Potential Group Purchase - Wiseco GS650 741cc pistons

Hello! Any new here?

I'm located just at few km of the famous "mont ventoux" (the little french pike's peak). That swap would be perfect for me

Tkent, could you try to keep that subject lead "refreshed" in the first post on the first page? (with the list of people interested, the price for each piston, and a "booking closed date") If you do that it will motivate everyone and so we won't wait for anything.

Personnally, My bike is entirely disassembled, even for the engine. powder coated black painting for the frame and steel parts next week then I'll start to re-assemble everything. So if I could get the pistons before end of march it would be ok for me... even I still have a lot of work on the head, and the frame, that date would be ok for me.

[tkent02]

Probably half the springs heavier, half stock. If that don't do it..... That will do it.

I don't remember hearing about anyone who has done the 550/650 mod having clutch issues.

If it does start to slip will we have to go with a different clutch assembly or just a little bit heavier springs?

[tkent02]

Very nice smooth tight transmissions, bombproof in my experience, but the clutch is a slightly harder pull than the later type with the lever on top of the clutch cover. Some are smoother than others, but none have the butter lever feel of the 850s. I put a better lever and perch on my 450, it made it a LOT easier to pull, don't know if the 550 will need it, don't know if it will need bigger clutch springs with the 650 top end. My 550 is fine now, but if the bigger engine makes it start to slip.....

That's about it on a 650. On a 550, split the cases and hog out the upper one until sleeves fit in the case. It's quite a bit of grinding.

Yeah I'm pretty sure I saw your pics of removing material about a year ago on the 550 bottom. 6th gear will be nice.
Plus at least from my experience 550's are super smooth shifters.

[tkent02]

That's about it on a 650. On a 550, split the cases and hog out the upper one until sleeves fit in the case. It's quite a bit of grinding.

So aside from the cylinder boring, pistons, wristpins/circlips, head and base gaskets and honing, carb syncing....
What other machining, mods or parts will be required to make this big bore kit work?
What else will it take to fully complete the swap?

Hey borish what part of France are you from? Last summer I spent a lot of time 45 min south west of Toulouse.

[tkent02]

A stock GS1000 would perhaps even have trouble keeping up with a 550-650-740 or a GS650E-740cc on tight twisty backroads.

Hell a stock GS1000 would have trouble keeping up with a well ridden 450 on tight twisty backroads. Quick and nimble trumps massive and stable on tight roads, unless your definition of tight is 70mph sweepers.

[Chuck78]

Yes $95 per piston is AWESOME. If I weren't so tight on money for the next 2 months I'd be buying up 2 sets! The 650 head/piston design is by far the ultimate / mist efficient / most high performance design of all 2 valve GS's. A stock GS1000 would perhaps even have trouble keeping up with a 550-650-740 or a GS650E-740cc on tight twisty backroads. That's saying a lot. If I didn't have a GS750 & a Rickman looming to get a 750-894cc, I'd be building up bunches of GS550-650-740cc's & GS650E-740cc's, this is a really potent setup and a fair bit lighter than the bigger 4's, plus much more cornering clearance.

Tom, my local buddy David "drey6" is in between jobs currently, in college, coaching high school wrestling team, but when he gets some more regular income, he'd likely buy a 2nd set off of you this summer if you bought some spares.
If my house were sold now, I'd be buying 3 sets... for now, just 1 set is a struggle on the budget.

[tkent02]

We have five buyers counting you. If we get it to seven sets of pistons, the price will be $95 per piston. I'll do an extra set or even two if necessary to make it go, but I'd rather wait a little while, as would some of the others. I guess we'll see how much of a hurry I'm in once I try the 550/675 with the stock pistons... If it goes like hell I'm in less of a hurry.

I'm not saying I'm all in, but If it's a good spring at work here, I would really want to do this.
Just got a lead on a 650 engine too....would be nice to have one on the bench to build up a litte.

ok! So what is the status of this potential group order now? thanks!

[tkent02]

Yes they are made for a 650 head.