Saving Old Seagulls

So, I took part in my first Lerryn rally last year, in a borrowed inflatable and with my LLS. Very wet but a lot of fun. Came away with the notion of having a better rig next time. My host, a Lerryn resident, used my Curlew on his 16'-ish Padstow Sea boat, but being a heavy boat and 4 up not very fast. He also wanted a bit more oomph. So I have managed to get a 12' Portabote to go with the Curlew for myself, and a Seagull 6 KSR1100 for the Padstow.

Now, the big question for the "6" is - is it a roller big end? or has it been replaced with a plain bearing version. As a first step, I have had a look at the con-rod through the inlet port and it looks to be a lot thinner than normal - see picture. So I'm thinking it's a roller and has to come apart. Crank end and flywheel taper is now soaking in wd40 before I try to remove the flywheel and take the bottom end off. I've got a spare Curlew crank with a no.4 con-rod to fit until I can inspect and overhaul the roller crank.

looks fine, much thinner than normal ali conrods.

Thanks H-A. So I'm presuming that confirms it is a roller crank. I'll get it apart and take some pictures.

dandrews wrote: ↑Sun Dec 06, 2020 6:16 pm Thanks H-A. So I'm presuming that confirms it is a roller crank. I'll get it apart and take some pictures.

yep

Don't take it apart until your sure it's necessary, is there any rust or discolouration around the big-end needles or excess play in the big end?

Yours looks like it hasn't had a hard life from here, so leave it alone!

Oh that wasn't yours it was H-A's.

And I don't know if there is anyone in the UK who could rebuild your crank.

And yes it's a needle crank.

I have some new needle rods with bronze little ends & silver caged needle bearings at £35.00

Thanks Charles, I'll get it apart to the point of being able to inspect the crankcase as per H-A's photos then decide what to do.

Just got the flywheel off and next step is to remove the powerhead from the driveshaft tube. Taking it slowly.

Under the flywheel, I found a couple of pieces of broken plastic, but I cannot see anything that they might have come off. The ignition module looks intact. Anyone recognise the pieces? The smaller one has a bit of a thread on it.

Part of the carb choke shroud.

Spot on Charles.

I didn't notice that as I was looking for something with a bit broken off it and it turns out the choke shroud has been replaced.
I have separated the powerhead from the drive tube. Just need to undo the crankcase from the block and withdraw the piston. Photos of the crank & big end soon I hope.

I guess I should check the inner exhaust while I'm at it but the exhaust tube seems well stuck onto the block.

dandrews wrote: ↑Tue Dec 08, 2020 2:06 pm I guess I should check the inner exhaust while I'm at it but the exhaust tube seems well stuck onto the block.

I have had to cut a couple off Kingfishers, they can be very stuck.

Well that was an interesting afternoon. Separated the crankcase & block & took the head off.
Pictures as follows
The head The bore The inner exhaust (couldn't get the exhaust tube off yet but it looks pristine by eye. The big end pics follow in the next post

And the big end Its all a bit tarry but no sign of rust or bluing, although one side of the slot through which you can see the needles looks a bit rough.

But the problem is - The big end pinches in the crank webs about 20 degrees either side of TDC & BDC so it will not even fall under the weight of the piston.

Maybe it was already like that or maybe I did it when removing the flywheel - followed the service manual and it only took a couple of firm blows with a lump hammer on the flywheel nut.

Oh well, i'll split the crankcases and get it onto a couple of v-blocks with a dial gauge and see what is going on. That way I can also get some better close-ups of the bearing.

In the meantime, any tips on re-using the head gasket?

And if you want any pics of any other bits while its apart just let me know.

Remove the piston & clean the crank & rod with fuel mix, remove all the waxy deposit with a paint brush.

This is what i do to remove flywheels, as the cranks bend very easily
You can anneal the gasket on the gas stove, cherry red and quench in water.

I don't need any pictures thankyou.

Thanks for the puller photo H-A. Presumably you have to first remove the flywheel to drill & tap it before you can screw the studs in use the puller. So the puller is only good for the second dismantle onwards? Or did you drill the flywheel in-situ? I must look into making one.

https://www.icloud.com/sharedalbum/#B0pJ0DiRHJE6a0t

iCloud photos & videos of crank alignment measurements should be viewable via the above link for 30 days.

The crank cleaned up nicely, and no longer sticks so I guess it was stuck with fuel residue rather than distortion. It also has a coppery finish near the big end. The rod rocks on the pin about 30-40 thou at the small end tip, and has about the same amount of slide on the pin end to end.

I set up a crude alignment rig with a vee block and a dial gauge - I know I should use knife-edges but I thought I'd try with what I have to hand.

Do not really understand the results. With the flywheel end in the block, the driveshaft end wobble is about 1 thou. Other way round it is 5 thou. How can they be different?

Need to put my thinking cap on.

See what you all make of it.

Hope people find this interesting - it is a journey of discovery for me too! All comments gratefully received.

Do you have a lathe? If so put the crank between centers and do the test again. it would be interesting to see the results.