Primary Drive Gear Lash Numbers

[Tobyjugs]

Good evening chaps.

Does anyone know the range of the lash numbers used on the primary drive gear wheel? (Then one on the end of the crankshaft) For a 4LO or YPVS engine

The smallest I have is 82 and the largest is 92. I have another which is either 90 or 96 it very badly engraved.

[midlifecrisisrd]

I've had a 79 and sure I had a 98

Steve

[Tobyjugs]

Hi Steve I have two primaries, one definately reads 86 and the other I think is also 86, but if you live in Australia it could be 98.

Hmm 

I wish they marked them better.

[midlifecrisisrd]

Oct 18, 2020 12:36:26 GMT 1 Tobyjugs said:

Hi Steve I have two primaries, one definately reads 86 and the other I think is also 86, but if you live in Australia it could be 98.

Hmm 

I wish they marked them better.

They are always the same way up so should be relatively easy to work out which 😉

Steve

[4l04ever]

I think the lower numbered ones are from aircooled bikes

[dusty350]

I've had a 79 for Lc/Pv. Not sure about all the aircooled models, but the 400's are definitely different to Lc/Pv's. Aircooled on the right;

20200514_090707 by dusty miller, on Flickr

Dusty

[reedpete]

There are a whole pile of Aircooled ones as there are different types across the years plus obviously the diferent tooth counts...makes LC/YPVS a little easier.

[Tobyjugs]

Oct 18, 2020 14:08:22 GMT 1 midlifecrisisrd said:

Oct 18, 2020 12:36:26 GMT 1 Tobyjugs said:

Hi Steve I have two primaries, one definately reads 86 and the other I think is also 86, but if you live in Australia it could be 98.

Hmm 

I wish they marked them better.

They are always the same way up so should be relatively easy to work out which 😉

Steve

I just checked them and your right they are all written in the same direction or plane.

I ended up using a 92 drive and 62 driven making it 154. The average gear wheel clearance measured over 12 points was 0.058 mm. That's the smallest average I've measured up until now.