layshaft bearing-bushing up-grade

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speirmoor said:
With a heat gun you'll need alot of heat.Best to do when ambient temperature is favorable.If you dont have a slide hammer try some threaded rod with your largest socket and improvise something.
Click to expand...

I can't see the need for any kind of slide hammer?

The ball bearing is usually a fairly tight fit on the end of the layshaft so it should just a be matter of getting the casing hot enough and then the layshaft and bearing can easily be pulled out together.

http://www.doov.com/apps/nortoncompanio ... s&Itemid=8
 
Yes 39C is plenty hot.I remember doing mine when it was freezing outside and no heat in the garage.This made the heatgun less effective . Only suggested slidehammer for worse case scenario hopefully you wont need one.
 
Today's another day. I'll get myself a heat gun and fry that mother!
Speirmoor yesterday was our first real hot day for summer. Another today. We can get week runs (or more)of days like this. Makes it too hot to ride. Winters here are usually better for a ride. Never gets freezing but can be a bit wet.
 
Success! Got that sucker out today. Bought myself a heat gun for the princely sum of $20 at Bunnings. The cheapest on the shelf. The layshaft was pretty tight though even with copious quantities of heat. Not much to get a grip on though so I attached a pair of vice grips with 2 pieces of 3mm ally to protect the shaft and that allowed me to give it a good yank and out it came! I felt like a dentist pulling out a tooth. :lol:
So then it was off to see Murray at Cyclecraft for a new layshaft bearing as well as a new mainshaft bearing, kisk start shaft and a few extra bits and pieces. So that means that tomorrow I should have the gearbox back together and be moving forward.
Thanks to all for your help and I'll let YING have his thread back. :roll:
 
Mark F said:
Success! Got that sucker out today. Bought myself a heat gun for the princely sum of $20 at Bunnings. The cheapest on the shelf. The layshaft was pretty tight though even with copious quantities of heat. Not much to get a grip on though so I attached a pair of vice grips with 2 pieces of 3mm ally to protect the shaft and that allowed me to give it a good yank and out it came! I felt like a dentist pulling out a tooth. :lol:
So then it was off to see Murray at Cyclecraft for a new layshaft bearing as well as a new mainshaft bearing, kisk start shaft and a few extra bits and pieces. So that means that tomorrow I should have the gearbox back together and be moving forward.
Thanks to all for your help and I'll let YING have his thread back. :roll:
Click to expand...

That is good news Mark.
FWIW, the harder they are to get out the more it tells you that the journals are in good shape.

Make sure the new ones go in straight and level, no kiddy wompus. That is how some journals get munched. The other way is when the bearing goes.
 
Thanks Pvisseriii. The only tricky part now is getting the new bearing on the layshaft and in the case. Just lots of heat again I guess.
 
Mark F said:
Thanks Pvisseriii. The only tricky part now is getting the new bearing on the layshaft and in the case. Just lots of heat again I guess.
Click to expand...

Well no not really.

Depending on what bearing you are using you will either press the ball bearing by using something close to the same size as the outer race and tappy tap it home into the casing and then the shaft onto the inner race of the bearing.

If a two piece roller is used then the out race will be put into the casing as the ball bearing was applied, the inner applied to the shaft ( properly oriented) then the shaft will simply slip into the outer race ( rollers).

Although a straight forward operation, it should still be done judiciously and with caution.
 
That's right,never heat a bearing or it's inner race. Freeze the layshaft and gently tap on the inner until home.Two camps of thought here, roller vs.standard ball,you all know my leanings.
 
Done! Couple of anxious moments getting the bearing started straight in the gearbox case. :roll: But straightened it up and then drove it home with a socket on a long extension. It was tight even with heat. I used a 2 piece roller bearing and even started off putting the inner on arse about face on the layshaft. Damn. Out with the bearing puller. Then I got the inner cover bolted back together and realized I couldn;t get the gear lever roller thingy back in the quadrant. So off with the cover again. Oh well this is how you learn I guess. :lol:
 
Mark F said:
... So off with the cover again. Oh well this is how you learn I guess. :lol:
Click to expand...
I always thought Nortons went back together at least 3 times during rebuilding. I thought it was just the normal procedure.

Dave
69S
 
Mark F said:
Then I got the inner cover bolted back together and realized I couldn;t get the gear lever roller thingy back in the quadrant. So off with the cover again. Oh well this is how you learn I guess. :lol:
Click to expand...

Or, read the manual? :wink:

http://britmoto.com/manuals/Manuals/750_man.pdf
Section D9.20:
Since the quadrant roller cannot be fitted after the inner cover is fitted, it is imperative that the roller is fitted into the quadrant knuckle at this time.
Click to expand...
 
So ,,My 6000 miles from new MK3 as how many hours left on death Row with this bearing :?: Plus i thought roller bearings lasted longer than balls :?:
 
john robert bould said:
So ,,My 6000 miles from new MK3 as how many hours left on death Row with this bearing :?:
Click to expand...

There's no set time, but the Portuguese bearings (usually brass cage) fitted to late Commandos tend to fail prematurely.



john robert bould said:
Plus i thought roller bearings lasted longer than balls :?:
Click to expand...


Maybe so, but Mick Hemmings recommends the 6203TB ball bearing in preference to the roller.

http://www.mhm.demon.co.uk/cat/PriceList.pdf
LAYSHAFT BEARINGS (STANDARD TYPE)........................................................04 0100 3.13
ROLLER REPLACEMENT FOR ABOVE,(NOT RECOMMENDED)......................06 7710 16.26
SPECIAL RACING BALL BEARING,THE ANSWER!............................................TX 1366 23.50
Click to expand...
 
As I understood Mick the reason that he does not like Rollers in this application is "side-loading" (Rollers need to run absolutely true and G/B's flex).

Vince
 
DogT said:
Mark F said:
... So off with the cover again. Oh well this is how you learn I guess. :lol:
Click to expand...
I always thought Nortons went back together at least 3 times during rebuilding. I thought it was just the normal procedure.

Dave
69S
Click to expand...
Damn right Dave! If I had gotten everything right first time I probably would have been on the road months ago. :lol:
LAB. Read the manual? Now were's the fun in that? :lol:
I went with the NJ203E bearing. It had already had the Portuguese bearing replaced with an Italian ball bearing but while it was apart I decided to change it anyway.
Now I can go and pull my primary apart again so I can fit my new clutch centre and alternator rotor. Then it's all down hill. I hope. :roll:
 
Good luck Mark, it's downhill once and uphill 3, resulting in at least 2 more downhills? Got it?

Dave
69S
 
NJ203E (E is for engine applications) J is for journaled. C3 =radial internal clearance is greater than standard.Life is short, buy German.
 
>>There's no set time, but the Portuguese bearings (usually brass cage) fitted to late Commandos tend to fail prematurely.<<

LAB
Since I have a 72 I'm guessing it isn't a "late commando" so should I still think I must replace the bearing?

Thanks
Bob
 
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