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07-10-2021, 12:17 PM | #31 | |
Registered User
Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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Quote:
If you are getting new pick ups, you can get them from Electrex World £36 each Type P08. 460 ohms. Or with a bit of modification Brads suggestion Yamaha CY-7, 200 ohms But you might as well wait till Ive tried!
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Golf-My favourite game. While my wife plays I'm in the workshop. |
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07-10-2021, 12:44 PM | #32 |
Lord of the Rings
Join Date: May 2013
Location: Norwich
Bike: M900sie
Posts: 5,936
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Despite what you have been told by an expert, pickups and also crankshaft position sensors do fail intermittently. This is usually brought on by rising heat. After the engine has cooled down the sensor/pickup will function again.
Yours is not a heating problem, but rather affected by increasing revs. In my mind I don't see why a weak pickup would fail to see the trigger as it sped up. I know that it interrupts a field, but not what is producing the field. If it is the sensor then replacing it should restore the field, but if it is the trigger, then that should be suspected.. Unless of course the trigger is common to both pickups? A high resistance connection somewhere in line between the pickup and igniter might cause this problem, especially if the current decreases with revolutions. Or maybe just the subtle increase in vibration could jiggle a connection out of contact? I'm sure that the pulse from the pickup is quite a low current? So wouldn't put up with much interference?
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07-10-2021, 01:28 PM | #33 |
Registered User
Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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It is common , isnt it, its the raised lump on the flywheel that passes both coils. That leaves the pick up.
As Sherlock said When you have eliminated the impossible, whatever remains, however improbable, must be the truth.
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Golf-My favourite game. While my wife plays I'm in the workshop. |
07-10-2021, 02:06 PM | #34 | |
No turn left unstoned
Join Date: Jun 2010
Location: leicester
Bike: M750
Posts: 4,555
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Quote:
The way I see it, once you've eliminated the impossible, whatever remains is nothing more than "the possible" ..... of which there may be many variants. But then again, why would you believe Sherlock ? After all, his very existence defied "the truth". I know that isn't of much (if any) help in solving your problem though. I remain intrigued and wish you luck. An afterthought ...... Could it be that both your cylinders, and Jerry's, have developed vertigo in their old age ? |
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07-10-2021, 04:02 PM | #35 |
Registered User
Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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No cant be that...one of the tests I did was to start the bike rotated 90 degrees, but the fault remained on the back cylinder!!!
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Golf-My favourite game. While my wife plays I'm in the workshop. |
07-10-2021, 04:35 PM | #36 |
Old Git
Join Date: May 2006
Location: Cricklade
Bike: Multiple Monsters
Posts: 2,872
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vertigo !!!!???? ha ha im ust more confued than ever ,, but Patrick and me can try and co-op on this ,, It was made by Italians so we should be able to sort it out ,,'' in vino veritas[''
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08-10-2021, 11:53 AM | #37 |
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Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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I wont break open the champagne yet, but I think I may have solved the issue! I need to balance tune and road test yet.
This morning I installed a new pick up coil for the vertical cylinder. On start up with the colourtune in place on the vertical I was immediately able to see it was receiving a spark and firing throughout the rev range. I then set up the strobe and again I was now able to see the strobe working at all engine speeds, I was also now able to confirm that the dynamic timing was spot on at both idle and revs. So it would appear that it was indeed my vertical pick up coil that was causing the issue. Inspite of inspecting the old coil carefully I could see no fault on it , let alone a fault that might only develop at speed. In summary, for a fault on firing of a single cylinder, it is relatively easy to swop coils, HT leads, plugs, LT wiring to see if the fault changes cylinder. A fault in the carb or pick up does involve a bit more dismantling and rework effort. The fault can be made all the more opaque by apparently seeing the correct resistance in what turned out to be a faulty pick up coil. I would also now recommend using a Colourtune, (not necessarily as a quantative analysis tool for tuning), but theres nothing like being able to physically see into the firing (or in my case, non firing ) chamber. Although the non working strobe at revs was indicating the same thing the colourtune let you physically see the spark stop working as the revs were raised. So it may be axiomatic that you find the fault in the last place you look........but its always a shame when its the last place you COULD look rather than the first!
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Golf-My favourite game. While my wife plays I'm in the workshop. Last edited by PPuxley; 08-10-2021 at 11:58 AM.. |
08-10-2021, 12:45 PM | #38 |
Lord of the Rings
Join Date: May 2013
Location: Norwich
Bike: M900sie
Posts: 5,936
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Eureka!
It was screaming pickup to me, but it doesn't help when people tell you that pickups either work or don't work. So what we have learned here is that not only can a pickup failure manifest when it gets above a certain temperature, but also when engine revolutions exceed a very low threshold. This proves that they can work just a little bit, but not enough! I'm delighted you've cracked it and without mauling the carbs too. You only ever find what you're looking for in the last place you look unless you insist on continuing to look after you've found it..
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08-10-2021, 12:54 PM | #39 |
Bronze Member
Join Date: Nov 2016
Location: Glasgow
Bike: M1100evo
Posts: 267
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Excellent news ! Waiting intently on the report of your shakedown run and pics of the final job. Smashin’.
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08-10-2021, 01:01 PM | #40 | |
Transmaniacon MOC
Join Date: Sep 2013
Location: Sutton In Ashfield
Bike: Multiple Monsters
Posts: 6,085
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Quote:
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Roast Beef Monster! Termignoni and Bucci - Italian for pipe and slippers! S4 Fogarty, S4R 07T, 748, Series 1 Mirage |
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08-10-2021, 02:39 PM | #41 | |
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Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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Quote:
Just taken it for a spin up the lane , less than a mile round trip. Well, thats better! When I said it was running a bit flat before, it certainly was, I was riding a 450 single dragging another dead 450 around!! Just a tad crisper now Weather looking a bit grim here so thats it for today. Thank you for all your input. But here are the requested piccies of the finished article (which have actually been posted already on the build blog) Album
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Golf-My favourite game. While my wife plays I'm in the workshop. |
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08-10-2021, 02:51 PM | #42 |
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Join Date: May 2007
Location: Stockbridge
Bike: M900
Posts: 1,984
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Yay!
(It’s obvious now you’ve found it)
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08-10-2021, 02:59 PM | #43 |
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Join Date: Apr 2021
Location: Reading
Bike: M900
Posts: 600
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Of course I knew exactly what it was all along and was only doing it for all of your entertainment.
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Golf-My favourite game. While my wife plays I'm in the workshop. |
08-10-2021, 04:44 PM | #44 |
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Join Date: Sep 2020
Location: Nairn
Bike: S4r
Posts: 99
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So glad you found the issue, even if it did lead you a merry dance!
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