RPMs = MPH

[CDNRatMan]

ok found it

http://www.gearingcommander.com/

[CDNRatMan]

  While digging about in some old files I found this. Not sure where it came from but it was set for a Drifter 800. I'll try and hunt down where I got it from.

[Tfrank59]

OK I'm not going to buy a cone shaped airbox. Actually I may not do much more to the bike it runs pretty well the way it is and under the influence of Troll I have been bold enough  to take her up above 4000 even to 5000 RPMs and she did run like a top.  Plenty of power for what it is, an 800 cc V-twin

[greenbarn]

OK I remember browsing that before and just forgot about it. So basically the only thing I haven't done on my bike is the modification to the airbox. My bike was a California bike and I already did the desmog, and I've already changed my main jet, so to complete the process I would just have to gut my airbox, then maybe some tweaking of the needle setting and mixture screw to get it just right. I do have aftermarket exhaust also.  I was actually browsing online and looking at some of those air cleaners that look forward and come to a point– I wonder if one of those would produce the same affect as grampsizing

A couple of things to add from my perspective:
Front-facing cone filter:  Big mistake IMO.  Fugly or not, they are hard to tune and don't do well in the rain.  My boy bought a Shadow 750 with one.  Big difference in riding in a headwind, or how much filter oil on it, and ESPECIALLY doesn't like the rain.  We got caught in a downpour this spring, and it wouldn't even run.
Grampsizing-  One of the top 3 mods to the 800, IMO.  It will require changing the jets probably more than what you can find in a premade kit, but they are hard to find, and the directions are simple.

[Tfrank59]

even if the numbers on the chart I posted were used for break-in,  following those speeds for shifting would be lugging the motor badly, which I can't imagine is a good thing at any time.

[kw-retrorider]

Tfrank: Actually the owner's manual (p.41 in mine) shows some numbers under the heading of "Break - In"....which is the first 1000 miles.

There is one set for the break-in period , which corresponds to the way I drive normally as noted....shifts at 20, 30 40 and 50 mph.

Then a second set after break-in which are more aggressive with shifts at 30, 45, 60, 75 and 90 mph.

The numbers you quote are in the owner's manual (page 50 in mine) under "Shifting Gears"...and they are as you stated them, but I can't make any sense out of them.

[Tfrank59]

Ratman, I think you're going to have to give me a call and I can talk you through it because I'm stuck here in western Washington  but for what it's worth the only required tools are maybe a pair of needle-nose pliers, roll of electrical tape and some zip ties

[CDNRatMan]

TFrank I'll buy the tach and when we met in WI in 2 weeks you can help install it. There will be lots of guys there with the correct tools.

[pcarrell]

Going into 5th gear at only 27mph?  Each gear, save 1st, is only good for 6 mph?

Something sounds fishy about that!

[Tfrank59]

Yep, glad to help.  BTW, the owner's manual provides this chart for when (at what MPH) to up-shift gears:

1st to 2nd: 9
2nd to 3rd: 15
3rd to 4th: 21
4th to 5th: 27

with the exception of 1st to 2nd it's way off, as anyone who knows anything about engine sounds can verify without a tachometer.

[kw-retrorider]

Tfrank: Thanks for the numbers.  So with the stock gearing and easy riding/shift up speeds every 10 mph starting at 20 mph for the shift from 1st to 2nd, seems the engine is at about 3500 rpm.

I took the opportunity to ask, because you had the tach. I looked around the sight again and found the links to the gear ratio commander and previous discussions about sprocket changes...so could have found these numbers another way. In my past reviews, everyone was talking about how great the sprocket changes were, without using a tach or showing some numbers. I finally found the numbers. So I get it.

That said, I ride one up and have put over 15k on in the last 4 years. Haven't had the urgent sense of looking for another gear on the top end. Also haven't grampsized...but good to know it doesn't kick in until 4000 rpm, which I am not routinely running at in any gear...except maybe 5th if I am going over 60 mph.

At 25k, just had the original chain (and sprockets) changed with a sunstar x-ring recommended by my local dealer (and stock sprockets). So for the moment, happy with the performance of a stock carb, baffled roadhouse, predictable choking/starting and an average of 50 mpg. If I get bored in the next 25K, maybe grampsizing and sprocket changes will be next. I know these things are subjective and personal.

All good - thanks again for the field numbers and the comments by Troll on the grampsizing.

[Tfrank59]

Well I like the idea of making one's own backing plate – that's pretty easy, probably easier than cutting up the plastic stock one, so maybe I'll try that. Thanks a lot

[Troll]

Personal preferences...I think they are FUGLY, and do not go with the rest of the Drifter...As far as performance, goes, who knows... I made my own backing plate and I'm using a 7" K&N with the original cover. Today I rode 185 miles between 55 and 70 mph and got 47 mpg

[Tfrank59]

OK I remember browsing that before and just forgot about it. So basically the only thing I haven't done on my bike is the modification to the airbox. My bike was a California bike and I already did the desmog, and I've already changed my main jet, so to complete the process I would just have to gut my airbox, then maybe some tweaking of the needle setting and mixture screw to get it just right. I do have aftermarket exhaust also.  I was actually browsing online and looking at some of those air cleaners that look forward and come to a point– I wonder if one of those would produce the same affect as grampsizing

[Troll]

http://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....

[Tfrank59]

What 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

[Troll]

The 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!

[Tfrank59]

okay 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

[Tfrank59]

okay 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?

[Troll]

Looks 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.

[Tfrank59]

Okay 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