Late 70's 750 converting to 1000cc?

[ToddB3]

Hey guys,

Just wondering if anybody out there knows if it would be an easy task to install GS1000 cylinders and head to my 750's bottom end? I've found a junk yard close by that has a 1000cc engine with a cracked bottom end but the cylinders and head look OK and thought for the price if I didnt have to do any major milling on the bottom end to fit it would be some cheap ponies.

 

[humhead]

1000 cylinder blocks do not fit a 750. your best bet for a power increase is a wiseco 850 kit. If you must have 1000cc, you have a couple of choices. Find a good 1000 motor & mount it in the 750 frame OR Find a good running GS1000.

Terry

 

[ToddB3]

I should have figured that, do you know of a good place to start looking for a 850cc piston kit?

 

[Hap Call]

I should have figured that, do you know of a good place to start looking for a 850cc piston kit?

http://wiseco.com/

They make a 844cc kit that is a 2 mm overbore at 10.25 compression ratio. MSRP is $440.19 but dealer cost is $264.13 so you may be able to negotiate with a local motorcycle speed shop and get a better deal. I did that and got it for 20% over dealer cost plus shipping.

Hap

 

[KW]

It's a 4mm overbore. 750's are 65mm - 850's are 69mm

 

[massakins]

Hap, don't give away all of my secrets.....

 

[Guest]

http://www.pro-flo.com/pro-flo_wiseco_suzuki_big_bore_kits.htm

$365.95

 

[terry]

It's always a bit of a gamble, but for that kind of money you may well find a good running GS1000 engine on ebay etc (preferably the 1980/81 big port engine) which is a simple fit in a 750, (longer rear mounts need to be fabricated, but that's not a big job) and a big increase in power. If you still want "more power", spend the money on a Wiseco 1085 or 1100CC kit! Cheers, Terry. :twisted:

 

[ToddB3]

That thought had already crossed my mind, I could probably find a 1000cc engine that needs new rings and valve seals and still come out ahead in horsepower and money than the 850 kit. I'm sure that the electrical harness from the 750 will probably work on the 1000 also, please correct me if I'm wrong.

 

[earlfor]

Hmmm, guess it depend on how you look at it. Seems that taking off 2mm all the way around would do it.

Earl

It's a 4mm overbore. 750's are 65mm - 850's are 69mm

 

[Hap Call]

Hap, don't give away all of my secrets.....

Sorry about that Pat!

Hap

 

[SOS]

8) Is the 79GS 750 and 1000 on the same frame? 8)

 

[Hoomgar]

I'm pretty sure they are identical.

 

[humhead]

Is the 79GS 750 and 1000 on the same frame?

NO! They may look similar, but they are different. You can see for yourself by looking at the parts fiche at alphasports website.

Terry

 

[Anonymous]

is the 1000 engine heavier or wider then the 750 engine? How does putting a 1000 engine in a 750 affect handling and such...obviously its more powerful but at what cost?

 

[ToddB3]

I'm sure the 1000cc engine is a litttle bit heavier and most likely wider but I use the GS as a cruiser and camping bike, I'm just looking for some reliable grunt on the straights.

 

[marcovandevelde]

The GS1000 engine width and heigth is nigh on identical to the 750. They made the first GS750 oversized to take some serious punishment. What would be a nice upgrade also is to put in a 4-valve GS1100 like I did. Only other mod is the ignition (change el.unit to points, or change existing points ign. to electric) Anyway it will fit the GS750 frame easy also, even with some room to spare, as the 4 valver will be slightly shorter. All you need are new (longer) rear mounts. The weight isn't that much more than the 750 lump, maybe a couple of KG's. The benefit is the bigger torque and serious power increase, like 60 HP for the 750 to 100 HP for the 1100. Ofcourse it is always a good idea to upgrade forks, brakes and rear shocks aside wether you're fitting a bigger engine or not.

Good luck, Marco.

 

[Anonymous]

would my 4-into-1 fit the 1000 or 1100? I have been looking at this as an alternative...i just dont want to add this motor and have the bike handle worse then it did before...of course brakes will be upgraded as will suspension which needs it anyway.

 

[humhead]

The brakes & suspension are very similar. The rear brakes are identical except for the brake line. Front brakes use different calipers. The fork tubes are 2mm thicker & 17mm shorter on a 1000. The triple trees are different.
In order to mount a better front end on a 750, you will have to machine the lower triple to fit the 750 frame.
After realizing the amount of time & money necessary to do this right, I saved enough $ to buy a 1000. Now I have 2 great bikes to enjoy.

Terry

 

[terry]

As much as I agree with Terry that both bikes are great and if you have the room/want two bikes then it's almost economically sensible to buy the 1000/1100, fitting a 1000 engine into a 750 is a "no-brainer", the frame was very well designed and built, and can handle the more powerful engine with no problems.

Even though the 750's brakes would be laughed at nowadays, they're the same as the early GS1000 items, and if your 750 is like my 1979 "Police Special" with twin discs (and wire wheels!) then I'm sure that this set-up is more than acceptable to pull it up with the larger displacement engine.

Sadly Martin (Brit 7/11) doesn't contribute to this site much any more since he sold his Suzy's and bought a Triumph, but he could have told you everything you need to know mate, he had a GS750E with a monster GS1000 engine with a 1260cc big bore block and the best of everything inside it as his daily rider/drag racing toy, and although much modified, it started I believe like the bike you're thinking of building, and just, er, evolved.................... Anyway, food for thought. Cheers, Terry. :twisted: