Crankshaft Balance Factor.

[laird387]

Hi axulsuv,

I am sure you are absolutely right - and I only wish I had had the knowledge to tune my bikes more scientifically, but I didn't, so needs must.

One useful piece of kit I did use - and still have it - was an american spark plug with a glass body so that you could see the colour in the combustion chamber - I found that very effective, science in an empirical fashion if you like !!

It was even more useful when one of my first cars, a Morris Eight fitted with an SU carburettor, needed tuning - and since 650 Triumphs used a similar carburettor it would probably have worked for them.

As ever - enjoy.

[axulsuv]

laird387, A color tune , had one years ago !But trust me , I still do MY bikes by feel ... ( and I can't afford to replace my wideband sensor array after two stroke tune ....!) But multi cylinder cars get the full work up . You would appreciate the XK150 I just finished , 3 webbers, starts like its fuel injected , hot or cold , and will slam you into the seat and it's air conditioned too ...

And keep your photo's and stories coming , it's not history if you don't share it !

Glenn

Edited January 9, 2014 by axulsuv

[ask greeves]

Firstly XK 150's never came with webber carbs, so i consider 'it's a load of crap' Then again Jay Leno has a vehicle with an 1920's aircraft engine, to which he had fitted twin turbo's.....so it's whatever ring's your bell...go ahead an do it. When you've been through the whole cenario...been sold aftermarket equipment, which in reality, is inferior to the proper article, you can become very cynical, to a large majority of what is said on this web site. Isn't this a motorcycle trials site...how can xk 150 or alvis or 4.4 range rovers have anything to do with trials bikes, unless of course your trying to impress the reader ! Laird 387 has given us valuable insight into the history of motorcycle trials, a picture is worth a thousand words and his information excellent, the advance/ retire trick was used by many riders, your never going to be able to do that with a modern crankshaft ignition, but then again i'm a purest. The majority of the modified bikes (in my opinion) haven't been made better, they've just got caught up, in a 'modern day' money making exercise and it's great...because that means there's going to be less proper trials bikes, who's value will most likely increase. 'Teardrop tanks' a prime example of modern crap, they look nothing like anything which was ever produced, but slap a triumph or james or anything badge on it and in the beholders eye...he is the dogs danglers...yes i'm cynical.

Edited January 10, 2014 by ask greeves

[ask greeves]

The balance factor takes into account the resistance offered to the flywheel by the piston/conrod assembly, which when rotating at an oblique angle, causes an out of balance situation. The engine manufacturer may produce thousands of conrods and flywheels, these would be made to certain limits, may it be BSA, Enfield, AMC, they would all have there 'own take' on what they considered the best 'balance factor'. The production line would take any conrod and any pair of flywheels and assemble...knowing that they would work, within a certain rpm range. The secret is to have the vibration range higher than the rpm range. We're talking mass production, so similar to 1 in a 1000 winchester rifle, where all the parts just by luck are exactly as per the blue print. Modern day rebuilds are blue printed, so as to get as near as possible to the exact limits. As your rebuilding your AMC, your in the excellent position to get it spotis bolikus....hopefully ! The process would involve assembly without the piston/conrod, but with a weight on the bigend journal equal (plus/minus balance factor) to that of the piston/conrod, then the flywheels are spun and any alterations could be made, then the assembly reassembled complete....is it worth it !

Edited January 10, 2014 by ask greeves

[davetom]

Hey ' Ask Greeves', isn't this all getting a bit childish?

Jon asked a perfectly sensible question about a classic trials engine, parts of which may have been altered, drilled, changed for rebore etc over the decades since it came off the line.

You then suggest he doesn't know what he's on about and rant against modern technology .

He backs up his question and experience by referencing his day job and examples where modern tech helps old tech.

Other experienced, knowledgable people back up the use of modern tech.

You then rubbish that answer suggesting cars aren't relevant, when he was only answering your initial rude inference.

Face it mate, you should have just been a gentleman first time round and apologised

[ask greeves]

Davetom, Ho I see, your not allowed to reply to a public posting, unless you agree with the content. Where have I said "I don't agree with modern technology" Lets face it PAL you'll probably get loadsa 'backup' to your posting, from people who really don't understand and want to get a life......bring it on. Wide band sensors don't think so.....dynamic balancing of a single cylinder engine, possible,(all sounds very technical, to the uninitiated) but don't think so. Persons with an IQ of one survive as do persons with an IQ of 150...it's just the life style that changes. If you consider a posting childish, surely replying would put you on the same level as the original post, but then again if you consider that 'you need a life' then it becomes understandable for you to reply. I wasn't to keen on the manner and name dropping of the original post and replied ( I consider) in a similar vein, I don't want to join your 'little clique' of yes men, who agree with anything which is posted.

Edited January 10, 2014 by ask greeves

[davetom]

Disagreement, opinions, guesses, I welcome them, that's what forums are about and here for.

Bad manners and rudeness they ain't here for. You got stuck in a corner and you dug deeper.

I'm not rising to your bait and won't post further on here, your doing just fine on your own.

[axulsuv]

Firstly XK 150's never came with webber carbs, so i consider 'it's a load of crap' Then again Jay Leno has a vehicle with an 1920's aircraft engine, to which he had fitted twin turbo's.....so it's whatever ring's your bell...go ahead an do it. When you've been through the whole cenario...been sold aftermarket equipment, which in reality, is inferior to the proper article, you can become very cynical, to a large majority of what is said on this web site. Isn't this a motorcycle trials site...how can xk 150 or alvis or 4.4 range rovers have anything to do with trials bikes, unless of course your trying to impress the reader ! Laird 387 has given us valuable insight into the history of motorcycle trials, a picture is worth a thousand words and his information excellent, the advance/ retire trick was used by many riders, your never going to be able to do that with a modern crankshaft ignition, but then again i'm a purest. The majority of the modified bikes (in my opinion) haven't been made better, they've just got caught up, in a 'modern day' money making exercise and it's great...because that means there's going to be less proper trials bikes, who's value will most likely increase. 'Teardrop tanks' a prime example of modern crap, they look nothing like anything which was ever produced, but slap a triumph or james or anything badge on it and in the beholders eye...he is the dogs danglers...yes i'm cynical.

Dear Sir; I have been doing this for over 4 decades ... And my services at the facilities I do restoration work and engine building is taking pending appointments about a year in the future ... And it was a ground up restoration on the XK150 , and then after delivery the owner came back and said he wanted more oomphh ! So he paid for a different intake manifold , cams , and a trio of webers . I'm more than willing to do what the customer wants to pay for . But I take ZERO shortcuts . And Jonv8 at the start of this thread was asking a question about some detail he wanted the particulars on , so voices were heard , and although I'm across the pond I can speak proudly of Jon's knowledge , as I contacted him a few months ago about a customers Bugatti type 37 replica , with a rover powertrain that I had never seen here in the states before ,with a strange drivabilty problem and in 2 e-mail conversations , I was able to deliver the car back to a very happy customer . NON OF US KNOWS EVERYTHING !

And the only stupid question is the one you are afraid to ask .!!! I went to the one person in my world of contacts that I thought would know what I needed , That is part of the beauty of the information age we live in , WE CAN SHARE THOUGHTS AND INFORMATION ! And if you haven't noticed , we share all kinds of thoughts here , world politics , the economy , GREAT jokes , saving endangered species and the list goes on . Yes this is a Trials website , and undoubtedly the best one there is , But we are ADULTS (for the most part ?) and can converse with our friends and expand our knowledge base .

Glenn

And Yes that is Cooper / MG #1 , I get some fun stuff to play with ...

[htrdoug]

And I'm stuck up here working on Subaru,Hondas,and Nissans

[axulsuv]

Maybe you should come and visit when MY! new shop is finished this fall ... (winds prevailing in my direction ) (aka , my a$$ is on the line ...)

[laird387]

Hi, Gentlefolks,

As a humble septuagenarian who grew up in a family whose mode of transport was a 1934 Ivory Calthorpe 500cc with a home made child adult sidecar fitted in which my mother and baby brother travelled whilst I, from the age of nine travelled on a 'bum pad' pillion seat behind my Dad I believe I can justifiably claim to be a motorcyclist at heart.

None of my grandparents had any form of transport other than public transport.

My great-uncle, father's Dad's brother was a motorcycle engineer, with his own garage and filling station business. In his teenage years he had been apprenticed at Bradbury's, who had nominally been sewing machine manufacturers who were diversifying into motorcycle production as a sideline. Uncle Dick was attached to the motorcycle project and became a test engineer, test driver for them. One of his memories was driving the first ever motorcycle fitted with a foot gearchange from Bradbury's works in Oldham to be exhibited on their stand at 'The Motorcycle Show' in Olympia, London. In my youth I spent many hours in his garage listening to his tales of 'how we used to do it' and helping him strip and repair motorcycles.

Later he branched out on his own and produced a motorcycle of his own on which the only parts that he did not manufacture with his own hands and machine tools were the magneto, the acetylene lamps and the rubber tyres. He sold several to enthusiasts who used them in hill-climbs, so the machine was called a 'Mountaineer'. He joined with his fourth customer and they entered two Mountaineers in the first ever 'Scott Trial' when it was opened as a public competition rather than just a competition between the Scott factory testers.

My own cousin, Mick Broom, trained as a motorcycle engineer, raced his own restored vintage racers and sidecar outfits then joined with Lord Hesketh to produce the Hesketh twin, the last genuine British manufactured motorcycle. He spends his life now keeping Heskeths from around the world maintained from a devoted and loyal band of customers.

Why am I bothering to relate all this?

In an attempt to show all the blinkered seemingly narrow-minded so called trials enthusiasts, whose only input to motorcycling is the ownership of a trials bike, that it takes all sorts to grapple with the problems of creating and maintaining motorcycles and just because someone has special knowledge in a somewhat different field of earning capacity it doesn't mean they are any less keen on motorcycle trialling in all of its different aspects.

Please - don't take yourselves too seriously, enjoy your sport in whatever format you prefer - but don't be too ready to decry others views just because you don't share them, unless you actually KNOW (from experience) to the contrary.

Try living with my motto: "No man is worthless - he may at least serve as a very bad example...."

Edited January 11, 2014 by laird387

[jon v8]

Mr Ask Greeves,I don't need a lesson on how or why crank balancing is done,I rebuilt my first bike engine at the age of nine and have been playing around with with bikes since then.From the age of 19 I've earnt a living building,testing and doing warranty work sub contract for two major diesel engine producers.For the last 20 odd years I have run a garage specialising in all Land Rover products from 1948 to present day.So I should have by now a fair grasp of basic engine theory.What I asked for in my first post was opinions from people with ACTUAL experience of altering balance factors for trials use.I was not name dropping either,I mention Don Morleys name as most people on here reading about P65 stuff will have read or know about his book "Classic British Trials Bikes". For most of the different marques he states the biggest improvement to be made to improve low speed running is to alter the balance factor from usually 70 back to 60%. I cant see why you think my original post was in any way rude,it was and still is a genuine question.You clearly don't have any experience in this,or I would have hoped that by now you may have told us all its a good job or a waste of time.

Having it done dynamically is being done as a favour,which I will return with firewood,its being done by a very good friend who has done many single cylinder cranks,but none for trials use.So he is keen to see how well it works too,this is how knowledge is built...

The advance and retard lever will be fully functional as the Lucas mag in the attached picture will be providing sparks.

[ask greeves]

I find it difficult to understand why persons on this particular thread, have to quantify themselves, maybe they are wanting in the self esteem stakes. Auxlove surely your refering to a KIT CAR bugatti (with a Buick type engine)....not a REPLICA bugatti (Ivan Dutton is the only person, I know of that builds replica Bugatti's) , but then again ..if your wanting to impress..carry on. Jon v8 Please don't misquote me, nowhere have I said you were rude, would seem you have problems following the thread, hope you both have a long and worthwhile relationship. Its amusing how people tend to believe anything which is written in print, the many cases of people in the public eye for example, believing thier own hype, Persons on this particular thread quoting Don Morley, a scribe's personal suggestion, as if it's the end all solution, to a comlpex problem. So you don't want to have lessons on how crank balancing is done, you know it all, so you want to go straight from A to Z , if you know it all, then why ask balance factors, if you were completely ofay you would know from the 'hyperthetical model' how the differences effect an engine.

[woody]

Jesus H Greeves, what's gnawing at you? Jon (whom I don't know) asked what seems to me, a perfectly reasonable question in his original post. I haven't a clue what he was on about technically, but understood that all he wanted was for his bike to run as smoothly as possible. Straightforward enough. Don Morley may not know his a*** from his elbow technically for all I know and he does make a few factual gaffs in his Spanish trials bike book, but he may well have got that percentage from a factory rider from that era. Who knows? As for name dropping, you're joking, surely?

As for people having trouble following the thread, read it again. Your first reply was sarcastic within its first sentence and you've carried it through ever since. You chide people about wanting to quantify themselves whilst all the time treating everything they say with a fair amount of derision, itself suggesting they're talking crap and you know better. Hypocritical !!??

You never once tried to help, you went straight down the sarcastic route. If you have an opinion on whether there is any benefit in trying what he suggested he'd like to do, or if you have a suggestion for the percentage required for smoother running, or how to do it, then why not just help the man?

And if you must pick issues with people's standards, I'd suggest you spell check your last sentence...

[jon v8]

Mr Greeves, I think this has gone far enough,I clearly don't know it it all or I wouldn't be asking what I thought was a reasonably sensible question.I have followed ALL the answers on this thread and apart from having to ask my wife about the Bridget Jones diary bit I think I have grasped where everyone is coming from.If I mistook your post where you stated you didn't like the manner of my original post,(Which I took that you meant was rude or inappropriate) then I apologise.

I don't think I suffer from low self esteem,none of my friends or relatives have ever suggested that this is the case.

Mr Morley's book is one of the only practical guides to riders using old bikes now,I rarely believe all I read - another good reason to ask my original question,I've already chatted to my riding mates and apart from one who checked the balance factor statically on his Norton 500T, nobody seems to have much practical experience.So,maybe now you can see why I thought it sensible to ask a wider audience.

Seeing as you have rubbished most of the posts on this thread perhaps you could tell us why you think dynamically balancing a single cyl crank is such a waste of time,what your own practical experience is,and what has led you to become so cynical by your own admission ?

Edited January 11, 2014 by jon v8