Hawk Talk

[hertz9753]

Originally Posted by Ariel Red Hunter

Good, you got it to work. I hope that will help you in your more "adventurous riding". I hope you eventually watch the other two as well. A lot of good tips on riding on there. Especially on using the clutch. Lucky you, your bike is about 150 pounds lighter than what those guys were learning on. Yes, folding foot rests are wonderful - except when you've got to get back down a steep hill you couldn't climb!

You right click on the video and left click on Copy video URL. When you want post the video here you right click and then left click on paste. I only post online with a computer because my phone makes me look like my ignition is retarded...

[Ariel Red Hunter]

Originally Posted by hertz9753

You right click on the video and left click on Copy video URL. When you want post the video here you right click and then left click on paste. I only post online with a computer because my phone makes me look like my ignition is retarded...

I think you explained all of that beautifully. The problem is - - I'm too stupid to understand it.

[Ariel Red Hunter]

I see that 2 of the three British WO films have been downloaded to various places here at C/R yesterday and today. I started Hawk Talk to get as much information as possible in one place, in order for people to have more success finding the info. I wish some one would help me out on this by downloading all three of them to this column. There is a lot of information in those videos, to help people all the way from "This is my first motorcycle" on up. I know the information is old, but I think 80% of it is still valid.

[hertz9753]

The power of the edit button. I also saw the other posts of those videos...

[Ariel Red Hunter]

Originally Posted by hertz9753

The power of the edit button. I also saw the other posts of those videos...

I know my computer is getting a little old, and maybe that's why I can't find the edit button on my keyboard.

[hertz9753]

Originally Posted by hertz9753

The power of the edit button. I also saw the other posts of those videos...

Originally Posted by Ariel Red Hunter

I know my computer is getting a little old, and maybe that's why I can't find the edit button on my keyboard.

When you make a post the edit button is on the bottom right next to quote and it looks like a pencil. There is also the multi quote button labeled MQ. You click that on every post in a thread that you want to reply to and click on quote on the final one.

[Ariel Red Hunter]

Way back when, in the 1920's there were two main manufacturers of motorcycle carburetors in England, Binks and Amac. The Amac was a variable venturi carb, like the keihin and the mikuni, except it required two lever control. One control lever (on the handle bars) lifted the air controlling piston, and the other raised and lowered the needle. The Binks had a better idling circuit and used emulsion tube control of low end mixture. Amac was the larger company and bought out Binks so as to be able to use their patents. They changed the company name to Amalagated Carburettors, Limited. Amal for short. within a year or two, they were able to utilise the emulsion tube idea in order to have a one lever carburetor. Then three or four years later, someone came up with twist-grip control. So endeth the lesson for today.
So, I was going through some old notebooks I was going to throw away, when I came across my old tuning notebook for the Amal GP carb fitted to my BSA Gold Star. I was going through it when I had an "Oh yeah" moment. Some other tuner had told me, and I wrote it down, on a simple main jet test. He called it the Roll-Off Test. This simple little test will tell you where you are at, main jet wise. First, get the engine well warmed up on your way to your favorite low travel, but high gear road. Now get well up into the power band in high gear. Apply full throttle. Keep it going like this for 3-4 seconds so that the carburetor is settled in and the engine pulling hard. Now rotate the throttle back to 7/8ths of it's wide open position. The pecularity of these style carburetors is they will richen up for about a second when you do this. So, if you get a tiny power surge, your main jet is too lean, or small. If the engine staggers slightly, or has a hard hesitation ( a hiccup), it's too rich. Simple, huh?

[OUTERLIMITS]

Originally Posted by Ariel Red Hunter

Way back when, in the 1920's there were two main manufacturers of motorcycle carburetors in England, Binks and Amac. The Amac was a variable venturi carb, like the keihin and the mikuni, except it required two lever control. One control lever (on the handle bars) lifted the air controlling piston, and the other raised and lowered the needle. The Binks had a better idling circuit and used emulsion tube control of low end mixture. Amac was the larger company and bought out Binks so as to be able to use their patents. They changed the company name to Amalagated Carburettors, Limited. Amal for short. within a year or two, they were able to utilise the emulsion tube idea in order to have a one lever carburetor. Then three or four years later, someone came up with twist-grip control. So endeth the lesson for today.
So, I was going through some old notebooks I was going to throw away, when I came across my old tuning notebook for the Amal GP carb fitted to my BSA Gold Star. I was going through it when I had an "Oh yeah" moment. Some other tuner had told me, and I wrote it down, on a simple main jet test. He called it the Roll-Off Test. This simple little test will tell you where you are at, main jet wise. First, get the engine well warmed up on your way to your favorite low travel, but high gear road. Now get well up into the power band in high gear. Apply full throttle. Keep it going like this for 3-4 seconds so that the carburetor is settled in and the engine pulling hard. Now rotate the throttle back to 7/8ths of it's wide open position. The pecularity of these style carburetors is they will richen up for about a second when you do this. So, if you get a tiny power surge, your main jet is too lean, or small. If the engine staggers slightly, or has a hard hesitation ( a hiccup), it's too rich. Simple, huh?

Does this same principle apply to a PZ or Mikuni carb used on the hawk?

[Ariel Red Hunter]

Originally Posted by OUTERLIMITS

Does this same principle apply to a PZ or Mikuni carb used on the hawk?

Absolutely! That is why I put it on here. Both the Mikuni and the Keihin round slide carburetors are clones of the Amal design.

[2LZ]

Originally Posted by hertz9753

The power of the edit button....

On a different note, depending on what PC I'm on, the edit button doesn't show up. It's true! Then, if it's there, sometimes it won't show the entire paragraph that I'd like to edit, just the first sentence or part of it.
It's weird...... I think my IT people at work are on to me. ;-)

[Ariel Red Hunter]

Must be getting close to winter, the number of posts has dropped for the last week or so. When I was in my forties, on our dairy farm in western Michigan, I somehow heard about a 500cc Triumph Trophy twin, high pipes and all. Three-hundred bucks later and it was mine. I used to take Sunday off, except for chores. So, after church and breakfast, I would ride all over that farm. Whole place totalled up to 600 acres, and a little less than half of it was woods. There were deer trails through the woods, and I used to ride them for a couple of hours on Sunday afternoons. Mucho fun. And those Triumph twins sounded so sweet without mufflers. I couldn't get too radical riding that bike, as I had cows to milk twice a day, plus normal farm work to do, so I couldn't risk getting injured. But I had a young friend "Party Time" Postma. He owned one of those 360 Yamaha's, and he rode like the wind, no cares, all balls. So I'm out doing little jumps and doing figure eights out in a hay field when he shows up. Yes I had just mowed and baled that hayfield during the week. Now I knew he was a better rider than me, or he just didn't worry about the consequences. After he cut a couple of hot laps on the Yamaha, I offered him the Triumph to ride. It had a good set of Dunlop Knobbies on it, and I had the carburetor just set up to really work. The carb. was an Amal Mono-Bloc, and those were really good carbs. So he asked me how do you ride it, and I told him it was heavier than what he was used to, so just kinda go with the flow. Very easy bike to ride fast, as long as you didn't try to get careless with it. So he rode it, faster and faster - man, that engine was really singing, and he had an ear to ear grin that was worth the price of admission alone. When he stopped by me, engine idleing as smooth as a hound dog drinking milk, he says "Wow, this thing is really fast, and s-o-o-o easy to ride!" Well he made my day, what else can I say. Thanks for the memory, Allen.

[Ghenghis]

I'll add a bit of info I read about intake spacer length. Says a lower geared quick revving motor does better with a shorter carb to head spacer length. The Hawk, mine at least, was geared far too low from the factory, it had 15/45 sprockets, I put a 17 on the front and I can tell zero difference in power, as in there was no loss of power, it made the bike far better to ride and greatly increased the top speed.

The 167FMM isn't a fast revving engine but it does make decent amounts of torque in it's mid range, so this is where we'd benefit most from our efforts to increase power, the 17/45 sprocket combo seems to do a good job of targeting this mid range power. My research says that a longer intake tube between the carb and head is exactly the type of setup you want for an engine that's a little slower revving. Since there is more mass of air/fuel flowing you get a better cylinder fill from that setup. Too long of a distance from carb to head and you'll get fuel pooling in the head. There's also some sciency bits, I'll quote them here:

The intake system on a four-stroke engine has one main goal, to get as much air-fuel mixture into the cylinder as possible. One way to help the intake is by tuning the lengths of the pipes.

When the intake valve is open on the engine, air is being sucked into the engine, so the air in the intake runner is moving rapidly toward the cylinder. When the intake valve closes suddenly, this air slams to a stop and stacks up on itself, forming an area of high pressure. This high-pressure wave makes its way up the intake runner away from the cylinder. When it reaches the end of the intake runner, where the runner connects to the intake manifold, the pressure wave bounces back down the intake runner.

If the intake runner is just the right length, that pressure wave will arrive back at the intake valve just as it opens for the next cycle. This extra pressure helps cram more air-fuel mix into the cylinder

Might be worth a shot to experiment with this. Also, the intake tube running up to the carb definitely benefits from keeping a uniform circumference throughout it's length. The Hawk airbox would seem to wreck any benefits gained from this as the tube opens up into a box. You'd be better off running the intake tube into the box and having a round style filter on the end of the tube, merely using the box to keep water/debris out, tossing aside the Hawk's lawn mower filter.

[hertz9753]

If you want a new a Uni Filter I have one or you could buy the K&N filter, seal it with grease on the bottom and sealing the top bracket is your choice.


http://www.knfilters.com/search/prod...d=3985091&rw=1

[Ariel Red Hunter]

Originally Posted by Ghenghis

I'll add a bit of info I read about intake spacer length. Says a lower geared quick revving motor does better with a shorter carb to head spacer length. The Hawk, mine at least, was geared far too low from the factory, it had 15/45 sprockets, I put a 17 on the front and I can tell zero difference in power, as in there was no loss of power, it made the bike far better to ride and greatly increased the top speed.

The 167FMM isn't a fast revving engine but it does make decent amounts of torque in it's mid range, so this is where we'd benefit most from our efforts to increase power, the 17/45 sprocket combo seems to do a good job of targeting this mid range power. My research says that a longer intake tube between the carb and head is exactly the type of setup you want for an engine that's a little slower revving. Since there is more mass of air/fuel flowing you get a better cylinder fill from that setup. Too long of a distance from carb to head and you'll get fuel pooling in the head. There's also some sciency bits, I'll quote them here:



Might be worth a shot to experiment with this. Also, the intake tube running up to the carb definitely benefits from keeping a uniform circumference throughout it's length. The Hawk airbox would seem to wreck any benefits gained from this as the tube opens up into a box. You'd be better off running the intake tube into the box and having a round style filter on the end of the tube, merely using the box to keep water/debris out, tossing aside the Hawk's lawn mower filter.

This is very true. When I wrote about Joe Craig (the man who was very responsible for Norton's death-grip on TT and GP racing for 20 years), I didn't get very far into the intake system length part of his dissertation. He spent years on a dynomometer testing everything you can imagine. You might want to go back through this column, Hawk Talk, and read what he had to say. Understand, from 1928 to sometime in the first third of the fifties, this is all he did. He was an engine man, and he only worked on one type of engine, what came to be known as the Norton Manx. The Manx was a single cylinder engine made for racing, in 350cc and 500cc sizes. All air-cooled singles share a certain heritage. We can learn much from other successful designs. I am going to try to find the "intake and induction factors" part of his interview, and print it up this afternoon.

[hertz9753]

http://www.ebay.com/itm/270761406708...%3AMEBIDX%3AIT

I can't remember who used that to mount a filter inside of the air box. He also used something else mount it to the carb.