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Post by Walms on Feb 19, 2016 18:40:20 GMT -5
+1
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Post by Ned on Feb 19, 2016 18:50:01 GMT -5
Nice to see Jorgen and John playing nice You need to start another thread. That was entertaining.
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Post by speedgeeza on Feb 19, 2016 19:32:43 GMT -5
Yarn Part 2 Tea break over, it was back to work in the "deep strip" bay for the two "super heros" along with more "Lording" it over fellow apprentices with an air of superiority . A little time later, the chief tech from the test house was back, with a rather concerned look on his face. "Would either of the two mechanical Geniuses like to come and start "their" engine for the second part of the pass off test? Just a head up, it's seized solid!" Oh dear... Word spread quickly and revenge was swift, if not harsh! The engine is started with the use of an airstarter which drives the external gearbox, providing rotation to the hp side of the engine. The airstarter (60,000rpm) looks very much like a turbo charger, driven by bleed air from a miniature gas turbine located on the back spine of the aircraft. But in the test house, a large roots type compressor feeds a massive accumulator for the job. Drive between the airstarter and the gearbox is transferred by a quill shaft which has a waisted section in the middle, a fail safe in case the need arises. The need had just risen! The test house crew had snapped two quill shafts trying to start the engine and were down to their last one. The chief tech did recall one or two instances during his twenty five years of working in the test house when the shaft had snapped, but the situation recovered once a new one was installed. Not so in this case. He'd never had an engine seize. What to do? Out came the AP's and after some considerable time, the remedial procedure was discovered. Two "special tools" were required from stores which also took some considerable time finding. One was half of a quill shaft (gearbox end) welded to a solid piece of square section steel. The other was a six foot length of pipe. With the quill shaft tool inserted in the gearbox, the pipe slid over the extension and both me and my accomplice hanging off the pipe like gorillas, we began bouncing up and down... (Yes, this is a Rolls Royce approved technique!) With the aid of another body, there was a resounding crack from within the engine, and it was free. The engine went on and completed its test without any more issues. Honour restored! Well, sort of. Lets just say, having been given such a large slice, there's a particular type of pie I don't care for the taste of.
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Post by triplecranks on Feb 19, 2016 22:50:57 GMT -5
Actually we agree more than you think lol. The loctite 620 bridges the difference and does not deflect like a solid oring as long as the loctite is placed minutes before the case is torqued. The lab failures were with o-ringed seals I think? Not sure. I do know, and I do NOT want to jinx myself, I have only had one failure and that was due to the customer not centering the seal. This was confirmed by the customer. Knock on wood!!
I have rejected several seals from my machinist which were probably ok but not perfect to my standards. Quality control is CRUCIAL.
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Post by triplecranks on Feb 29, 2016 19:44:54 GMT -5
The one I tore apart when I was 19 LOL! I never paid much attention to it as the old parts just go in the trash bin. I pulled a virgin early H2 crank apart today (either a 72 or 73, not sure) and after reading this thread I took a closer look. It had had factory rubber lab seals.
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Post by Jim on Feb 29, 2016 20:48:18 GMT -5
Makes you wonder how many engines "fail" the leakdown test because the owners don't know they have factory lab seals.
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Post by triplecranks on Feb 29, 2016 21:29:42 GMT -5
So true. I never gave it much attention until I saw rotortiller mention it.
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Post by Jim on Feb 29, 2016 22:27:23 GMT -5
In fact, I wonder if that's why my 1971-built H2 is still running fine with original seals.
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Post by triplecranks on Feb 29, 2016 22:51:58 GMT -5
In your case Jim, I think riding on a very regular basis has a lot to do with it.
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Post by acceleration on Mar 2, 2016 19:44:20 GMT -5
Our shop has been rebuilding our own cranks and some for our friends and vintage road race club guys for a few years.Triple cranks and RD and RZ 350 cranks, did a modifided RD 350 crank to fit a Suzuki 250 for one of the vintage road race guys.Some welded race cranks.OEM seals for the triple cranks and Lab seals on some Yamaha's.No issues or failures yet.Key seems to be using inspected quaity parts.No China stuff or low grade.And taking the time to blueprint the clearances and check and double check, and check and double check, the run out all along the way of the process.Recently did an H1 500 crank and an H2 750 crank.And doing an H2 750 crank right now.Couldn't find anyone around here to do them properly or that wanted to "take the time to do it right" So we tooled up and and can do them in the shop on our projects.It sure make things a lot easier and peace of mind when putting together an engine.
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Post by triplecranks on Mar 2, 2016 22:56:54 GMT -5
Well put!
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Post by Tripnut on Mar 10, 2016 17:06:14 GMT -5
I already had a crank for my H1E's second engine at Chris Applebee's for lab seals, new bearings etc when I spoke to Gary Clark about the H2A I'm rebuilding. Gary recommended using rubber seals and to be honest his argument was fairly strong that the rubber seals can last thousands of miles as long as the bike get's ridden regularly so why take a risk on changing the design of something that works. Gary also said that the crank cases are not line bored like the Yamaha's that use lab seals so can be very slightly out of line which can wreck the seal.
Chris didn't make any comment's one way or the other but his lab seals do use an outer O-ring which makes me think that if you are going to introduce rubber back into the mix you may as well use rubber seals.
My H1E seems to be running well and as far as I know it's never had a crank rebuild so the seals are probably over 40 years old and still work ok. The bike had also been standing in the window of a Kawasaki dealer for 10 years and standing doesn't seem to have harmed the seals either, just everything else.
Still have time to make my mind up because I have barrels and heads at Johns for a reed conversion and they cant finish the crank rebuild until they have the piston weight for the balancing. I'm leaning towards using rubber seals.
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Post by Walms on Mar 10, 2016 19:22:54 GMT -5
Not line bored? Even if they just used a boring bar, the journals should have little run out from the factory. What are they like now? Good question! 40 years of abuse... It would be a shame to wreck a crank trued to within a thou in crappy cases. This makes me think a good group buy would be a ground test bar, or cheap out and get one turned. With high spot blue, you could determine the condition of your cases pretty quick.
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Post by Tripnut on Mar 10, 2016 20:15:40 GMT -5
It's only stuff I was told, Gary uses labs on his drag bike because of the meth killing rubber seals but he advised that rubber was better in any other case.
Chris (who uses words sparingly) didn't give up any advice other than he can do it whichever way I want which makes me think it's six of one and half a dozen of the other. You pay's your money and makes your choice.
Changed the exhaust on the H1 yesterday so took a look inside and the bore on the center cylinder has an indent running from the inlet port to the transfer port so the engine probably has been at least badly re-bored at some point and the ports havent been re-chamfered so it may have had the crank done sometime during it's life.
Labs should last longer but rubber is more forgiving (not sure by how much though) of any out of true in the crank / cases.
Am thinking that the real answer is to put the cases together, line bore them oversize to fit bearings with oversize outer cases that have the same size and number of bearings as original and then use labs but it's probably not going to be a cheap fix and in the long run it's probably just worth fitting rubbers, using the bike often and getting a rebuild done every ten years. Nothing will last forever. In ten years I will be 65 so I will probably only need one more rebuild and another just before I sell it at 75 years old. Not such a bad deal.
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Post by Tripnut on Mar 10, 2016 20:42:07 GMT -5
Apparently the meters on the triples were speced to last 6 years which is why they waver back and forth these days. Makes me think that the whole bike was only intended to last five years max so they are all living on borrowed time. Five years is about what I would have expected as a maximum from rubber seals if the bike ran 8k easy miles per year. We are talking about a hooligan bike which was targeted at kids who will change their bike at least every two years (probably to get a car), long after the guarantee had run out. Don't expect miracles.
I remember rebuilding every second hand two stroke I ever owned after thrashing it to death for two months, then it would last another six months of thrashing before I had to do it again. This was all a normal part of being seventeen+ in the late 70's and early 80's.
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