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Post by tom93gts on Sept 22, 2012 12:46:19 GMT -5
From what I see on the forums the normal fuel economy for the re5 is somewhere between 30-40 MPG US.
My best tank ever is now just a bit over 24.
Aside from that the re5 is running extremely well. It starts up and drives seemingly perfect.
I have timing set at 8.5 degrees with the Rotary Recycle electronic ignition. I put in a fuel valve so it's not leaking when parked. Jetting is all completely back to stock, carb has been recently ultrasonically cleaned. I'm running out of ideas.
What else can I look at in my effort to hit 30mpg? That is my goal where it would be good enough that I could ride up into the mountains around here without worry of being stranded.
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Post by wayne on Sept 22, 2012 15:22:12 GMT -5
That's mysterious. When I have had severe economy issues on other bikes (not rotaries) it's always been traced to either fuel leaks (leaking choke valves) or incorrect jetting to begin with.
When you say that all your jets are back to stock, I presume you mean that you've got the jets in that came with the bike. For reference the main ones would be 90 or 87.5 PMJ and 180 SMJ.
That "economy run" I did was with the 87.5 primary jet, the smallest standard PMJ. However, I have found that even with a 102.5, the overall consumption doesn't vary as much as you might expect. Even ignition timing out by 8 degrees has no obvious effect on consumption).
What air filter are you using ?
Might be a silly suggestion but have you checked that your choke butterfly is correctly engaged with the pins on the choke lever ? I have seen a situation where the choke butterfly was on all the time. Not as bad as it sound as the butterfly will flap open as rpm rises anyway. But you never know.
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Post by mike500 on Sept 22, 2012 16:33:13 GMT -5
im getting about 40 imp mpg running a 120 pmj like wayne says check the choke plate is engaged properly it is very easy to assemble it and get it located wrong so choke is stuck on
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t140v
3rd Gear
Posts: 422
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Post by t140v on Sept 22, 2012 17:47:40 GMT -5
Evening Tom, on my last decent run out to Bakewell in Derbyshire I got about 40 to the Imperial gallon, I'm running with a 112.5 main jet and did 120 miles round trip, 80mph motorway and quite a bit of 35-40mph.
Regards Stuart.
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Post by hitch007 on Sept 22, 2012 23:57:44 GMT -5
Just my two cents... Iwas a bit concerned about mpg after I got mine running. 70 miles to the reserve was not what I was expecting, even from a rotor!! I carried out a little experiment. After upping the main jet to a 95, I went for a ride (mainly flat) using only the primary throttle circuit i.e. no more than a 35 deg throttle opening. This was easy to doas i can feel a little spring resistance when the port valve starts to open.
All in all, 42.5 IMPG was the result. Not too bad I reckon. When I refueled, the fuel light had just come on, not yet on reserve and had used 12l to top up.
So.... if you twist that throttle, you will get poorer mpgs but with the larger jet I was still able to cruise at 60 mph on the primary circuit getting reasonable mileage
I do think my carb needs an OHaul but at the moment can live with it. After all, you don't see these machines often in NZ!! Very proud to own one.
Cheers y'all!!
Gareth Nu Zillind
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Post by tom93gts on Sept 23, 2012 2:00:59 GMT -5
I have the 87.5 primary jet and never changed secondary so would guess it's going to be the 180, and am certain the choke lever is correctly positioned between the pins. I do hit the highway at about 75mph so probably then I am in the secondary throttle body, also maybe a little spirited on some of my accelerating since it's been running so well. Maybe I should take a big highway loop at a steady 60mph to get a "best case" number.
Didn't realize secondary jet was so bit, hitting the secondary at all sounds like it really can affect things.
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Post by wayne on Sept 24, 2012 4:37:52 GMT -5
All true re running on secondary or primary etc etc. But for reference, I've pointed out before that I've done a pretty hard run with rpm constantly between 5 and 7 thou and still managed, without checking my notes, about 29 mpUSg. This was almost matched by a second RE5 so there's nothing special about my one.
That run would have to have been on both primary and secondary throat the whole time (and is not the run shown on the video).
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Post by tom93gts on Sept 24, 2012 10:22:27 GMT -5
Forgot to answer the air filter question. I am running the reproduction replacement from Rotary Recycle.
Thanks for the numbers Wayne. I hope one day I can get there so I can feel confident on stretches of road where it might be an hour before the next filling station.
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Post by wayne on Sept 24, 2012 16:27:32 GMT -5
I run Jess's filter in my A model. It's consumption is not as good but that engine has compression that varies between 104 and 116. Still does around 33 usg. I think that the RR filter works fine so no issue there.
Tom, I just went through my notes and found an interesting thing. My original bike with original carby regularly got about 29 mp USg at steady expressway speeds (110-120 kph) which equates to about 4 to 4,300 rpm (ie secondary open). This was about 10 years ago.
I found a carby back then which didn't cure the hesitation but the bike just ran better with a much lower idle, just nicer. I know it had a 90 PMJ. I note that the consumption improved markedly and almost identical expressway rides were returning 35 mp USg. This is the carby that eventually lost its hesitation and is still on the bike.
Who knows what was going on inside that original carb.
As the dyno guy said to us while scratching his head over the inconsistencies......"I think I need to read up on these carbies"
I'm not sure that even doing that helps much !!
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Post by stevejones on Oct 10, 2012 20:09:42 GMT -5
Garath from NZ, where are you from ?
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Post by hitch007 on Oct 11, 2012 0:48:12 GMT -5
I'm a kiwi, live in Blenheim. If you're not a NZer, that's at the top of the Sth island.
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