Balance shaft replacement (AR)

Post by **gregorious77** » 21 Feb 2015, 21:39

I had the dreaded whine after an extended service interval due to lots of laning and forgetting to check mileage and change oil!!
So first job was to disconnect the balance shaft and see how bad the vibes are as I have read on here that it doesn't make that much difference.
I removed the gear and took it to work to measure up and had a spacer made up out of silver steel.

I fitted this to the balance shaft and reassembled the engine.

Took her out for a run but the vibe are not nice at all. Standing on the pegs in MX boots had my whole lower legs vibrating and I can imagine being pretty uncomfortable on a days trail riding.

Rode it home, dropped the oil and water and whipped the clutch cover off ready to begin the journey of balance shaft removal joy.

Post by **gregorious77** » 21 Feb 2015, 21:53

So the removal of clutch and new spacer on balance shaft was a breeze with a rattle gun as this was the 2nd time this week that I have done this job.
Next stage was to remove the balance shaft, oil seal and bearings.
Generator cover off - easy.
Shaft out - easy (looks worn on one side as I expected).
Clutch side bearing out - little fiddly getting the gear selector stuff out the way but no biggy.
Generator side bearing - nearly ended in me torching the bike and claiming the insurance!!!!

I used a socket that just fit through the tunnel to the other side to persuade the bearing out but what actually happened was the bearing sat itself and the front lip broke away piece by piece until there was just a lipless outer race left with no way of tapping it out from the other side!!!!

Post by **gregorious77** » 21 Feb 2015, 21:58

In the end I had to get the MIG welder out (steering bearing trick) and lay a couple of beads on the race so it would shrink a bit on cooling and I had something to hit with a drift from the other side.

Still didn't want to give up easily. I guess it was happy in there.

all out finally ready to get new bearing and shaft fitted.

Post by **helisupp** » 21 Feb 2015, 22:07

Knackeredmk1 has a tool for bearing removal, it's on one of his posts.

I suppose he would rent it out for a couple of quid ( deposit read).

Can you let us know if you do still have the tool knackered

Post by **knackeredMk1** » 21 Feb 2015, 22:13

I do.

Post by **gregorious77** » 21 Feb 2015, 22:15

The horse has already bolted on that one but I got it out in the end.
Anyone else looking to do this though I would strongly recommend using the tool!!!

Post by **gregorious77** » 22 Feb 2015, 20:57

Might get it sleeved. anyone know the diameter of the bearing face on the shaft?

Post by **helisupp** » 22 Feb 2015, 21:53

A new one was not expensive when I last bought one from LT.

They must have them in stock, or they may now exchange them as S.E.P. Repair them.

Post by **fallenmikethebike** » 22 Feb 2015, 22:13

Yea, exchange at LT, £90 or so, plus bearings, plus gaskets.
Mike

Post by **gregorious77** » 22 Feb 2015, 22:23

OK 90 exchange is not so bad I guess. Looked at the sticky which said £118 in 2014 or £45 for sleeve and grind.
There is a local machine shop that does engine components down the road from me so they were an option to sleeve thats why I asked.

Post by **knackeredMk1** » 22 Feb 2015, 22:58

Five year's ago they where £50 new.

Post by **Lukep749** » 23 Feb 2015, 19:59

gregorious77 wrote:The horse has already bolted on that one but I got it out in the end.
Anyone else looking to do this though I would strongly recommend using the tool!!!

Been there, bought that tee shirt, done two of them bearings, TIG welded a M12 dome nut to the edges of the bearing housing, screwed a M12 studding through the engine, one swift firm tap with the hammer they dropped out, best done with engine out of bike and help from Rich1960.

Post by **helisupp** » 23 Feb 2015, 20:44

Just need to buy a tig welder then I will be sorted.

But I do have a good spare shaft in stock just in case I need one.

Post by **2stroke** » 23 Feb 2015, 21:49

Hi Greg, have you got a picture of worn balance shaft by any chance?
I just removed mine and would like to compare to worn part, because not sure.
Here is not very good quality picture of mine:

https://www.flickr.com/photos/129446366 ... 626680591/

Another thing I noticed during dismantling : kickstart spring stopper plate was bent and cracked:

https://www.flickr.com/photos/129446366 ... 008024123/

Is that a common thing? The hardest thing for me was to hammer the crankshaft out of one of the crankcases. Used some heat.

Also, Knackeredmk1- how that balance shaft bearing tool looks like? I might need it

Post by **knackeredMk1** » 23 Feb 2015, 22:08

Look in the FAQs for bearing tool.

You will need a new stopper plate.

Balance shaft replacement (AR)

Balance shaft replacement (AR)

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