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Post by wayne on May 23, 2012 1:46:29 GMT -5
Okay, thanks Dan.
Well that's very interesting given that 4 of the 5 bikes run rich. My A model runs "lean" and I noted that it's temperatures are higher than the others. This could mean that the my A models temperatures are perhaps correct (??) and all the others are too cool.
Perhaps then I might have a play with reducing the size of the SMJ on my stock jetted M and see if I can even out that dip in the power curve.
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Post by goandy on May 23, 2012 6:47:08 GMT -5
No, I meant richer. Sleep deprived night shift moment I'm afraid. Dan- maybe you're right and I'm wrong- I'm certainly no expert. I would say though that I have always experienced significant carbon build up and black sooty exhausts in rotaries- the only ones which are clean and lean have burnt up or have been washed clean by a coolant leak.
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Post by wayne on May 23, 2012 17:29:13 GMT -5
This is Steve Thompson's graph. Things to note, stock except for AM air filter (possibly Sam's red racing filter). Best carburetion of all. Very similar to my graph in the flattening of output correlated with the excessively rich early mixture. Dyno guy suggested running without filter to try and get the mixture a bit leaner. The blue trace is with filter, the red trace without. The bike was unhappy without its filter spitting and coughing and that can be seen in the uneven red trace but it did put out 0.7 more hp. Dyno guy said probably closer to 1hp as the air quality was getting quite contaminated at that stage. Dyno guy notes that a fuel/air mix somewhere between the two traces would be ideal.
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Post by wayne on May 24, 2012 0:01:29 GMT -5
This is my A model. It was running a 102.5 to cure the hesitation but the first test (blue line) is with an 87.5 to return it to stock. Note that this bike is running considerably leaner than the others. Yet it is an NOS carby with identical jets to the red M (first graph) and Steve Thompsons M (compare to blue graph in previous post....same jets, both RR AM filters). Finally, note the red graph. This is with a 102.5 PMJ. Yet the run is leaner and there is less power. As an aside, this bike has now had its hesitation cured and will run hesitation free with a stock 90 jet. It turns out that in this bikes case, I had goofed big time with the cable set up and when set correctly, hesitation gone. Unfortunately, when checking my third bike which still needs a 100 jet, the cabling was confirmed correctly set. Damn- I was wishing I'd goofed on that one too. Two down, one to go.
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Post by wayne on May 24, 2012 0:06:21 GMT -5
Final RE5 graph. This bike is running a 100 primary and an RR AM filter. It's very close in jetting and setup therefore to the A model red graph above. But this bike runs on the rich side like the rest of them. For whatever reason, the dyno guy examined this graph and said that it was indicative of an engine with good internals.
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Post by wayne on May 24, 2012 0:10:37 GMT -5
Right, now just go out and buy a Norton Classic Rotary. For your interest. I believe that this bike is completely stock. Also note that the book claims max hp at about 9,000 rpm (79 hp)which is well above redline. Kim terminated the testing at redline (7,000). This graph is apparently close enough to perfect that you wouldn't want to touch anything on the bike. While the straight horizontal line is roughly ideal fuel air mix, the expert said that something around 13.5 in practice is closest to perfect. I can still see Kim's grin................ Kim Hunter's results-
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Post by wayne on May 24, 2012 0:22:04 GMT -5
Final couple of points. The dyno guy said that fuels today are quite different to back then. He notes that energy density is greater rendering 1975 jetting probably too rich and that is indicated in 4 of the 5 RE5 graphs. For interest of Australian riders, he notes that extensive testing that they've done shows BP 98 the best bang-for-bucks with Caltex second.
As an aside, Steve stores a number of bikes and noted that he has found the BP fuel the most stable over time.
For myself, I find a difference in fuel economy between 95 and straight 91 but no better economy between 95 and 98. In fact, I have a gut feeling that it doesn't run quite as well with 98.
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Post by goandy on May 24, 2012 5:33:26 GMT -5
It would be interesting to see where the restriction is on our bikes- the rapid drop off in power certainly indicates that. Next time, although it would be loud, maybe try dropping the mufflers and do a quick run (as long as a/f ratios are ok).
I've heard in the past that a SU style carb can make a huge difference in power too...
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Post by wayne on May 25, 2012 3:09:48 GMT -5
We had a bike with the early model big stingers (Spark arrestors in Suzi speak) but didn't have time to swap them about to see the difference. I believe the smaller stingers did snuff some horsepower.
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Post by hunter on May 25, 2012 7:40:30 GMT -5
Hello Andy, I think the restriction is the carby and intake diameter just can't get enough air in. Maybe an SU will help. The Norton has An SU type H1F4 cv typr carby , throat size 1 1/2 inches serving each rotor. Also each rotor is just under 300cc whilst the RE5 is 500cc. The odds are against the RE there in my view.
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Post by hunter on May 25, 2012 7:41:05 GMT -5
The video clip on u tube has had over 1,000 viewings.
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