My bike's been great since doing the 883 to 1200/Thundermax conversion and now that the bike is more fun to ride I've been giving it some hefty throttle around town.  One thing I've noticed though is a rattling sound coming from the left side when I accellerate really hard.  I was wondering if anyone has any idea what it might be?

I've read that the clutch spring on the 883 is weaker than the 1200, so I'm still running the 883 clutch spring, could the clutch be causing the rattling?

 

King chops are you sure its not "pinging" that youre hearing?

KC,

Mine was doing something similar a while back. Drove me nuts. Turned out to be 2 noises Occasionally I got pinging. That stopped when I switched to only using 98 octane fuel. 

FYI,  The hotter your engine is, the more likely your engine is to ping. The farther your timing is advanced, the more likely your engine is to ping. The higher your compression ratio is, the more likely your engine is to ping. The lower the octane of gas you use, the more likely your engine is to ping.

Another annoying rattle, also under heavy load turned out to be one of the clamps that holds the shield around the engine exhaust pipe. It was tight when cold, but became loose only when very hot!  Took me a while to find it!

Hope this helps ya.

Mungrel

 

Thanks guys, did a bit of reading about pinging after you all mentioned it and it sounds just like the problem.  Would also make sense considering the higher compression with the big bore kit now fitted.  Last time I filled up I think it was with 95 so I'll try it specifically with 98 octane fuel and see if it occurs again.

Found a good write up on it here: http://www.dansmc.com/gas.htm

Thanks for your help.

 

 

KC, what AFR are you running?

Mungrel, I had the same thing. Tightened the heat shield clamp up and away went the noise.

Greg,

Not sure, I've just received the cable to allow me to plug the Thundermax into my laptop so I'll check it out tonight and let you know.

Greg,

AFR both front and rear is: 9.30

Alby,

Thanks for the suggestions but I'm pretty well convinced it's the pinging issue, I'll drain the fuel over the weekend and put 98 octane in there and I may also play around with some alternative maps on the Thundermax.

KC

I changed my overall AFR settings in the program by clicking the configure button and selecting closed loop module settings. click in the box next to AFR overide enabled. From there you can adjust your AFR to see if there is any change. I went from 13:1 down to 12.7:1 which works for me. Its is worth having a fiddle, as long as you don't make crazy adjustments all should be good. If where you go isn't any better just go back to your start point.

Greg/Alby,

Yep was reading about both in the Thundermax manual last night, I will definately experiment with those over the weekend. In fact it would make sense to try those before I change the fuel as I would prefer to know that it works with any fuel that I use.

I finally got a chance to try fine-tuning my Thundermax to get rid of the pinging. I tried several things, ie I tried going to the 309 Sportster map to see what a difference that would make, but that generally ran worse than the 415 map. The 415 is newer so no surprises there. I re-loaded the newer map - 415, but I also increased the accelleration fuel to 12.5 in "Basic Settings" and the pinging is gone. I gave the bike a few good "drag" runs and didn't hear any of the pinging. And I'm still running on premium 95, so next fill I'll be sure to get 98 but it's good to have solved it without changing fuels.

RT,
The setting for accelleration fuel for the 415 map was also 12, the pinging was the same when I ran on either map, the 309 map generally ran worse in terms of over-all power and I also got an engine temp light when I ran that. Yep, might try increasing it to 13 and see how that goes.

Waaaaayyyyy too much money for a dyna KC...............but nowhere near enough for a softail.