1100 head vs 1150 head power differences

[nastyjones]

This winter I want to do a couple of mods to the old 80 gs 1100. The bike has 36 mm 1150 carbs w/Dynojet stage 3 kit & a V & H pipe. Here's my 2 choices.
Take my 1100 head & install 1 mm over intake, then a good street/strip port job. My machinist says about $650-$700 for this work.
Pick up an 1150 head to use & install HD studs. How much of a power diff. is there between these 2 combos?
And what about cams? Can I use 1150 cams if I keep the 1100 head?

[stetracer]

This winter I want to do a couple of mods to the old 80 gs 1100. The bike has 36 mm 1150 carbs w/Dynojet stage 3 kit & a V & H pipe. Here's my 2 choices.
Take my 1100 head & install 1 mm over intake, then a good street/strip port job. My machinist says about $650-$700 for this work.
Pick up an 1150 head to use & install HD studs. How much of a power diff. is there between these 2 combos?
And what about cams? Can I use 1150 cams if I keep the 1100 head?

Don't even think about keeping the 1100 head get a good 1150 head and do the same mods you want to do to your 1100 head and you will like it the best.
If you just want a little bit more then get the 1150 head and have a Nicely ported street port done on it and keep the valves stock it will work as good as your 1100 head with 1mm over valves
The 1150 head is just so much bigger you can go 29.5/24 in the stock seats. The ports are larger with more meat to work with.
A 1150 head set up with 29.5/24mm valves with a Nicely ported head work some good valve springs at least but I always recommend and use on all my own head builds is titanium retainers because with the titanium retainers you are lighting up the valve train enough to lower the seat spring pressure and that will add life to the rockers, cams, and the tips of the valves plus allow you to use larger cams safely. I would also recommend some good cams to go with it. Something in the 370/350 range.
It depends on what all your looking to achieve for the mods.

[stetracer]

Beware of who you have do your head it is easy to make it go slower if you don't port it right. I have seen some car guys mess up heads taking material off the bottom of the port.
Here is a pic of a Nicely Ported 1150 head that is on my 85 GS1150 1198cc motor. This head has 29.5mm intakes and 25mm exhaust with epoxy floors the seats had to be changed to run the 25mm exhaust valves. I did this because I like a bigger exhaust valve and don't like the exhaust valve much smaller than 5mm of the intake valve especially when your sprayin it with a 90hp shot of No2.

[nastyjones]

Wow, thanks for such a comprehensive reply. The motor will be street driven with an occasional trip down the strip. I'm reluctant to epoxy the floors because 99% of my riding will be on the street & I understand epoxy won't stand up to daily driving.
My machinist is one of the best bike motor builders here in Canada. He has built a top fuel bike and built my 9 second GS1000 years ago so no worries.
Now that you know where the bike will be driven, do you still recommend cams in the 370/350 range?

[stetracer]

Wow, thanks for such a comprehensive reply. The motor will be street driven with an occasional trip down the strip. I'm reluctant to epoxy the floors because 99% of my riding will be on the street & I understand epoxy won't stand up to daily driving.
My machinist is one of the best bike motor builders here in Canada. He has built a top fuel bike and built my 9 second GS1000 years ago so no worries.
Now that you know where the bike will be driven, do you still recommend cams in the 370/350 range?

I have never had a problem with epoxy falling out. But You don't have to go that extreme with the epoxy floors.
I would still get a 1150 head open it up to 36.5mm port and if your budget allows for it do the 29.5/24mm stainless valves some good springs and titanium retainers set the seat pressure at 45lbs and mill .040 off it. some HD1150 cylinder studs add some 370i/350e lift cams set at 107i/109e some pistons would help 1166cc 10to1 would work good with this head a 1260cc 10to1 would be best and if you can find a set of the 38mm CV carbs they put on the gixxers back in the day they were air/oil cooled. It would make for a nice street bike motor. Oh don't forget to weld up the crank and the clutch basket. And you might as well under cut the tranny while your in there. Some good case studs would be a good thing to add also

[nastyjones]

Wow, You just spent my next 10 years of bike budget, lol.

[mr wu]

[QUOTE=stetracer;1916319]I have never had a problem with epoxy falling out. But You don't have to go that extreme with the epoxy floors.
I would still get a 1150 head open it up to 36.5mm port and if your budget allows for it do the 29.5/24mm stainless valves some good springs and titanium retainers set the seat pressure at 45lbs and mill .040 off it. some HD1150 cylinder studs add some 370i/350e lift cams set at 107i/109e

So what kind of $$$'s for this set up ???? Ballpark figure ???

[stetracer]

[QUOTE=mr wu;1916478]

I have never had a problem with epoxy falling out. But You don't have to go that extreme with the epoxy floors.
I would still get a 1150 head open it up to 36.5mm port and if your budget allows for it do the 29.5/24mm stainless valves some good springs and titanium retainers set the seat pressure at 45lbs and mill .040 off it. some HD1150 cylinder studs add some 370i/350e lift cams set at 107i/109e

So what kind of $$$'s for this set up ???? Ballpark figure ???

About $4 grand going with the 1260cc pistons and if you do all your own work

[rapidray]

Mr. Wu, this is a shot of a head I am doing now. Ray.

[rapidray]

Here is another shot. Ray.

[rapidray]

And another. This one shows the epoxy in the roof before I started shaping it. I haven't done the floors yet but you can see how much I am raising the ports with these spigots. Never had any of THIS epoxy ever come loose in all the years I've been using it. Ray.

[rapidray]

This is going on a 1640 motor, with flat top pistons for bracket racing. The spigots are 44mm inside diameter & the valves will be 31mm intakes & 28mm exhausts. With 44mm Lectrons & 12-1 compression it should run easy 8.20s in the quarter at about 165-168 mph. I do the same work on street motors, on a smaller scale of port mind you, but have never had an issue with the epoxy. I'll add more photos after I get the epoxy in the floors too. Ray.

[rapidray]

This is the epoxy I use. Ray.

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=11151&productId=1000665&langId=-1

[GregT]

Nice work...

How long does that stuff keep, Ray ? Devcon is available here in NZ and is commonly used but it has a limited shelf life...

[rapidray]

I have never had the Valspar go bad before I ran out & had to order more. Ray.