Balancing the lower end?

[David Jackson]

As you are no doubt tired of hearing... I have the SE stroker flywheels going into a 113" SE motor. What about balancing these flywheels? Necessary? What factor? Who to do it?

Thanks Mike;

David J.

PS I got all three of the V Twin tuning books from Baisley today ... lots and lots of info.

[Mike]

Tired, Yes! Tired of hearing from forum users, no way!!!! We believe balancing to be worth the added cost, typ. $175.00. We sublet this to NorthWest Machine (Dick Elverude-Monty Shelton's Porsche engine guru and old timey H-D drag racer). He uses a dynamic balancer and a 60% factor. Some like to weld the crank pin once done, but we have to be careful of the heat pulling the wheels out of true. We have not been doing this but T-man Perf. has, we are considering it and are working with Baisley to test trueing and welding. Just adds time, cost, communication and running around.
BTW; cases are done, waiting paperwork to ship back.
Thanks, Mike

[David Jackson]

Well I have learned A LOT this winter; and probably most of it from this forum!

While my bike is apart is a great time to think of all these things, such as balancing. Perhaps I should ask the service mngr to get the particulars from you about the balancing guy?

On the subject of balancing ... last time the motor was apart I investigated the mercury filled (or partially filled) tube which Balance Masters puts in a groove in one of the flywheels. There was an article in Cycle World about it; and Balance Masters shows examples of better balance with their systs. I was all set to have it done until I talked to a tech at Life Style Cycles who told me he had one of those tubes come apart on him once.

Do you have any experience or opinions of the Balance Masters balancing method?

Glad to hear about the cases; now I can wait for the Wood Carb and then for the balancing!

Regards;

David Jackson

[Mike]

I know one shop owner that swears by the Balance Masters and I know others who have had similar experiances to Life Styles. None of the top engine builders that I work with use this method (Zippers, Axtell, T-Man and Baisley). May be a message there!? I like the idea of a dynamic system but we've had good and acceptable results with the current methods.
Regards, Mike

[David Jackson]

Hi Mike;

I would imagine that one case of the tube coming apart is more than enough to sour someone on the idea.

To have my flywheels balanced by the firm you recommend; can you let me know the particulars for contacting them or is that something you would prefer to do on a customer's behalf? In other words; should I ship you the flywheels or can I ship them directly to Northwest?

Thanks;

David Jackson

[Mike]

Northwest prefers to have these handled through a dealership or Baisley. We'll need the pistons, rings, pins and clips total weight in grams (one total for all is fine since it all hanges off one crank pin). Typ. takes two weeks. We also check for trueness and correct what we can before balancing.
Regards, Mike

[David Jackson]

Hi Mike;

I understand that Northwest prefers the balancing go through a dealership or through Baisley. My engine is at a dealership now and that dealership can send the parts to Northwest directly or they can go through Latus; whatever works best.

The same dealership which sent you my cases has the rest of my parts. I will ask the service manager to contact Latus for the address if that would be best.

Thanks;

David Jackson

[Mike]

Northwest's phone number is 503-648-6742, nwmach@easystreet.com. We'll be fine with whatever Dick prefers.
Thanks, Mike

[zigzzagz]

What are the advantages of welding the crank? On bikes run very hard I've heard of runout being checked and the cases having to come apart because of this. This could be stopped by welding? My wheels are not welded, or balanced and I rue the thought of the cases having to come apart again as when I first built the 124" the timken-less crank issues in my 2003 B motor were not known about. Both the shop and I first heard of this about 6 weeks after the build so I held my breath and rode the season, 10,000 miles and pulled it down the next winter. So if I wanted to take care not to have this issue, and as a result the cases taken apart again, what precautions would I take? I do like to ride my bike hard, no point not to with a big strong motor like that but I could probably cut burnouts to a minimum if I had to. So what say you?

[Mike]

Welding the crank eleminates the possibility of crank shift about the crank pin, causing it to go out of true. Typ. causes for this are sudden stoppages of the crank (I.E.; burnouts, drag race launching, bogging, high rpm downshift, locking up the rear wheel or primary drive, crashing and anything else that could cause the motor to suddenly stop). It's not a bad thing to do and when done properly, will not pull the crank out of true but must be done after truing and balancing. We've always done this on race motors and with pressed crank assemblies many builders are welding just to be safe. Indicating pinion shaft runout is the main method to determine if a crank assy has shifted, without tearing the motor down. It's a good idea to record this number when assembling so it can be referred back to.
Thanks, Mike

[David Jackson]

Hi Mike;

We have sent my crank to Northwest and he should have it in a day or two (Monday or Tuesday). FWIW he suggested sending the crank assembly in an original box for safety's sake; and also suggested that possibly Fed Ex will treat it more carefully than UPS will; so we sent it in the box it came in via Fed Ex.

At the beginning of this thread you mentioned a balance factor of 60%. In the past I seem to remember a balance factor of 42% but I don't remember for sure if that was for Sportsters or just what. I do seem to remember that different balance factors applied to different rpms; in other words a lower end can't be balanced for all rpms so a range is chosen and after that a balance factor to maximize smoothness in that range. I telephoned BW to see if he would recommend a particular balance factor for my motor but he said balancers all have their pets and 60% would be OK; and that my motor will not be a high rpm motor (true). I looked and looked in the three volumes of V Twin tuning I just bought but found no reference to balancing flywheels at all - did I miss it?

I imagine that Mr. Elverude can balance to whatever factor he likes; can you enlighten me a little on different balance factors please?

Thanks;

David Jackson

[Mike]

Yes, the balance factor is a function of rpms. The higher the rpm the lower the factor used because as rpm increases the rotating mass increases and therefore a lower value is required to match the reciprocating mass at the chossen rpm you want in balance. This has been a moving target lately and I think people are experimenting. HD uses a lower value but I cannot remember what that is.
Thanks, Mike

[David Jackson]

Hi Mike;

Thanks, as always, for your answer about balance factors.

The only written reference to balancing the lower end I could find is in some old books published as reprints by Floyd Clymer back in the 1970s and being reprints of older English books; one Speed and How to Obtain It; no author and no date, and the other being Tuning for Speed by P.E. Irving (of Vincent fame). These books are pretty old but they also say there is no one ideal balance factor.

The method they are using in these old books is static balancing; and they are dealing mostly with single cyl 30 inch motors of the 1950s and 1960s I think.

It would probably be a good idea for me to talk with Mr. Elverude and see what rpm range the factor he uses will be for.

I would hope there would be some easy formula to use; but I bet there isn't.

Regards;

David Jackson

[Mike]

What we are after is to get the "sweet spot" where we spend the most time. The dynamic guys tend to use a number lower than the static method for reasons I have yet to understand. It may a carry over from the car industry. Dick has raced cars and Harley's so will be looking at it from a strong experiance viewpoint. Baisley has always used 60% in everything, as far as I know. Even our AMA racer spinning to 9k uses 60%, though logic says it should be lower. I used to have a copy of Irvings book "Tuning for Speed" but lost it and have not been able to find another copy since (by the way, it was autographed when he was on one of his last tours talking about Vincent and BSA put on by the OVM club [I believe] here in Portland. A friend, who was an antique dealer at the time, found it in an estate sale, purchased it and gift'd it to me. I really miss that book!!!).
Thanks, Mike

[David Jackson]

Mike;

I sent you a pm about where you can get that book.

I had a nice conversation with Mr. Elverude this AM. Sadly he suffered a heart attack last Sunday though he sounded good and feels he will be back in the swing of things in a week or so. He remembers those old books too!

He was talking about a "sweet spot" from 2,500 to 3,500 rpm and my fear is that may be too low; but he told me that is what he does for you and for Baisley and that is good enough for me!

I read a post on a V Twin website which said that another way to reduce vibration is to mount the motor with the rear motor mount snug (supporting the motor of course) and then to shim the front motor mount so that the mount is not using up some of its flexibility to start with. Sounds clever to me!

I also have one of those Sputhe Engineering motor mount gadgets which is supposed to keep the motor in line on the front to back axis I think.

Regards;

David Jackson