it would be air tight, and it worked great. I poured some alcohol into the shaft hole and no alcohol leaked out the other side. This is a good way to test your old caps. I can print 15 rings in about 20 minutes. I plan on printing about 500 of these so I don't have to do it again for a few days .

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[digger]

And it just keeps getting better, you are amazing. Looking forward to the “rest of the story” seems like you are always figuring out ways to improve things.

[cfairweather]

I am very happy to report I am almost done with this project except for making a bunch of buttons. This morning, I installed four of the buttons and seals for my current GL1000 project bike and I am very happy with the results. The depth, fit and everything is correct as I can get it. I am confident that these will work as well as the original buttons and the look is very close to the original. See the below picture. I have done a few sets for some of you using my 3D printed PETG caps. I am willing to redo these using my new acetal plastic injected buttons. Or, I will send you a kit and you can install them yourself.
All you have to do is pay the shipping. In a few days, I will list these button kits on EBay.

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[Liam]

I am totally in awe of this. Every time I look at your work I am in awe. There are a number of things that you have done, grab rails, paintwork and now these, all work to make a ruffian like me totally jealous.

[redglbx]

Great job CF ! I second Liam’s sentiments, again good job !

[Rat]

Pretty special alright !

Gord

[cfairweather]

Thanks. I started making the buttons this morning but it is a slow process, one at a time. I have done over 100 so far.

[cfairweather]

I have finished the kits and they are available on eBay. I sent them to a five individuals that I knew would try them out, so look for some feedback. I think people will like them, but I want everyone to give their honest opinion. The picture below is a kit. The black thing is a press tool. You place this over the button when you press it in. I use an arbor press, but a drill press might work ok too if you put something flat in the chuck, like an old flat valve or a bolt. The nylon washers are cheap insurance. You optionally place these around your slide rods to prevent any metal-to-metal contact. I had to order these washers from China, but I made everything else.

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[Old Fogey]

One final point which I forgot to mention to Cedric. Sorry!!
It is possible to distort the cap. I found this out the hard way way back when I started using Pete's buttons. After fitting a couple of buttons, the the pistons would no longer slide ino the caps. It doesn't take much distortion for this to happen.
So, what did I do wrong?
Firstly, the cap hole was not trimmed back enough meaning that the button needed more pressure than usual. I think Cedric's final edition of the cap is now the same outer diameter as Pete's; I make the cap hole EXACTLY 25.5mm.
Secondly, I had no internal support, so there was nothing to take up the additional pressure. I found that that an old front brake cylinder reservoir is perfect in height and diameter for this.

[robin1731]

One final point which I forgot to mention to Cedric. Sorry!!
It is possible to distort the cap. I found this out the hard way way back when I started using Pete's buttons. After fitting a couple of buttons, the the pistons would no longer slide ino the caps. It doesn't take much distortion for this to happen.
So, what did I do wrong?
Firstly, the cap hole was not trimmed back enough meaning that the button needed more pressure than usual. I think Cedric's final edition of the cap is now the same outer diameter as Pete's; I make the cap hole EXACTLY 25.5mm.
Secondly, I had no internal support, so there was nothing to take up the additional pressure. I found that that an old front brake cylinder reservoir is perfect in height and diameter for this.

[Old Fogey]

First set of customer's carbs rebuilt with the new caps.

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[cfairweather]

They look good to me.

[cfairweather]

Did you use the nylon washers?

[Old Fogey]

Did you use the nylon washers?

Yes, I did. They may help. It's not until you really look at the various parts of these carbs that you realise how poor the design is mechanically and the first year's are the worst.

[cfairweather]

So what do you think of these buttons? Did they go in ok? Did you use 25.5mm or a slightly larger hole. Did you measure the distance of the hole to the bottom of the button? 44.7mm is ideal if you use the washers. The spec is probably 44.5 +- .5mm but I can't say for sure what Honda had in mind. Yes, not a great design.