Author Topic: Pinking (pinging)  (Read 9141 times)

Online RichardL

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Re: Pinking (pinging)
« Reply #45 on: 08.11. 2009 13:28 »
Well, I don't know if it's really helping a101960, but I'm learning a lot, having read the whole Wikipedia topic "Octane Rating" ( http://en.wikipedia.org/wiki/Octane_rating#cite_note-6 ). I see where the 99 RON corresponds to the typical U.S. premium gas that I use with 9:1 pistons. As to the name of the method used for determining U.S. "octane", I found this:

"...in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2."

However, we just say "octane."

John (a101960),

I see that BP is trial marketing BP Ultimate 102 at a very limited number of outlets but I don't know if any of these are close to you. Nevertheless, I would not think that you should actually need to go that high in RON rating to cure the pings. It's the other possible causes that need to be eliminated.

While I think timing, mixture or coke are still the most likely culprits, I amuse myself by trying to think of obscure causes for problems. I wonder if anyone here has seen examples of head gaskets not quite made correctly, wherein a small bit overhangs the cylinder. (I can't say I've seen it.) Such an intrusion could cause detonation or pre-ignition.

Finally, for now, I think you were being too modest or, maybe, tongue-in-cheek, when you said you were not mechanically inclined. I went back and looked over several of your historic posts and I would have to say they show a lot of knowledge, interest and mechanical understanding. Maybe it's this sticky problem making you less "inclined" to dig into the engine, yet again. Hang in there.

Richard L. 
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline a101960

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Re: Pinking (pinging)
« Reply #46 on: 08.11. 2009 15:15 »
Richard,

I am O.K. with electrics, it's my job - aircraft electrician. I am O.K. stripping down and re-assembling (just a matter of common sense) however, machining and such stuff is way out of my league. I am a firm believer in not messing with tasks that are beyond my capabilities. I truly admire some of the projects undertaken by some of the members of this board, but I am only to aware of my limitations. Returning to the issue of pinking, I noticed that when "The Motorcycle" magazine road tested the RGS back in 1962 when 5 star leaded petrol was freely available the tester commented even than that the RGS was prone to this problem. I have also read somewhere that the A10 cylinder head design leaves much to be desired.

John

Online chaterlea25

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Re: Pinking (pinging)
« Reply #47 on: 08.11. 2009 17:14 »
HI John,
If the problem still exists after you have decoked the engine, try the simple solutions first,
add some octane booster,
I still wonder if the 99 octane petrol you buy has been sitting there too long due to not enough customers for it, it goes off fairly quickly
Try some colder running plugs  NGK B8's or equivalent.

Another thought does your bike have a siamise exhaust system and Goldie type silencer?
make sure there are no leaks on the exhaust system, (a bugger with the siamise setup)
I just wondered are you hearing the "goldie twitter"? or blow at a joint due to vibration/ stress at a certain speed

Have you checked the fuel flow from the tank / taps, carb banjo, etc to make sure you have a good and constant flow to the main jet,

I remember having to rebuild a Triumph T140 which holed a piston because the owner had'nt switched on the second petrol tap before going on a long dual carriageway journey,
Apparently at a certain speed /vibration level, fuel was not reaching the carb farthest away from the one tap that was on!
HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline t20racerman

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Re: Pinking (pinging)
« Reply #48 on: 22.08. 2011 19:23 »
Now that my A10 is run in and being thrashed I think I can add some thoughts and observations.

My bike has 9.1:1 pistons, spitfire cam, SRM crank, polished rods, nitrided crank etc and it has always been ridden hard. It has been off the road for 11 years, until recently, and always used to pink under load but not at constant fast cruising speed (70-85mph). I used to use normal 4* and simply stopped the pinking by backing off the manual timing a bit when loading it up.

It is now rebuilt but with gas flowed head and bigger 32mm concentric Carb.I took it for its first long and quick run this weekend and the pinking was awful. I too used 99 octane fuel. Without a manual advance and retard mechanism it would have been totally unrideable! (You need to get manual).

When cold it loves full advance and doesn't pink for the first 8-10 miles. After this it pinks badly under load AND at constant cruise mode too. To really accelerate fast you have to retard the ignition big time as you give it a handfull. You can then accelerate very quickly indeed - flying past cars, trucks etc. To maintain a fast speed you have to leave it retarded a fair bit too.

However when you slow down it coughs and splutters due to the retard and you have to advance the timing to ride slowly in traffic.  Seems odd, but for slow running I have a lot of advance, and a LOT of retard for high speed.

Seems to me that your only solution is the manual advance and retard - and like me you'll have to adjust the timing all the time on the move, and move it the opposite way to which you might expect!

Incidentally, my racing two strokes all have ignitions which retard as the revs rise.

EDIT
One other thing - I'm using the B10 something-or-other plugs out of my TZ350 as these are much cooler. I'm going to investigate cooler plugs that help prevent pinking in the near future.
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Offline A10Boy

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Re: Pinking (pinging)
« Reply #49 on: 22.08. 2011 20:42 »
Totally different opinion.

The best solution in my view would be to ditch the 9:1 pistons and fit some nice 7.25:1 pistons and that's that. Way high compression in ancient engines with modern fuel just doesn't work.
I wonder why anyone would build an engine for road use that is virtually un rideable and would destroy itself with excessive detonation, it's beyond my understanding to be honest.  *conf*
Regards

Andy

1960 A10 - Black Golden Flash
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1974 Kawasaki Z1a
Yam XJR 1300

Online bsa-bill

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Re: Pinking (pinging)
« Reply #50 on: 22.08. 2011 20:59 »
Not un ridable Andy, my project went through a bit of pinking but mostly I managed to tune it out, but I have ditched the 9:1 in favour 8:5 mostly to try to get the thing to reliably start, this again is I reckon down to a maggie not being up to full spec.
There can't be any combinations of pistons, cam, whatever that have not been done over the years to these bikes but to a new owner (or not so new) it still a thrill to do it your own way - because you can
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline t20racerman

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Re: Pinking (pinging)
« Reply #51 on: 22.08. 2011 21:32 »
Not un ridable Andy, my project went through a bit of pinking but mostly I managed to tune it out, but I have ditched the 9:1 in favour 8:5 mostly to try to get the thing to reliably start, this again is I reckon down to a maggie not being up to full spec.
There can't be any combinations of pistons, cam, whatever that have not been done over the years to these bikes but to a new owner (or not so new) it still a thrill to do it your own way - because you can

Agree with that Bill - not unrideable at all - just takes a bit more fiddling with and the end result is that I have a VERY quick A10 with the low down grunt of a tractor, which is exactly what I wanted. My 300 mile round trip this weekend seems to refute the 'unrideable' tag as I had a brilliant time.  *smile*

I like to ride my bikes hard and fast and if to do this I have to fiddle with the advance and retard mechanism, so be it. Certainly cheaper than a new pair of pistons.  *smile*
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Offline BSA_54A10

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Re: Pinking (pinging)
« Reply #52 on: 23.08. 2011 11:52 »
And I bet you were all waiting for me to say it so here it is;-
Fuel is not petrol
Petrol as we knew it no longer exists
Fuel is designed to be burned in computer controlled fuel injected engines
Not in viscosity/volume controlled motorcycles.

In a large part, fuel contains most of the hydrocarbon byproducts that are no longer allowed to be used in industry.
The composition can vary day to day.
The only stable consistent "fuel" is avgas
Bike Beesa
Trevor

Offline A10Boy

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Re: Pinking (pinging)
« Reply #53 on: 23.08. 2011 12:59 »
t20racerman
Quote
Without a manual advance and retard mechanism it would have been totally unrideable! (You need to get manual).

Just offering the other opinion, you dont necessarily need to get a manual if you use pistons with a CR more suited to todays fuel. Its a matter of choice of course and that would be my choice. Having said that, I have an AJS CSR with high compression pistons and a Manual mag and it's great fun.  ;)



Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline t20racerman

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Re: Pinking (pinging)
« Reply #54 on: 23.08. 2011 13:48 »
The only stable consistent "fuel" is avgas

Very true. Use it in both my racebikes, and the A10 ran superbly on it. Only problem is that it is almost unobtainable in the UK now - being illegal to sell it to anyone other than those directly filling up an aeroplane!

I'm going to try to richen it next by raising the needle and fiddling with the jets and slide cutaway. A powerjet Carb might help as well..  I'll keep you posted  *smile*

1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Offline Topdad

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Re: Pinking (pinging)
« Reply #55 on: 23.08. 2011 14:33 »
This may sound daft but do you live near an airfield with light aircraft? If you do give any of the operators a call and see if they will sell you some avgas . As near to "proper petrol " as you could get and if it still pink's it's head off and you've checked out what the other guy's have suggested then you've got to  have a look at the top end or valve timing for a problem, regards BobH.
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Offline A10Boy

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Re: Pinking (pinging)
« Reply #56 on: 23.08. 2011 20:01 »
Trev

I would have put money on it !!!  *smile*
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline Rich

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Re: Pinking (pinging)
« Reply #57 on: 23.08. 2011 20:35 »
To get back to the original post, going up a hill at 50 to 55 in top and opening the throttle to maintain the speed is probably the reason why A101960 bike pinked in the first place, surely a gear change would have been more appropriate to maintain the revs so as to lighten the load on the engine.
Timing wise we have set it up from 31 degrees through to 35 degrees in stages using a timining disc making some difference to the overall preformance.
I have a similar engined bike (super rocket) be it a bit more run in than John's but I do not load the engine going up hill in top when I can fly up the hill in 3rd.
On another note is John still about? I have not seen a post for from him for some time

Offline cyclobutch

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Re: Pinking (pinging)
« Reply #58 on: 25.08. 2011 19:01 »
Thinking that I might be getting a little pinking off my iron head when at lower revs, in lower gears. I've covered 1300 miles or so now since it was all put back together. I run the highest octane I can find at the pumps and also add Castrol valve master with octane booster. Seems OK in top gear. I certainly didn't notice anything amiss in the first 1000 miles or so although I have been taking it easy running it in. I've got a concentric fitted, but all in I'd have to say she's running very well.

Back in the day the bike had a tendency to blow head gaskets, slightly concerned that the noise I can hear might be that - it always first started manifesting itself in that way i.e under load. Checked the points and all looked clean and gapped OK. I gather that if I want to speculatively back the ignition off a little (auto advance on my mag) I have to go in through the timing side. I guess I could tighten the points gap a little.

Plugs in the bike are B6HS, Haynes says B7HC, should I consider changing these perhaps?
Various, including ...
'58 Iron Head Flash Bitza


Offline t20racerman

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Re: Pinking (pinging)
« Reply #59 on: 25.08. 2011 22:53 »
Plugs in the bike are B6HS, Haynes says B7HC, should I consider changing these perhaps?

That seems a very hot plug to me! With NGK the higher the number the cooler the plug. B6 seems way too hot. Try B8HS if you think your engine is pinking. I run B10s in mine!
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"