Hawk Talk - Page 9

Jmcgee · 10-12-2016, 07:22 PM

Ok, I just read what he said, he is saying from the air box to carb to the head. at least that's what I understand from it.... and yes he is somewhat right but do the head too and it will get better flow if done correctly.

Ariel Red Hunter · 10-12-2016, 10:28 PM

Quote:

Originally Posted by Bruce's

I have read it ,and you clearly state do not polish the heads intake tract ,and near the bottom of the paragraph you clearly state the exact opposite to me ,cleaning up the intake tract all the way from where it begins to the head is the trick .In one sentence you say to clean it up is the trick ,the other sentence says don't polish it ,which at least to me ,is exactly how you clean up something like that .What is the difference between polishing an intake ,or cleaning one up to you ? to me ,it's the same thing ,but it appears you might have a different idea about it .Have you got any data from the Hawks you either did or didn't clean up the intake on for a comparison ?

You think TO THE HEAD means go ahead through the head? Cleaned up, well I didn't clean up any Goldstar heads. But others polished the intake passage on their Goldstar heads, and all I can tell you is the dyno showed no advantage to a finely polished head. Now as to cleaning up intake tracks on heads, that is pretty much a holdover from the days of cast iron heads and cylinders in the case of flatheads. Foundry technique has really improved out of all recognition since WW 2. Improved step by step until now. The only head that I had that needed an experts touch was the one on my AJS 350, which , according to the flow expert I consulted (Jerry Branch), was not strangled on the intake side, but was suffering from extreme constipation on the exhaust side. I think the average guy is well counseled to leave the head alone. If you want to do head work on your engine, make sure you can buy another head, because it is not difficult to screw one up. Do you need to ask how I found that out?

Ariel Red Hunter · 10-12-2016, 10:42 PM

Quote:

Originally Posted by Jmcgee

Ok, I just read what he said, he is saying from the air box to carb to the head. at least that's what I understand from it.... and yes he is somewhat right but do the head too and it will get better flow if done correctly.

Yes, but getting better flow in the head is the problem. It takes a real expert with a flow bench to really do the job right. And don't forget a bigger intake valve with the right under valve head tulip shape all helps intake flow. But this whole thing is an expensive road to go on.

Jmcgee · 10-12-2016, 10:48 PM

Quote:

Originally Posted by Ariel Red Hunter

Yes, but getting better flow in the head is the problem. It takes a real expert with a flow bench to really do the job right. And don't forget a bigger intake valve with the right under valve head tulip shape all helps intake flow. But this whole thing is an expensive road to go on.

Getting more flow in the head does not take a flow bench.... if you want modern day John Force flow yes, but old school drag racers done it by hand without a flow bench... bigger hole, smoother edges = more flow

Jmcgee · 10-12-2016, 11:08 PM

This is an old school air cooled single cylinder, you don't have to worry about matching the flow in the ports, you don't have to worry about hitting water jackets.

Now you can't get stupid with the die grinder but it can easily be done if you are partially competent with a die grinder (Dremel).
it's actually easy, look it up on google and youtube, with car heads it's basically the same thing. Open the hole a little, smooth the edges get flow.

if you get silly and remove too much and open a hole you can possibly ruin a head, but drag racers have used epoxy to reshape ports so if you don't hit the valve seat you could still save the head.

Ariel Red Hunter · 10-14-2016, 11:42 AM

Exhausting, this thread, Huh? But plenty of good opinions have been posted on here, and I want to thank everyone of you who have been involved in this thread. I once upon a time was a newspaperman, so I tend to think of my work here as a column, and responses to it as commentary. And all of you as readers. I think the exhaust side of the Hawk is where the biggest gains can be made. There are more manufacturing flaws in the stock exhaust system than can be believed. Once the exhaust valve opens, the first order of business is to get it out of the engine as quickly as possible. Start with what they are using for an exhaust gasket. Whatever it is made of, raggety bits of it hang out in the exhaust stream right at the joint between the head and the head pipe. First thing I would do about that is replace that gasket with a copper o-ring from a Honda 230. Next comes that head pipe. All the photographs of the inside of that pipe that I have seen are a gas flow disaster. Sloppy bubble gum welds on the inside of the head pipe cause turbulence in the exhaust gas flow. Turbulence in the exhaust pipe acts to restrict the gas flow. Next comes the catalytic converter. It is too small. And thus even more restriction in the exhaust pipe. I know why they put it there. They use less very expensive platinum that way. So, I would put a mandrel bent head pipe there to replace the stock one. Next comes the muffler. I don't know enough about the muffler because the pipe leading to it is so bad, I can't tell if the muffler is another restriction or not. But I would buy one of those complete exhaust systems, along with the copper o-ring gasket, and put it on. Now I would definatley plan to re-jet the carburetor, because with less back pressure, and improved flow, it will run too lean. You've already adjusted the valve clearances, I hope. Combined with the work you did on the intake side, it ought to be a runner.

Ariel Red Hunter · 10-16-2016, 09:51 AM

Restrictions in the head pipe do not just cause reduction of exhaust flow. It also raises the temperature of the exhaust valve, the head, and the oil temperature. Not good, huh?

So, let's review what we have either done, or at least thought about doing. The engine/transmission package, including air-box through muffler has been streamlined as much as we can in order to get a greater weight of fuel/air mixture through the engine per power stroke, or two revolutions. We have changed the front fork oil to the flavor of your choice. You have changed the brake fluid to D.O.T. 3 or 4. You have the tires on it, front and rear that suits your riding style, as well as the terrain you routinely ride on. You have installed rim locks so that you can run low air pressures off road. You may have even gone so far as to use co2 in the tires, because Pete told us how it allows low pressure off road, where the tires stay cool, but expands and raises tire pressure when the tires heat up, like on road riding. You keep your spokes tight. You check, and correct, if necessary, tire alignment. You watch very closely the swing arm bushings, which tend to go bad very quickly. When they go bad, a simple machine shop job on the swing arm lets you change to roller bearings. You have made sure that the front and rear axles and the swing arm bolt are well greased. You make sure that the motor mount bolts stay tight. Locktite really helps with this. Also brake caliper bolts need the same attention. That's all I can think of for now. M-r-r- a-ha-ha-ha.

BlackBike · 10-16-2016, 03:43 PM

Quote:

Originally Posted by Ariel Red Hunter

Restrictions in the head pipe do not just cause reduction of exhaust flow. It also raises the temperature of the exhaust valve, the head, and the oil temperature. Not good, huh?

So, let's review what we have either done, or at least thought about doing. The engine/transmission package, including air-box through muffler has been streamlined as much as we can in order to get a greater weight of fuel/air mixture through the engine per power stroke, or two revolutions. We have changed the front fork oil to the flavor of your choice. You have changed the brake fluid to D.O.T. 3 or 4. You have the tires on it, front and rear that suits your riding style, as well as the terrain you routinely ride on. You have installed rim locks so that you can run low air pressures off road. You may have even gone so far as to use co2 in the tires, because Pete told us how it allows low pressure off road, where the tires stay cool, but expands and raises tire pressure when the tires heat up, like on road riding. You keep your spokes tight. You check, and correct, if necessary, tire alignment. You watch very closely the swing arm bushings, which tend to go bad very quickly. When they go bad, a simple machine shop job on the swing arm lets you change to roller bearings. You have made sure that the front and rear axles and the swing arm bolt are well greased. You make sure that the motor mount bolts stay tight. Locktite really helps with this. Also brake caliper bolts need the same attention. That's all I can think of for now. M-r-r- a-ha-ha-ha.

Spokes...check here

POW ! IMPALEMENT GOES THE INNER TUBE AT 50MPH .. man speaks the truth

Ariel Red Hunter · 10-17-2016, 04:57 PM

Brooklands was a race track built in a suburb of London, England. In the course of time, houses crept closer and closer to Brooklands. Noise! OMG! We must do something! So, in order to race there, some kind of muffler had to be put on the machines. Eventually, in order to be fair to everyone racing there, a standard silencer was designed, and, wonder of wonders, the bikes were actually faster with the muffler on than with a straight pipe. I don't see why you can't make one for your Hawk, if the spirit so moves you. So, think of a trapazoidal metal can, with the exhaust pipe going into the can at the lower front corner. It has been found that the exhaust pipe should stick into the can 2 inches. Now the most critical part. The volume of the can must be 6 times the swept volume of the engine. E.g. 1500cc's or a quart and a half. Next, the exhaust goes out the diametrically opposed corner, or, the upper rear corner. This pipe also goes in 2 inches, and comes out to a fishtail with many holes drilled in it. Perhaps the more astute of you have already figured that if you make that final exhaust pipe out of a short nipple, a little bigger than the inlet pipe, you could mount a spark suppressing screen, 4 - 6 inches long in there. Using the fishtail to screw it in or out. Be sure to coat those threads with that heat resistant permatex thread compound, to make it easy to unscrew it on demand. For you guys who have a tig or mig welder, this is pretty simple. You could even make it out of 1/8 inch aluminum, and pop rivet it together. Just use the marine type pop rivets as they have solid heads. I can hear it now "ARH has finally blown a gasket". "ARH is crazier than a bedbug with the clap."

pete · 10-18-2016, 01:31 AM

meany meany moons ago....
when I was racing Speedway TQ Midgets they bought in the 98db rule
The best way to quiten them down was use a V8 car muffler the big oval buggers..
there was no power lose as the volume of the muffer was more than able to flow
all the gases from a Suzuki GSXR 750...

they also tryed the same with the solos " speedway bikes" but that diddn't
fly as it is a international class with rules set in stone and with a 9 times world champ
reading them the riot act they backed down real fast...

..

..

Ariel Red Hunter · 10-18-2016, 02:56 PM

I just had a flash. If you used a Dremel type tool to cut out the sides of the fishtail, and either welded or pop riveted the spark arrester screen on the inside of the fishtail, you're spark arrester problems would be solved. What do you guys think of that idea?

Jmcgee · 10-20-2016, 08:18 PM

Tinkering, I found a massive restriction in the little "carb to head" intake runner, felt like 3/16 at the top that port match would open up for more flow.

Ariel Red Hunter · 10-20-2016, 10:17 PM

Quote:

Originally Posted by Jmcgee

Tinkering, I found a massive restriction in the little "carb to head" intake runner, felt like 3/16 at the top that port match would open up for more flow.

I wrote about that whole subject a few days ago, but I never specifically called out the intake runner. My bad, sounds like. You found this mismatch at the head end of the plastic runner?

Jmcgee · 10-20-2016, 10:19 PM

Quote:

Originally Posted by Ariel Red Hunter

I wrote about that whole subject a few days ago, but I never specifically called out the intake runner. My bad, sounds like. You found this mismatch at the head end of the plastic runner?

I believe its aluminum,it is between the carb and the head. Where my jap bikes have rubber carb holders.

Ariel Red Hunter · 10-20-2016, 11:15 PM

Quote:

Originally Posted by Jmcgee

I believe its aluminum,it is between the carb and the head. Where my jap bikes have rubber carb holders.

Oh? Maybe they up-graded to aluminum. The earlier ones had a plastic (phenolic?) spacer, from what I've seen on various youtube videos.

10-14-2016, 11:42 AM	#126
Ariel Red Hunter Join Date: Jun 2016 Location: akwesasne, NY-13655 Posts: 2,220	And the discharge side. Exhausting, this thread, Huh? But plenty of good opinions have been posted on here, and I want to thank everyone of you who have been involved in this thread. I once upon a time was a newspaperman, so I tend to think of my work here as a column, and responses to it as commentary. And all of you as readers. I think the exhaust side of the Hawk is where the biggest gains can be made. There are more manufacturing flaws in the stock exhaust system than can be believed. Once the exhaust valve opens, the first order of business is to get it out of the engine as quickly as possible. Start with what they are using for an exhaust gasket. Whatever it is made of, raggety bits of it hang out in the exhaust stream right at the joint between the head and the head pipe. First thing I would do about that is replace that gasket with a copper o-ring from a Honda 230. Next comes that head pipe. All the photographs of the inside of that pipe that I have seen are a gas flow disaster. Sloppy bubble gum welds on the inside of the head pipe cause turbulence in the exhaust gas flow. Turbulence in the exhaust pipe acts to restrict the gas flow. Next comes the catalytic converter. It is too small. And thus even more restriction in the exhaust pipe. I know why they put it there. They use less very expensive platinum that way. So, I would put a mandrel bent head pipe there to replace the stock one. Next comes the muffler. I don't know enough about the muffler because the pipe leading to it is so bad, I can't tell if the muffler is another restriction or not. But I would buy one of those complete exhaust systems, along with the copper o-ring gasket, and put it on. Now I would definatley plan to re-jet the carburetor, because with less back pressure, and improved flow, it will run too lean. You've already adjusted the valve clearances, I hope. Combined with the work you did on the intake side, it ought to be a runner.
	1

10-16-2016, 09:51 AM	#127
Ariel Red Hunter Join Date: Jun 2016 Location: akwesasne, NY-13655 Posts: 2,220	Un-finished phrase and other stuff. Restrictions in the head pipe do not just cause reduction of exhaust flow. It also raises the temperature of the exhaust valve, the head, and the oil temperature. Not good, huh? So, let's review what we have either done, or at least thought about doing. The engine/transmission package, including air-box through muffler has been streamlined as much as we can in order to get a greater weight of fuel/air mixture through the engine per power stroke, or two revolutions. We have changed the front fork oil to the flavor of your choice. You have changed the brake fluid to D.O.T. 3 or 4. You have the tires on it, front and rear that suits your riding style, as well as the terrain you routinely ride on. You have installed rim locks so that you can run low air pressures off road. You may have even gone so far as to use co2 in the tires, because Pete told us how it allows low pressure off road, where the tires stay cool, but expands and raises tire pressure when the tires heat up, like on road riding. You keep your spokes tight. You check, and correct, if necessary, tire alignment. You watch very closely the swing arm bushings, which tend to go bad very quickly. When they go bad, a simple machine shop job on the swing arm lets you change to roller bearings. You have made sure that the front and rear axles and the swing arm bolt are well greased. You make sure that the motor mount bolts stay tight. Locktite really helps with this. Also brake caliper bolts need the same attention. That's all I can think of for now. M-r-r- a-ha-ha-ha.
	0

10-17-2016, 04:57 PM	#129
Ariel Red Hunter Join Date: Jun 2016 Location: akwesasne, NY-13655 Posts: 2,220	Brooklands Cans. Brooklands was a race track built in a suburb of London, England. In the course of time, houses crept closer and closer to Brooklands. Noise! OMG! We must do something! So, in order to race there, some kind of muffler had to be put on the machines. Eventually, in order to be fair to everyone racing there, a standard silencer was designed, and, wonder of wonders, the bikes were actually faster with the muffler on than with a straight pipe. I don't see why you can't make one for your Hawk, if the spirit so moves you. So, think of a trapazoidal metal can, with the exhaust pipe going into the can at the lower front corner. It has been found that the exhaust pipe should stick into the can 2 inches. Now the most critical part. The volume of the can must be 6 times the swept volume of the engine. E.g. 1500cc's or a quart and a half. Next, the exhaust goes out the diametrically opposed corner, or, the upper rear corner. This pipe also goes in 2 inches, and comes out to a fishtail with many holes drilled in it. Perhaps the more astute of you have already figured that if you make that final exhaust pipe out of a short nipple, a little bigger than the inlet pipe, you could mount a spark suppressing screen, 4 - 6 inches long in there. Using the fishtail to screw it in or out. Be sure to coat those threads with that heat resistant permatex thread compound, to make it easy to unscrew it on demand. For you guys who have a tig or mig welder, this is pretty simple. You could even make it out of 1/8 inch aluminum, and pop rivet it together. Just use the marine type pop rivets as they have solid heads. I can hear it now "ARH has finally blown a gasket". "ARH is crazier than a bedbug with the clap."
	0

10-18-2016, 01:31 AM	#130
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,261	meany meany moons ago.... when I was racing Speedway TQ Midgets they bought in the 98db rule The best way to quiten them down was use a V8 car muffler the big oval buggers.. there was no power lose as the volume of the muffer was more than able to flow all the gases from a Suzuki GSXR 750... they also tryed the same with the solos " speedway bikes" but that diddn't fly as it is a international class with rules set in stone and with a 9 times world champ reading them the riot act they backed down real fast... .. .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
	0

10-18-2016, 02:56 PM	#131
Ariel Red Hunter Join Date: Jun 2016 Location: akwesasne, NY-13655 Posts: 2,220	Spark arrester for a Brooklands "Can". I just had a flash. If you used a Dremel type tool to cut out the sides of the fishtail, and either welded or pop riveted the spark arrester screen on the inside of the fishtail, you're spark arrester problems would be solved. What do you guys think of that idea?
	0

10-12-2016, 07:22 PM	#121
Jmcgee Join Date: Sep 2016 Posts: 86	Ok, I just read what he said, he is saying from the air box to carb to the head. at least that's what I understand from it.... and yes he is somewhat right but do the head too and it will get better flow if done correctly.
	0

10-12-2016, 11:08 PM	#125
Jmcgee Join Date: Sep 2016 Posts: 86	This is an old school air cooled single cylinder, you don't have to worry about matching the flow in the ports, you don't have to worry about hitting water jackets. Now you can't get stupid with the die grinder but it can easily be done if you are partially competent with a die grinder (Dremel). it's actually easy, look it up on google and youtube, with car heads it's basically the same thing. Open the hole a little, smooth the edges get flow. if you get silly and remove too much and open a hole you can possibly ruin a head, but drag racers have used epoxy to reshape ports so if you don't hit the valve seat you could still save the head.
	0

10-20-2016, 08:18 PM	#132
Jmcgee Join Date: Sep 2016 Posts: 86	Tinkering, I found a massive restriction in the little "carb to head" intake runner, felt like 3/16 at the top that port match would open up for more flow.
	0