TOPIC:

hey guys, have a few engine questions for the gurus out there. im new to the whole modding and tuning thing. i have a 750 that im interested in turning into a 810 with wiseco's help. my questions are: will this still be streetable or is this more for drag strip useage? do i need to get new cams or can i just rejet? has anyone used this kit themselves? and lastly, if i do do it, do i need anything else to accomodate the kit, such as a oil cooler or something else. any help or suggestions would be much appreciated. ive done alot of work to my 750 and have fallen for it. id hate to just give it up because im power hungry. i ride mainly highways but quite alot of city riding during full blown summers. so that tells what its applications going to be. thanks!

im not very experianced with the smaller motors but where i come from cubes is cubes! most aftermarket piston kits start at around 10.25:1 compression which shouldnt be a problem to drive on the street.where problems usually arise is when guys start building their streetbike motors like dragbike motors that are only good at a very limited rpm range like 8500-10,000 rpms.id say put a good header and the 810 kit in there ,while the head is off do a valve job on it and check you guides and springs.pull the pan and check things out before you get to crazy and maybe toss a camchain in it,keep your stock carbs and rejet them.you can always put cams in it later if its not enough for you.goodluck,happy wrenching!;)oh yeah,an oil cooler probably wouldnt hurt;)

Post edited by: wireman, at: 2007/02/04 11:13

thanks wireman, im off to go do pricing!

An oil cooler is a good idea, and it's easy, just get the oil pan and cooler/hoses from a GPz750.

steell wrote:

An oil cooler is a good idea, and it's easy, just get the oil pan and cooler/hoses from a GPz750.

this is the guy you want to listen to about the 750 stuff!

oil cooler, eh? ive seen one fashioned by the oldkawman. does anyone know of this guy and if his reputation is solid? also, like wireman said, steell you seem to be the 750 man. any pros of the 750 that you seem to enjoy (since you do have 3). i like my 750 because its frame isnt too big and it isnt too small and the engine makes adequate power. the only problem ive really hit is, i dont feel like the 750 has as much of a cult following as the 1000 does. i like seeing that someone else out there supports the 750! steell, do you have any mod ideas yourself, or at least why you like the 750?

check lorcans website:evil:

one other thing i forgot to ask. does anyone have a rough idea what kind of power increase putting that kit on my bike will do to the stock 74 claimed ponies it makes? five hundred hard earned ones is alot for just a ten horse increase, unless my torque goes through the roof? just another question i have to help make me salivate better about what this COULD turn into. the little 3/4 liter bike that could.

What year is your 750 and is it a GPz?

I've installed a few of those 810 kits. It's been a long time since I've had anyone ask about one.

If all you intend to do is the big bore you can expect a slightly stronger motor pretty much all the way up the scale but nothing radical to speak of.

If you want that seat of the pants thrill then you need to look above the block to the cam shafts and behind it to the carbs.

Are you carbs Mikunis or the Keihins that came on some of the 750's back then? I can't remember which models had which but it seems to me the Mikuni's were on the GPz and other models got the Keihins. Those particular Keihins were not a great performance carb. They had air chokes instead of enricheners. Those double butterfly carbs were performance killers.

At the very least, if you have Mikuni carbs, you want [if you don't already have it] a jet kit for the CV carbs. Even a stage I kit will be a help to compensate for the additional piston demand for air from the bore increase. A stage III with K&N filters would be better.

The thing is, it's a disease and once you have it, there is no cure. One thing leads to another and that's generally followed by something else, etc.

JMO

Larry C

Post edited by: larrycavan, at: 2007/02/04 18:48

Post edited by: larrycavan, at: 2007/02/04 18:53

My 750's are two cylinders, nothing to speak of in the hp department
The GPz750 is getting a 1105 J motor if I ever get all the parts in the same location
The motor that was in the GPz750 is now in my nephew's 79 KZ650SR.

According to the GPz750 FAQ, the 810 kit with the 83-85 GPz750 cams, the GPz750 head, and the head shaved .030", and a decent 4 into 1 exhaust, is good for 100 hp.

Stock GPz750 is rated at 85 hp, and it uses Mikuni BS34 carbs.

You can download the 750 manual if you don't have one.

kz.mbsween.com/

My 750 had the kit installed when I got it. The previous owner who is a friend did it or had it done. The cams are stock. There is a Mac 4->1 on it and I'd say that it feels like a pretty good 750. Not dramatic performance like a modern sportsbike and certainly not 100hp. Definitely streetable.
If your carbs are Keihins then the biggest problem you may have is finding bigger jets - I hear they are near impossible to get.

Post edited by: JR, at: 2007/02/04 21:01

JR wrote:

My 750 had the kit installed when I got it. The previous owner who is a friend did it or had it done. The cams are stock. There is a Mac 4->1 on it and I'd say that it feels like a pretty good 750. Not dramatic performance like a modern sportsbike and certainly not 100hp.

That makes sense, since you are missing the rest of the package and mods.

According to the GPz750 FAQ, the 810 kit with the 83-85 GPz750 cams, the GPz750 head, and the head shaved .030", and a decent 4 into 1 exhaust, is good for 100 hp.

The cams, carbs, head, and half point of compression, add 11 hp to the stock KZ750's hp rating (85 vs 74).


One version of the GPz750 FAQ