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Post by steve w on Jan 20, 2012 13:53:59 GMT -5
hi just been studying this problem. there is a adjusting screw on the secondary butterfly and if this has been moved buy mistake it could be keeping the butterfly slightly open and causing your problem ,its the one that is adjusted onto the carb body.it might need backing of a bit. if its slightly open it will cause vacuum to early. hope this is some help. i used to work as a carburettor specialist so have some sort of idea, and also a re5 mechanic back in 74. steve w
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Post by riversidogs on Jan 21, 2012 9:42:57 GMT -5
I have seen those screws on auto carbs and on some auto fuel injection units. In most cases they are used to prevent the throttle plate from sticking against the carb body if it closed too far. In this case I would set it to just prevent the plate from touching the carb body.
Tom
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Post by tom93gts on Jan 21, 2012 20:13:59 GMT -5
Looks like the screw to set the minimum opening on the throttle plate in the housing was holding that open a bit too far, allowing vacuum into the secondary and causing it to open up. i closed that down and it seems good so far.
Now however i found a drip inside the secondary. When running, if i look at the brass pin coming through the upper left of the secondary throttle body fuel just slowly drips from it and pools in the bottom of the secondary. i think this one has been a problem as long as i have owned the re5 because when parked it usually leaks fuel out the intake elbow until the carb is dry. So much fun!
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Post by wayne on Jan 21, 2012 22:16:31 GMT -5
That brass pin is the accelerator pump jet. It could be worth checking that you have the correct settings on the actuation arm for the accelerator pump. Original setting was at 35 degrees and Bulletin 9 moved it to 27 degrees. Either can work.
Unfortunately you need the carb off to adjust it but if it's dripping fuel at all times it makes me wonder if the fuel pump is being activated way too early. Have a look at the little arm under the carby that is driven by a pushrod covered by the accordian-like boot. It shouldn't move until you've wound the throttle a little bit. Check to see if that little arm has been depressed perhaps too early.
Wayne
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Post by tom93gts on Jan 22, 2012 22:16:35 GMT -5
The fuel pump isn't activating early, it doesn't move until about 30 degrees. I will check with gauge to be certain, but that doesn't look like the problem. i need to check how fuel gets into the accelerator pump and how it gets out, but it the dripping just seems like fuel getting through some place it shouldn't. It will drip just at idle, and even after shut down.
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Post by tom93gts on Jan 29, 2012 19:36:39 GMT -5
Today determined the leak on the accelerator pump jet was due to the jet not being fully seated. I took a screwdriver after it and was able to get another 1/8 turn out of it. Everything is back together and it runs the best since I have owned it! Maybe I will get another couple miles per gallon out of it too now that there is no fuel dripping in there.
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Post by wayne on Jan 29, 2012 22:49:23 GMT -5
Excellent work. And one that I'll keep in mind for the future as well.
Wayne
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Post by tom93gts on Jan 30, 2012 11:44:06 GMT -5
Took it out for a further ride today, to work. It's about 9 miles and 5 of those miles are highway so I was able to get the speed up. It was nice being able to smoothly run all the way through the rpm range without any strange flat spots of hesitations. The re5 is a really nice highway bike, I am quite impressed! I hope the fuel economy goes up a little now that I have the fuel drip fixed, if it can manage to go closer to 30 miles on a gallon then a 100 mile range wouldn't be out of the question, keeping fingers crossed.
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Post by wayne on Jan 30, 2012 17:54:06 GMT -5
My current setup gives me the best fuel consumption figures I've ever had.
With an 87.5 primary jet and everything stock combined with sensible riding (easy through the gears keeping rpm 4000 or below) I regularly get 37 mp USG. If I ride it briskly it will drop to around 34 mp USG and a bit harder will bring it back to 29 mp USG.
The bike can be surprisingly economical and I've found the 87.5 jet to make a measureable difference to economy. It is, I believe, the smallest stock jet.
I have a 4% odometer error which is better than stock or the K81's I usually use as the Metzeler lasertechs have a higher profile so you should have no problems breaking the 30 mpg barrier.
Wayne
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Post by drpaul on Jan 31, 2012 7:30:46 GMT -5
Today determined the leak on the accelerator pump jet was due to the jet not being fully seated. I took a screwdriver after it and was able to get another 1/8 turn out of it. Everything is back together and it runs the best since I have owned it! Maybe I will get another couple miles per gallon out of it too now that there is no fuel dripping in there. Can you explain which jet you found not fully seated? I think that is a problem with mine as well. Thanks. Paul
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Post by tom93gts on Jan 31, 2012 9:31:11 GMT -5
If you pull the top of the carb it is the one that has an angle on it such that as you turn it in, it would go toward the inlet side of the carb. I think it was the first one behind the tall brass post. This mostly caused bad fuel economy, occasionaly flooding, and fuel to leak all over the side of the engine when parked.
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