View Full Version : Rpm

06-25-2004, 05:32 PM
I finally got a digital tachometer (rev counter) last night.
My engine is running at 8800 rpm - what is the optimal rpm range for this engine? I have the Malossi big bore kit, taller gears, speed clutch, multivar with 7.5g weights, white contra spring & Leo Vince "S" pipe. I want to get some new roller weights so I can get the best top-speed and acceleration. I'm not sure if lighter weights or heavier weights would be best.
Anyone know what the peak rpm should be for best performance? and should I go lighter or heavier with the roller weights?

Thanks in advance for your help!

06-26-2004, 05:00 AM
Hi there

The original engine with the factory fitted exhaust develops max power 7700-7800 rpm, when you fit a malossi big bore kit retaining the original exhaust the power seems to be the same.

When fitting an aftermarket exhaust the like leo vince S you probably want to aim to 8500 rpm.

Here is the what you should be looking at, rpm that the engine holds when accelerating from low speed ie 20 km/h and what rpm is the engine reaching at max speed, the reason i mention this id because the variator does not hold the engine rpm constant across the operating rev range of range.

You will find that as the bike increases its speed the rpm slowly climbs as the bike gathers more speed. For example if you set your rollers weights for the engine to hold 8000 rpm as the bike takes of you will find that by the time the bike reaches max speed the engine rpm has climbed to aprox 8500 rpm. so you have to bear this in mind when setting up the roller weights.

I personally have set my variator for the engine to hold 8000 rpm at max speed,but that means that the engine pulls 7200 rpm when taking of, my acceleration has suffered slightly but my riding is most of the time flat out on dual lane roads y my bike pulls 125 km/h on the speedo approx, its hard to tell the speedo markings stop at 120 km/h and on downhill stretches the needle goes all the way to the ditech emblem on the speedo.

My set up is malossi big bore kit, longer gears, hebo adjustable clutch, malossi multivar, yellow contra spring, and 10.5 gr rollers standard belt, I did try the white spring again but i could not keep rpm down, i believe because of belt slip, i thing my white contra spring had lost its tension.

how you set up your variator will depend on what type of roads you spend most of time, there is no point in setting the variator for the engine to hit max power when accelerating from low speeds which will favour stronger accelerations if you spend most of your time flat out at max speed because the engine will turning higher rpm beyond max power or viceversa.

I would suggest you purchase 8.00 gr and 8.5gr and try and see waht you thing, best the thing to is try the scooter on a known road which allow to test max speed, and incline where you can check speed the bike will pull up the hill.

i hope this helps


Joe Rubido

06-30-2004, 04:45 AM
Excellent reply from JRTurbo! Just what I was looking for! :)

mdtoney - I have the same exhaust and it has two restrictions in it. One at the front near the cylinder and one in the expansion chamber.

You see them easily. It's a tube that sticks out in the front, that should be removed.
In the back, if U remove the mufflex you'll see a small tube hear as well. You have to cut the chamber in half to remove this...

I don't know if U were aware of this or not, but it's definetely worth looking in to.

I bought my exhaust in the EU, germany to be precise, and it maybe that you don't have the same regulations we do in the US.

Im putting my exhaust back together today, hopefully, after removal of all restrictions we'll see how it performs after that.


06-30-2004, 02:49 PM
I agree, excellent response from JRTurbo. After I got the rev counter, I got an impact wrench so I can work on the transmission myself, and not have to pay the crazy prices for labor at the dealer!
I didn't know there were restrictions in the "S" pipe... I'll take the pipe off and look at it - I definitely want them out of there!

07-01-2004, 11:33 AM
Raid - Please let us know how it runs with the restrictions removed. My friend has a machine shop so he can cut and weld everthing for me, but he lives quite a ways out of town so I want to make sure that removing the restricitons will make a noticable difference before I head out there.
If anyone else has already removed the restrictions on a Leo "S" pipe, did you notice much of a difference??

07-01-2004, 11:42 AM
mdtoney.....curious as to where you purchased your tach and cost........would make set -up easier to fine tune thanks.........

07-01-2004, 12:35 PM
I got it from Brand New Engines http://www.brandnewengines.com/pages/14/index.htm
The price is $35 + shipping ($4.25 to Seattle). Maybe you can find it cheaper somewhere else??? This was the only place I looked.

07-01-2004, 01:36 PM
Thank's for that info...one more question,does the tach lead have a clamp or plastic part that goes around plug wire?Or is it a bare wire lead?Thank's in advance...........:peace:

07-01-2004, 01:38 PM
No clamp and no bare wire - it's a shielded wire, you just wrap it around the sparkplug lead 4-5 times and zip tie it to itself (ziptie and directions included).

07-01-2004, 01:58 PM
and you feel the meter give's you accurate reading's?

07-01-2004, 02:00 PM
As far as I can tell - I was just interested in max RPM so I got the bike up to top running speed and looked down and it was reading steady at 8820rpm

07-01-2004, 02:08 PM
Cool man..thank's for the info...going to order one now from Nothern Tool..$36.99 + shipping of course.....I'll post result's when testing.....