Hawk250 Port & Polished Head

[JerryHawk250]

Originally Posted by Megadan

I am good at inspiring "Bad" ideas.

it's only a bad idea if it blows up. Lol. I Just had to grow a pair and go with it. I just can't Believe as long as this forum has been here no one has done this

[Megadan]

Originally Posted by JerryHawk250

it's only a bad idea if it blows up. Lol. I Just had to grow a pair and go with it. I just can't Belgrave as long as this forum has been here no one has done this

Eh, it won't blow up. It may have a theoretically shorter life-span with higher compression, but with that oil cooler on there that should be negated. These engines come with low compression and conservative ignition timing to go with their terrible ports.

Oh, and I am glad to see I am not the only one to beat up that exhaust valve guide lol. Hard not to with how tight that bowl area is.

[JerryHawk250]

Originally Posted by Megadan

Eh, it won't blow up. It may have a theoretically shorter life-span with higher compression, but with that oil cooler on there that should be negated. These engines come with low compression and conservative ignition timing to go with their terrible ports.

Oh, and I am glad to see I am not the only one to beat up that exhaust valve guide lol. Hard not to with how tight that bowl area is.

yeah I know it won't blow up. Lol the dual cooler setup will help more. The higher compression should make up for the conservative timing. It doesn't quiet have as much room to work with as a 6.0 Chevy head lol.

[Megadan]

I am definitely interested in your finished product.

I think most people haven't bothered to do this because it has yet to be quantified in any way, even if simply a "wow this is so much better" review after doing said work. With three of us now going down this path, and showing just how much room there is to grow with these heads, I think more will hop on board. I know there are many who wish the Hawk had a bit more power - heck I am one of them. This is a much cheaper way to get similar power to the OHC CB250 engine without having to spend hundreds on a complete engine swap. All while keeping the unquestionable durability of the OHV CG motors.

As I have said before. When I first started modding this bike, if I had known how bad the head was, I would have done this before anything else. While a de-cat or aftermarket exhaust definitely helps these engines breathe, you only feel it in the mid range. These engines are too restricted at the top end, and you can feel it when you wind them out. Even if just basic port work and no head milling gave an extra 2hp, I would have still done so.

[david3921]

Originally Posted by JerryHawk250

I took .040" off the head. Now waiting on keepers from CSC so I can put it back together. I have more pictures on my camera these are just a few I took with my phone.

Do you have to run premium now with higher compression?

[Megadan]

Originally Posted by david3921

Do you have to run premium now with higher compression?

It is definitely a good idea. These engines ran conservative timing and relatively low compression, so they could get away with regular. Taking 1mm off the head bumps it about a full point in compression to around 10:1.

[JerryHawk250]

I always run premium with no ethanol .

[pistolclass]

no corn oil... wish we had that up here in CT. everything is 10%. taking a run up to NH to see my property and pick up a hand carved wood sink/vanity. Wish it wasn't 2 degrees up there, I would hang the hawk off the truck and go for a little adventure.

[Ariel Red Hunter]

Originally Posted by pistolclass

no corn oil... wish we had that up here in CT. everything is 10%. taking a run up to NH to see my property and pick up a hand carved wood sink/vanity. Wish it wasn't 2 degrees up there, I would hang the hawk off the truck and go for a little adventure.

I don't know how close you live to the sea coast, but most marinas have ethanol free fuel available...ARH

[JerryHawk250]

Originally Posted by Ariel Red Hunter

I don't know how close you live to the sea coast, but most marinas have ethanol free fuel available...ARH

I live close to the coast so ethanol free fuel is available everywhere.

[Megadan]

The only way to reliably get ethanol free at most stations around me is to get premium fuel. Even that is no sure thing, but far easier to find than regular without ethanol.

I have gotten into the habit of adding Marine grade Stabil to my tanks when I fill. It does a great job of controlling moisture issues as well as slowing the degradation common from ethanol fuels.

[pistolclass]

I'm 20 minutes to long island sound. I never thought about getting it from a marina.i can be at one In 10 minutes. The CT river is close to my house and there is a marina every 1/4 mile to the mouth of the sound.

[JerryHawk250]

Originally Posted by Megadan

The only way to reliably get ethanol free at most stations around me is to get premium fuel. Even that is no sure thing, but far easier to find than regular without ethanol.

I have gotten into the habit of adding Marine grade Stabil to my tanks when I fill. It does a great job of controlling moisture issues as well as slowing the degradation common from ethanol fuels.

Conoco in our area is one of the few companies that offer ethanol free fuel only.

[JerryHawk250]

Just realized I never posted pictures of the intake.

[Megadan]

Yep, our intake sides turned out pretty similar, I think a bit of finish work with some 80 grit sanding rolls would be the only other thing I would do, just to smooth the walls out a bit.