Head work cyl displacement ques

[pano]

I have a GS1150 head with oversize valves and street stip port that came off a 1229 bore. (skips old bike). My intent was to put it on another similar bore but I have gotten well behind expectations with my projects. I will be rebuilding my 821100e engine this winter with an 1166 and am thinking of using the head on the 1166. I am not sure if it will be too much for the 1166, I figure it will be fine just less power than a 1229. Thoughts?

The rest of the build will be RS36 carbs, welded crank, reinforced clutch basket, dyna s & coils, high vol oil pump gears, man cam chain tensioner, top end oiler, KN pods, G3 cams, SS brake lines, ikon shocks, perf clutch/springs (3), HD cam chain, Suzuki gaskets, super trap 4-1, probably forgot something. Thanks.

[Big Jay]

It will work fine. The bigger valves will really help it.

[trippivot]

The peak power will be higher in the rev range because port velocity of the smaller engine will take more R.P.M.'s to match the bigger one. It will work excellently

Big valve heads are great!! but you have some extra building issues to consider as they make it so you have to get your pistons specially clearanced to match. Did you get your 1166 piston set already fitted for your valve over sizes? Some overbore kits only have stock valve sizes cut into them.

if the head is milled to raise compression you will have more clearance work near the outer edge of the piston valve pockets as well.

just some tips I learned along the way -

[pano]

Pano,

Are you using HMP, doing it yourself, or have you found someone else?

I planned on doing it myself although I could consider HMP. Last I checked they quoted 800 for the assembly (a few yrs ago) if I brought in the parts and engine. It may be worth considering to prevent mistakes. My inlaws live nearby in Westboro maybe I should stop by to discuss.

[pano]

The peak power will be higher in the rev range because port velocity of the smaller engine will take more R.P.M.'s to match the bigger one. It will work excellently

Big valve heads are great!! but you have some extra building issues to consider as they make it so you have to get your pistons specially clearanced to match. Did you get your 1166 piston set already fitted for your valve over sizes? Some overbore kits only have stock valve sizes cut into them.

if the head is milled to raise compression you will have more clearance work near the outer edge of the piston valve pockets as well.

just some tips I learned along the way -

I definitely need to work those details, already have the 1166 pistons and did not consider the pockets. Putting the 1150 head on was a recent consideration. I could always buy new pistons and use the ones I have on something else.

[7981GS]

Take the pistons to a machine shop and have the valve reliefs opened up and cut a little deeper.

Eric

[Big Jay]

Wisecos, JEs, and MTCs should have big enough valve pockets.

[duaneage]

Whatever you decide use model clay on the pistons and measure it.

[Big Jay]

On these rocker arm motors, it is very easy to check piston to valve. When you get the motor rotated so that the valves are closest to the piston, you can put an indicator on the rocker arm, then use a screwdriver and push the rocker on down until the valve contacts the piston, and observe the travel on the indicator.