Finally I get to share some information for once instead of just asking questions :grin: Ok, I've got one question for after.
I am restoring a 1941 WD G3L. The forks were badly corroded and I had to cut one off just to get it out of the yoke. The other one as also badly corroded and not something I wanted to trust on the bike after the restoration.
I looked everywhere for replacement fork tubes (stanchions) and couldn't find any.
I finally got a pair from AMOC, but the part number was different and they said they had never had anyone use these fork tubes on a 1941 model and couldn't guarantee they would fit.
I took a gamble as the OD and length were the same (approx)
WD 1941 G3L uses part number W41-G3L-FF3. This 1 1/8th inch fork tube was used on the 41-45 models. But also continued to be used on the 46 and 47 models.
Part number 013348 was used for years 48,49 and 50.
In 1951 they changed the part number to 016322, which they used for models through to and including 1954.
What the differences were between the parts I am not sure.
I ordered part number 016322 which was listed with AMOC as "1 1/8 FORK INNER TUBES PAIR NOT FOR COMPETITION USE".
It arrived and I got a chance to put it next to the original part. is basically the same length, with the new part being approximately 1-2mm longer. Not anything that would affect the bike. The threading at the top is the same and takes the original bolt. The holes near the bottom of the tube to allow for oil flow are the same.
I did note three differences.
1. The original tubes have notches in the end near the bottom bush. I have no idea why they are there and what they are supposed to do.
2. The recess for the bottom bush (part number UF-40-G12M-FF191 (010692) is slightly shorter and the bush binds slightly when the circlip is put on. I am sure it is not a manufacturing error as the part number for the bush also changed in 1951. I will get them tweaked in the lathe by someone to shave of half a millimetre and they should be good.
3. The inside of the tube on the new version has a narrowing, and can be best described as though there is an internal bush within the tube. It starts near the top of the tube and extends not quite half way down the tube.
- It is wide enough that the Fork Damper Rod (40-G3L-FF55) passes through with ease and space to spare. My concern was that it would interfere with the with Fork Damper Tube (40-G12M-FF60-A) as the fork spring compressed and the Damper Tube would hit or bind with this inner restriction.
- I did a few checks without the fork spring installed. I slid the fork tube down inside the slider and over damper tube all the way until the fork tube bottomed out in the slider. At no stage did the damper tube come close to hitting this inner bush.
So, for those looking for replacement fork inner tube part number W41-G3L-FF3, then a possible option is part number 016322 as used on the 1951 -1954 models.
I will let you know if I have any other issues after I get the bottom bush recess shaved half a millimetre and assembled.
As to my question, it relates to the notches in the bottom of the tubes. If anyone knows what they are for and if I need them, please let me know? I can always cut them in if I have to.
Cheers
Al