750 maxim cam into 650 maxim

Ok help me out guy. i am going to be replacing my 650 cam with 750 cam come winter and have a few question....

I read that the cam are interchangeable in Chacal's write up. but are they a direct swap don't have to mess with the timing gear.

has anyone looked up the or found the duration and overlap.

can i swap out the whole cylinder head or just the cams. i would like to swap out the complete head after i have it milled .003 down to increase compression. or what ever i have to do to increase the compression.

What is the clearance when the valves are closing. it the YICS engine an interferance engine or none interferance.

i have read a few post over the forum and would like to see what happened to the project that were done. all i ready were never followed up on and don't know how they turned out.

 

As far as I know the cams are identical, they will fit with no problem. Remember, if you mill down the head you will also cause the cam chain to slacken; but it's possible to shorten it if you have to. Same goes for the heads, but keep YICS with YICS.

 

ok so the cam itself is identical just with different lobes on the cam itself. im looking for the most agressive i can get without custom makign one.

 

I'm not sure if 750 cams are any different from 650 cams, the way to tell is to measure from the top of the lobe to the bottom on both cams to see if they are different.

 

As far as swapping the camshafts.
The 650/750 exhaust are the same @ 7.80mm lift.
The intake is where the difference takes place with the 650 cam @8.50mm, and the 750 cam @ 8.80mm giving a 0.30mm increase in lift.

This should help in the mid to top range.

Another option exsists with the 85-86 XJ700 non-X cams.
The intake matches the 750 cams @ 8.80mm lift.
The exhaust is where the difference takes place @ 8.30mm lift. giving 0.50mm increase in lift on the exhaust.

This will help out the bottom to mid range.

I have not seen any published specs on timing, or duration for the 700/750 cams. They do use the same chain with different gears than the 650. So timing might be something to look closer at.

Valve to piston clearances should not be an issue with these cams, but you will need to clay the pistons to make sure.

As far as swapping heads.
The 750 head is directly interchangeable with the 650 head as long as you stay with the YICS match. The cylinder, and head must both have the YICS port. YICS is not interchangeable with non-YICS.

Ghost

 

any idea what kind of power gains you can get with 750 head on a 650?