My Hawk experience with a TT250 head on it.
 

So last night I finished up putting on the TT250 head on my Hawk after a long an painful trial and error trying to extract a broken exhaust stud out of the head.

When the TT250 head came I could tell it's casting was much better than the original Hawk, so I thought wow.....don't need to port this puppy....and I did'nt feel like it. Instead I looked at the original exhaust (Yeah I'm cheap, still use it) So I saw some room for improvement right at the neck of the header pipe, I opened up that and improved flow by quite a lot.

Now today was the 1st time I got to stretch it's legs on the highway, a hill that is a mile from my home I only managed 50mph indicated going up with my 17/50 sprockets. Tonight it did 58mph uphill indicated, HUGE increase in torque low down and mid. It really gets up to 65Mph fast now and then peter out, so I think I can get use my 44 I've got in the rear finally.

So I can post great findings with a TT250 head and a mild ported stock exhaust (Punched out baffles a long time ago)

now if you remove the cat it will really breath

Remove the cat for sure. No matter how good the TT250 head is, it can still benefit from port work. The results might be less dramatic but they would still be noticeable with the right carb and exhaust setup.

It is also a shame there couldn't be a comparison of just opening up the stock header pipe welds on the factory head. Between the weld intrusions at the flange and the cat, you can probably account for the majority of gains seen when installing the afternarket systems in place of the stock one.

P.S. You should include the pictures you took of the TT250 head for the other guys to see. ;)

Thank you. Very valuable information. ...ARH ;)

Remove the catalytic converter and you will see a big improvement. :D

I'll probably end up buying a full exhaust from flea bay/amazon when the times comes. But I'm excited about the wast improvement I got from the little I did. So these engines definitely has some potential still left in them, I guess the gamble will be a balance between reliability and output?

I'll post pictures of the TT250 head as soon as my google account has synced my phone up.

How will porting, cat removal, improved exhaust and best carb set up affect fuel consumption?

Hasn't hurt my fuel economy. 63 to 67 mpg

In my case, fuel economy suffered. That's because I can't stop myself from grabbing a handful of throttle every time I shift. The grin factor has gone way up. :D

TT250 head photos

https://photos.app.goo.gl/prcfUmTceBzhKxtS7

https://photos.app.goo.gl/FeuBQEkdsvauqKRH8

https://photos.app.goo.gl/9s7TjBUVmywHrQoD6

Block off plate made for air-injection port on TT250 head (Not present on Hawk 250 head).

https://photos.app.goo.gl/Sk7iJR2zxvGUfWmZ7

Improved thermodynamics should result in improved fuel economy - AT THE SAME SPEED - however, most of us have trouble restraining the right wrist from turning the loud handle UP!...ARH :yay:

I would love to see someone create an Arduino based $25 water-methanol kit that will work on that plated off injection port. Cooling & Mo Power in one SHOT!

You would end up with a very clean exhaust pipe and nothing more. That port goes directly into the exhaust.

Funny but I will give up MPG for WHP PDQ!!!! especially when your talking 60+

More Gas! More Air! ......More Fun!

Cool experiment. Thanks for sharing.

Curious, if you remove the CAT, will you then have lean issues?

I'd say you'd be fine with the cat removed, It will lean it out a tad bit but if it's like my Storm the muffler has enough restriction that it wouldn't need rejetting, mine ran fine for a few weeks with just the cat removed.

After fully opening the exhaust I had to go up in jet size a little.

Went for 170 miles today in new terrain with the Hawk, sure runs nice now. Got plenty of power

https://photos.app.goo.gl/9MExgnLJBEPNBwgW9
https://photos.app.goo.gl/yy8qRXAweuSkBELR8
https://photos.app.goo.gl/QcE3JhZ7g6or5Rat8
https://photos.app.goo.gl/QcE3JhZ7g6or5Rat8