GS1000 pistons in GS750?

[terry]

Ozman dropped the "loaner" 29mm smoothbore carbs off for me, (he's a top bloke!) but sadly they're physically too small for my big port head on my GS1000ST, the inlet rubbers for my 28mm "SN" carbs fit fine, but are still too small for the big port head.

I might have to try them on my 1979 GS750, along with the "ST" cams, spare Megacycle pipe, etc etc. Does anyone know if I can bore the 750 barrells out to accept the stock 70mm GS1000 pistons I've got left over since I fitted the "Yoshi's" in my "ST"?

I read in my old clymer manual that there were two options back then, 69mm Yoshimura pistons for their 850 kit, and another company (whose name escapes me) offered 70mm pistons for their 870 kit.

The question of course is (without pulling my bike apart just yet) are the 1000 gudgeon (wrist?) pins going to fit the 750 rods, are the pistons going to fit in the 750 combustion chambers etc etc etc. Any help from you "experts" would be appreciated, as always!

I was going to leave the 750 stock, but this is just too tempting! :twisted:

 

[Anonymous]

i think the sleeves might be a little thin if you bore that far on the 750 but i will ask mick hone when i am talking to hin next. i have a spare set of 33mm smoothies they will fit the st manifolds for sure .let me know if you want to try them and i will drop them at cos'es for you cheers ozman

 

[kevan]

Take the 750 sleeves out of the block, bore the block to accept a shortened set of 1000 sleeves and there you go. I have a 750 block from the late 70's and have bored out the holes to accept 1100 liners. There is enought material left of the block it shoud be fine. This is the plan for my 84 750. When the 1100 liners are in the block, then they will be bored out to accept a Wiseco kit. It should be 936 cc when it is done.

Kevan

 

[Billy Ricks]

Kevan,
Keep us up to date on the '84 project. I'd be very interested in the results.

 

[terry]

i think the sleeves might be a little thin if you bore that far on the 750 but i will ask mick hone when i am talking to hin next. i have a spare set of 33mm smoothies they will fit the st manifolds for sure .let me know if you want to try them and i will drop them at cos'es for you cheers ozman

Hey Steve, you're the man! Yes mate, I'd love to try the 33's, give me a yell next time you're coming down! :twisted:

 

[terry]

Take the 750 sleeves out of the block, bore the block to accept a shortened set of 1000 sleeves and there you go. I have a 750 block from the late 70's and have bored out the holes to accept 1100 liners. There is enought material left of the block it shoud be fine. This is the plan for my 84 750. When the 1100 liners are in the block, then they will be bored out to accept a Wiseco kit. It should be 936 cc when it is done.

Kevan

Sounds good mate, thanks for the info, I might see if I can source an entire engine rather than operate on mine, it's only done 18000 miles and runs like a swiss watch, but then again if I'm going to all that trouble I might as well fit a GS1000 engine and be done with it? :?

 

[Anonymous]

Thats true Tel, especially as the thou engine is lighter than the 750 anyway. As you know from my bike it can be made to fit fairly easily.

 

[terry]

Thats true Tel, especially as the thou engine is lighter than the 750 anyway. As you know from my bike it can be made to fit fairly easily.

Thanks Martin, yeah, an Aussie 7/11 might be good at that! So many projects, so little free time............... :wink: