HOW TO MAKE FELT CARB WASHERS

[Oddjob]

Just made 3 sets, I use metric hole punches and I find 12mm and 8mm good for this purpose. Unlike the link I find making the small hole first then punching the larger one around it. I tried it the other way and I was forever throwing them away due to one side being so thin it was starting to break up.

Will send you 2 sets Phil. One set for CB-500 as soon as he sends me his address.

[Sesman]

Ken, you are the chosen one.👍

[Oddjob]

Packaged and will be in the post tomorrow.

[Oddjob]

I have decided that I might as well buy a new punch set, the new one does both cuts at the same time so hopefully the quality will be much better. Also ordered some new felt, 100% wool felt. If the new ones turn out better than my other ones I may make a few sets and sell them. Might even be able to make the ones for the 500 swinging arm.

I'll update when I have all the tools and materials.

[Laverda Dave]

I'll pre order a set for the 400 when the production facility becomes fully operational please Ken 👍.

[Oddjob]

We'll see how they come out first Dave. Hopefully they'll be really good, at £90 for the punch I'd hope so.

I'll sell a few sets and recoup the outlay.

What's odd about the link that started this is it suggests 1/4" and 3/8". 1/4" is approx 6mm and 3/8" is approx 9.5mm. Which is odd as the shaft of the lifter arm is 10mm and the hole in the carb body is around 12-13mm. So the felt must have to stretch like hell to fit and most likely it would rip. Is the 400 felt washer the same as the 500/550?

Actually just noticed the felt washers on the link are going onto the choke not the lifter arm as in the 500/550.

Send me measurements of the 400 choke arm please Dave and the carb body recess. Do they not have the felt washers on the lifter arm as well Dave? Been many moons since I refurbed a 400 set of carbs.

[Laverda Dave]

I would need to take the carbs apart to measure them Ken. I have a spare felt in the set I got from Mike Nixon previously. I'll measure these and let you know. There are two sizes, one for the lifter arm and a bigger one for the choke butterfly shaft.

[Bryanj]

Ive got comfysofas carbs here in total dynamite condition i will see if they are there and measure them tomorrow

[Oddjob]

OK Dave panic over as Bryan has a set apart. The lifter ones look the same as the 500/550. I presume there are 4 in each set?

[Sesman]

Yep, four per set.

[Oddjob]

Cancelled the order for the punch set as I discovered it didn't do big enough punches to make the swinging arm felt washers for the 500. Ordered the bigger set (£160) which will allow me to make them.

Anyone got a felt washer off a 500 lying around, I seem to recall it was thin but how thin. The O/D bore is 26mm but what's the inside bore? which thinking about it will be the O/D of the bush, anyone got a genuine 500 bush? I threw mine away when I cut them out of the swinging arm.

[Bryanj]

Id of the felt is  not the od of the bush ken but od of the steel collar od of the felt is od of the bush, got brass bushes and collar upstairs

[Bryanj]

Brass bush approx sizes 21 id 25 od but if using brass you dont use the felt, that is only on the original 500 and 750 i think, maybe 450.
All the later onrs use a phenolic top hat type i think

[Oddjob]

I seem to recall the felt washer goes between the bush and the tube of the swinging arm Bryan, it then gets covered by that little top hat type plastic washer, presume it's there just to stop water entering.

Yeah, only the 500 uses it and only when using OE type bushes. Maybe some other bikes use something similar though.

[CB-500]

I currently have my 500 swingarm in bits for the fitting of bronze bushes, I have all the old components apart from the felt washers!! Can’t find them anywhere!

However here’s the measurements of what I do have:

Swingarm bush (no.10 parts fiche) OD-26.5mm ID-21mm

Pivot thrust bush (no.11 parts fiche) of which the felt washers fit against - hopefully the photo makes sense, sorry the editing was done quickly