Shift Return Spring Failure Poll

[Guest Natrix]

2,800 miles on 2004 Ballabio and no problems!

[Bill Hagan]

Mr infamous Sweep, people have been looking for you ...

what size is the coil boss on your ratchet arm?

 

In an earlier post Sweep says dealer found 15mm boss. I'd like to speak with his dealer about this, I pm'd Sweep but he did not reply.

 

KB

Think I already said this in a related post, but, as I am an age where I can't remember where I last put my glasses, I'll risk repetition by saying my Ballabio's boss was 15mm when the spring went out at c.6.5K.

[Baldini]

Bill,

 

Did your dealer check the action of the pawl arm/spring/shift plate assy before replacing on bike?

 

Did he suggest a cause for failure?

 

KB

[Bill Hagan]

Bill,

 

Did your dealer check the action of the pawl arm/spring/shift plate assy before replacing on bike?

 

Did he suggest a cause for failure?

 

KB

Yes re action and, as I understand it, found no apparent anomalies.

 

The dealer thought "cheap spring metal" a possible cause, but remains puzzled. Pete Roper is in town and staying with us. I showed him the sheared spring, and he agrees that is the likely answer, too.

 

My American Express bill came in with the U-Haul rental and gas charges on it. Kathi studied it and made some ... err ... wifely remarks, all of which means, I predict, she will be on a guiltless shopping trip soon.

[Baldini]

cheap spring metal

If it is simply bad metal, why do some bikes/riders break springs again & again, whilst some don't break them at all. It would mean that some original, and all replacement springs were bad but not those being fitted to most recent & current production, unless 03/04 bikes start breaking springs regularly....it just doesn't sound likely to me.

The pattern to me suggests that some bikes have a fault that causes repeat failures. Has anyone had spring break, replaced it, & had no further problems? It seems that the bikes breaking springs tend to repeat breakage.

Of course it could be down to how the rider uses the box...

Has anyone had spring break on an 00/01 bike?

 

The oversize boss causes the spring to bind & impairs function, but clearly if springs are still breaking with correct size boss, there must be some other factor.

 

KB

[docc]

I agree with KB on this. My 2000 Sport has had every kind of tranny failure known but not spring breakage. This phenomenon seems to show up in 2002.

 

While the springs certainly don't appear to be of a high quality, some bikes seem to break them over and over.

[Guest Bruce]

2000 V1100S, 7500 miles, no spring problem yet

[Bill Hagan]

cheap spring metal

If it is simply bad metal, why do some bikes/riders break springs again & again, whilst some don't break them at all. It would mean that some original, and all replacement springs were bad but not those being fitted to most recent & current production, unless 03/04 bikes start breaking springs regularly....it just doesn't sound likely to me.

The pattern to me suggests that some bikes have a fault that causes repeat failures. Has anyone had spring break, replaced it, & had no further problems? It seems that the bikes breaking springs tend to repeat breakage.

Of course it could be down to how the rider uses the box...

Has anyone had spring break on an 00/01 bike?

 

The oversize boss causes the spring to bind & impairs function, but clearly if springs are still breaking with correct size boss, there must be some other factor.

 

KB

Logic is annoying.

 

You are right, of course.

 

Back to "beats me." I'll be watching here for more info.

 

Bill

[Guest Bruce]

Earlier today I discussed this with a very sharp Mechanical Engineer who said binding could do it or it could be a weak point where the metal is bent sharply. He asked where specifically the springs are breaking.

 

So while it is interesting to know that some break frequently while others not at all, knowing where they break is important to understanding the root cause. If those of you with broken springs can post this info ( pictures are best ) I'll pass it along and see if he has got any insight. Or send me a PM if you prefer.

[Guest jerroldt]

From my point of view a spring is a spring and shouldn't break unless the pivoting point causes it to wear thin. I think that the problem is with inferior heating/hardening processes and quality control in their manufacture. I know of few other bikes with this problem.

[jrt]

follow-up on that last post-

has anyone broken an aftermarket spring?

 

I am personally hesitant to infer too much (about the cause of spring breakage) from this poll, since it reflects the statistics of small numbers.

 

cheers,

Jason

[Guest Bruce]

Jason,

I know where you're coming from in terms of the samples size, DOE, so on and so forth, point well taken. None the less the frequency of breakage on some bikes is hard to ignore.

 

Having wrestled with some what similar problems in the past typically the broke pieces tell the story, particularly the spot where its broken. By examining it closely at 25-50x magnification and and knowing where on the spring it typically breaks, or if the break point is random, should indicate if its a tensile break or a fatigue break and possibiliy what the exact cause is.

 

The spring it self will be some sort of drawn steel and could have weaknesses, possibly from the begining or end of a run, no doubt who ever makes the spring bought it from a distributor. Next its cut to length and fed into a "Spring Machine" , maybe by MG or could be sourced. If there are any flaws up to this point they'd be almost impossible to detect. Chances are good it is not annealed. Possibly selectively annealed.

 

So, as mentioned before pictures of the broken spring are important. Ideally if you can blow them up 25 to 50 times the exact nature of the break should be quite evident. If you want to send me broken pieces I'll run them by my ME ( send me a PM to arrange ).

 

Just a thought, does MG still make a 5 speed and if so could they have gotten some parts mixed up? Don't its easy to do.

[al_roethlisberger]

I think this is a great idea, and offer from Bruce.

 

If anyone has their broken springs still lying about, we should take Bruce up on this offer to have the springs looked at

 

Thanks

[belfastguzzi]

Ideally if you can blow them up 25 to 50 times

 

I think this is a great idea, and offer from Bruce.

 

If anyone has their broken springs still lying about, we should take Bruce up on this offer to have the springs looked at 

NO.

 

I think Jaap should buy a giant electron microscope, for the good of the cause.

 

As a contribution, I'll donate a bit of broken spring to look (and wonder) at.

 

Someone should be able to draw up a list of other things that we could examine.

 

PS

 

Feel free to blow up my spring.

Given the steel quality, coating it in bicarbonate of soda and dripping some fizzy drink on it should do the trick.

[Bill Hagan]

I've been keeping mine (well, the part Kathi didn't throw away) as a $550 "For want of a nail ... " sort of souvenir, but will send to Bruce for such scientific study as he cares to make.