I agree with everything XYZer just posted while I sitting in favored bar (brass ring, royal palm beach, 0030 hrs, drinking pitchers of coors lights, reading the forum, eating chilli. Life is good.. All our experience also indicates light on the counterbalance area, needing more weight. What we did having three engines between us was as follows: disassembled all three engines at the same time. Weighted all pistons, connecting rods, everything, then tried to match up similar parts. I remember grinding several ounces off of connecting rods, drilling holes in flywheels to remove a little metal from the rim, etc. this got us close, but we had three engines to work with 8 years ago.

Guys, technically - it is so easy to balance a single cylinder - a little time consuming but not hard. After all, didn’t you get a Listeroid to tinker with it? So, we know that pulling the flywheels off has been discussed on numerous other threads, not hard to do when you have a flywheel puller. Bubble balancing, or pendulum balancing both flywheels so they are the same weight is not hard, but takes time. What you end up with is two flywheels closely matched. Put your newly closely balanced flywheels back on the machine.

Next step is using an accelerometer to give you a numerical readout of how well you are doing. It is possible to see the improvement by carefully noting the up and down bounce but numbers are nice. Most people or their children have an IPhone or an IPad. This $4.99 application will give you the IPS (inch per second – acceleration in the X, Y, & Z planes). Now you have numbers to verify you need to add more weight or remove some. Here is the link:

http://dld-llc.com/Vibration2Manual/Credits.html#Introduction

Early on in this thread there was an eBay link to order strips of ¼ oz weights with adhesive backing. The strips are about 6 inches long and each weights 3 oz each in total. I ended up with 6 oz on the inside rim and 6 oz on the outside rim for a total of 12 oz on each flywheel. In other words, my counter balances were 12 oz too light. Yours will likely be different.

Here is the method we used. Assume that on your identically balanced flywheels, either the counter balance is too heavy or light. Measure the amplitude of Y and Z direction IPS with your $4.99 application. Mine started out at 1.8 IPS in the Y direction and less than 1 IPS in the Z direction. After adding 6 oz on each flywheel next to the counter weight, we got 1.4 IPS in the Y and 1 IPS in the Z. Next with 12 oz on each flywheel, we got 1.2 in the Y and 1.1 in the Z. This is where we stopped. Visually, you can see the slight movement (vibration) front to back and very slight movement (vibration) up and down. I’ll shoot a video and post in a day or two but you’ll see a Metro 6/1, mounted on a nursery cart with wheels (moves easily), running so very smooth. I took the time to post these details because, it is so easy to do on a single cylinder using this application, I want others to benifit,    

Made some quick calculations which reflect a typical 6/1 is only sucking in 16.5 cubic feet of air per minute which is not a lot. So I have to wonder how much is there to gain from removing the surface restrictions discussed in porting near the airfilter. To me, the greatest restriction in the air flow would be the intake valve opening area and would present the greatest opportunity for improvement. Improving airflow in this narrow area seems reasonable. ORIGINAL POST HAD MATH ERROR WHICH WAS CORRECTED BELOW.

Diameter   4.5   in   Bore   D
radius   2.3   in   Bore   r
Stroke   5.5   in   Stroke   h
            
Volume   87.5   in^3   V=pi*(r^2)*h   
            
Assume   650   rpm      
   5.4   intake strokes per second      
   473.8   in^3 per second      
   0.28   ft^3 per sec      
   16.5   ft^3 per minute      

When I calculated this for my 20/2 GTC it comes out to be 48 cubic feet minute through the airfilter and intake pipes which is more significant.

Diameter   4.75   in   Bore   D
radius   2.38   in   Bore   r
Stroke   5.5   in   Stroke   h
            
Volume   97.5   in^3   V=pi*(r^2)*h   
            
Assume   850   rpm      
   7.0   intake strokes per second per cyclinder
   1381         in^3 per second         
    0.81          ft^3 per sec      
   48         ft^3 per minute      

Home Depot stock number is 759 541 and comes in a pack of two different size springs for a total of four. The sizes are: 7/16 in X 2 inch X .062 in with a safe working load of 18 lbs - these are the two you don't want to use. In the same package is: 9/16 in X 3 in X .054 in with a safe working load of 9.55 lbs - this one worked well for me out of the box. So for a couple dollars you may have a repeatable solution. Remember, where the India guy decided to drill the stud hole for the other end of the spring is probably random but I hope it will be close.

I also have a metro 6/1 which have setup to run at 800 rpm because I need 4,400 watts out of the power unit. In my analysis I calculated no more than 60 mph rim speed on the flywheel, I urge you to calculate yours. With my carefully examined flywheels I drive them at 800 rpm which, is as I recall, 56 mph. This is, in the opinion of most, the absolute maximum you should ever drive an India flywheel, probably too risky even at 800 rpm, but anything higher on a spoked flywheel is too dangerous. I respectfully offer this opinion as a Metro owner driving mine at over speed at 800 rpm.

There is an excellent thread on the sister forum at: http://www.microcogen.info/index.php?topic=913.0

The comments about a machine shop in Tenn working on a custom ground camshaft for about $300 got my attention, but, as far as I know this has not come to pass yet. Can anyone provide an update or a source?

Bruce

Cujet (Chris) look at all the shit you started by posting this undiscovered topic years ago.