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H1 frames

This is a discussion on H1 frames within the General forums, part of the Caferacer.net Forums category; I found myself reading Kevin Camerons thesis on the Kawi H2-R http://www.mojokawasaki.com/history/...nsidelook.html , I have to read it at least once a year. I bounced ...

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Thread: H1 frames

  1. #1
    Senior Member magnetoczar's Avatar
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    H1 frames

    I found myself reading Kevin Camerons thesis on the Kawi H2-R http://www.mojokawasaki.com/history/...nsidelook.html , I have to read it at least once a year. I bounced my R5 frame for one of my H1 engines off him. He's always interesting and obliging. Thought I might share his thoughts with you guys, something to pass the winter doldrums by a bit more quickly.

    Kevin,
    So here I am with two good H1 engines, one breathed on and one a stocker. Engines that were to power a USCRA sidecar, but now due to many things (the birth of another son is one of them), racing is out of the picture for awhile, if not forever. However, being of the "gotta' fettle" ilk, I am looking at an R5 roach that I possess and the engines and thinking, hmmm. I just got done reading your article on the Kawi RR'ers for the 2nd or 3rd time, and I see that you thought the Kawi frame was alright. I look at it and see it as a heavy ill-conceived frame. To begin with, the top head steady runs back to a T, not at the juncture where it would connect directly to the two side tubes that run down to the swingarm mount, but rather 6 inches before that place, and then there's bends in the top tubes after that(?) Wouldn't I be better off with the R5 frame, say with a reinforced swingarm, as the R5 is of Yami racing heritage as I understand it. Seems a bit lighter and more compact, also. I'm looking to build some kind of a neat cafe bike to take out on a Sunday morning and smoke the young squids on their modern sportbikes.

    What do you think, if I may bother you for your thoughts. Oh, and I have both the CD and points set-ups. Someone told me the 72's with the points were a bit hotter than the later engines (the stepped on engine I have is a 72'). Were the points one of the reasons the 72's were hotter, assuming this is true?

    Thanks,
    Doug

    The 1972 engines were not emasculated in their porting in order to make the Z1 look better.

    You are of course quite right that on the 500 H1-R chassis, the top steering head "brace", because it Tees into a crosstube, is quite useless. This is a feature of many chassis copied from the original 1950 McCandless Norton racing design, but in that original, the top tube brace ran to the engine cylinder head, which was bolted into the frame tubes, making quite a stiff arrangement. By 1976 Kaw and Suz were running a pair of tubes back from the top of the steering head, each joining a tank tube at the point that it curved downward. Thus these top tubes and the normal tank tubes, with the head, formed
    triangles that in the 1980s would evolve into the twin aluminum beams of today's most common chassis type - the Kobas.

    Even with the 1971 350 Yamaha, Kel Carruthers and Don Vesco moved the engine ahead a couple of inches - as a means of putting more weight on the front tire so the bike would not run wide as it accelerated out of turns. Therefore simply shoe-horning a 500 triple into an RD chassis might make an unnecessarily exciting ride. I think the stock 500 production chassis was usually crooked, since they completed the welding on one side, then moved on to the other side.

    How is that little boy who was so enthusiastic about propellers?

    KC

    Kevin,
    Sounds like I either I have to find a 76' H1 frame, or simply make the R5 swingarm an inch or so longer, which might also be helpful in keeping the front wheel on the ground.

    Should I use the CDI or the points (?), I have both.

    You might have me mixed up with someone else concerning the propellers, and that might be an interesting study in and of itself, propellers that is. Someone should write a book concerning trials and tribs' of them, seems they became quite an art. That whole WW2 thing with the radial engines and variable pitch props is like Lord of the Rings stuff to me; HUGE engines of single, double, or triple rows of supercharged air-cooled cylinders attached to propellers the size of the wind harvesters of today. I visited the Curtis Museum this summer and they had a double row Pratt and Whitney (I believe) sitting on the floor. No airplane could possibly fly with something that big in its nose.

    When I gaze upon and consider the amount of work and time that goes into the development of the state of the art technology of even 60 years ago, the huge blocs of time, effort and money that was sown in to obtain a vermacht, I am in awe. On the one hand I love the fabulous machines what with their unique sounds, fabulous hp and torque figures, and all the idiosynchrocies that cause them to seem to have souls and be alive, and on the other hand it bothers me that so many of them lived such short lives and ended their lives slamming into the earth or at the bottom of the ocean. What a waste.

    A friend of mine brought a boom box and a tape of radial engined pylon racers to the bike shop back awhile ago; what were they, the Ju Ju bee's or something. The sound of one of those fat little radial engined planes approaching the microphone was unbelievable! All you heard was this fabulous induction sound followed by the WAAAAAAA as the plane passed over. Wouldn't want to pay the maintenance bill on one of them.

    I have a two year old son, Cole; very, very interested in all things mechanical. Show him once and he's got it. And just last Wednesday I had my second boy, Gus. At 55 I am now done breeding and will have the snip-snip done.

    Somebody's got to make some new people though; the young people are sure slacking in that department -

    Doug

    The Curtiss Museum is good - I plan to go back soon for another sniff
    'round. I've made a bit of a study of his career.

    There were three basic US prop layouts in WW II - the Hamilton-Standard Hydromatic (the ones with the big, spherical-ended dome at the center), the Curtiss Electric (these had a more nearly pointed aluminum fairing over an electric pitch-changing mechanism), and the Aero Products, which seems to have no hub at all. You're right - not enough has been done with that historical subject.

    I thought it was your little boy who looked into our living room and saw the two-bladed prop sitting there and exclaimed "Propeller!".

    In the war, a Merlin V-12 might run for 250 hours but, in the commercial flying that followed, engines such as the P&W R-2800 and Bristol Herc achieved TBOs of 3-4000 hours. The same basic engine, subjected to differing duty cycles, might last 10X longer in commercial than in SAC use.

    Today, the large fan engines in airliners are given just enough throttle during take-off to give required margins, given the runway length, all-up weight, and air density. What ages a jet is the same as what damaged piston engines - time at temperature. The best engines today TBO at 25,000 hours and they are planning the next generation to last just as long as the airframe, or 50,000-hr (the B747 that was Flight 800 had 93,000 flight hours).

    But in 1949, with 2000 of the new J-47s in service on B-47 bombers, TBO was running 17 hours!

    I'd certainly rather use the CDI, because its timing doesn't depend on
    exactly how the crank happens to be whipping at the moment.

    KC



  2. #2
    Moderator jbranson's Avatar
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    Talk about a propeller head...damn that guy knows something about everything!
    JohnnyB


  3. #3
    Senior Member Geeto67's Avatar
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    I thought you were putting an h1 engine in a rz frame, I didn't realize you were talking about an R5 like the precursor to the rd350 frame - a frame I personally don't look all that highly on. If you want to put an h1 motor in a lighter frame you could try putting it in a kh400 frame (since the s3 frame was the most balanced frame kawasaki made) or something more modern like an fzr400 frame.

    That exchange is really interesting, Mr. Cameron has probably forgotten more about motorcycle and aircraft engineering then I can ever hope to learn.

    and you can look up the specs for an h1 to see why the earlier ones were faster than the later ones (mostly timing and carbs, with the exception of the 69 bridgeport cylinders the porting was the same on all the h1s). They switched to points on the 72 for reliability not power, the early h1 boxes has a limited life and made a nasty buzzing sound, later ones were a better design:

    http://kawtriple.com/mraxl/




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  5. #4
    Senior Member magnetoczar's Avatar
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    well, I have the R5 so that's a strong point for putting an H1 in one, but as I understand it, the R5 was a copy of that periods Yami race frame and actually had a steeper head angle than the later Rd frames. They seem to be able to handle 60 or 70 ponies that you can squeeze out of an RD engine, so they should be able to handle what that engine will throw at them. And if I perhaps add a little to the lower tubes and bring the engine up an inch, then make the swingarm a bit longer and brace it, it should be decent. This is all stuff that I am thinking of doing, I haven't commited to it yet. I like to get plenty of opinions before I do something and I certainly respect what you have to say. Later air-cooled 2 strokes are something new to me as my forte is more with the old Brit stuff.

    Dgy


  6. #5
    Senior Member Camelhairy's Avatar
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    quote:
    well, I have the R5 so that's a strong point for putting an H1 in one, but as I understand it, the R5 was a copy of that periods Yami race frame and actually had a steeper head angle than the later Rd frames. They seem to be able to handle 60 or 70 ponies that you can squeeze out of an RD engine, so they should be able to handle what that engine will throw at them. And if I perhaps add a little to the lower tubes and bring the engine up an inch, then make the swingarm a bit longer and brace it, it should be decent. This is all stuff that I am thinking of doing, I haven't commited to it yet. I like to get plenty of opinions before I do something and I certainly respect what you have to say. Later air-cooled 2 strokes are something new to me as my forte is more with the old Brit stuff.

    Dgy
    Dgy,
    I wouldn't bother with the R5 frame. After all Kevin said about the H2 frame being good, I built 2 frames/swing arms for him. We moved the motor as far forward as the wheel would allow and also lowered it and brought the rake back a few degrees. The SA was built up of 16 ga sheet metal. The TD2 frames were OK but the front end pushed pretty bad, especially for a light rider that couldn't pull his weight up on the tank. A beer belly helped a lot....or a fat head. The main problem with the H1 is a junk SW. Brace it like I did to Rocky's and box in the cross brace. I don't think the rest of the frame will cause any problems, but it wouldn't hurt to box in around the SH if you want and lenghtening the SA a couple of inches would get some more weight on the front end...or stop exercising and gain 20 lbs.

    FC


  7. #6
    Senior Member magnetoczar's Avatar
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    Thanks FrankC. Given yours and Geeto's advice, I will trash my R5 plans and go with a modified H1 frame.

    Dgy


  8. #7
    Senior Member Geeto67's Avatar
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    quote:
    Thanks FrankC. Given yours and Geeto's advice, I will trash my R5 plans and go with a modified H1 frame.

    Dgy

    how far away from NYC is sand lake ny? If you feel like making a trip one weekend I'll go over all the frames I have (1971-1976) and some of the race braced parts I have.

    I have to add that the H1R and H2R racing frames are completely different from the street h1 and h2 by the way. None of the parts are interchangable from the R to the street bikes and the "R" frames were built with a view toward strength rather than weight since the H2Rs were approaching 100rwhp. Denco built 90 and 110 hp street bikes and with mild gussetting they were potent street performers on stock street frames. The early H1R frames were too flexible because initially kawasaki sought to make them ligher than stronger, Kenny Roberts used to complain that his 69 H1R wanted to spit him off on every turn. By the time they got to the 76 kr750LC (yes it was liquid cooled) the frame was sorted but the days of the two stroke 750s belonged to the TZ750 and kawasaki would have had to redesign or give up.

    with proper gussetting you could potentially put 80-90 rwhp through an s3 frame, which is why the h1 into s3 frame swap is popular (it does require a little fab on the mounts as the s3 is narrower than the h1).



    Edited by - Geeto67 on Jan 28 2006 2:12:20 PM

  9. #8
    Senior Member magnetoczar's Avatar
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    I'm like 3 hours up the road (just a bit east of Albany). I'll probably just go with the 73' that I have an follow the gusseting stuff that's online. I'd like to buy a 76', if you or anybody has one for sale.

    Thanks,
    Dgy


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