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Discussion Starter #1
I am very interested in the swap. I love to get stock parts from another bike and use them as high performance parts on others. I'm shopping around for GS850 pistons and plan on boring and running them in my CB360. I want increased performance but still want the bike streetable and relaible.

I understand that this is a pretty straightforward mod but I would still like to gather as much info as possible before undertaking this.

CrazyPJ, you say you milled .025 off the head to increase compression, what are your thoughts on NOT doing this? Will I be negating any benefits of the larger pistons by not milling? Again, I'm not building a race bike.

You said you made your own gasket for this mod, do you think I could buy one off you? I've never made a head gasket before.

On top of this I plan on a port and polish, gonna upgrade my carbs but still have to do more research on my options. Any carb suggestions? Keep in mind I like low budget performance.

In the future, I may upgrade my cam with one from Megacycle. Do I have other cam options?

Thanks in advance fellas.
 

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You need to specify how your measuring if your throwing numbers about.
0.025 means nothing, .25 what? bananas?
0.025" is a measurement, specifying inches, twenty five thousandths of inch for the numerically challenged
Get a gasket from Lani at copper gaskets, he's made a few for me since I made my own.
If you skim head you have to re-time cam, if you don't, you don't.
You may have trouble finding GS850 pistons, they are discontinued by Suzuki (I checked) nothing much has turned up on eBay in last 8 months.

PJ
 

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Stock CB360 is 67mm IIRC, so you are looking for pistons at say 2mm O/S at 69mm or maybe 3mm at 70mm?

CB450 is 70mm if it can be bored into those sleeves and if the wrist pin is compatible, that could be a place to start.

GS750 pistons in 69mm bore (2mm O/S) are available from Wiseco if their crowns are the right shape.

If you slip in cams with more lift and duration, you will probably want more compression to compensate for the loss in low end performance. And then you will want a set of 32mm VM Mikuni carbs or something more racey and costs start to fly out the window pretty fast.

Maybe a slightly higher compression with stock pistons and cam may be a more cost effective option.

At least a 360 has a much better 6 speed than those poor people with CB350s.
 

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Wiseco's are HEAVY pistons.
They would probably work OK as long as stock cam and lowish rpm was used or, fit Carrillo rods
GS pistons are lighter than stock Honda so crank survives quite happily at 12,000 rpm (cam bearings are different matter though :D)
You don't want 32's on a street motor and I'm pretty sure most people running them on 'race' motors would be happier with 30's if they set the up properly. (they are easier to set up than 32's)
 

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Discussion Starter #7
quote:Originally posted by crazypj

You need to specify how your measuring if your throwing numbers about.
0.025 means nothing, .25 what? bananas?
0.025" is a measurement, specifying inches, twenty five thousandths of inch for the numerically challenged
Get a gasket from Lani at copper gaskets, he's made a few for me since I made my own.
If you skim head you have to re-time cam, if you don't, you don't.
You may have trouble finding GS850 pistons, they are discontinued by Suzuki (I checked) nothing much has turned up on eBay in last 8 months.

PJ
I'll contact Lani at copper gaskets for my needs. Thanks for the tips.

I've been looking on ebay for those pistons for a month now, I was suprised at how uncommon they are. When they do show up on ebay, whatdo you think is a fair price to pay for a set?
 

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I was looking for longer than a month and bought the first (only) set I saw.
If you see any, just buy them.
Still going to be cheaper than custom pistons (at least $700.00 a set of four)

PJ
 

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Discussion Starter #9
So I just pushed the "Buy it now" button on ebay and purchased a set of GS850 pistons.. We'll see how badly this project snowballs from here..
 

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quote:Originally posted by tripod808

So I just pushed the "Buy it now" button on ebay and purchased a set of GS850 pistons.. We'll see how badly this project snowballs from here..
LoL .... now that's heart.
 

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quote:Originally posted by roccitycafe

bike bandit appears to have them new, wrist pins and ring sets as well...
Dunno where they got them, Suzuki don't have any stock, only 1mm OS. (I checked ASMC)
Are they aftermarket?
 

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Discussion Starter #13
quote:Originally posted by crazypj

You need to specify how your measuring if your throwing numbers about.
0.025 means nothing, .25 what? bananas?
0.025" is a measurement, specifying inches, twenty five thousandths of inch for the numerically challenged
Get a gasket from Lani at copper gaskets, he's made a few for me since I made my own.
If you skim head you have to re-time cam, if you don't, you don't.
You may have trouble finding GS850 pistons, they are discontinued by Suzuki (I checked) nothing much has turned up on eBay in last 8 months.

PJ
PJ,
What thickness of copper gasket are you running in your bored out 360?

Do you happen to know the stock engines' gasket thickness?
 

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quote:Originally posted by crazypj

quote:Originally posted by roccitycafe

bike bandit appears to have them new, wrist pins and ring sets as well...
Dunno where they got them, Suzuki don't have any stock, only 1mm OS. (I checked ASMC)
Are they aftermarket?
no clue, no need to buy them at the moment so I probably won't find out, I think the next twin I get will be a 350 anyway
 

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quote:Originally posted by crazypj

quote:Originally posted by roccitycafe

bike bandit appears to have them new, wrist pins and ring sets as well...
Dunno where they got them, Suzuki don't have any stock, only 1mm OS. (I checked ASMC)
Are they aftermarket?
no clue, no need to buy them at the moment so I probably won't find out, I think the next twin I get will be a 350 anyway
 

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Discussion Starter #16
quote:Originally posted by roccitycafe

bike bandit appears to have them new, wrist pins and ring sets as well...
I also found that http://www.bore-tech.com/SuzukiPistons.html carries standard sized GS850 pistons and rings.

I'm still shopping around though, does anyone have a source for standard sized GS850 rings?
 

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Hey Pj , When you say re time the cam, how'd you do that. I'm nearly done with my ha 850 piston conversion, but not sure how I should take this next step. I was thinking about slotting the cam bolts to adjust the cam timing. Any advice?
I've already bored the cylinders and put in my gs Pistons, in my cb 360 with a copper gasket from Lani.
 

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Haven't seen PJ around in a long time. I think slotting is an option or alternate bolt holes that are offsett incrementally
 

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Okay, thanks for the reply, I started this crazy project cause of his posts, this is the first Hangup I've run into. Glad I finally joined the forums! ��
 

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post a more generic thread about slotting/timin cam, and the more experienced will be likely to comment. they might not check cb360 specific thread
 
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