Pinging/detonation
- bikeymikey748
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- Location: Montreal, Canada
Pinging/detonation
Took the ‘X’ out for its first run last weekend.
No bueno
The motor’s ‘pinging’ noticeably under load (accelerating from a stop/lugging it in a higher gear). Runs without issues under any other circumstances/rpm./road speed.
It’s never done this before. Nothing was done over the winter that might have precipitated this, premium fuel made no difference.
Checked timing thinking it might be too advanced. Seemed ok, though moving the backing plate over a broad range affected the timing very little. You’ll recall I made a clear cover for the RH motor end-cap and set the timing dynamically (engine running) with a timing light. Advancer function seemed fine as well, but did not verify its function at various rpm’s other than for full advance.
I’m thinking the 42-year-old springs on the advancer unit may have lost tension and timing is advancing too soon. As well, the idle speed is sometimes slow to drop down when the throttle is closed (another advancer fault indicator?). Still waiting on arrival of NOS advancer unit.
Finally, noticed worn area on the advancer unit tip. Very slight contact on the 1-6 pick-up. Pickup is secure, and there is very little play on the advancer shaft.
Any thoughts on the issue while I await the new advancer, anything I might have missed, anyone else have a similar experience?
Mike C.
No bueno
The motor’s ‘pinging’ noticeably under load (accelerating from a stop/lugging it in a higher gear). Runs without issues under any other circumstances/rpm./road speed.
It’s never done this before. Nothing was done over the winter that might have precipitated this, premium fuel made no difference.
Checked timing thinking it might be too advanced. Seemed ok, though moving the backing plate over a broad range affected the timing very little. You’ll recall I made a clear cover for the RH motor end-cap and set the timing dynamically (engine running) with a timing light. Advancer function seemed fine as well, but did not verify its function at various rpm’s other than for full advance.
I’m thinking the 42-year-old springs on the advancer unit may have lost tension and timing is advancing too soon. As well, the idle speed is sometimes slow to drop down when the throttle is closed (another advancer fault indicator?). Still waiting on arrival of NOS advancer unit.
Finally, noticed worn area on the advancer unit tip. Very slight contact on the 1-6 pick-up. Pickup is secure, and there is very little play on the advancer shaft.
Any thoughts on the issue while I await the new advancer, anything I might have missed, anyone else have a similar experience?
Mike C.
- NobleHops
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Re: Pinging/detonation
Mike, check for the little pin in the advancer shaft that engages the detent on the bottom of the rotor. They can fall out and the variable timing can cause Interesting Things,
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)
Tucson, Arizona, USA '80 CBX, sort-of restored :-)
- bikeymikey748
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Re: Pinging/detonation
Thanks for the input, Nils, but nope…that little buggar is still there.
Got to thinking…the timing marks are only for cylinders 1&6, you can’t verify the timing for the other pairs individually. That assumes I guess all the pickups are properly positioned. I checked, mine were not. The distance between the centers of the pickups was not the same. As well check the photo.
I came up with this to verify the pickup orientation. The angles are drawn at 120deg. You can note the upper one (1&6) is not in line as it should be. I believe it’s position is such that when adjusting the timing for this trigger, the other two will actually have their timing be advanced slightly. Seeing as the mounting holes are elongated I have corrected for this.
Hopefully, the new advance unit will only help out as well. Stay tuned for updates.
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Re: Pinging/detonation
Also check the clutch cover bore where the advancer shaft rides. These can gall and eventually seize.
Dave
Dave
- NobleHops
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Re: Pinging/detonation
That seal acts more or less as the bearing, no harm in replacing that if the clutch cover is off.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)
Tucson, Arizona, USA '80 CBX, sort-of restored :-)
- bikeymikey748
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- Location: Montreal, Canada
Re: Pinging/detonation
Thanks, Dave, for chiming in. I’m always worried about those and check them any time the cover is off. Though, no unusual deposits in the sump since the rebuild and very little play on the shaft (I checked it during the course of this latest mystery).
Good idea, Nils. I replaced all the engine’s seals during the course of the last recent rebuild. I don’t imagine this particular one could be problematic so soon? Still, the source of my woes is as yet an unknown, so…
- shiskowd
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Re: Pinging/detonation
Mike - as I've posted before I'm a fan of Ignitech digital ignition kits for the CBX. They eliminate the troublesome ignitors, use stock 2.2 ohm coils and provide an option to freeze the advancer mechanism to use a digital ignition map to take care of the advancing. Completely plug & play for both the 'Z and Prolinks (I've used on both). They also only use one of the pickup coils for timing (like a crankshaft position sensor on a modern engine) so the pickup spacing is a non-issue. All for $216USD plus shipping.
https://www.cbxclub.com/forum/viewtopic ... 950#p97950
Rol (land of Oz) sent me ignition maps that's he's tested/dyno'd with non-race engines that work great. Something to consider.
https://www.ignitech.cz/en/
https://www.cbxclub.com/forum/viewtopic ... 950#p97950
Rol (land of Oz) sent me ignition maps that's he's tested/dyno'd with non-race engines that work great. Something to consider.
https://www.ignitech.cz/en/
2022 KTM 890R, 1982 Pro-Link, 1979 CBX 'Z, 1975 Moto Guzzi 850T
Long Sleeping '79 CBX Restoration > viewtopic.php?f=102&t=11699
Long Sleeping '79 CBX Restoration > viewtopic.php?f=102&t=11699
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- bikeymikey748
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Re: Pinging/detonation
Gotta say that Ignitech ignition sounds like one hell of a deal.
With shipping/taxes/duty my NOS advancer costs is kinda pricey for what it is.
Still…fingers crossed it’ll solve my problems, will know in a few more days it’s inbound.
With shipping/taxes/duty my NOS advancer costs is kinda pricey for what it is.
Still…fingers crossed it’ll solve my problems, will know in a few more days it’s inbound.
- bikeymikey748
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Re: Pinging/detonation
So…this came today.
Night & day difference! Though my ‘calibrated’ thumb and forefinger could not detect much difference in the spring tension between the old bit and the NOS part, the change in how the X now runs is impressive.
Night & day difference! Though my ‘calibrated’ thumb and forefinger could not detect much difference in the spring tension between the old bit and the NOS part, the change in how the X now runs is impressive.
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Re: Pinging/detonation
Glad to hear the short riding season is back on.
20 years ago the 469A was available from Honda for around $100.00.
Just curious as to the cost and source of yours.
20 years ago the 469A was available from Honda for around $100.00.
Just curious as to the cost and source of yours.
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Re: Pinging/detonation
So you are saying the old advancer/springs were the problem? This is curious and most interesting.
Dave
Dave
- bikeymikey748
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Re: Pinging/detonation
Seems like.
I bought THIS last fall (the Yamaha, not the church ).
Slow to return to idle/erratic idle, and poor drivability. A quick look revealed a tired mechanical ignition advance mechanism. I played around with the springs and voila! Thankfully, it kinda pointed me in the right direction with the ‘X’, though the detonation of the Honda was much more apparent when accelerating. The spring condition wasn’t as obvious as those on the Yamaha and seeing as the Honda is a motor that likely would not suffer McGyvering such an important unit without dire consequences I found a NOS replacement, and gave it a whirl. It sure made a difference. I’m guessing the 41-year-old original’s springs had lost some of their tension and the timing was advancing too much, too soon.
I didn’t verify the old unit with my timing light (it has an ignition advance function) before leaping to replacing it.
Maybe when we get ANOTHER rainy day I’ll throw it on and see exactly how much it was advancing the timing at certain RPMs.
- bikeymikey748
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Re: Pinging/detonation
Would you believe $210.00 CDN, from the good folks at CMS?steve murdoch icoa #5322 wrote: ↑Wed May 17, 2023 9:27 pmGlad to hear the short riding season is back on.
20 years ago the 469A was available from Honda for around $100.00.
Just curious as to the cost and source of yours.
They mistakenly shipped me a 469 unit at first, refunded my taxes/duty on that unit and then found the proper 469A replacement and told me to keep the 469, it was too convoluted/pricey to interest them in having it back.
So now my ‘X’ runs as God and Irimajiri san intended and I have a nifty paper weight