Tight mag housing

[scooterslag]

Just in the process of rebuilding my SX150 engine after it blew a drive side oil seal. while I was fitting the new drive side seal, I replaced the crankside as well and then started to re-assemble the engine. Following Sticky's book, I fitted the mag housing gasket, greased up the housing itself and set about tapping it down with the handle of a hammer. after a few taps, it seems reluctant to go any further, I checked to see if anything was obstructing the housing but nothing seems a miss. I removed it then tried again but this time turning the crank so it would seat itself in the outer race easier but still nothing. It gets so far down then stops, I don't want to get too heavy handed and as Sticky says in the book- it shouldn't be a tight fit. When I rebuilt the engine four years ago, it just sat in there lovely- this time? the casing and mag housing are both Italian, any ideas?

[scooterslag]

A few pictures ( bit s**t quality I know)



this is as far as I can push the housing down



I tried a spare mag housing ( SIL make but with no bearing or seal in it) dropped in no problems, so must be something I did when I put the new crankside seal in. I'm certain that the seal is seated in far enough, really can't see whats causing the problems

[WINTERMODEL150]

Hi,is it a new crank?

Dean

[scooterslag]

Hi,is it a new crank?

Dean

hiya dean, no its not a new crank, its been in the scoot for a couple of years, cheers Paul

[Diablo]

I'd take it back off Paul,tape up the oil seals/ bearings then lightly dress it with a flap wheel.
You don't have to go mad with it. Offer it back up and hopefully you can fit the nuts on the studs and draw it in to the crank chamber.
Using the nuts to pull it in allows you to turn the crank after each half turn so less likely to pop the spring on the seal. Obviously stop again if you meet lots of resistance.

[blue]

Have you greased the seal?
Take you crank out and try fitting your mag housing to your casing, if that fits try fitting your crank into your mag housing.

[bristolmod]

when you removed/ refitted the drive side seal etc, did you use an Impact Driver to remove the 4 retaining screws?

It may well be that when you loosened/ tightened them by using said driver and hammer, the driver itself may have been touching the inside of the casing

Even a minute indentation/ scuff in that area can cause the maghousing to bind on the way back in

Just a thought as its happened to me in the past

Chris

[scooterslag]

I'd take it back off Paul,tape up the oil seals/ bearings then lightly dress it with a flap wheel.
You don't have to go mad with it. Offer it back up and hopefully you can fit the nuts on the studs and draw it in to the crank chamber.
Using the nuts to pull it in allows you to turn the crank after each half turn so less likely to pop the spring on the seal. Obviously stop again if you meet lots of resistance.

Cheers for that Al, I took the crank out and tried it in the mag housing and it ( after a bit of turning) snapped in the housing no probs. I also tried the mag housing in the cases and once again- no problem with the fitting. Before I removed the crank I tried greasing up the seals and outer race but the bugger was still tight. Going to finish my brew and have another crack at the beast, missing my lammy on the road big time.

[scooterslag]

when you removed/ refitted the drive side seal etc, did you use an Impact Driver to remove the 4 retaining screws?

It may well be that when you loosened/ tightened them by using said driver and hammer, the driver itself may have been touching the inside of the casing

Even a minute indentation/ scuff in that area can cause the maghousing to bind on the way back in

Just a thought as its happened to me in the past

Chris

Hello Chris, cheers for that, I tried the mag housing in the cases minus the crank and it fitted with no problems, but its another thing to watch for when I next do a rebuild, cheers for the replies people, hopefully I can get the bugger sorted. Paul

[Avantone]

If it's tight getting it in, just use plenty of lube, push it in and gentle press it all the way in.

If it won't go all the way, get it on the floor and try from a different angle.

Don't bang it too hard or your big end will pay the price.............