I have a Vokes filter which I intend on fitting to my WD/CO/B (I know they weren't factory fitted, but I've got it and not got anything else to put it on yet). My filter is missing the rubber feet, what do people use in place of the original feet?
Also, has anyone found a suitable material for the cloth filters inside, seems a bit of a waste having a massive tank top filter, but not actually using it to filter anything. My experience has come from running big engines in got dusty places where dust ingestion is an engine killer, maybe not such an issue in Wiltshire!
The filter itself is made from a series of felt tubes going back and forth with special clips for the ends to attach. I have samples and some thin felt but never got round to doing anything about it yet. Ron
Thanks Ron, I’ve found the feet on vintage supplies. I’ll check the sizes tomorrow and get some on order. I’ll look to get some felt and stitch it up. I hadn’t thought to do it that way, I’ve been unsuccessfully looking for some kind of tubing.
I've always run the Vokes on my M20 as a 'dummy' without the felt tubes as I didn't want to risk upsetting the carb mixture. But it's always been quite noisy because of acting like an engine amplifier. This morning I took my filter off with the intention of fitting those original felt tubes and clips to the outside ducting tubes only..... For visual effect and sound deadening. I'll take pictures and report back on the result. Ron
Hi Ian, do you know what thickness of felt you used. It's quite expensive stuff, so don't want to to order something too thick and waste money. I was estimating about 2-3mm based on Ron's picture.
Ron, the India Office spec M20 is listed as having a 150 main jet (instead of 170 ?)and a 6/4 slide with needle on position 2. It had a Tallflow though, didn't it ? The WB30 also went down 2 sizes if fitted with the Burgess air filter.
Were there published settings for late-war WD with Vokes ?
The 3 rubber feet, are made of rubber, only for the Australian contract they used felt.
There will be more dataplates made for the Vokes filter, if anyone needs them, but not by me, but someone from the Dutch Ariel club, have his email somewhere. (now with the correct depth etching)
The felt is easily available in craft stores, at least that's where I bought it, just cut into strips, and sow the edges together, and turn inside out, nothing difficult.
Vokes elbow sets will be available again in a couple of weeks, waiting on some small parts. Price will remain the same for now.
Hi Ron,
I fitted a nos Vokes filter to my WM20 in 1985, the noise from the intake was very pronounced especially if you had been riding for 3 or 4 hours, it started to get to you. I always kept a record of fuel fill ups and found out that by fitting the filter it gave me quite a few more miles per gallon. I had all the felts fitted. I seem to think that I may have altered the needle position, don't recall changing any jets though.
I sold my original filter because I realised they weren't fitted at the time of the Desert campaign in the Middle East...(at least not to M20s)...In fact they were only fitted to the last two wartime contracts...
When I decided to put my M20 back into European theatre colours and markings I also decided to return it to a more correct overall spec. for it's year of manufacture, so I also wanted to refit the 'non cut off' tank that was on the bike when I bought it..
Personally however, I really liked the sound the induction made with the filter fitted...Ian
I've fitted the two original felt tubes and three clips that I had to the outer spouts as planned. The slightly damaged end, I super glued, taped and used tying wire. Cleaned up my original elbow and I'm using a new piece of Lex's hose. My Frank Brown Bollock protector was treated to a soak in warm water and Fairy liquid.
The new sheet of felt I have is 2mm. I have read somewhere that the carb might need some adjustments after a filter is fitted, but can't remember where right now? Ron
Main jet:-120 (early machines - no air cleaner) needle (Early models had needle located in third notch from top)
Main jet:- 160 (late machines with air cleaner) needle ( Length 2 7/8“ Located in fourth notch from top)
Although to me it doesn't make sense to fit a bigger main jet with the filter???
My Filter came from Australia, and the feet looked to be made of rubber. But of course, just because it was there, doesn't mean it's from an Australian contract.
Yes its me who wants to have another batch made of the ID plates.
Have not ordered yet though, bit busy with my own work.
And although the man at vintage plates wrote me he can do it he also mentioned that he cannot control the effect of the acid very much.
So.....it's a bit of a risk to order and then -maybe- end up with 15 plates that are not as I would like them to be.
Ofcourse given the global distress we are all in this is complete nonsense and peanuts...
Fairy liquid ? is it what I think it is ?? did you pee over it?
I've ordered some felt sheet, some spring clips and some rubber feet, so should have a working filter by the end of the week (assuming I can work out how my wife's sewing machine works!).
Do people think that I should be increasing the size of the main jet? Can someone explain why the main jet was increased with the matchless. I understand that the filter might reduce the airflow through the carb, but don't understand the relationship between air flow and main jet size.
The India Office machines with filter went down two sizes on main jet. This would seem correct, and reflects the fact that normally when we remove an air filter, we 'up' the main jet as more air entering means that it needs more fuel too to retain the same mixture. I wonder if the late-war Matchless reduction in main jet reflected other changes ?
What Rik said Tom. Like I said, it makes no sense to me to increase the main jet when you have reduced the air flow? I just didn't want to mess around experimenting with jets and needle position. Hence my lack of felt tubes.
The following info on air cleaners is from this Ariel hand book,other info on the Triumph 3HW is I think that the main jet was changed from 150 to 140 if an air cleaner was fitted.