I had a Honda NX650 single lots of torque but really easy to ride, always wanted to put a white brothers pipe on it but never had the money so had to live with the muted stock pipe. The PO said that it had a 720 (I think??)kit in it. Honda did away with the kick starter that year when they put that motor in the "Street"NX. I remember that the starter crapped out and I had to have it rebuilt. It was a california model with all of the emissions/smog gear still on it, but I bought it off of another Navy guy when i was still in Japan. Back then the Yamaha TRX 850 was kinda new a popular there, and I was thinking of trying to get one of those and i remember reading an article where some guys were trying to race that motor on dirt track state side and they ended up making a twingle out of it trying to get it to hook up, but it had some other issues and ended up not being able to compete. that's the only other time i'd ever heard of one. anyway that's an awesome looking motor, I too also like the quick change cam, really trick! I wanted to ask you about the oil pump, you said it's a high volume?? where do you get those and about how much do they cost? Cj
The twingle is getting close
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Didn't the Atlas have a cushdrive primary? Probably not up to it though, even if it did. Something on the rear wheel would have to help some though, even if you had to replace it every so often.
Would it be at all possible to get a video with nice sound when you fire it up??
Would it be at all possible to get a video with nice sound when you fire it up??
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bpatton said:
I have an Atlas clutch here but I don't think it would do me any good. I do have the stock mk3 cush in the rear wheel. I plan on installing the rear belt drive at the same time. I will likely take a look in the tranny also since I haven't had it open for at least 10 years.
I will try to get some video when I start it. Not to sure how the sound will work though. I will get my daughter out there, she's the video camera pro. Jim
HaHa, I saw where this was going just when you posted the anvil shooting link! Is that some type of special coatings on the front of the pistons? What are the clearances? Looks like you're running radiused followers. Is that an oil trough the cam is in? Like the quick change cam and timing gears. Lots of fun stuff going on here! Thanks for sharing!
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The pistons have a low friction coating on the skirts and ceramic coat on the tops. Clearance is set at .0057 and the bore has a very fine plateau finish to go with the thin low tension chrome ring. There are radial power ports to expand the top ring. The bores are burnished with Quick Seat and the engine will be broken in with Mobil 1.
The gudgeon pin buttons are turned from aluminum.
The followers are 3.5 inch radius ground and the cam is a 2s. The radius grind makes the timing closer to stock but you get to keep the higher lift. It also allows me to use a .060 oversize intake valve without it tangling with the exhaust valve. Jim
The gudgeon pin buttons are turned from aluminum.
The followers are 3.5 inch radius ground and the cam is a 2s. The radius grind makes the timing closer to stock but you get to keep the higher lift. It also allows me to use a .060 oversize intake valve without it tangling with the exhaust valve. Jim
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Jim. Love it!
Have you seen one running before?
Guessing a couple of wheel choc's will be requred.
Have you seen one running before?
Guessing a couple of wheel choc's will be requred.
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Not many example of twingles to find online. Puch has some but sounds exactly like any small 2 stroke.
The crank stress still might be an issue as sucking by two big intake gulps at once restrains pistons reversing at TDC. Boost helps relieve crank wipe by this factor.
If maxing out on RPM might be wise to hit kill instead of snapping throttle shut.
I bet the fueling map will be dramatically different from 360 fueling.
Here a BIG THUMPER to ponder
http://thekneeslider.com/archives/2008/ ... otorcycle/
The crank stress still might be an issue as sucking by two big intake gulps at once restrains pistons reversing at TDC. Boost helps relieve crank wipe by this factor.
If maxing out on RPM might be wise to hit kill instead of snapping throttle shut.
I bet the fueling map will be dramatically different from 360 fueling.
Here a BIG THUMPER to ponder
http://thekneeslider.com/archives/2008/ ... otorcycle/
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Better have a big bag of popcorn, this weekend is dyno day at the Comstocks for the local Norton club and then another race motor has to be delivered to Kenny and then a couple fuel injection systems have to be delivered and then the rack full of Norton heads to rebuild and barrels to rebore is overflowing and Matt is out of headsteadies again. Someday I will get to finish mine. Jim
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After not killing myself by my own hand I found key to happiness, a place to be, something to do and things to look forward to, so if not crippled in pain, quit ya belly aching " )
How would one arrange for a dyno test in between your intervals of mania?
Could also assess the possibility of your injectors fitting the tight space available at intake and crank shaft end.
Quit wasting mental energy on after thought secondary stabilizers and put it on the transforming rear area. To a man even those complaining bitterly about the lack of top end on their twingles, said nothing but nothing pulled like it out of turns, image that steam locomotive torque being as potent going into them too. Might find the funnest way around a curve on isolastic Commando ain't really a curved path : )
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I'm patient, I have to be on my budget 
I would seriously consider a compression release. My 640 single was very difficult to kick to life without it at about 12 :1 comp.
With it, pull the lever bring her up, release, kick and brummmm.
The Yamaha TDM/TRX850 flatracker that was built as a twingle peaked my interest years ago when I read about it, and always wondered what if....
I would seriously consider a compression release. My 640 single was very difficult to kick to life without it at about 12 :1 comp.
With it, pull the lever bring her up, release, kick and brummmm.
The Yamaha TDM/TRX850 flatracker that was built as a twingle peaked my interest years ago when I read about it, and always wondered what if....
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Will, ain't practical and barely possible to fit effective size poppet type release in Norton Hemi head. Jim suggested to me to tap ern in upper bore but that would be both ugly and not very effective. Only one way I can think that is both doable, functional and not ugly wart sticking out, lift exhaust valves a few thousandths. If Jim don't do it I'll have my idea created here. Its almost a vital feature to keep us old farts kicking em off to impress the youngsters used to thumb commensers.
Done right only takes about 70 lb to sideways fracture a knee, about 40 for elbows in case of single handed attempts. Done right a karate kick can impart hundreds of ft lbs force just fine though.
Done right only takes about 70 lb to sideways fracture a knee, about 40 for elbows in case of single handed attempts. Done right a karate kick can impart hundreds of ft lbs force just fine though.
The early Yamaha XS 650's had a nifty lever built into the rocker cover to offset the valve for starting.
http://www.650motorcycles.com/CompRelease.html
http://www.650motorcycles.com/CompRelease.html
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Yes that is along the lines I was thinking, but did its release allow to start and run when open or just to turn over past TDC then close and kick thru? Basics pretty straight forward but couple options of where to perice the head or covers and be robust enough and still oil sealable. If Peel venting works right her releases would suck air in their seams. Main mystery is gap that eases kicking yet starts before releases released. Minds focused here assist new levels of aether processing.
Now how would a half ass smart but mostly more lazy dude do this?
Now how would a half ass smart but mostly more lazy dude do this?
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