Hawk Talk

[Ariel Red Hunter]

If you choose to re-make the Hawk into a corner scratcher, like I have been talking about, something is going to have to be done about the swing arm bushings. When you put your Geoff Duke face on, you won't like that hinged-in-the-middle feeling. Urethane bushings are better than what's in there - and bronze bushings will really tighten things up. Front fork oil up-graded to at least Dexron ATF. If you want it a little firmer, try Mercon ATF. I would try to find Ferodo lined pads for the brakes. Remember, if you put Ferodo pads on, you have to warm them up before you get real serious. This is why 175's, 200's and 250's are so much fun. You really get to run the little bastards as hard as you can without getting into serious trouble. Maybe that's why I loved my little Model 14 AJS so much. Just ride the heck out of it, and enjoy. The Model 14 wasn't perfect - it came with 17 inch wheels. Even so, it would get right on down the road. Somewhat the same engine as a Hawk but tuned pretty good right from the factory. My uncle raced a 350 "Cammy" AJS on the board tracks in the 1920's. It was fast, but fragile. His nickname for it was "the valve swallower". The world has made tremendous strides in metalurgy and lubricants since those days. Back to the Hawk-a-thon. Be sure to change the brake fluid to DOT 3 or better. If you want to spend the time and money, you could do some work on the camshaft, to get more overlap. Pull the head to make sure the valve seats are good. If you are going to be running a lot at continious high rpm, look after the valve springs. If you can find high octane fuel without ethenol in it, run that. Pay attention to spoke tension. And have fun.

[Ariel Red Hunter]

I thought I covered reducing friction pretty well, but I just remembered that when I visited Andy Kolbe's BSA/Honda shop in Woodland Hills, Calif., they were working on their Gold Star flat tracker. I think they were getting it ready for the Sacramento Mile. Sacto, we called it. Anyway they were testing various ways to grease the wheel bearings. They spent all afternoon and evening trying different bearing greases. They would grease it up, mount it on the bike, and have the same guy spin the wheel, and time it with a stopwatch until the wheel stopped. Vaseline was the winner. They replaced the modern spring type rubber seals with leather seals that they punched out on the spot. "I can't believe that made any difference" I said. "Oh yeah, the leather seals barely touch the axle, and the tire revolved about 2 minutes longer." That is what is known as taking pains.

[fredweb]

Originally Posted by Ariel Red Hunter

I thought I covered reducing friction pretty well, but I just remembered that when I visited Andy Kolbe's BSA/Honda shop in Woodland Hills, Calif., they were working on their Gold Star flat tracker. I think they were getting it ready for the Sacramento Mile. Sacto, we called it. Anyway they were testing various ways to grease the wheel bearings. They spent all afternoon and evening trying different bearing greases. They would grease it up, mount it on the bike, and have the same guy spin the wheel, and time it with a stopwatch until the wheel stopped. Vaseline was the winner. They replaced the modern spring type rubber seals with leather seals that they punched out on the spot. "I can't believe that made any difference" I said. "Oh yeah, the leather seals barely touch the axle, and the tire revolved about 2 minutes longer." That is what is known as taking pains.

Vaseline has a melting point of 99deg F. I wouldn't expect that to last long in a bearing. It will run out the bearing and probably catch fire after the bearing heats up. The grease being used isn't as important as how its used. If you want to reduce friction use lithium based grease and just barely coat the balls and race. I used to grease the bearings and then use compressed air to blow out the excess. This reduces friction and in turn reduces the heat generated. Vaseline is not a very good idea at all.

[Ariel Red Hunter]

Originally Posted by fredweb

Vaseline has a melting point of 99deg F. I wouldn't expect that to last long in a bearing. It will run out the bearing and probably catch fire after the bearing heats up. The grease being used isn't as important as how its used. If you want to reduce friction use lithium based grease and just barely coat the balls and race. I used to grease the bearings and then use compressed air to blow out the excess. This reduces friction and in turn reduces the heat generated. Vaseline is not a very good idea at all.

I didn't know lithium grease was available in 1960. They may have used the Vaseline for a benchmark. I've used Vaseline grease for this and that for years and never had melting at low temperature problems. I've used it on cows before for barb wire cuts, and their body heat is 104, I think. Anyway that's the number that sticks in my mind. I doubt the flash point for vaseline is anywhere near 99f.

[fredweb]

Originally Posted by Ariel Red Hunter

I didn't know lithium grease was available in 1960. They may have used the Vaseline for a benchmark. I've used Vaseline grease for this and that for years and never had melting at low temperature problems. I've used it on cows before for barb wire cuts, and their body heat is 104, I think. Anyway that's the number that sticks in my mind. I doubt the flash point for vaseline is anywhere near 99f.

The flash point for vaseline is around 200deg F. certainly low enough to be ignited by friction from a poorly lubed bearing. putting vaseline on a cow is a lot different than using it for a bearing grease. My point was that the grease used is less important than application and use provided that the grease actually stays on the bearing surfaces and prevents friction heat. anyone that uses vaseline for bearing grease is asking for trouble. I've only been a mechanical engineer for 25 years but what the hell do i know. go ahead and use vaseline. They will sell you all the bearings you want i suppose.

[Ariel Red Hunter]

Originally Posted by fredweb

The flash point for vaseline is around 200deg F. certainly low enough to be ignited by friction from a poorly lubed bearing. putting vaseline on a cow is a lot different than using it for a bearing grease. My point was that the grease used is less important than application and use provided that the grease actually stays on the bearing surfaces and prevents friction heat. anyone that uses vaseline for bearing grease is asking for trouble. I've only been a mechanical engineer for 25 years but what the hell do i know. go ahead and use vaseline. They will sell you all the bearings you want i suppose.

Hmmm. The flash point I found for Vaseline is stated at 182 degrees Centigrade to 221 degrees Centigrade.

[fredweb]

Originally Posted by Ariel Red Hunter

Hmmm. The flash point I found for Vaseline is stated at 182 degrees Centigrade to 221 degrees Centigrade.

You are correct. I F'd when i shouda C'd thats still around 400 F and thats still within practical range for a metal on metal friction. First theres smoke. THen theres fire. but way way way before that you have damaged bearings and maybe even a broken neck.