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Post by hudson on Mar 5, 2020 23:47:40 GMT -5
Also check the passage from the #62 main to the veturi, Maybe use carb. cleaner with the little red tube they come with to see if it flows to the secondary venturi and follow with compressed air. But remember carb. cleaner in the eye really hurts.
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Post by tom93gts on Mar 12, 2020 11:25:30 GMT -5
Pulled carb off again twice last night for cleaning passages and jets. I think I have everything unclogged but I still can't get it above 4k rpm. I need to review the cable/port timing procedure again, maybe something isn't opening at the right time. I think I remember having this same problem a few years ago and resolving it by changing the timing of the valve on the rotor housing, will investigate that next.
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Post by wayne on Mar 12, 2020 18:04:26 GMT -5
If the port valve timing is only a little out of whack, it won't prevent the bike from revving past 4000. And from memory, there isn't enough slack in the cable to adjust it so badly that it isn't opening at all or so little that it would cause that problem- IMO from recall. I may be wrong.
Nevertheless, checking the PV is definitely the next thing to do. As a rough ballpark, the actuation of the Accelerator Pump and the Port Valve should be very close together. If your AP is still at factory setting (35 degrees), the actuation of both AP and PV should occur at the same time. If your carb has been adjusted to bulletin 9 specs, then the AP should actuate a smidgin of a turn of the throttle grip before the PV starts to move.
If you do this rough check and it appears they're in the ballpark, I wouldn't hold the PV responsible.
But do check them and set them correctly, it at least eliminates one uncertainty. While you're at it, if you have a protractor gauge you can figure out if the AP is at original factory (35) or Bulletin 9 spec (28).
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Post by timpa136 on Mar 13, 2020 11:36:13 GMT -5
Got the needle and seat sorted out so no more fuel leak, but now I can't get it to rev past about 3500 without the choke on. Will look at all the cables to the carb and make sure everything is timed correctly next, eventually, when I get around to it. Tom, I go back to your original observations. An additional test is to run it up to the missing point in RPMs ( warm it up first) and pull down the accelerator pump. If it is lean, the RPMs should respond, either flare up or stumble as in overrich. Tim
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Post by tom93gts on Mar 13, 2020 11:55:03 GMT -5
Got the needle and seat sorted out so no more fuel leak, but now I can't get it to rev past about 3500 without the choke on. Will look at all the cables to the carb and make sure everything is timed correctly next, eventually, when I get around to it. Tom, I go back to your original observations. An additional test is to run it up to the missing point in RPMs ( warm it up first) and pull down the accelerator pump. If it is lean, the RPMs should respond, either flare up or stumble as in overrich. Tim Thanks for the suggestions. The behavior is slightly different from original now. Previously I couldn't get it past 3500 unless choke was on, now with choke I can get it to about 4000 but it won't go beyond that even with choke. I'll try your accelerator pump suggestion and see what happens, then go through the PV timing procedure and see where I am with that.
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Post by wayne on Mar 15, 2020 16:35:46 GMT -5
Tom I just had a recollection. I'm sure a friend of mine dealt with a similar issue and it turned out to be a port valve stuck in the closed position.
EDIT: My friend called. The port valve is "hard wired" to the throttle cables. Take the cover off the port valve mechanism and turn the grip. If you can't twist it beyond the point where the two plates touch, then the PV is seized closed. It can be freed in most cases.
If you can twist it smoothly beyond the point where the two plates touch and continue to turn, then no problems with the PV.
The bad news, if your PV is okay, my friend is struggling with a similar problem on a customer's bike at the moment and it's got him stumped. He's the most experienced RE5 fettler we have in this country. He's run through many of things we've discussed. He notes, by putting his hand 'round the back of the carby while accelerating the engine that the instant the the diaphragm arm starts to move the bike simply wants to die as if it's run out of fuel. In your case, I understand the bike doesn't want to die, it just won't accelerate beyond 4000.
I'll keep you posted.
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Post by wayne on Mar 16, 2020 0:21:57 GMT -5
Tom, more from my friend Steve Phelps. This is not a solution (yet) but just read and consider:
"Wayne, just pottering around on Mark’s bike here in between showers his morning. I just read the post on the forum which sounds like the same problem I’m working on Marks bike today… heres what I found so far…
I have a spare carb that I made up from parts etc, not perfect by any means but which seems to work as expected, ie revs freely etc.
I put his carburetor back to original – still has the original problem of dying over about 4000rpm just as the secondary opens – verified by feeling the butterfly lever behind the float bowl. The problem isn’t related to the diaphragm or float bowl upper cover assembly which I swapped over.
It seems his carb body has a problem/blockage around 4000rpm that is stopping secondary system mixture getting through when the secondary butterfly valve is activated…mixture seems too lean at that point.
I then took the vacuum tube off the secondary diaphragm, so only the primary system is operational (and the accelerator pump),ie with no vacuum to the diaphragm the secondary butterfly valve is immobilized to see how it behaves with the primary system only.
I found the primary system alone can get the engine rpm up to around 4000 at about ½ throttle then with more maybe 5000rpm or so but then there is very little further response past 5000rpm the further you turn the throttle, though the engine doesn’t die... 5000rpm seems to be about the limit of the primary system (with no load).
At that speed If I open the secondary butterfly by hand slowly pushing the lever up behind the float bowl, it will take a small amount of secondary throttle valve movement without any significant increase in rpm, but then any further movement of the butterfly and the engine chokes and dies as if out of fuel…It seems the secondary mixture is too lean and fuel isn’t getting through the secondary system as it should…A spray of AEROSTART in there and it revs up to the readline easily…so I’m going back to the fuel passages in the lower carb to see if I can find anything wrong there, as that is the area where the white oxide seems to have developed in the lower fuel passages to the main jets etc. The jets themselves are fine.
That’s it so far….
Steve"
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Post by goandy on Mar 16, 2020 19:06:19 GMT -5
An SU carby conversion will fix the rev problem...
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Post by tom93gts on Mar 17, 2020 10:38:14 GMT -5
An SU carby conversion will fix the rev problem... I keep thinking this same thing, maybe at this point an SU carb would be the easier way to go.
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Post by pmcburney on Mar 18, 2020 19:17:07 GMT -5
Yes and no.
A carb swap will cure the bike of all of its carb-related ills, but its a long and fraught path to go down - AMHIK
First you'll need a carb in good nick, then you'll need to make an intake manifold, rehash the cabling, sort out the oil injection, fit a suitable air cleaner, and then comes the tuning - there's no way on earth you'll be able to fit up just any carb and have it work right out of the box... A member here spent considerable time with an AFR sensor mounted to his bike, many road miles at different loads and rpm and a file to get the absolute perfectly-shaped needle for his SU carb on his bike.
I estimate I've spent hundreds of hours on my carb conversion (Mikuni BST40) and similar dollars and while it works very well, it isn't a quick or easy fix - you'll need plenty of patience and mechanical nous to get it right, and even then it still won't be 'perfect' (ask me about FI...).
Good luck.
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Post by wayne on Mar 18, 2020 19:38:16 GMT -5
Thank you PMCBURNEY for the honest appraisal.
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Post by pmcburney on Mar 18, 2020 19:40:48 GMT -5
Thank you PMCBURNEY for the honest appraisal. It is what it is, mate - stock or aftermarket, carbs on RE5s are a Pandora's box of time, money and angst. BTW, as you know, I blame a certain R Steain for where I'm at now with my carb adventures. The irony...
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Post by wayne on Mar 18, 2020 20:43:37 GMT -5
Dicky? Helping you with an RE5? I've never heard him go beyond "Burn it" for RE5 advice.
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Post by tom93gts on Mar 18, 2020 22:16:21 GMT -5
Today I started off by following Tim's advice and pulling down on the accelerator pump just as I get the revs up to where it stops and I got through. Then I revved up again and it went right through to 6k with no issue again, now it seems to have no issue revving, I wonder if something was just stuck on the accelerator pump and pulling down manually got it freed up? Anyway, it seems I can rev all the way through the range now. We'll see if it's still fixed tomorrow, keeping my fingers crossed on that. Next problem to work on is getting it to idle with the choke off. After warming up it stalls as soon as I switch off the choke. I think last time this happened to me it was the primary jet plugged up, but I just checked it a couple days ago. I'll pull it again but don't have much faith in that.
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Post by timpa136 on Mar 19, 2020 9:35:19 GMT -5
Next problem to work on is getting it to idle with the choke off. After warming up it stalls as soon as I switch off the choke. I think last time this happened to me it was the primary jet plugged up, but I just checked it a couple days ago.
I have had to pull the primary pilot jet out to clean it on a ride. When you do, blow into the empty carb body. Wayne has posted a good PIC
of the small port behind the closed throttle blade to make sure that is clean. Next, Taking precautions for your eyes as Hudson suggests, with
the pilot jet, plug one side hole and spray .with practice, a clean jet will have a smooth round full pattern out the end when it is clean.
I carefully reinstall the o ring onto the jet and oil, lube it up.
Hang in there, you will get it and have that ah ha moment.
Tim
P. S. make sure that vacuum cap has a good cap/plug to prevent a vacuum leak there.
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