Mechanical/restoration supervision sought

**psyguy** · 18th April 2007, 18:17

Originally Posted by Ixion

Try Robinson's Foundry (odd name, but it's a bike site) in the UK. They have a lot of early 4cylinder Suzuki stuff. I'd have said that if Suziparts don't have it's looking grim, though maybe your bike is a bit young for them.

EDIT. Just checked Robinsons, for part no 12111-45110-100 (S/B 1.0 OS Piston for 1980 GS850G , still listed by Suzuki, BTW) , they reckon they have them in stock . Bloody dear though, 38 quid each.

Their website is shit BTW, until you know the trick you can never get anything to come up when you search.

thanks for this ixion

yeah, that site is really dodgy. your knowledge really helped as i could find the part only by the part number but not by model or description...

sent em an email first. i'm a bit more cautious now. the fact that the website tells you they have something in stock proved irrelevant with a few suppliers who all got back to me saying they have them no more. by the way, it seems it is a discontinued item.

anyhow, fingers crossed

**psyguy** · 18th April 2007, 18:26

Originally Posted by Alive

I am definately going to have to bring the xj900 around to see you...

thanks for coming over alive, showing your bike and sharing experience

when you undertake fixing those xj650's i'd be very keen to know how you go, maybe you could keep us posted

cheers

**Alive** · 18th April 2007, 18:26

That's some seriously good work you're doing Psy... Very impressive.

Great to meet you, definately have to go riding when you get her finished

**psyguy** · 19th April 2007, 20:24

very frustrating
emailed two dozen places
noone has any oversized pistons

have i maybe got the two last pistons in the world?!

**psyguy** · 19th April 2007, 20:56

mechanical help needed please

haynes manual suggests to:
"ensure that all the valve springs are fitted with the close coils downwards towards the cylinder head"

can someone please explain to me what that means?

i've posted a couple of photos of the new springs
they are all marked with green paint on one side - top or bottom - (but sides do not appear different to each other, at least not in their shape)

the old springs that were in the head are exactly the same (but there are no paint marks)

i'm not sure i'm explaining this well but that's probably cos i'm confused here...

cheers

**jonbuoy** · 19th April 2007, 21:22

Do they mean they are a progressive springs? - If that is what they are meaning then it looks kind of like the green paint should be on top. Bummer about those pistons. Maybe a few might come on on ebay? Do Wiseco or anyone else make an aftermarket or big bore kit?

**psyguy** · 19th April 2007, 21:41

Originally Posted by jonbuoy

Do they mean they are a progressive springs? - If that is what they are meaning then it looks kind of like the green paint should be on top. Bummer about those pistons. Maybe a few might come on on ebay? Do Wiseco or anyone else make an aftermarket or big bore kit?

could they be "progressive" without looking any different in shape from side to side???

sorry to say, but wiseco has nothing listed for 850. they do oversize for 750 - to bring it up to 850!!! i recon the inserts on the 850 are too thin to bring them a whole engine size up - to a 1000

may need to go with the standard pistons if i get too frustrated surfing ebay three times a day seven days a week hoping for something to come up

**Ixion** · 19th April 2007, 21:52

Valve springs, it's not the shape its the coil spacing. Look at your first picture, note the spring in the centre. The distance between the coils at the top is manifestly different wider apart) to the distance between the coils at the bottom. The "close together" coils go at the bottom.

Pistons: If you are on standard now, why are you overboring to 1.0m (+40 thou) surely there can't be that much wear? Are the bores scored badly? If not, why not try for +20 pistons (0.5mm Pt no 12103-45830-050). Of course they may not be available either, but it doubles your chances. And that number is a supercession number which often means that they've adopted a part used in another model, so even more chance.

**jonbuoy** · 19th April 2007, 22:13

I read on one of the SOHC forums you can get the skirts built up with some kind of metal spray coating called PC-9 you might have to send them away though

http://www.swaintech.com/store.asp?pid=10964

**psyguy** · 19th April 2007, 22:35

Originally Posted by Ixion

Valve springs, it's not the shape its the coil spacing. Look at your first picture, note the spring in the centre. The distance between the coils at the top is manifestly different wider apart) to the distance between the coils at the bottom. The "close together" coils go at the bottom.

Pistons: If you are on standard now, why are you overboring to 1.0m (+40 thou) surely there can't be that much wear? Are the bores scored badly? If not, why not try for +20 pistons (0.5mm Pt no 12103-45830-050). Of course they may not be available either, but it doubles your chances. And that number is a supercession number which often means that they've adopted a part used in another model, so even more chance.

mate, you know your stuff ... that's why i posted this thread - hoping to learn from others. cheers for all your help!

i actually figured it would have to do with the coil spacing! and i looked at the springs but could not see any difference there... and now that you pointed it out to me, it suddenly became so obvious...

yup, the green paint mark goes on top, i can see that...

now, i haven't measured the bores myself but at a reputable shop ("henderson reconditioners", i think) i was told the bores are up to 3 thou out of new and that honig would bring them to 4 thou - and that's just the limit of wear that the manual suggests is when you need a rebore (i don't have the experience so the manual is like a bible to me)
also, i come from a "metric" country so inches and parts thereof are very confusing for me, i can't really visualise what they mean...

no, the cylinders are not badly scored, just lots of minor vertical lines that would, i believe, disappear with honing (sorry, can't get it visible on a photo)

i didn't go for 0.5 pistons as they have been discontinued a long time ago and are listed as such on many websites, while the 1.0 are still listed as available
so i ordered 1.0 from alpha-sports, but, as you know, got only two pistons ...

if you are able to take an accurate measurement of the cylinders i'd be quite keen to come over and find out where i stand, for certain

**Ixion** · 19th April 2007, 22:43

If they're only 4 thou worn, they'll easily clean up at 20 over . Are the later (supercession) pistons unobtainable? They'll be obsolete for sure, but often stocks are availble for a long time after they're obsoleted by Suzuki . Alpha-sports still list them as available. If necessary there's no big deal about boring two cylinders to +40 and two to +20, just pick balancing cylinders (one up one own each size) .

I don't have an internal mic, I usually just go by feel and a thumbnail, but I'd believe what a reconditioner said, it souns sensible.

**psyguy** · 20th April 2007, 00:21

spares direct uk quoted me 0.5 oversized pistons and rings they have in stock
all 4 sets ... 300 pounds, plus postage

and i would be left with the other two new pistons and 4 sets of rings 1.0 i already paid for...

this is getting more and more complicated...
but i'll make a decission eventually

**pete376403** · 20th April 2007, 08:44

Desperate situations call for desperate measures...

I have a set of MTC forged pistons that have been removed from a GS1000. In good condition except for a bit of pitting on the crowns due to high compression and shitty petrol. IF you CANNOT source 850 pistons anywhere else you could see if the MTCs can be turned down (the skirts are quite thick) to suit, The crowns could also be reduced to get the comprtession back to reasonable. Piston rings are required, but they are the same size as Honda Civic Shuttle 1500.

I have heard that the 850 is basically a 1000 top end on a 750 crank so if this is true the MTC sizes should be pretty close.

Also PM me your address (or post it here if you like) and I'll send up the factory manual. I started to scan it into the PC but it's going to take forever.

**pete376403** · 20th April 2007, 09:24

Another thought - have you tried suziparts in Adelaide? All they do is nos for zooks http://www.suziparts.com.au/

**psyguy** · 20th April 2007, 09:44

Originally Posted by pete376403

Another thought - have you tried suziparts in Adelaide? All they do is nos for zooks http://www.suziparts.com.au/

tried it, no luck

however, i'm now onto 0.5 oversize (instead of 1.0 that's impossible to find), as somebody might have these still in stock

but thanks for your "desparate option" suggestion, i'll see how i go, i'm certainly getting a better understanding of various options

i'll pm you the address

cheers