Two-stroke performance tuning?

**Skunk** · 11th June 2009, 21:41

Ahh, I see now. Clever. Only I've got two rods at 90°. Hmmm, might pay someone. I just need to get an idea of the balance factor I want.

**SS90** · 12th June 2009, 11:48

Originally Posted by speedpro

The % was simply the weight measured at the little rod divided by the piston weight etc.

Nice work Speedpro. I was wondering if you had the data from that work? just so we could see what factor you got.

Teezee, I was just wondering how Thomas was getting on with his explanation/pictures. (Tell Thomas no pressure!)

Just remind Thomas that the correct balance factor is chosen on a variety of factors (capacity, intended purpose (rpm's etc), method of mounting ("isolator blocks" or not) just as an example, but also angle of the cylinder in relation to the crank ("laydown", or "straight up")...both have different ideal balance factors (which then change again, dependent on the above factors.

Also, remind Thomas the type of balancing procedure (method) used is also dependent on rod position. (%age at what position?)

Also, remind Thomas of why I cut this crank in the first place, (and the shape chosen was not "random", and the amount of material I used was dependent on the crankcase volume I wanted.)

As I have previously stated I would remove MORE material from around the crank pin area to better balance the crank (or like Speedpro suggested use Mallory metal on the opposing side)

I am looking forward to Thomas's posts on this subject.

Tell Thomas I said Hi!

**TZ350** · 12th June 2009, 20:22

SS90 Thomas has already covered here and in the ESE thread most of the things you are telling me to remind him about, it would be a bit like telling someone how to suck eggs.

He says others have posted some prety good ideas and that anyone can open a free account with Scribed where they can download "Tuning for Speed" by Phill Irving.

You could get yourself a copy, its an interesting read.

http://www.scribd.com/doc/15392252/T...rcycle-Engines

Phill Irving talks about CrankShaft Balancing and Balance Factors on pages 107 to 110 of the book which can be found on page 61 of the PDF.

Thomas says it's all anyone needs for working on a single cylinder crank.

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**SS90** · 12th June 2009, 21:17

Originally Posted by TZ350

SS90 Thomas has already covered here and in the ESE thread most of the things you are telling me to remind him about, it would be a bit like telling someone how to suck eggs.

He says others have posted some prety good ideas and that anyone can open a free account with Scribed where they can download "Tuning for Speed" by Phill Irving.

.

Perhaps you could remind Thomas that, much like his early ESE racer engines (designed by taking too much information from an outdated, (yet in depth) book has the effect of building an out dated engine.)

Like the expansion chamber and port time areas Thomas built for the bikes (based on 70's tech), he got a 70's tech engine.

Now, I first read the Phil "slide rule" Irvine book when I was 18.

If I remember correctly, it was first printed around 1965.

Logically, certainly, not EVERYTHING printed in a 1965 is out of date, but if you where to take everything in there as gospel, you will end up with a 4 stroke engine reminisent of a Vincent Black Shadow (the bike he is credited for developing)

Certainly tecnologically advanced for the day, but by todays standards "a little bit behind the times"

Like with the ESE bikes, Thomas got engines reminisent of 1976 RM125's (because he simply "did what the book said".......Maybe if Thomas rode a 1976 RM125, then rode a 2001 RM125.... he will see what I mean.

While Thomas is having his eggs for dinner ( chewing is ok....he doesn't need to suck them) he could remember that, like I have previously written (pressure points being very important when dealing with Two stroke power), such things must be taken into account when choosing the correct balance factor.

Remind Thomas again (just to take away confusion) that I do not advocate 42%...... I advocate more like 50% (in this type of engine)

Has Thomas told you when he is going to have the time to write a few things himself? (he said he would)

I look forward to Thomas's experience with such things. Because the link Thomas posted is Phil Irvines experiences (in the 60's) I am interested in Thomas's experiences....as Thomas always says "it's the Buckateer way"

**TZ350** · 12th June 2009, 21:28

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SS90 you do seem overly obsessed with Thomas, as Thomas says, you can make a mountain out of a mole hill if you want too or you can KISS.

.

**SS90** · 12th June 2009, 21:41

Originally Posted by TZ350

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SS90 you do seem overly obsessed with Thomas, as Thomas says, you can make a mountain out of a mole hill if you want too or you can KISS.

.

Tell Thomas I am not obsessed with him, I would just like to see Thomas write something himself.... (Thomas did say that he would do that, including some hand drawn pictures)

Thomas (and his friends) where critital of my posts, and I would like Thomas to contribute (I would like to see Thomas show me where I am going wrong with my engines), because I really am interested in Thomas's input.

Can Thomas also explain the effect of primary compression on a balance factor?

**Chambers** · 12th June 2009, 21:49

Originally Posted by SS90

I am going wrong with my engines), because I really am interested in Thomas's input.

Your looking a little obsessed, its a bit obvious that your not genuinely interested in Thomas's input.

**Pudding** · 12th June 2009, 21:51

SS90 your starting to look a little nasty.

**bucketracer** · 12th June 2009, 21:57

Originally Posted by Pudding

SS90 your starting to look a little nasty.

Who's the little boy getting in a Tis Tis then ?

**SS90** · 12th June 2009, 22:03

**bucketracer** · 12th June 2009, 22:06

I want, I want, I want, No I demand,
I demand, Nooooooo its not fair,
Wareeeeeee Mummy Mummy they are not playing nice.

They wont do as I say.

Tell them off Mummy
Tell them off or I will hold my breath untill I turn blue.

Seriously SS90, forget Thomas, get past him and contrabute something interesting yourself.

.

**SS90** · 12th June 2009, 22:09

Originally Posted by bucketracer

I want, I want, I want, No I demand, I demand, Nooooooo its not fair, Wareeeeeee Mummy Mummy they are not playing nice. They wont do as I say. Tell them off Mummy Tell them off or I will hold my breath untill I turn blue.

**FastFred** · 12th June 2009, 22:35

SS90 "I demand" does sort of sum it up.

You just don't have the persional touch that gets cooperation from people do you!

I can see, socially its always been a hard road for you hasn't it.