New (to me) 400c

[Busby]

And jusr because

[url=https://flic.kr/p/2mPMzzB]

[5port]

 
Yes, a very good looking colour IMO.  Looks like good paintwork as well.  If we had seen more of this colour in UK in '76 it would be more popular.
Mind you, blue Oyster is pretty good!



Original Marine Blue on my RD250/400C.
Bike was W.German '76 RD250C (they came with rear disc). The Fuel tank and Oil tank are original Marine blue 400C used.  The Sidepanel was NOS bare Marine blue with repro 250 sticker. Frame and swinger paint is original with some small touch-ups on frame. Engine is 250 in pic, 400 also available.   
Also, in the pic, the Blue is quite strong.  In sunlight the greeny shade comes through.

Cheers

5port

[pidjones]

Pretty!

[Busby]

Yes the blue was a great colour as well, I think this year was the best for colours for the rd’s

[Busby]

Well it’s about time I got back to the bike.

I thought I would take a squint at the motor, it has great compression so I am hoping it will just need the seals changing.

First I drained the oil
7F2A2E0B-DC00-4A69-9C58-72CA3AADC3

Umm that does not look good.

[Busby]

I mean, how bad can it be!

Apparently very bad

24B3A474-097C-4F

[url=https://flic.kr/p/2n9acRQ]DFA40B11-5B3A-4CCB-946D-D3B527A94C8F[/u

[url=https://flic.kr/p/2n9fCFW]5C50283B-415D-4087-A26E-760F772A68C0 by

It looks like the right hand crank seal has failed allowing gear box oil into the crank.

[Busby]

As I said at the start it had great compression, yes it did but only on the left hand cylinder😕

The motor has had a rebore, the left hand cylinder still has the honing visible, there is no carbon build up on the pistons or head so it obviously failed soon after it was done.

FD5AE67C-B394-4F22-86C2

The right hand bore is completely ruined, you can see a score on the liner

[Busby]

Another view of the crank showing the corrosion on the webs

537520FB-6E05-49E8

[pidjones]

Ssd, but I doubt it is irreparable given heavy use of the wallet.

[robrd]

Hi Busby, i've seen a lot worst crank's fitted to bikes and apart from looking bad they run ok. If I was doing this I would leave them to soak in oil and then lightly rub down with wet and dry to make it look good again, don't get it on a grinder or alike as you can easily throw it out of balance by taking away too much metal.

[Busby]

Hi robrd, the inner bearing on the right does not feel that great I think that while it might be ok as it’s apart probably worth getting  it redone. I was hoping to get away with it but It would always be nagging me.

[Tailchaser]

Hi Busby,

Here's the before and after pic of my 250E Crank; I'd say your's isn't that bad and is certainly repairable.



Cheers,

Jeff

[5port]

As I said at the start it had great compression, yes it did but only on the left hand cylinder😕

The motor has had a rebore, the left hand cylinder still has the honing visible, there is no carbon build up on the pistons or head so it obviously failed soon after it was done.

FD5AE67C-B394-4F22-86C2

The right hand bore is completely ruined, you can see a score on the liner

Looks like the top ring was broken  at the end on installation?  This can happen as the rings go past the inlet port and, very likely if pot is turned at all.  Really, you need to have the reeds off and help the ring ends with fingers as they go past the inlet port.  How deep is the scoring? Often only 0.2mm or so and, you get away with a 0.5 rebore.
Cheers

5port   

[5port]

Another view of the crank showing the corrosion on the webs

537520FB-6E05-49E8

Hi,
Quite a few USA bikes have been in floods, the green on the rods is the copper plate corroded.  Yours might have been, or left with plug(s) out and water got in.  The crank looks great for good rebuild.
Overall, It is much better than some UK bikes that had stood in damp sheds for 30 years.  It is going to be very nice.

5port

[robrd]

I wouldn't worry about it, I would go ahead and get a rebuild, I can't see a lot wrong with your crank at all.