GS 1000 parts id

[Ole]

Hi folks

I have recently bought three  GS 1000 engenes,  two in boxes and one assampled, mostly because it is always nice too have some spareparts on the shelf.

When i took a closer look at the parts i found a pair off Camshafts markt "Pupy"   Is this the Youshimura camshafts?  I also found a set off Mikuni carbs which i think is the VM 29 Smootbores. There where also a set off pistons and a matching barrel. I roughly messured them at 73 or 73,5 mm  Can anyone tell mee what make these pistons are. I`ll put some fotos here and i hope you folks here at OSS can help with some answers.  I hope you can read my english.

Best Regard   Ole

[kochic]

Look like a Wiseco number on the piston.

 

[cnap504]

Yep looks like 29’s, big drain caps on the bowls located directly under the main jet (alllowing main jet changes without having to remove the bowls).  Also thin wall spigots on the manifold side.  Looks like POP Y to me, POPS Yoshimura, could be

Edited December 27, 2021 by cnap504

[jb]

Nice find! 
as above, looks like a wiseco part number on top of the piston. You’re correct that popy is yoshimura cams, and they are smooth bore carbs…. identified by the small square boss on the carbs body just above the float bowl 

[Ole]

Thanks for the replays.   I think i will try to use the parts and build a modified engine.I have a nice running GS 1000 so i have plenty off time too work on the second engine. I have a newer CV head.  Is there any advantages off using that (bigger ports) and is it possible to get carb to head rubber that will fit with the 29 Mikunis?  Is the Yoshi cams plug and play or do i have to make any conversion with valves/buckets?

[BigT]

According to some GS racers I know,   the small port head (78-79) provides better port velocity and cylinder filling. this gives a broader powerband. this will match better with the smooth bore 29s

The large port head would be better for peak horsepower, with large carbs, if you were drag racing, or a totally built race motor, like for the Phillip Island Classic

[Ole]

It make sense, i think i will go with the old head. I have a last question: the flywheel on one of my spare engines is machined down (see picture) and there is jusy a disk left, why?

[Swiss Toni]

Less inertia = quicker to pick up?

Edited January 14, 2022 by Swiss Toni

[Ole]