Hi Guys,

I have owned my bike for about 5 weeks, it's bone stock and this is my first HD. While babying it through break in I did not really notice much in the way of detonation, but then again I was easy on the throttle and easy on how much throttle I gave it. Now that I am through the 500 mile break in and able to go up in RPMs I am getting a lot of detonation (at least that is the sound I think it is from reading through the forums). The sound is sort of an unmistakable clatter, rattling sort of like a diesel engine, or like a car about to stall and it happens only when the bike is hot and under load (a hill, going on to the freeway etc).

Of course it is hot where I live (I live in Central TX), but there is nothing I can do about it. It gets to be over a hundred for months and months at a time. Over half the year it's above 90, and as I understand it these bikes are running lean. I took it to the dealer and they said it sounded like a Harley and to bring it back if I kept noticing the sound... I made sure that a tech rode it before I came back for it and someone did for about 10 miles. Unfortunately, I noticed the sound on the 35 mile ride home (as I usually do)! And then again every time I rode it this week. And I am under the impression that I am damaging it every time I hear it.

Yes, I could baby it like I did for the first 500 miles and yes I could slowly, methodically rev out each gear to make sure that I don't put it under a too much load, but I don't think I should have to do that.

In looking over threads for the last 5 hours I see a lot of problems after mods have been done, which leads me to believe that my stock bike should not be pinging. If this is a common problem for EFI sportsters then is there a simple solution? I know if we were talking about pre-07 I would just re-jet, but what do I do with an EFI bike? Is it right that I am a bit surprised that a $13k OTD bike in 2011 is detonating?

I have noticed a bunch of people say to tune it but that is major bucks! I did not buy this bike to have to tune it to ride it and planned to slowly mod it over the years.

Anyhow, I appreciate any help or insight y'all can give!

Thanks!

 

Are you sure you're not hearing the valve train? It's common to hear what sounds like a sewing machine coming from the engine, especially with stock pipes. If you are hearing what sounds like rocks being rattled in a can, then you may have a problem.

What grade of gas are you using? That could be another issue, if you are using low grade gas the engine will not run optimally.

If you're not convinced with what your dealership told you, take it to another or and Indy and tell them your problem. If they tell you the same, then you have confirmation. If not, then you'll have your problem solved.

 

Hi, thanks for the response!

I use 93 octane only. The sewing machine sound doesn't bother me as I expect that and have heard that since the day I started her up. The sound I am hearing sounds like this (and it happens around 3500 rpm (that's a guess because I don't have a tach):

http://www.youtube.com/watch?v=XiBzxxvy3FQ

It's that dieseling clatter, knocking, rattling sound.

 

theres a chance the rpm isnt as high as you think vs. your load and actually lugging the motor which will be excessive shaking and knock. With the stock pipes is hard to judge rpm well. Mine use to lug a bit. After i added my slip-ons and Xied's it pretty much cured that. I think part of it is now i can actually hear the exhaust and not just the valvetrain and better judge engine rpms and shifts.

 

Yup, was about to say the same thing. The only time I've heard my bike make any noise similar to that is when I accidentally miss a shift and lug the engine a bit.

Try revving the engine a bit higher than you usually do and see if it still has the issue.

 

First HD... Without a doubt you are lugging the engine. These engines like to be at high RPM. About what speeds have you been shifting at? I usually shift into 2nd around 25-30, 3rd at 40, 4th at 60, and 5th anything above 70. That's just me though.

 

I typically shift into 2nd at 30, 3rd at about 45, 4th about 55-60 and I really don't use 5th that often (TX cops are everywhere and the speeds where I ride don't go above 65). That seems like the RPMs are high enough and even when I really rev it out (I mean carrying second out to about 55) it happens at about 50... I have ridden dirt bikes for the last 20 years and I am used 12.5K rev limits so I am not worried to wind her up a bit, but then that sounds starts happening... It does not happen at low RPMs it happens at high RPMs, under load (or that is what it seems like to me). With those shift points do you think I am lugging it? Or is this a matter of running lean and detonation occurring? Again, I appreciate the help guys!

 

I have 17,000 on 2007 1200C, my shift points work to be a lot lower than yours. The comfort zone for my shift points is approximately 10 times the gear I'm in, normally I shift into 2nd at 20, 3rd at 30, 4th at 45 and 5th at 55. 53 is about as slow as I can go in 5th and then only on the level. A time or two I've had it near 80 in 3rd but I seldom push it that hard. Sportsters are long legged.

 

The problem was indeed detonation due to running lean and extreme heat. Got some VIED's and dropped it down to 13.8 AFR and most of the detonation is gone. Also got an oil temp gauge and found that it was getting pretty hot on the days where temps were breaking 110 so also got an oil cooler. To further help it along I am also using octane booster and so for the most part it is solved.