wrong bearing?

[hendy]

Folks,

I'm building my first lambretta engine and think I may have made a mistake with the bearing I have bought for the mag side of the crankshaft.

It's an Li125 series 3 casing.
I've bought a GP mec-eur crank with 2205 bearing.
I thought I could use this crank in my casings if I used the 2205 bearing and omitted the spacer normally used in the LI125

However, I fitted outer seal, then L shaped retainer, then 2205 bearing, then inner seal. The L shaped retainer is loose between the bearing and housing (I estimate 1mm of play). Also, the inner seal sits a little higher than I'd expect so that it fouls the groove for the circlip. This 'feels' wrong, even if I can force everything together.

Have I bought the wrong bits? Should I have used the smaller bearing and the spacer?

I don't just want to push on and get a fully (but wrongly) assembled engine.

[wack 63]

I'd guess the bearing isn't fully home so try heating the mag housing with a hot air gun or with a gas burner around the sides of the spigot. You really need a drift to tap everything down square but you could use the old 205 bearing as a drift on the inner seal if you don't want to risk damaging it by removing it.If it still won't go down then removal of the bearing will be needed to see why.

[hendy]

i guess i'll have to take the bearing out then. I had the housing so hot that the bearing just dropped in then i gave it a tap with a drift to make sure and it sounded fully home.

I've got to admit i'm a but lost here: the housing is clean as a whistle (got it vapour blasted yesterday), and as i said the housing was so hot that the bearing just dropped in, so everything is nice but it seems wrong that the seal retainer is loose.

I've just measured the distance between the top of the bearing and the bottom of the circlip groove and it's 5.6mm. The inner seal is 6mm, so I'm pretty confident that I could get the circlip in the groove, but I'm not confident that the bearing is properly installed.

Can you confirm that the L shaped retainer should not be free to move when the bearing is installed please?

[wack 63]

I must admit its something I've never checked for play. Some pattern ones are crap but if you used the original one and the bearing dropped straight in then the only other thing is the outer seal is not fully home or too tall and not allowing the L washer to seat properly? I've had a batch of outer seals that were slightly too tall even though supposed to be 6 mm. At a push you can carefully take a touch off the inner seals edge on a bench grinder stone.

[hendy]

i've sort of got it now. I stripped it all back down and the 'problem' is with the L shaped retainer which is 4.2mm thick but sits in a 5mm recess. Obviously it won't sit tight. any idea if this is supposed to be like this or not?

[hendy]

I've sussed it out with the help of the chap at buzzsolomoto who kindly measured the dimensions of a mag housing for me so I could compare (I didn't just pester a random bloke, I had bought the kit from him so it seemed reasonable to ask his help). In case you're interested, it was a combination of factors:

- The recess for the retainer was slightly deeper on mine than 'normal'
- I had pushed the outer seal in too hard and deformed it slightly so that it didn't press against the retainer at all
- I had heated the housing up so much to get the bearing in easily that when I put the 'L' in it rattled around.

I stripped and rebuilt it all then left it to cool and it is all lovely and snug now.

Experience I guess.

Thanks for your help.