lobe centers when using a turbocharger?

What lobe centers are recommended with stock cams and using a turbo??
Bike is a kz 900 4 cylinder and/ or a 900 twin (1978 big bore model!)
I once rad that the inlet has to close earlier and exhaust later. Makes that sense??
Thanks

Martijn

I don't have a clue, but could you provide some info on the 900 twin? :blush:

after steels question, I have to ask, how are you going to change the lobe center on a stock cam?
That is built into the cam profile.

The lobe centers can be changed by slotting
the sprockets.I believe they lower them to
100-105 compared to 110 (stock).

Stock timing is fine. If you want to get smart you can "spread" the lobes by timing them for less overlap. I run 110/115 on my 750 (105/105 stock).

I have a KZ1100 with too much compression (12.5:1)
and it was a real load on the starter..
i advanced the intake cam 2 degrees and retarded the exhaust cam 2 degrees.
Works great!

sorry, duplicate post

Post edited by: FloridaBiker, at: 2007/11/20 08:24

it's going to be a 864cc kz750 twin, new pistons of 84mm and of course resleeving. Since the hotter cams are rare to get or quite expensive to remanufacture I 'm planning to bolt a turbocharger with a singel carb on it:woohoo:

A few thoughts dragged from the dim recesses of my memory that probably need correcting (Please do so if you don't mind)

I'm on the GPz mailing list and recall a member of the same name that I think lives in the NL, is that you??

Are the pistons left over from some kind of group buy, or maybe an individual that had several custom made for himself?

I corresponded with Steve Darlington about a guy he knows that built a 750 twin for roadracing and ran into serious problems with the bottom end when he hit the 90 hp level, are you familiar with the story?

I recall reading something about a guy in Europe (Germany I think, but I'm not sure) that had custom pistons made for a 750 twin, are the pistons you have from this guy (or related)?

I think that where I heard about using the exhaust cam (another one actually) as an intake cam in the 750 twin, been meaning to do that but haven't got around to it yet.

Can you refresh my memory?

what you are reffering to is the degree of the cam shaft, when you advance a cam you get lower end power, but it falls off on the top end, and vise versa when you retard the cam.
since we are dealing with two seperate cams you have the oppertunity to advance one and retard the other, which can affect compression in the motor

steell wrote:

A few thoughts dragged from the dim recesses of my memory that probably need correcting (Please do so if you don't mind)

I'm on the GPz mailing list and recall a member of the same name that I think lives in the NL, is that you?? could be but I only have KZeds

Are the pistons left over from some kind of group buy, or maybe an individual that had several custom made for himself? the pistons are oversized pistons which are still used in other engines, not custom made, not in a motorcycle

I corresponded with Steve Darlington about a guy he knows that built a 750 twin for roadracing and ran into serious problems with the bottom end when he hit the 90 hp level, are you familiar with the story? euh no, but good information

I recall reading something about a guy in Europe (Germany I think, but I'm not sure) that had custom pistons made for a 750 twin, are the pistons you have from this guy (or related)? I know the guy, indeed Germany. He had the pistons custom made for , if I recall correctly, for approx $400 for each piston. Mine are $100. See at twinbikes.com

I think that where I heard about using the exhaust cam (another one actually) as an intake cam in the 750 twin, been meaning to do that but haven't got around to it yet. Is correct!!! approx 20 degrees more duration and approx 1,2mm more lift.
Can you refresh my memory?

Thanks for your information!