MKII Square with swingarm

herblesjak
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MKII Square with swingarm

Postby herblesjak » Sat Nov 03, 2018 4:46 pm

Hi to all,

new into the Square Foure world, bought a few weeks ago this special bike.
Ridden it for only 50km now, but all i can say is wow, don't know any other british motorcycle engine which is smooth like that one :)
The handling and the brakes are great too.
Think about it to open the engine, cause the bike was into a collection for over 20 years, it stands all the time.
But the engine should looking good inside, it has an cartype oilfilter fitted and only ridden 6000miles before it went into the collection...

Regards from Austria

Herb

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roger.fellows
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Re: MKII Square with swingarm

Postby roger.fellows » Sat Nov 03, 2018 6:06 pm

Hello Herb, welcome to the club and the forum.

Can you hear lots of people shouting 'strip it first'?

You might get away with it, others will be better qualified to confirm or not. It would be a great shame to have a seizure.

Roger

herblesjak
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Re: MKII Square with swingarm

Postby herblesjak » Sat Nov 03, 2018 7:45 pm

Hi Roger,
i read a lot about broken rods caused by blocked oilways.
But the foreowner told me the engine undergone a whole engine restoration, including cleaning the oilways and sludge trap and fitted an oil filter cartrige type too, since then 6000 miles.
I think blocked oilways are not the problem. Problem is, this was done in the 90‘s...
Are the original conrods the weakest point in the engine and is it the most important thing to change it?
Herb

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Re: MKII Square with swingarm

Postby roger.fellows » Sat Nov 03, 2018 9:51 pm

I'll leave somebody on a higher pay-grade to answer that one Herb. I decided to renew mine.

That's a great-looking machine, and yes, the smoothness spoils one for riding anything else.

Did you ask whether the previous owner had rebuilt the engine himself or had it done for him?

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robjameson
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Re: MKII Square with swingarm

Postby robjameson » Sat Nov 03, 2018 11:26 pm

ANY square four with an unknown, questionable, slightly doubtful, ‘did the sludge traps’ engine, I would strip for peace of mind.

If I bought a square tomorrow, I’d strip it, check it and replace the rods for club ones.

If you don’t, and you throw a rod, replacement crank cases are like hens teeth, and it will have been an expensive exercise.
Rob Jameson
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1957 Ariel VH
1956 Ariel KH (LARGE project!)
2016 Honda CBR600RR

herblesjak
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Re: MKII Square with swingarm

Postby herblesjak » Sun Nov 04, 2018 8:48 am

The previous owner rebuild the engine by himself, he built the whole bike.
Think i will open the engine and change the rods, it would be a much more stress-free ride then...

Does the Club Rodes weight the same as the original rods? I mean, no rebalancing of the crankshaft is required?

I open the timing case for a look to the oil pump. The pump which i found is not the original i think, its signed SDD
Does anybody know this oil pump? Asked Draganfly, they said its not built by them.

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roger.fellows
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Re: MKII Square with swingarm

Postby roger.fellows » Sun Nov 04, 2018 10:11 am

Hello again Herb, there's a piece about rods on the Draganfly website. It seems the new rods - also available through the club - are a little lighter than Mk11 originals.

With 180 degree cranks and diagonally opposite pistons rising or falling together I can't see much of a problem. I suppose the balancing process would have to be dynamic anyway? ....... I am not an engineer!!

Details of the Sq4 spares officer in the members' section of the Club website.

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Vincent.vanGinneke
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Re: MKII Square with swingarm

Postby Vincent.vanGinneke » Sun Nov 04, 2018 12:05 pm

Hello Herb,

Very nice SQ4 in a swingarmframe, (on my wish list now & then..)
I googeld this SDD pump and it gets mentioned on this forum :
https://www.a7a10.net/forum/index.php?topic=12357.15
scroll down a bit.
Looks like it's a '90 BSA A10 cast iron body high delivery pump, perhaps a predessesor to the (anodised alloy?) SRM ones that are available right now.
Nineties date ties up with when the previous owner worked on it.
Good luck with it!

p.s. if that oil tap is only manual with no starter cut-out you could consider this one : http://www.kingpincomponents.co.uk/oil- ... d-fittings
more peace of mind at 48,- GBP....

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Re: MKII Square with swingarm

Postby paul.jameson » Sun Nov 04, 2018 8:40 pm

Looking at the photo of the inside of your timing case tells me that the engine was built by someone who was not too familiar with the Square Four engine. The upper end of the timing chain tensioner is in the wrong place and the support for the tensioner is not tight enough. Cleanliness inside the engine is fairly poor.
So strip the engine, clean out the sludge traps and get every bit of dirt out from within the engine that you can. Once you have dismantled the engine you will realise just how tiny the sludge traps are. Any dirt inside the engine is likely to end up in them as modern detergent oils clean the engine insides for you. In time, the sludge trap gets full, prevents oil getting to the big end and then your con-rod goes out through the crankcase. So strip and clean the engine, probably fitting new club rods when you do this. I hope that after doing the strip down you think that it was not needed - but I would be very, very surprised if you think this. After removing the debris from the sludge traps I am sure you will think that a few more miles could have meant a blockage. Doing the strip will enable you to have confidence in the bike in future.
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

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Vincent.vanGinneke
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Re: MKII Square with swingarm

Postby Vincent.vanGinneke » Sun Nov 04, 2018 8:48 pm

may I add to this that I think a MkII has a double row chain, or am I mistaken ?
Probably does not really matter in function.


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