Splitting the crankcase problem - sprocket drive shaft gear clusters clings on ?

[400 Cafe Racer]

Hi Guys,

Having experienced a significant "Screech" noise from the unit for some 7 or 8 seconds after returning from my second ride after purchasing the bike, I was reluctant to run it any more without proper investigation.  It sounded much like a tight crank main bearing to me. So to ignore it and carry on using it seemed a bad idea. The unit was rebuilt by PO about 3000 miles ago.

I have got to the final stages of stripping and seperating the crankcases.  The Hondabond seal is broken and the cases have moved apart about 4mm.

The problem I have is that ONE SIDE of the final drive sprocket shaft (the side where the sprocket shaft comes though the case)  and the shaft in front (with blanking plug), both insist on clinging to the bottom half of the case, while everything else sits on the upper half as I pull the cases apart - hence the bottom case will not lift off. I have tapped gently to see if the seal and bearing were just "gripping" the bottom half with friction, but it will not seperate.

Is there anything I have missed ?

Appreciate your thoughts.

Thanks   

Dennis

[K2-K6]

Missed? Primary drive chain and shaft?

[Bryanj]

Primary shaft still in would stop you splitiņg cases but shouldnt makegearshafts stick

[400 Cafe Racer]

Hi K2-K6and Bryan,

Thanks for your replies. I can confirm that the the primary shaft has been removed, and that the primary chain and sprocket are "resting" in the upper crankcase half.

I have attached some photos to show the problem.

1. (Clutch side) Shows the shafts resting on the upper half
2 and 3. (Oil pump side) Show the shaft; oil seal and bearing gripping the  lower half. I have tried tapping them down but they do not release, ??

Are there any other parts that I should have removed (can't see anything in the manual)??

Thanks for your help

Dennis

[taysidedragon]

Previous owner may have put sealant on the seal edges, sticking them to the case.
Tap the sprocket drive shaft a bit harder with a hide mallet. You may have to carefully prise the seals loose, trying not to damage the cases. 😕

[400 Cafe Racer]

Hi Gareth,

Thanks very much for your suggestion, it sounds like a good plan. I just wanted to be sure there wasn't any mechanical fasteners I had overlooked before resulting to any force that may cause damage.

I will pour a little cellulose thinners around the seal and give it a minute or two to soak, which should soften any Sealant that may be around the seal and bearing.

I noticed when I was removing some of the casing bolts they were extra tight to rotate, even when the initial "crack" of movement had happened. On full removal I found the whole of the threaded area was almost "loctighted" with excessive Hondabond that must have run down into the threaded alloy casting. This was quite noticeable when trying to remove the bolts, almost like a torsion bar feel.

Cheers 

Dennis

[400 Cafe Racer]

Thanks for your replies Guys,

The Shafts have now dropped into the upper casing after releasing the sealant and the casings have come apart.

Please see my next post on "CAUTION with sizing your shell bearings on the crank", for the results so far of my findings.

Cheers

Dennis