[Cheekygrin73]

So am now up to 9100 miles.. rear tyre is flattening out. Seems reasonable mileage, will change at 10,000 which is pretty good for any bike tyre. May as well opt for the same or michelin if in the price range - its just a workhorse, dont need anything too low-end, or anything too sporty. Sport-touring if you will, with good slow wear rate.

Anyways, I got my Dr. Pulley sliders through - 20g weights. Anyone run these, what mpg do you get and what rpm do you have at 7000?

On the standard set up, I pretty much run equal mph and rpm from about 45-50mph. Probably because I am over 200lbs.. I never seem to get much more than about 56mpg with my AN266 Givi fully extended - worse than that in Winter it seems.

I got the 20g weights as I was looking to increase my mpg a fair bit (I am not looking for pay back on fuel savings right away!) but more for the lowered screaming of the engine at highway (highway plus ahem...) speeds and more settled drivetrain response.

additional question other than to those who also have 20g weights - does this give a higher top speed? I am not sure I want to explore that...

Why? things I notice riding the bike hard - torsionally it is not very stiff. It corkscrews a fair bit and the forks also have a bit of slop and wander - amplified when the frame is bucking and weaving at high cornering speeds on a bumpy highway.

Not enough to warrant a steering damper, but enough to notice the limitations of the materials and design - yeah, its just a scooter.. so long as it is steel and this flexing does not fatigue it beyond design basis too quickly then whatever, really..

 

[TwoWheelTim]

Not sure how much I can contribute, our bikes, riding style, and physical characteristics are so different. However that is impressive tire wear. What air pressure do you run?

I have 18g DPS and like them a lot. 6900 RPM and I am going 70 MPH actual. Fast as I want to go on a scooter on public roads. Your MPG sounds pretty decent though. I have a lifetime average of 59MPG.

I doubt you gain any top end with the weights (20g), you will probably never reach red line though. Did your acceleration improve over the stock weights?

Ride on.

 

[mikeyMarine]

ok I'm an idiot, can somebody splain to me the benefits or even difference of running an engine at higher rpms under a lower torque vs lower rpm and higher torque, my twisted mind sees an engine so overtorqued that it can't even reach red line as experiencing some substantial bearing and shaft stresses or wear and gasoline oomph is still required to generate these forces,

my limited experience has been the only time you get something for nothing is when you get wimmin mad, you get lots more than you paid for and genrally more than you want in the ear department I do understand fine tuning for a particular style of driving, but I also understand it makes all other styles suffer the consequences

 

[Daboo]

I tried a 21g and 23g weight once. Acceleration with the two was down. MPG looked like it would be fantastic with the 23g and just better with the 21g weight. I didn't leave the 23g weight in for longer than a few miles. It was like constantly having a car in too high of gear all the time. I didn't believe the vibration would be good for it in the long run. I find the 19g weight has me at 5300 rpms at 70 mph indicated on flat roads with no wind. The 18g weight is at 5800 rpms.

I've kept records of both bikes, so there's about 75,000 miles of similar riding to compare. Even with the OEM weights being 1000 rpms higher generally, the MPG in the same situations hasn't really changed except for summer/winter gas variation between OEM weights and 18g and 19g DPS weights. What you do get for advantages is better acceleration and a more relaxed feeling when cruising with the lower rpms.

I also noticed something when I did the SS1000 last year. I had in the 19g weights then. MPG went down when my speed got up to 75-80 mph (gps, not indicated). Why? Because you're still pushing a brick through the air and the air resistance is like a hand holding you back. I don't think you'll hit redline, or any higher mph at top end.

One of the things I noticed when I bought my 2008 400, is that it is less settled than the 2007 400 was. There were times when I had just sold the 2007, that I wished I had it back. You would think the two bikes would be the same, but they aren't. I like the 2008, but it is just like you describe. Get on a bumpy road at 90+ mph, and the bike loses its composure. Of course I've only done that once in a few minutes of stupidity, so it isn't worth worrying about. Nor do I intend on doing it again.

Chris

 

[Daboo]

...I have 18g DPS and like them a lot. 6900 RPM and I am going 70 MPH actual. Fast as I want to go on a scooter on public roads. Your MPG sounds pretty decent though. I have a lifetime average of 59MPG...

You might have the DPS weights in "wrong". Or you made a typo. Even if you weigh over 200 (and I'm not that much lighter), you should be at about 5800 rpms. Maybe a couple hundred higher with a worn belt.

Here's a link to a post with pictures of the "wrong" way versus the correct way to install the DPS weights. I put "wrong" in quotes because it isn't a bad way to install them at all. I rode like that for months. Acceleration is great and the weights will move the rpms up with any load increase on the bike in a moment's notice. It felt to me, like I had added 100ccs to the bike. With a load, the rpms would jump up like you wrote, to about 6900...and then accelerate fast from there.

The first time I did this totally surprised me. I opened the throttle to merge into the freeway traffic. Rather than just the normal surge of acceleration, my head jerked back and the bike leapt forward! Then it felt like someone shifted and the acceleration kept going even more. I had the biggest grin on my face while trying to watch some heavy and fast moving traffic all around me. My disappointment was that I had car bumpers too close and couldn't explore this new behavior of the bike. My reason for changing the DPS weights back to the correct way? I knew this was going to earn me a performance award eventually. It was just too much fun.

Chris

 

[cliffyk]

The speedometers on Japanese motorcycles are so inaccurate--all I have ever owned have read fast (my '03 400 and many others reported here have been +10% fast)--that reports of X RPM at Y MPH need to state "indicated" or "actual/corrected" (GPS, other instrument, etc.) to be comparable. The tachometer is not all that accurate either, but leaving that aside;

With 18g sliders and a very modified ramp plate my '03 400 turns 6400 RPM at an actual (via GPS) 70 MPH (this would be an indicated 77 MPH on an uncorrected stock speedometer)--here is a chart of my observations:

The second column, driven RPM, represents the calculated RPM of the CVT driven pulley (based on MPH, tire size and final drive ratio). The CVT ratio at that point can be calculated by engine RPM/driven RPM = CVT ratio. The final column, change vs OEM is the change in engine speed versus my same observation while running the OEM rollers and ramp plate. With the stock rollers engine RPM/100 tracked actual vehicle speed very closely at speeds over 50 MPH; for example at 70 MPH (GPS) the tach would read 7000 RPM.

MPG is a very consistent 55 around town (I have a "heavy" wrist), and 62+ on the highway (70 to 75 MPH).

Regarding torque, the 400 engine produces its maximum torque at 6000 RPM (pre '07) and 5800 RPM ('07+); HP peaks at 7600 (pre '07) and 7300 ('07+). As by definition these are also the points marking the engine's most efficient range of operation, it is not surprising why fuel economy improves at highway speeds.

It takes X amount of horsepower to maintain any vehicle at speed Y (assume flat grade and still air at STP). That HP can be generated at an engine speed at which the engine is operating efficiently or inefficiently, with the obvious goal for best economy (at speed Y) being to arrange gearing so that the engine is operating most efficiently--at the target vehicle speed.

For kicks, here is a motorcycle version of my How Much HP Does It Take to Go How Fast? online calculator--the default values for vehicle weight, drag, frontal area, etc. are based upon me (210 lbs) on a "wet" '03 400 Burgman, guesstimated then dialed in to improve accuracy, and have proven to be pretty close to real world numbers I have gathered for other bikes...

 

[TwoWheelTim]

Opps, Thanks Daboo!

My numbers match yours and cliffyk's, I went out and checked. I have noticed a worn tire will raise the RPM a few hundred too.

Cliffyk's figueres also match what I see regarding MPG. Most engines get their best MPG at their peak torque (generalization). When I start running above 6000 rpm, the MPG starts dropping.

 

[Daboo]

Yup, same here. I've read reviews that question why anyone would want a tach on an automatic scooter. Well, with the 19g weights, the closer I can keep the rpms to 5300, the better the mileage is. Once the rpms get to 6000 or above, the mileage drops.

I know what I see happen. Cliffyk can tell me why.

Chris

 

[bornagainbiker]

Here's a link to a post with pictures of the "wrong" way versus the correct way to install the DPS weights.

Chris

Chris, do you have the link?

Also the Dr. Pulley list for the 2007+ 400 says that they recommend their 16g,17g or 18g from the standard 19g rollers (10-15% less)?
I was going to get the 18g on their recommendations, but your and other reports are that the 19g are preferred.

Colin

 

[Duster]

When I ordered my Dr Pulley sliders from
http://www.buggypartsnw.com
I had ordered the 20g weights.
They sent me an email saying that those were
the same weight as stock rollers, but based on
their experience, they thought that I would be
more satisfied with 19g sliders...so I went
with their recommendation.
The listing for Dr Pulley products is in the left
column on their website...look for the 26 X 13 size.

 

[Daboo]

Here's the link. viewtopic.php?f=47&t=57247&p=527799#p527799 I'll go back to the other message and add it there too.

There's nothing wrong with 18g DPS weights. I just prefer the 19g weights. I don't drag race with the bike, and the 19g weights will still move the bike fast enough that I get away from traffic easily. And with the 19g weights, my freeway rpms are just a bit lower which I prefer. You won't go wrong with either.

Chris

 

[bornagainbiker]

The listing for Dr Pulley products is in the left
column on their website...look for the 26 X 13 size.

Yes fully aware of the sizes, just search for Suzuki Burgman 400 and it selects the correct sizes for you.
Here is their pdf list showing the stock sizes and their recommendations in red.
http://www.drpulley.info/drpulley_docs/Typenliste.pdf

 

[bornagainbiker]

Is it worth getting the DP Sliding Pieces also?

 

[Daboo]

IMHO, no. I've never seen any wear on my OEM sliding pieces, so I don't see any reason to change them.

Chris

 

[cliffyk]

+1, I have over 30k miles now and there is no sign of any wear on the stock dampers...

 

[Cheekygrin73]

Thanks folks - useful to know.

Am intrigued what I will get on fitting the 20g weights. The objective was heavier as most of my driving is highway, and I wanted the engine to scream less at 70(ish..). I only have a short amount of city use.

Should be fitted next week, lets see the change..

HANG ON a second - is the 20g weight the same weight as stock rollers? Just re-reading one of the posts here!!

:shock:

 

[Daboo]

The weight is only one part of the equation. The Dr Pulley weights are not round like the OEM weights. Even with the same weight, you'll get better acceleration at city speeds and a drop in rpms on the highway.

Chris

 

[Cheekygrin73]

So win, its full of win. Why doesnt everyone do this?

I am intrigued what you mean by vibration on your 23g weights - with 20's the objective was not to nail it at high speeds, just calm it down for a lower rpm at highway cruising speeds.

 

[Daboo]

If you've ever driven a manual transmission car, you've found yourself in the wrong gear at times. Like being in 5th gear instead of 3rd. The whole driveline jerks and vibrates till you change to the right gear or you get up to speed. I got the same feeling when I used the 23 gram weights. Was it something so bad I couldn't live with it? No. But it made me wonder if I wasn't trading the life of something in the drivetrain (probably the CVT belt) on the 400 for a few MPG.

Chris

 

[Ralph M]

These engines were designed to rev, it's not a big block Chevy cut down the revs too much and
not only are you doing the engine no good but will loose top speed as it wont rev hard enough
to produce it's full power. Dropping cruising revs a bit if you cruse for long distances is no bad
thing but don't go too far.