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Posted by Troll
- July 03, 2016, 18:34:10 PMhttp://www.vulcandrifterriders.com/mods/grampsize.pdf
Several articles about it on the forum, including that it WORKS! Raise the needle one notch and see what happens...Putting a K&N in is a good idea, but you won't reap the true benefit of that until you do something to open up the air intake...ie. Grampsizing. That engine should wind all the way to the red line in at least the first 4 gears....
Posted by Tfrank59
- July 03, 2016, 18:05:35 PMWhat exactly is "grampsizing"? – I already have a Dynojet kit in it, but I'm running the stock air cleaner. maybe you're saying I need a different e-clip setting on my jet? remember it went flat when I was running it with no air cleaner (your suggestion), but it did improve performance in the mid range as I said. that is why I'm contemplating spending 55 bucks for a k&n air filter. please advise
Posted by Troll
- July 03, 2016, 17:05:25 PMThe reason it went flat above 4000 is that the high end mixture is too lean. Put a K&N jet kit in and "grampsize" it, you will be AMAZED!
Posted by Tfrank59
- July 02, 2016, 22:11:09 PMokay I tried riding without air cleaner on there and it made a big big difference in the mid-range from about 3500 RPMs to maybe 4200, above that it seems like it went flat. even so it's worth it to buy an aftermarket air cleaner like a K&N. thanks for the tip
Posted by Tfrank59
- July 02, 2016, 21:25:18 PMokay I'll try that, but it probably means I need to get a K&N Filter right? The other question I have is will more air improve torque and horsepower at the lower RPMs also?
Posted by Troll
- July 02, 2016, 20:40:34 PMLooks like pretty much the same results I have with my W-650. 70 mph=4000 rpm...now, here's a thought for you to ponder...a 4 valve cylinder head doesn't flow well below 4000 rpm. After I did a "sheflectomy" on my 650 and installed a Dynojet kit, when the engine hits 4,000, it will now slide you back on the seat...You really need to let more air in. As an experiment, take off the air box cover and go for a ride. A short ride won't hurt anything, unless you live in Arizona and ride during a dust storm.
Posted by Tfrank59
- July 02, 2016, 19:22:01 PMOkay as promised here's what I got on my bike, which has stock gearing, tire sizes, etc. My disclaimer is I was shouting into my voice recorder 
the MPHs and RPMs, probably got some parallax looking at the speedo, and anyways it's off by a few MPHs--they all are, so these values are approximate. But my numbers do give the basic idea, and again I found that there's no point peaking a gear above 4000 as the torque really drops off at that point. For the higher gears I don't have all the data (a bit dangerous I found) but you can interpolate and fill in what you need (sorry the columns are misaligned):
GEAR MPH RPM
1st 10 2000
15 2400
20 3500
25 4000
2nd 20 2700
25 3000
30 3400
35 3900
3rd 25 2000
30 2500
35 3000
40 3400
48 4000
4th 45 3000
50 3500
60 4000
5th 65 3700
70 4000