650 Rebuild!

Hey kids

The time is upon us. Some horrible bottom end clunking noise from the berg the other day, and Ive been itching to tear into it for a while. Oil showing flakes for the last few changes. Hoping to return it to a much better state than what I got it in, inside and out!

at 170hrs on a full rebuild.

Ill use this thread for advice and updates for those doing something similar.
Wouldnt be possible without the teachings of bush mechanic, Dr.c and a few others, you guys are golden.

So I was hoping to find something obviously wrong, but so far Ive only got some tired looking mains, a dead output bearing and a sneaking suspicion that the balancer bearings are cactus. I havent ripped the left side off the shafts yet, but ill do that in the next few days.

Edit: apologies for the huge photos, computers arent my strong point!

Rotor be gone!



New engine upgrade?



Cases came apart without a splitter! Just gentle taps with a plastic hammer on the crank and output shaft.



Heres the right side main, SKF. I think I know where some of the flakes have come from!



And my liner from a few different sides, Its actually in good shape so I dont think Ill bother replacing- probably a hone and the next size piston.



And heres the Wossner piston- the wrist pin journal is toast!

Resized the pictures!

Gearbox output bearing, feels super sloppy and is banged up to hell.


Wossner piston at 170hrs. Never used much oil, but the oil control ring doesnt have much life left. Also scratched up on both skirts. As you saw before, the wrist pin journal is worn badly. New piston in the works. Wossner is cheapest by a mile but I suspect theres a reason for that.



Onwards!

Bushy

Ive actually heard good things about ProX and they seem quite expensive? a good $50 on what the Wossners cost, Ill hunt around now youve told me something different.

Quick question, can I reuse the inner main bearing race if it looks like its in good nic?

And Goose, ive had a solid read of that thread, its all great info. I had to tear myself away from his 710 thread, my plans were running wild haha!

8551DA
10503-16

So definitely a wossner 650, but im not sure of the size (A,B,C).

And Ive learnt that Ebay isnt the place to be comparing prices haha.

Im a big fan of using oxy torches so that method seems the goods.

Ive been using a small copper plumbing bolt to jam into the gears which worked perfectly last night- the entire motor is now in bits. For the clutch basket inner I threw the motor back into the bike, got 6th gear and stood on the back brake. Cracked the centre nut off perfectly.

My balancer is a bit of a concern. It doesnt have any up-down play, but its happy to wiggle side to side a tiny amount. Maybe half a mm measured at the end of the balancer. I cant find any measure of how much play is too much!

Im looking forward to baking my cases, as a chef I am super experienced with tasty baked goods.

True, thats interesting info. I dont doubt it because I remember thinking the squish was huge last time I had the head off.

Removed mains and gearbox seals, gently heated the case with a gas torch, a few drops of cold water into the bearing, one solid hit with the deadblow on a 30mm socket. Didnt expect them to come out so easily if Im honest.

After removing the gearbox output bearing its pretty clear its eaten something nasty, rollers and outer race are scratched up badly.



Having issues getting this bad boy off, without removing it I cant take out the LHS main bearing. Ive tried prying with two screwdrivers and heating, but I think ill just stop being cheap and go buy a gear puller.

Gentle encouragement with the blowtorch, I suspect getting it off was the easy part.

Frame and a few other bits went to the powdercoaters last week, figured I may as well go to town on it. Ive degreased, polished or cleaned just about every other bit on the bike. New bolts on the way too, and I even shouted myself a new 8mm socket! Before:



The plastics have always been the biggest let down on an otherwise great machine- theyre all woefully UV stained and banged up from being thrown down the road so many times. So ive slowly been sanding them back by hand- its tough but the results are great.



Motor is all in bits and waiting for the good stuff to go back in. If it wasnt obvious, staying organised is key here. I know where every single bit is hiding and it will pay off in the long run.




My biggest issue so far (and berg ownership in general) has been the lack of parts in Australia, and the price I pay for shipping is huge. Not to mention the price of berg bits is high in general, and exchange rates are ******. A pretty mediocre shopping cart from Taffys comes to $415- quite a bit for some seals, gaskets and a few other bits. No piston or mains! As usual Ive balked a bit here haha.

Ive had cringeworthy dealings with some of the australian KTM parts suppliers- wrong parts, no refund, no communication ect. Mototech holds up, however they dont stock dedicated berg parts.

Onwards!

If I choose to remove the balancer and rebalance my crank, I'd assume that a spacer would have to be machined to fit between the main bearing race and the crank but I've never heard mention of this being done. Maybe something matching the counter Balancer and shimmed as normal? I'm pretty sure that the balancer bearings are toast and I'm keen to have a go running the bike without it. Big believer in the kiss theory.

Anyway, I've found a place that has the heat transfer tool and they're happy to replace the bearing inners for me. The RHS inner is heat scortched from the failure- every shade of blue and purple on one side.

Meanwhile I've been spending lots of time of the chassis, repainting, cleaning and replacing. The thing looks great even in bits.

Yeah kayeffes, I was picturing just leaving the balancer bearings on the crank. Didn't think of pulling the bearings apart and just using the inner races. The tech drawings still show the little lip between the two bearings in the balancer itself, possibly measure that and shim accordingly?

Not useless info at all!

Quick update, got the frame back from the powdercoaters. Pictures do it no justice, it looks unreal!