1230 cylinder/piston specs.

[Guest]

Any one know the specs I should be looking for to verify that a used set of cylinders and pistons is good? Just purchased a cylinder bored to 1230 and the matching pistons. Have a friend that has and is very proficient at reading the gauges to inspect stuff like this. Just would like to know some numbers to ask him to look for. I'm expecting the 1230 pistons to be factory Suzuki 77mm's rather than Wiseco's. Wont know for sure till they arrive. Want to get this checked out sooner than later so I can return the whole lot if it ends up being out of specs.

If anyone noticed a problem in the pictures I should have spotted this would be helpful too.

http://www.ebay.com/itm/231225438065?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

[blowerbike]

looks like wiseco's..maybe i misunderstood what you was saying..
some scuffing..seller should have cleaned the gasket surfaces and washed everything up for an auction anyways..
price is cheap so you should be ok if things measure out ok.

[cdnoel]

The little C

I noticed the little C on the piston tops and figured that was a Suzuki mark. 77's are available from Suzuki so I'm wondering if these will measure out to a true metric piston.

If I'm not mistaken Wiseco's have been making non metric pistons and using 20 thousandths of an inch to get close to 1mm increments. If they are Wiseco's I'll most likely find them to be 60 thousandths of an inch over rather than 3mm.

Looking for piston clearance specs, Taper, and blow by tolerances. My friend will have some knowledge from cars that will translate but he'll need me to provide some numbers.

Working 7 10's right now and won't have time to go bother my usual machine shop.

[rapidray]

Stop over thinking this. Wiseco DOES do 1, 2 & 3mm overbores. NOT just increments of .020. As long as the piston to wall clearance, measured on the pistons 1/2 inch below the wrist pin holes, doesn't exceed .0035, you are good. Hone the block just to break the glaze, install new rings, end gapped correctly, & put it together.
Ray.

[jbthomp]

Just measure the new pistons and compare that to the original piston size. If they are bigger then they are oversized. Check the manual for the piston to cylinder clearance it will be the same whether you are using stock or oversized pistons. If your friend knows what he is talking about he will already know how to measure out of round and taper those are in the manual as well.

[rapidray]

I am an ex Suzuki dealer mechanic & have been racing GSs for over 35 years & have NEVER seen a FACTORY Suzuki 77mm 1230 piston for an 1150!
Ray.

[blowerbike]

some things are not in a manual...
i like using used rings if they spec out and are not sharp.
that's just me

[cdnoel]

24-3

part 24-3 on my local dealers parts fiche on line. Part number 11211-00A07-100 available for $45.88 each = 3mm over sized pistons for the GS1150's. www.apexsportsinc.com They'll be a true 77mm's guaranteed which is slightly smaller than the 60 thousandths pistons. If I have these and try to use Wiseco rings I'll be filing end gaps for hours. I'm not over thinking I'm planning not to spend hours filing end gaps.

Was fine when I discovered this problem on my YZ465 but that was only one piston. The little step at the locating pin on each one was very tedious to fine tune on two rings. This piston was 1mm over the rings 20 thou over. This time the problem would be with 8 rings and three times worse. Might even crack some rings trying to squeeze them in.

[Steve]

They'll be a true 77mm's guaranteed which is slightly smaller than the 60 thousandths pistons. If I have these and try to use Wiseco rings I'll be filing end gaps for hours.

It has been MANY years since I have filed any rings, but I seem to remember that you file them to fit the CYLINDER, not the PISTON.

In other words, it won't matter what piston you have in there, you are going to be filing rings.

.

[GS1150Pilot]

part 24-3 on my local dealers parts fiche on line. Part number 11211-00A07-100 available for $45.88 each = 3mm over sized pistons for the GS1150's. www.apexsportsinc.com They'll be a true 77mm's guaranteed which is slightly smaller than the 60 thousandths pistons. If I have these and try to use Wiseco rings I'll be filing end gaps for hours. I'm not over thinking I'm planning not to spend hours filing end gaps.

Was fine when I discovered this problem on my YZ465 but that was only one piston. The little step at the locating pin on each one was very tedious to fine tune on two rings. This piston was 1mm over the rings 20 thou over. This time the problem would be with 8 rings and three times worse. Might even crack some rings trying to squeeze them in.

You seem to be disregarding what Ray was telling you. I doubt there are many members here who have rebuilt or overbored more GS motors.

[blowerbike]

way over thinking this.
compare it to nothing else and just check the end gaps...may not need filed at all.

[rapidray]

If I'm not mistaken Wiseco's have been making non metric pistons and using 20 thousandths of an inch to get close to 1mm increments. If they are Wiseco's I'll most likely find them to be 60 thousandths of an inch over rather than 3mm.

1 mm is .0393, a hair under 40 thousandths. Where are you getting .020? That makes 3mm almost .120 overbore, .1179 to be exact. Wiseco, & just about every other piston manufacturer, makes their pistons in either 1 mm or 1/2 mm increments. Just because Alphasports lists the 77mm piston for 49 bucks doesn't mean that all of everything you need together will be less than Wisecos. You still need 4 of everything, pistons, pins, ring sets & 8 clips. The Wisecos are a good part too. Not my favorite but still good.
Ray.

[cdnoel]

off by a factor of two.

Thanks for the advice. I know you all have been around the block more than I have by far. That's why I'm seeking advice. I'm apparently off by a factor of two as I've slept since working on my last top end.

Not crazy though as I have run into problems fitting new rings to vintage pistons before for the reasons previously stated. In simpler terms a new second over ring will have just about the right end gap if fitted to a bore matching a new second over piston. You might not have to play with the end gap much at all. Try to fit a new second over ring to a bore matching a vintage metric second over piston and your ring ends will overlap. Get ready to file for a while.

I know the piston ring is fitted to the cylinder but in the case of rings that are stepped to align with a locating pin on the piston the end gap can be a real bugger to file. The cutting wheel on my end gap file only takes off the end gap, it doesn't replicate the step.

Just received my parts and all looks good preliminarily. No locating pins to deal with either. I see the Wieseco W under the wrist pin so I definitely got Wiseco's. Doesn't mean they aren't vintage though. Ring end gaps are between .5mm and .6mm. I'll have to dig out my manual but this seems wide to me. Perhaps ok but definitely not new specs.

[rapidray]

Aftermarket pistons, & even stock pistons used for different purposes, will have different & usually BIGGER end gaps.

http://www.cp-carrillo.com/LinkClick.aspx?fileticket=Q7LAfTKUjgE%3d&tabid=74

Ray.

[gearhead13]

part 24-3 on my local dealers parts fiche on line. Part number 11211-00A07-100 available for $45.88 each = 3mm over sized pistons for the GS1150's. www.apexsportsinc.com They'll be a true 77mm's guaranteed which is slightly smaller than the 60 thousandths pistons. If I have these and try to use Wiseco rings I'll be filing end gaps for hours. I'm not over thinking I'm planning not to spend hours filing end gaps.

Was fine when I discovered this problem on my YZ465 but that was only one piston. The little step at the locating pin on each one was very tedious to fine tune on two rings. This piston was 1mm over the rings 20 thou over. This time the problem would be with 8 rings and three times worse. Might even crack some rings trying to squeeze them in.

Where do you see a 3mm over piston and rings for the 1150? part 24-3 is a 1mm overbore piston. part # 11211-00A07-100 is 1mm over the part # with the 050 at the end is .5mm over.
If you get a set of rings that require a ton of filing, they are probably the wrong oversize and after filing the ends, the rings will fit in the bore more like an oval egg shape and will probably never seal.