[dsn_klr650] dyno runs

[Ted Palmer]

ChrisRl wrote:

> Well I removed the airbox from my KLR 250 and drilled some extra holes > near the intake periscope. The air intake area is now about x3. I > cleaned the box and replaced it. Now when the engine is seriously > pulling, revs high or low the engine is noticably louder, more of a > hollow and loud sounding engine noise. Why is this?

It's just like drilling some extra holes in an exhaust muffer. The airbox is designed to be a muffler for the intake system.

> Something to do with the petrol/air ratio?

I doubt it.

> Would it be lower with air finding its way > into the carb easier now? I know I'm a bit alone on this as this mod is > on a 250...but in principle you 650 guys should have a few answers.

Yes, the principles are the same. Just about any mod that changes the airflow through the airbox will change the way the airbox deals with the pressure waves coming up from the intake.

> Would altering the carb for a slightly richer mixture reset matters and > provide some more power....perhaps?

It probably won't change the sound from the airbox but you might get a bit more power. Maybe. Did you do a dyno run to establish a baseline before you changed anything? Mister_T

[Alan L Henderson]

At 08:59 AM 5/14/2000 -0500, you wrote:

>Hi All, > >Well I scanned the dyno run graphs on my old scanner here at home. >Unfortunately, if I raise the scan resolution to make the graphs legible, >the files are about 7MB each. Even the zipped version of the two graphs is >about 5MB. I think these files are just too big to post to a list. They >take forever to send/download. > >I'll try a different scanner tomorrow and try to get smaller, postable >files. There are no earth shattering revelations in the runs, but I do >think the group will be interested in seeing how a stock A13 performs on the >dyno. > >Jim

Typically scanners default to .bmp or some other non compressed format when saving. This makes the files very large as you have found out. Load the graphics program that you use the scanner with, load the picture file back into the program and than go to the "save as" in the file menu. Choose "jpeg" might be listed as "jpg" and under the options set the compression at about 60 to 70 provided that 100 is the best quality and 0 is the most compression. Save the file in this format then check the file size, should be much smaller. The jpg picture format always uses compression so that even if you choose the best picture quality the file will be smaller that if it were saved as a bmp file. You can experiment with the amount of compression used to find how far you can go before you noticeably effect picture quality. I have found that the 60 to 70 range is a good balance. Hope this helps. Alan Henderson A13 Iowa E3 Microtek ScanMaker