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Post by drpaul on Dec 17, 2011 19:32:29 GMT -5
OK, here's an update on the '76 RE-5 I've been reviving. All fluids fresh, new oil filter. Have been oiling rotor apex seals and compression is 120 psi. New air filter, lightly oiled. Today installed petcock kit, oiler check valve and carb kit from RR. Also bought spark plug adapter but can't find the NGK LMAR9E-J locally so have one on order. Premixed fuel/oil 50:1 til I'm sure oiler is working properly. Anxious to try it (hasn't been started in over 20 years), I put the original plug in and it started right up but RPMs went straight up to 7-8K so I hit the kill switch. Have diddled with idle adjustment and the pilot screw but no change - just runs right up to redline. Pulled the air intake tube off and the secondary bore is wet with fuel and the little brass nipple protruding into the venturi is dripping gas. I might add the choke unloader diaphragm is shot but a replacement was not included in the rebuild kit. Is this part available? I'm pretty sure I've got a carb problem but need some advice on sorting it out. Any advice is greatly appreciated.
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Post by wayne on Dec 17, 2011 20:12:35 GMT -5
You mention the secondary throat, but when you pulled the air horn off, was the primary butterfly closed or very nearly closed ?
That protruding brass rod is the accelerator pump outlet. If it's dripping gas, I would tend to think that perhaps your accelerator pump is partially activated.......and it shouldn't be if your throttle is at idle. Sounds like something is hung up there holding your throttle partially open.......
Just an aside, you can probably reduce that fuel/oil mix to 100:1. That's all that the metering oil pump puts out anyway and fouling plugs when starting long layups can be a problem.
Wayne
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Post by drpaul on Dec 17, 2011 20:36:18 GMT -5
Both throttle butterflys appeared to be closed. On the premix ratio, I thought I would err on the side of caution. Thanks!
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Post by riversidogs on Dec 17, 2011 21:27:01 GMT -5
I do not know if RR has one made up yet. I used the fuel pump rubber from a holly carb to replace the old one but some fine machining is required. It is possible after not running for 20 years that there might be some corrosion built up in the throttle bore that is holding one of the throttle plates open. You might check the linkage around the choke unloader to make sure it is allowing the throttle to shut fully. Also check to see that the choke lever is positioned correctly when the side is assembled.
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Post by wayne on Dec 17, 2011 22:14:58 GMT -5
As well as the idle stop screw, check the stop screw under the throttle grip body on the handlebar. Under that block is a screw with a small locknut. Undo the locknut and screw it out as far as it will go. At least it's one less thing that may be holding something open.
Re the choke assembly, a quick check is that the choke butterfly is fully open with the air horn off and choke lever up. If you haven't located the choke lever correctly, the choke butterfly will be closed when you look in from the air horn side (although in reality, it shouldn't make much difference as the choke is lightly spring loaded and airflow will open it anyway if it is not correctly located on the choke lever pins).
Wayne
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Post by drpaul on Dec 18, 2011 7:02:58 GMT -5
I will check these things today. I'm certain the choke lever is working correctly but will reexamine the throttle side as I haven't really looked carefully at the grip and cables as they seem to work normally. As for the unloader, what exactly is it's function? I'm certain the diaphragm is cracked and leaky so would it be best to disable it and get rid of that vacuum leak? Thanks to all responders! I have NO experience with these motors so all advice is greatly appreciated. I'm thrilled the thing runs!
I said "motors" because when I was a kid growing up fascinated by cars and farm machines, I asked my uncle, a mechanical engineer, the difference between an "engine" and a "motor". He told me that engines (steam, internal combustion) had pistons and motors (electric, turbine) didn't. That simple distinction, right or wrong, stuck with me!
Paul
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Post by supersaki on Dec 18, 2011 18:30:12 GMT -5
All the underloader does,is to open the choke flap partially,when the choke is on and the revs increase. You can remove it so that there is no air leak but you will need to control the choke manually. Hope this helps. Regards,Roy
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Post by drpaul on Dec 20, 2011 6:58:07 GMT -5
All the underloader does,is to open the choke flap partially,when the choke is on and the revs increase. You can remove it so that there is no air leak but you will need to control the choke manually. I believe I will replace the old and cracked diaphragm with a piece of gasket material to disable the unloader and take care of the obvious vacuum leak that results. Haven't had time to check out the other throttle cable suggestions yet but hope to get to them in the next couple of days. Thanks to all and Merry Christmas!
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Post by drpaul on Jan 1, 2012 7:40:26 GMT -5
UPDATE! After carb removal I replaced the cracked choke unloader diaphragm with a piece of non-permeable gasket material to eliminate any vacuum leak there. I inspected all throttle cables, linkages and shafts for freedom of movement and everything seems correct. The primary and secondary throttle valves are closed when the grip is rolled forward. Still, after starting the RPMs go right up to redline even when no throttle is on. I placed a piece of stiff wire on the secondary throttle lever (the one actuated by the dashpot) and secured it closed. This completely eliminated the over-rev problem and throttle response was normal up to around 3-4K rpm where, I suppose, the secondary would begin to kick in. So, it seems that something is permitting the secondary to open in an uncontrolled fashion. I will go back and look at the linkages between the throttle butterflys but it seems that the primary should put a "hard stop" on the secondary until it has reached a certain open point. Another question: could a misadjusted port valve exert any control over the secondary throttle valve that cannot be overridden?
Sorry for running on here. I'm thrilled the thing starts and runs and I'm anxious to get this fueling problem sorted out. Thanks for any advice and HAPPY NEW YEAR!!
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Post by supersaki on Jan 1, 2012 17:08:10 GMT -5
I would check that the vacume pipe from the diaphram is connected correctly.It sounds like it might be connected directly to the inlet manifold and thus ,when the bike starts it opens the secondary choke.Hope this helps,Roy
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Post by wayne on Jan 4, 2012 2:35:18 GMT -5
You are correct. There is a hard stop that is supposed to hold the secondary closed.
The secondary throat should not be capable of opening until the primary port is open 41 degrees. There is a limiter plate and linkage designed to do this.
Wayne
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Post by drpaul on Jan 4, 2012 20:18:14 GMT -5
You are correct. There is a hard stop that is supposed to hold the secondary closed. The secondary throat should not be capable of opening until the primary port is open 41 degrees. There is a limiter plate and linkage designed to do this. Thanks. I'll check that out tomorrow.
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FC Zach
3rd Gear
Eagleville, TN
Posts: 335
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Post by FC Zach on Jan 4, 2012 23:45:18 GMT -5
I might add the choke unloader diaphragm is shot but a replacement was not included in the rebuild kit. Is this part available? Correct, the unloader is a sub-assembly separate from the service kit. If you want to repair it you'll have to contact Barb/Jess at RR to get a replacement. If I remember correctly you'll have to send your damaged unit as a core in exchange for the new unit.
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