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Post by bk2112 on Dec 6, 2021 20:05:21 GMT -5
I am going through the different parts on my 75a model revival project. The vacuum hose to the petcock was completely plugged up. I got a clean pc of tubing and tried to see if I could move the diaphragm by sucking on the tubing. I can not. There appears to be a blockage between the hose nipple and the small hole in the chamber. Even with the diaphragm removed I am not able to move air through it. My question: Is there any sort of check valve in there that I will damage if I try to run a wire through it to un clog it?
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Post by wayne on Dec 7, 2021 23:52:33 GMT -5
Just pulled one apart and been playing with a paperclip up the vacuum line. Nothing up there that you're going to damage. Probe away.
Petcocks are the same but if you're ordering parts etc just letting you know the 75 is the M model, the 76 is the A. You'll avoid any confusion.
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Post by bk2112 on Dec 8, 2021 18:37:55 GMT -5
That's great. I'll probe it to see if I can get the passage open. Thanks Wayne!
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Post by multistrada1 on Jan 3, 2022 18:38:57 GMT -5
I've had my petcock apart a few times. the diaphram is not compromised and the vacuum circuit is working, but I cant run the engine hard without putting
it in prime position, other wise it will starve for fuel.
Anyone else have this issue?
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Post by timpa136 on Jan 4, 2022 10:41:12 GMT -5
I've had my petcock apart a few times. the diaphram is not compromised and the vacuum circuit is working, but I cant run the engine hard without putting
it in prime position, other wise it will starve for fuel. I was told the petcock would flow plenty of fuel all things being OK. I can only relate things you may have already checked. Perfect vacuum hose, check with a vacuum pump complete circuit by checking at the manifold end. Maybe spring expanded, again I have not needed to do this to seal a leaking o ring. Gas cap clean in solvent tank and insure venting. Any chance the petcock venting hose is plugged ( extends up in the tank) Some aftermarket needle and seats are smaller than specs. My experience has always been a plug breaking down acting as you describe. Tim |
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Post by wayne on Jan 4, 2022 17:44:50 GMT -5
Just further to Tim's comment, I've found the little metal elbow that sits on the inlet manifold, what the petcock vacuum tube connects to can be very loose on some bikes. May pay to remove it, put sealant 'round the mating surface and reinsert into the manifold. If it's very loose it could be supplying inadequate vacuum not to mention affecting the bike's carburetion further down the track.
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Post by ROTRE on Jan 5, 2022 20:54:11 GMT -5
I've had my petcock apart a few times. the diaphram is not compromised and the vacuum circuit is working, but I cant run the engine hard without putting it in prime position, other wise it will starve for fuel. Anyone else have this issue? I have this issue as well, but only when the bike is really hot. |
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Post by timpa136 on Jan 6, 2022 0:09:01 GMT -5
On a Really hot day?
There is a modification to the radiator but more so addresses a tendency to vapor lock
and cause drivability issues mostly at slow speeds in traffic for example.
Does running on prime fix yours, too?
Tim
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Post by ROTRE on Jan 9, 2022 6:02:45 GMT -5
On a Really hot day? There is a modification to the radiator but more so addresses a tendency to vapor lock and cause drivability issues mostly at slow speeds in traffic for example. Does running on prime fix yours, too? Tim I though it did but i was wrong, sometimes it does sometimes it doesnt. I have found my bike is very tempermental to ambient heat, riding atm in Australia with ~27deg C ambient temps has made for a wide range of performance issues. At first the bike runs great then after 10mins of riding it starts the hesitation issue under load on hard throttle. I thought it was a fuel issue and have been chasing that. I recently took my bike to a friend who is a rotary expert and has a couple of RE5's himself and he diagnosed the problem straight away, as he had it with his. In short the timing was not set up for hot temperatures, causing detonation. He took a couple degrees out of the timing and it has run fine since. (mind you it was only 2 days ago) but on first ride back in traffic at over half temp on the gauge with fan on it didnt have the dreaded hesitation ive been chasing a fix for since i got the bike. Also i went for a ride later still in hot temps on my test ride of 30km and the problem only surfaced slightly once on an elevation change up a small mountain. I turned around and redid that same piece of road and the hesitation was not there so go figure lol. I will post this finding in a new thread also. |
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Post by timpa136 on Jan 9, 2022 10:04:20 GMT -5
Glad to hear the improvements.
Tim
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Post by wayne on Jan 9, 2022 15:11:50 GMT -5
CosmicRE5 if I'm reading you right, fan is on with over half temp and ambient ~27 degrees? Fans shouldn't come on until your gauge is almost full to the right and at 27 degrees, you shouldn't be anywhere near fan temp. This suggests there's still a lot of sorting required. And that's GOOD news. It means you're nowhere near how this bike should run. Rarely my temp gauge goes right of half and I can't remember when last the fan came on (yes it works).
Out of interest, what was the timing and what did you change it to?
Timing doesn't effect the hesitation. That is a fuelling issue. I've ridden from 0 to 14 degrees static timing. It makes barely any difference between 1500 and 4000 rpm. They're forgiving bikes when it comes to timing and a couple of degrees won't do a thing unless, possibly, it's the straw on a camel's back host of other issues. If it's detonating (which I doubt), something is seriously awry.
Even the factory changed standard timing from 10 to 5 degrees in one fell swoop.
RE5's are temperamental when trying to sort and importantly, frustratingly inconsistent. One friend said to me when sorting an RE5 "it can run fine to the coffee shop and cranky on the way home and do the exact opposite next week".
Too many times I've celebrated "fixing" an issue only to find it return next ride. And I'm not talking just one bike. They are very individual and inconsistent when trying to sort a revived bike.
At this stage, I highly recommend not jumping to conclusions (AMHIK lol.......)
Riding in 40 degree AU temps shouldn't be much different to 27 once the bike is sorted. The bikes are fine from low single digits (Snowy ride) to 40 deg . If you're within the range of 5 to 10 degrees BTDC, you won't need to touch your timing and outside of this, as mentioned, hardly noticeable.
I'd suggest you still have a long road to go getting the whole balance right. This is not an insult or deriding your efforts. It's the long road we all go through (with one or two lucky exceptions) but you'll get there.
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Post by ROTRE on Jan 9, 2022 17:48:01 GMT -5
CosmicRE5 if I'm reading you right, fan is on with over half temp and ambient ~27 degrees? Fans shouldn't come on until your gauge is almost full to the right and at 27 degrees, you shouldn't be anywhere near fan temp. Over half temp at 27 degrees suggests there's still a lot of sorting required. And that's GOOD news. It means you're nowhere near how this bike should run. Rarely my temp gauge goes right of half and I can't remember when last the fan came on (yes it works). Out of interest, what was the timing and what did you change it to? Timing doesn't effect the hesitation. That is a fuelling issue. I've ridden from 0 to 14 degrees static timing. It makes barely any difference between 1500 and 4000 rpm. They're forgiving bikes when it comes to timing and a couple of degrees won't do a thing unless, possibly, it's the straw on a camel back's host of other issues. If it's detonating (which I doubt), something is seriously awry. Even the factory changed standard timing from 10 to 5 degrees in one fell swoop. RE5's are temperamental when trying to sort and most importantly, frustratingly inconsistent. One friend said to me when sorting an RE5 "it can run fine to the coffee shop and cranky on the way home and do the exact opposite next week". Too many times I've celebrated "fixing" an issue only to find it return next ride. And I'm not talking just one bike. They are very individual and inconsistent when trying to sort a revived bike. At this stage, I highly recommend not jumping to conclusions (AMHIK lol.......) Riding in 40 degree AU temps shouldn't be much different to 27 once the bike is sorted. The bikes are fine from low single digits (Snowy ride) to 40 deg . If you're within the range of 5 to 10 degrees BTDC, you won't need to touch your timing and outside of this, as mentioned, hardly noticeable. I'd suggest you still have a long road to go getting the whole balance right. This is not an insult or deriding your efforts. It's the long road we all go through (with one or two lucky exceptions) but you'll get there. Yeah I’m probably celebrating early I know haha but I’ll take any small win I can. With the temps I probably should have been more clear, yeah the fan is coming on later than just over half. Maybe not as high as you suggest though. I’m not sure what he set the timing at, he just retarded it slightly to see if it made a difference and on my next couple rides it did. But as you said that Will probably change haha. I will keep on plugging away at it, I have my jets coming to try so am looking forward to that, to see the effect of running larger jets. Thx for your insight as always Wayne it’s appreciated! Mark. |
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Post by wayne on Jan 9, 2022 17:52:43 GMT -5
Thanks Mark.
Keep notes of what you've done. Please make that thread outlining your, I hate to use this new age word but..... "journey" with the bike.
We'll all appreciate it.
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Post by wayne on Jan 10, 2022 0:35:05 GMT -5
For general reference, the M temp gauge. The fan comes on at 106 degrees which is 82% of the way between half way mark and 110 mark. The A model middle and right white lines are the same as the M re temps.  |
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quawk
2nd Gear
Posts: 150
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Post by quawk on Jan 10, 2022 9:57:37 GMT -5
Wayne, From what I gather from your above posts, you indicate the fan shouldn't necessarily come on until 106 degrees C.(222 degrees F.) and the temp gauge needle is nearly to the right hand white mark 110 degrees C.(230 degrees F.). Is this the usual or normal temp range for the fan to switch on on these bikes. I have never had my bike running long enough (yet) to reach that high of a temp but I have noticed my fan has never switched on. Have tested the fan itself and it does work, but was wondering if the switch had failed. From this it seems I just need to run my bike longer or in warmer ambient temp to see if the fan switches on.(We're in the middle of winter here in the midwestern U.S.) Do these engines like running at these higher temps? It seems like a considerable delay in the switch on time to start the fan.
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