Hitchcocks Forum

I'm confused about valve spring lengths for my 1958 Meteor Minor. I ordered new ones because the springs that were in the bike when I bought it were shorter than the service limits given in the workshop manual.



The Hitchcocks online parts books give the part numbers as 22044 and 21602, or VS392 for the pair. These were the ones I bought. They are about 1-3/4 inches long and the same length as the ones I removed.



The workshop manual gives the spring lengths as 2-1/32 and 2-3/32 for "early" models, which mine is.



My copy of the RE parts book for the 1958 Meteor Minor gives the valve spring part numbers as 35409 and 354100, Hitchcocks part number VS420. I've checked a WD James valve spring catalogue and these spring lengths are 2-3/32 and 2-5/32.



So the workshop manual and my copy of the parts book agree with each other (more or less) but disagree with the Hithcocks parts book and what was in the bike already. I'm leaving the original springs in for the moment, but does anyone know the right spring length, and what the consequences might be if the wrong ones go in?

I think the difference in spring length relates to the change from valves with hardened end-caps fitted and steel top collars to valves with hardened tips, no detachable end caps and alloy top collars. The latter set up being fitted from some time in 1958-9 onwards. I think (and remember, IKBA rules apply here,) the longer springs go with the steel (earlier) top collars. Does that make sense?

REgards, Mark

Hi Mark -- that would certainly fit with the workshop manual and my copy of the parts book, but it doesn't fit with what's on the bike and Mr H's online parts book. I think I'll ask them to clarify. Cheers, Ed.

Just to muddy the waters a bit more - and this was on a 700 twin I worked on - the slightly different length valves and valve springs found on earlier and later versions of these also had different length valve guides, some protrude further into the rockerbox than others and, if I remember correctly, the later, longer guides went with the longer valves [with no stem caps] and the alloy spring caps, the earlier steel caps being deeper and needing more room to move downwards over the shorter guides. Long story short, if the M.M. 500's did likewise, make sure the valve spring caps are going to clear the tops of the guides at full lift, with room to spare.

According to Mr H's parts books, the 1958 and 1960 MM valve guides had different part numbers, but how they differed I've no idea.

They will very likely differ in the same way as the 700 types I referred to above, where the amount [length] of guide protruding into the rocker box will differ between each type.

Solved. The part numbers on the online parts book weren't right. Now corrected, and I have the right length springs. Brownie points to Hitchocock's for sorting out quickly and effectively.

Ed, well done for pointing out the error and top chaps at H's for fixing it but which way did the mistake go? Or to put it another way, which guides go with which springs?!

REgards, Mark

I only know about the valve springs Mark -- the '58 MM uses the longer springs, and the part numbers are now as shown in the online parts book. Don't know about the guides -- my parts book and the online one give the same part number, so I'll assume I have the right ones unless there is reason to think not.

For many years the earlier type of valves/guides/springs/end caps were unobtanium and everybody was obliged to fit the latter assemblies. (shorter springs etc)


You will also have Alloy top-spring collars with the later springs?


If they are significantly scratched, scored/gouged as result of poorly fitting v/v spring compressor, replace them...