Detonation
Seasoned HDF Member
Joined: Jul 2007
Posts: 6,336
Likes: 67
From: SW Minnesota
With all due respect, many of us believe you are accelerating from too low of an rpm, and shifting way to soon. IMO, your minimum RPM after a shift, while accelerating, should be no lower than 2500. If I read your posts correctly, you're shifting up at 2500 rpm. Check your dyno chart and see where your engine is making power, i.e., running efficiently. You will probably see it is substantially higher than 2000 - 2500 rpm.
You don't have to believe the forum members....try reading some of the technical articles written by Donny Peterson or Joe Minton about how the TC engines like higher rpms, such as
http://www.americanrider.com/output.cfm?id=1021915
"In the second example cranking pressure and ignition timing are the more likely causes. Too much compression can lead to detonation. To oversimplify a bit: as the compression pressure goes up, the air/fuel mixture burns faster and can explode (detonate). A fast-burning mixture at low piston speeds can create the high-pressure condition needed to initiate detonation. The common cure for this problem is to use an ignition that has a slower advance curve, one that fires the spark plugs later in the lower rpm range. Higher octane gasoline may also help. You may have to lower the compression ratio, an expensive matter. Most importantly, never heavily load your engine below 2,500 and better yet 3,000; instead downshift and use a lower throttle setting to accelerate. "
You don't have to believe the forum members....try reading some of the technical articles written by Donny Peterson or Joe Minton about how the TC engines like higher rpms, such as
http://www.americanrider.com/output.cfm?id=1021915
"In the second example cranking pressure and ignition timing are the more likely causes. Too much compression can lead to detonation. To oversimplify a bit: as the compression pressure goes up, the air/fuel mixture burns faster and can explode (detonate). A fast-burning mixture at low piston speeds can create the high-pressure condition needed to initiate detonation. The common cure for this problem is to use an ignition that has a slower advance curve, one that fires the spark plugs later in the lower rpm range. Higher octane gasoline may also help. You may have to lower the compression ratio, an expensive matter. Most importantly, never heavily load your engine below 2,500 and better yet 3,000; instead downshift and use a lower throttle setting to accelerate. "
Thread Starter
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Cruiser
Joined: Nov 2006
Posts: 100
Likes: 0
From: Central Florida
I guess I will try to explain it one more time, it has nothing to do with what RPM I am riding at etc. Use this example and maybe I make people understand what I am talking about.
I am sitting at a dead stop at a red light, the light turns green and I release the clutch and give the bike gas, If I do nothing other than accelerate, when I reach 2000 RPM's, the engine starts pinging. Can I make it any clearer what I am talking about. I am not talking about riding along in 6th gear doing 45 mph, I am talking about any time the bike hits 2000 RPM's under any circumstances it Pings. I apologize for confusing everyone and possibly offending anyone because I am incapable of making people understand the issue, I will take it to the Dyno guy and see if he understands what I am saying. Thanks guys.
I am sitting at a dead stop at a red light, the light turns green and I release the clutch and give the bike gas, If I do nothing other than accelerate, when I reach 2000 RPM's, the engine starts pinging. Can I make it any clearer what I am talking about. I am not talking about riding along in 6th gear doing 45 mph, I am talking about any time the bike hits 2000 RPM's under any circumstances it Pings. I apologize for confusing everyone and possibly offending anyone because I am incapable of making people understand the issue, I will take it to the Dyno guy and see if he understands what I am saying. Thanks guys.
Tourer
Joined: Sep 2010
Posts: 471
Likes: 9
From: Far NorCal
OP, you said, "I still have the detonation right around the 2000-2500rpm range if I jump on it a little bit".
I thought just as others, you're too low on R's for JUMPING on it...so it made me wonder if you know you should shift down!
my 2 cents..bye bye
BTW, good luck with the problem.
I thought just as others, you're too low on R's for JUMPING on it...so it made me wonder if you know you should shift down!
my 2 cents..bye bye
BTW, good luck with the problem.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
I would go with '05Train's suggestion, He's ot a lot of experience with tuning. Whether its, your riding style, too much compression, octane, or your're just too large, retarding the timing in the narrow problem area should take care of it.
Road Warrior
Joined: Aug 2010
Posts: 1,268
Likes: 8
From: Detroit, the asshole of America
I wouldn't accept "they all do that if you give it heavy throttle from 2200 rpm" as an answer, that's a copout excuse from a lazy tuner who didn't calibrate it correctly.
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HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
Glider,
Although it does sound like it could be detonating, the fact that it occurs at 2000 rpms in any gear has me thinking. If the noise comes on at 2000 and goes away as rpms increase, it could easily be something else.
Another forum member posted recently with a similar situation, even attached a video/audio. The noise sounded very much like detonation but it only occcured at 3000 rpms at cruise. The source was a busted front motor mount.
Sure, you should have timing checked but I wouldn't be surprised if, after a tune, the noise is still hanging around. Just a thought that something about the collective harmonics at 2000rpms brings two parts into contact??
Although it does sound like it could be detonating, the fact that it occurs at 2000 rpms in any gear has me thinking. If the noise comes on at 2000 and goes away as rpms increase, it could easily be something else.
Another forum member posted recently with a similar situation, even attached a video/audio. The noise sounded very much like detonation but it only occcured at 3000 rpms at cruise. The source was a busted front motor mount.
Sure, you should have timing checked but I wouldn't be surprised if, after a tune, the noise is still hanging around. Just a thought that something about the collective harmonics at 2000rpms brings two parts into contact??