Author Topic: 750 K2 Transmission Bearings  (Read 347 times)

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Offline The Lone Builder

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750 K2 Transmission Bearings
« on: October 02, 2016, 09:55:27 AM »
Hi All,

After many years, yes years, slowly collected all the bits I thouhgt I needed to get my 750K2 back on the road, I finally decided "Today's the day!" Well that was yesterday. My first rebuild since I did a CB125S way back in 70-something!!

Bit of a story here. a friend who talked for years about making a trip to Vietnam, passed away last week. He never made that trip. I too have a trip I've been talking about for years - to ride from Belfast, Mpumalanga, South Africa, to the original Belfast in N Ireland - home originally. Well, I thought, I don't want to end up like old Rick, so I better get my skates on. Hence, yesterday became the day!

Anyway, decided to start on the engine which has been completely stripped, so I gave the crankcases and other bits a final scrub. They don't look at all bad - not like new, but better than I expected. So I was planning to replace crankshaft bearings, but on removing con rods, I noticed some deep scratches on the middle bearing shells. Manual recommends checking run-out in  such a case, so will do that this  week.

Then on to the transmission. This is where I hit the first real snag - snap rings on bearings. I had ordered bearings according to the numbers in the Haynes manual and was delighted when all arrived. But several of the bearings need a groove in the casing! Bu**er, should have looked more closely at the originals! So back to the online bearing guy.Living in Zimbabwe, local suppliers are like hen's teeth.

But now, eventually, to my questions:

1.   Can the counter shaft bearing - on gear shift fork drum - be replaced on its own, or do I have to replace it and holder as a unit? Do I need to replace it? It seems smooth enough, but when all others are new ..... How do I get it out?

2.   On the primary tensioner unit there is a needle roller bearing at either end. These are marked HK2520, and I think the dimensions are 25x32x20. Can anyone confirm these measurements and advise whether I should renew these at same time as all the others?

Thanks in advance, for what is probably the first of many questions.

Sean

CB750 K2 - From Belfast-2-Belfast
CB750 K1 - The less, said the better!
CB450 K1 - Stalled.
CB400F Supersport - Not Rusty any more!

Follow my journey through Africa @ http://Belfast2BelfastByBike.com