KSR1100

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Oyster 49
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Re: KSR1100

Post by Oyster 49 »

I’d also suggest putting it between centres and clocking it again. The other option would be to mount it in a lathe in a collet, or machined to size soft jaws which should run very true, then check the other end of the crank.

One thing for sure, there is not much meat around that crank pin!
dandrews
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Location: Woodbridge, Suffolk

Re: KSR1100

Post by dandrews »

Thanks for the comments, keeps me motivated.

No lathe. Hand tools only. But the workshop does have a wood-burning stove!
IMG_0900.jpg
I'm taking some time to think this through. Will share some more pics when I make some more progress.

Maybe I should just try to get one of those ready-made Bermudan roller cranks!

Worst case, I have a spare Curlew bottom end with no.4 con-rod I could use and just revert to a plain big-end.

In the meantime there are water passages to clear, the block to hone, rings to replace etc. and a heap of other tasks to keep me busy.

I also meant to say earlier that removing the gudgeon pin from the piston was a doddle - poured some boiling water into a mug, dunked the piston for 30 seconds and it pushed out by hand with a dowel.
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Charles uk
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Re: KSR1100

Post by Charles uk »

Why not ask yourself the following questions.

How much & where am I planning to use this Seagull,

On a scale of 1 to 10 how bad is the cylinder corrosion,

Are there any Bermudian cranks left & will one fit straight in your crankcase,

Does the crankshaft freely rotate when back in the crankcase,

Were the centres in both ends of the crankshaft there for checking the shaft or were they for centring that end of the crank with the centre on the inner face of the crank web for main bearing grinding & big end pin hole location,
Make it idiot proof and someone will make a better idiot.
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Nudge
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Re: KSR1100

Post by Nudge »

Were the centres in both ends of the crankshaft there for checking the shaft or were they for centring that end of the crank with the centre on the inner face of the crank web for main bearing grinding & big end pin hole location,
That is a very good point Charles, One I did not think of.
"THE KING OF BLING"!
Is it better to over think, than not think at all?
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Charles uk
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Re: KSR1100

Post by Charles uk »

IMG_5803 (5).jpg
Here's a picture of the drill guide /puller tool that I use for Wypac CDI flywheels on motors. In it you will see 6 holes 60 degrees apart & a crankshaft sized hole in the middle, 3 of the holes 120 degrees apart are 1 @ 4.8 mm diameter & 2 x 4 mm the other 3 holes 60 degrees away from these are 5 mm diameter

Pictured are a mk3 undrilled & untapped & a finished mk4, externally both are identical.

In the steel centre of all of the Wypac CDI flywheels is a shallow 4mm hole used for a fixing pin if used.

To modify a flywheel in situ remove the flywheel nut, starter cup & the spacer bush in that order, & with a cordless drill, drill the fixing pin hole 4 mm diameter 15 to 17mm deep ensuring that the drill is vertical & tap the hole with a 2BA tap as deep as possible.

I then drop the drill guide over the crankshaft end & with a 2 BA cap head in the 4.8mm hole fasten the drill guide securely to the flywheel brim uppermost, then using the 4mm holes in the guide drill 2 more holes in the flywheel around 16 mm deep, remove the drill guide & tap these 2 holes the same depth, the drill guide can then be fastened to the flywheel using 3 x 2 BA cap head in the 5mm holes.

Sometimes I remove the flywheel with a 3 legged puller tool, depends on which I can find first, hooked under the brim of the drill guide & using the centre hole in the end of the crank & sometimes I use a puller like H-A's with long cap heads but still with a pointed centre bolt as sometimes on really tight ones a tap with a toffee hammer in the puller bolt will shock them free.
Make it idiot proof and someone will make a better idiot.
dandrews
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Location: Woodbridge, Suffolk

Re: KSR1100

Post by dandrews »

Thank-you all for comments.

The puller details are extremely helpful Charles, and of a design worthy of a Vincent motorcycle.

In answer to Charles's questions,

KSR1100 will (hopefully) be used once a year for the Lerryn Rally, on my pal's Padstow Sea Boat. And if he enjoys the extra power, he'll use it several times a month instead of the Curlew that he uses at the moment (he uses the Curlew because it it lighter and easier to handle than his mariner 6). If he doesn't feel the extra power is worth the extra weight of KSR1100 over the Curlew, I'll use it on my 12' Portabote at Lerryn, and maybe every couple of months on the tidal river Deben out of Woodbridge, Suffolk. It should get enough use, or TLC while being stored in the dry, to keep internal rust at bay.

The cylinder shows some corrosion in the water passages, but I have not done a proper cleanup yet. I've certainly seen much worse. I'm struggling to get the exhaust tube off the stub to inspect the water inlet and the inner exhaust properly, and to get at all the waterways.

The Bermudan crank comment was a throw-away remark to see if anyone offered to sell me one! I do understand they are bigger and need the crankcase machining to fit. And that is the start of a slippery slope.

At the moment the crankshaft does has a slight "pinch point" when rotated. Not enough to stop it being easy to rotate by hand, but enough to feel that it is not perfect. I am continuing measurements with my crude rig and getting a good picture of what is going on. I'll post some pictures when I've got the full story.

The points about the centres are well made. But I do not have that option at the moment.
Last edited by dandrews on Mon Dec 28, 2020 11:48 am, edited 1 time in total.
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Charles uk
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Re: KSR1100

Post by Charles uk »

Salt water use & lack of TLC is the most common cause of death on later model Seagulls.

Your water jacket looks pretty good & unless there are rust flakes about to fall off I wouldn't clean it too much, clean bare cast iron & salt water is only a superfood for oxidation, I'd give a poke everywhere wit a wooden chopstick then a blow out with an air line up the water delivery tube, same treatment for the head.

A real good flushing with soapy fresh water after salt use tends to be the best salt remover, some people are known to put oil into the water jacket when dry, which can't do any harm.

Is the "pinch" on the main bearings or the big end?

When you look at the area around the holes that hold the big end pin you will see three places where the crank web is close to 3mm thick, treat your crank like the gentleman in the you tube video & you might well fracture one of these thin spots, he was working on a full circle crank with a lot more meat around a bigger pin.

I remove the exhaust tube by holding the cylinder in a large vice holding on the top & bottom face cushioned from the jaws with timber, exhaust facing up. Grab hold of the uppermost end of the tube & push & pull in every direction, it will work it's way off, it's only held with 1 screw & good fit & an "O" ring
Make it idiot proof and someone will make a better idiot.
dandrews
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Re: KSR1100

Post by dandrews »

I've made some more careful measurements on my crude wobble rig. Plotted the wobble at several points along the crank. Then gently "adjusted" it using a spreader made of 2 nuts & a short piece of studding between the crank webs. Here are the before and after plots so far.
Screen Shot 2020-12-24 at 17.45.24.png
Vertical axis is wobble in thou, horizontal axis position along crank in mm. Blue = before, green = after.
points to right of webs taken with driveshaft end in vee block, points to left with flywheel end in vee block, both as close to crank web as possible to simulate bearing position.

Above 80mm on the horizontal scale we are off the bearing surface and onto the taper and then at 130 onto the plain surface behind the threaded section. The gap is the woodruff slot.

The crank now runs much more freely in the bearings with no feel of a "pinch" which it had before. The con-rod also runs freely now the old fuel residue has been removed.

As the instability in the vee blocks on my workbench is about 1-2 thou, I'm getting close to the limit of what I can do without a proper metrology table, or even a lathe, but may have one more go at adjusting. I'll think about it over Xmas.

In the meantime, to the tune of "Wild Rover" -

"I went to a bike shop I used to frequent
and I said to the bloke there my crankshaft is bent
he said son we can't help you, I'm sorry to say,
your bike's a Norton, we only stock BSA
and it's no nay never .........."

Merry Xmas everybody.
andrew
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Re: KSR1100

Post by andrew »

Keen to see a pic of your rig! I have a couple cranks that need sorting, have been putting them off for a few years. Don’t have a lathe so would need to build a small rig.

Maybe this is the year I finally get them straightened enough to put back in service.

Merry Christmas to all!
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Charles uk
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Re: KSR1100

Post by Charles uk »

The reason I built the puller device was to avoid people damaging the crank whilst removing the flywheel.

Take a look at your needle cranks, they are basically a standard silver century crank with the big end portion removed, then 2 circa 14mm diameter holes are then machined into it 20mm away from the web centreline at the centre where the big end pin was.

The vast majority of needle roller crankshafts have parallel big end pins to give the largest grip area on the pin interference fit, but as the Seagull crank only had a 7/8" wide web (22.2 mm) there was insufficient wall thickness to permit a parallel pin (16/mm).

When these cranks were assembled the pin was pressed into a hole that was about 0.1mm smaller than the pin, the pin as it's solid & very hard is not going to squash instead the hole stretches but only in the 3 thin areas, reducing the grip, when you straighten these cranks with the internal jack method think what's happening to the grip area of the crank providing the crank webs are not spreading!

I was able to get these cranks rebuilt, which meant grinding the big end pin holes round & bigger, manufacturing new pins with the correct interference fit for the oversize holes & replacing the rod & bearings with new, reassembling & realigning, unfortunately the gentleman who did that for me, sadly passed away .

If you stretch the pin hole any more at all, your crank will become un useable without specialist welding, the same will apply if you crack the web.
Or try and find an experienced crank rebuilder that will have a look at it.
Make it idiot proof and someone will make a better idiot.
dandrews
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Re: KSR1100

Post by dandrews »

andrew wrote: Fri Dec 25, 2020 3:48 pm Keen to see a pic of your rig! I have a couple cranks that need sorting, have been putting them off for a few years. Don’t have a lathe so would need to build a small rig.

Maybe this is the year I finally get them straightened enough to put back in service.

Merry Christmas to all!
The "rig" is as simple as it could be. 2 vee blocks and a dial gauge. One vee block is mounted on a heavy vice with small neodynium magnets, the other supports the adjustable arm (I think it came with one either the gauge or the blocks) that the gauge is mounted on, again with magnets. The vee block is oiled and the crank clamped down with a piece of oil-soaked leather under the bolt end, tight enough to hold it securely but so you can still turn the crank. In the picture I have the flywheel end in the vee block and am measuring the runout on the driveshaft end. I then turn it end for end and measure the flywheel end.
IMG_1072.jpg
The blocks and the gauge came from
https://www.chronos.ltd.uk/product/dial ... -imperial/
https://www.chronos.ltd.uk/product/pair ... -capacity/
or similar - it is a while since I bought them

It is very much a lash-up - it should all really be on one solid base. But its a start. I try to compensate for the random error caused by the rig moving by a thou when I rotate the crank, by taking multiple measurements at different points along the shaft. Bend should show up as increasing runout the further you get from the bend. Rotational misalignment should give a constant reading along the shaft. (Assuming the shafts themselves are not bent).

If you are starting from scratch I'm sure the engineers on the forum could offer some better advice. See earlier in the thread.

I had a go at measuring a "new old stock" century crank
Screen Shot 2020-12-29 at 11.12.16.png
I have drawn lines on the graph and you can see that the distortion in the roller crank starts where the crankpin enters the driveshaft end web, but for the century crank it is at the other end of the crankpin. I think there is also about half a thou of run-out on the roller crank due to rotational misalignment of the crank web pin holes as the point of intersection of the lines is not on the x-axis.

I gather from the seagull service sheet that the runout should be less than 0.1mm / 4 thou measured between the bearings.

And the century crank is surprising bent given it a supposedly "new" item.

I should emphasise that careful attention should be paid to Charles' advice about how fragile these roller cranks are, if you are tempted to start straightening them yourself!

I have also removed the youtube link to the crank alignment "tutorial" video I posted earlier in case it leads others to make the same mistakes I have. I should also advise people to totally ignore the seagull service sheet 12, which I had been following and which has led to those mistakes. The factory guidance seems to have been a recipe for disaster.
dandrews
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Location: Woodbridge, Suffolk

Re: KSR1100

Post by dandrews »

Have been busy in the garden most of this year but making some progress on KSR1100. I have for the time being given up on the roller crank and have sourced a plain bearing version to replace it. I'll come back to the roller later. Just a few comments and questions -

It was the devil's own job to get the exhaust tube off. Soaking in WD40, multiple hot air gun heat cycles, and lots of "wiggling" with the block in a vice all to no avail. In the end I use wide "builders band" to clamp the tube to a 9"x2" block of wood fixed to the workbench and drifted it off with a long drift up the tube against the inner exhaust flange. (I should have put some padding under the builders band as it has scratched the paintwork0

The aluminium verdigris was "drizabone" despite soaking in WD40 for weeks. But it's off. That enabled me to thoroughly check out the waterways, which are now nice and clear.
IMG_1160.jpg

The block has some scorching to the paintwork over where the transfer ports run presumably indicating some past overheating - I can't see how there could be waterways around there so perhaps not surprising but is this something I should be worried about? And what is the core plug for? A casting mould feature? Or does it hide a tiny waterway?
IMG_1474.jpg
COUPLE OF QUESTIONS
What do people use to seal the inner exhaust flange to the block? The "gasket" such as it was disintegrated on dismantling. The replacement part no. TRN KF 010 does not seem to be available from Sheridans. Any idea what material they are made from?

The replacement plain bearing crank I have is from a Kingfisher and is identical to another one I have from a Curlew. (It is also wonderfully straight with no detectable runout!) The parts book shows them as the same part number for Curlew and Kingfisher. Also the flywheel balance weight is also the same for both in the parts book. This seems odd when the Century and 40 series cranks have different weights on the crank web. Oh well, it makes for better interchangeability but it is a bit of a puzzle.

To cap it all, it turns out that the Lerryn run this year is on the same day I have to drive to Scotland for New Year's celebrations. Oh well.
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Charles uk
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Re: KSR1100

Post by Charles uk »

Put the top half of the crankcase back onto the cylinder , then you'll see why there's no paint in the transfer port area!
Make it idiot proof and someone will make a better idiot.
dandrews
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Re: KSR1100

Post by dandrews »

Thank-you Charles, I see the problem. The scorched area is crowded by the flywheel housing. I can just detect similar scorching on my (still fully assembled) Osprey if I look carefully, although it is hard to see given how tight it is.

Another observation - I believe I have an excellent example of the truth of the advice in Chapter 1 of A. Graham Bell's 2-stroke tuning book, that blueprinting (correcting production errors) is one of the most important and productive things one can do to improve reliability and performance. Note the misalignment of the exhaust port and the inner exhaust in the picture below, caused by the drilling of the fixing holes in the wrong place on the aluminium flange. You can imagine just how much the exhaust is restricted by the rotational misalignment.
IMG_1512.jpg
I have also tracked down the material for the exhaust gasket by comparing with the part for the Curlew. It was "Flexitallic SF2400 compressed fibre sheet", ca 1mm thick. Described as an "aramid and inorganic fibre sheet sealing material bonded with nitrile rubber". Rated to 225C & 51 bar. I have found something similar on the RS components web site (albeit pricey). Any thoughts on cheaper alternatives anyone?
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Charles uk
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Re: KSR1100

Post by Charles uk »

Cut a coloured paper gasket using a scalpel & the cylinder exhaust flange as a pattern, then take a photo of the paper lined up with the inner exhaust bolt holes to show your readers how disgracefully this inner exhaust fits.


The gasket doesn't need to be made from any material that's too sexy, it's only hot around the exhaust & must not be damaged by water as it's fully immersed.

I've tried to send you my phone number but can't, give John W a call & ask him for my phone number & give me a call.
Make it idiot proof and someone will make a better idiot.
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