A problem with start freewheel

the sprague breaks free while winding the engine over, the idler clutch breaks free if the engine backfires.

why not read sparks article on it and do a check on spragues in the search feature? the doc dare i say it has it all - least i thought it did?

regards

Taffy

Taffy said:

the sprague breaks free while winding the engine over, the idler clutch breaks free if the engine backfires.

why not read sparks article on it and do a check on spragues in the search feature? the doc dare i say it has it all - least i thought it did?

regards

Taffy

Click to expand...

You can tell if it is the torque limiter giving in by the sound it makes, it's like a screeching grinding noise, if it is the sprague you don't that noise just a were.

Regards

Sparks.

Thanks Sparks

I have been chasing the wrong failure ! From your description on sounds my issue is the sprague because no screech just a whir from the starter

Must go read the doc on the sprague

Cheers

Mark

I checked the almighty Google and found an interesting way to repair the sprague by shortening the spring. Very simple and it works(tried the shortening).. http://www.mad-ducati.com/Technical/Sta ... lutch.html
Has anyone tried it in practise?

- Hannu

chilledspode said:

Thanks Sparks

I have been chasing the wrong failure ! From your description on sounds my issue is the sprague because no screech just a whir from the starter

Must go read the doc on the sprague

Cheers

Mark

Click to expand...

this has reached 'slap' status!!!!


regards

Taffy

Not true Taffy

The problem here is terminology, and poor consistency of it in the manuals (not the Doc) - it leads to a lot of confusion, not to mention threads where people apply home brewed names for parts.

Don't get me wrong I appreciate that everyone is just trying to help but for a guy like me that is trying to line up parts off an exploded view with people's description of how they fail its frustrating to go look at the 06 manuals and not find anything called a sprague!!!!

Both the shop manual and the owners manual don't deal with this particular set of parts worth sh*t Taffy. So someday when you feel so inclined you can explain to me why I should have poured thru the Doc looking for 'sprague' when it isn't even listed as a part title in my f*cking manuals....

Mark

Taffy,

I apologize for my poor language in the previous post - you're irritating sometimes...

Here is what my 06 manual shows by way of reference - no mention of a sprague

I am suspecting it is now called Free Wheel Part # 800.40.026.000

Along time back I chased this e-start problem and sparks comments combined with how I understood the failure mechanism suggested I had a friction coating failure on the gear wheel torque limiter. Some of the colder Hbg guys confirmed that at colder temps like <15C the 15W-** oil producede-start issues like I was experiencing and recommend 5W-**

It all made good sense so I figured I had it nailed and was just wating for the parts to arrive. Now this new thread comes along and it sounds exactly like my problem so I watch it and see that it goes off about spragues - but there is no sprague in the 06 literature so I write off to the e-start changes in 03/04 and it doesn't factor in to my problem, as I had done with other sprague reference on this topic before.

I am going to look at the older manuals and see if I can cross reference the parts names/numbers...

Cheers

Mark

yes the sprague is part # 26 as you say.

021.100 is the 'clutch' that sparks has modified.

regards

Taffy

Hi Taffy,

I just went through the 01-04 parts manuals and the language in all of them is consistent with what is in my 06 manual - so it simply comes down to you (and others) and I are using different english...

I stil don't know which part failed on mine (the torque limiter or the free wheel) but now that you have told me what the sprague is I have have some more reading to do in the Doc


Cheers

Mark

well until recently the freewheel wasn't even discussed. sparks has explained the difference in noise. 99% of the time it's the sprague.

that's really all i can say!

regards

Taffy

Sparks recent comment on the noise differences between the two is really what forced me to rethink things - that little gem of info should get added to the Doc under the e-start issues.

Without the noise trick, I don't know if there is any other way to tell which of the two (limiter or sprague) has given up.

I will order up both just to be sure - like the member from Iceland, I only have a 3 month riding season so I can't afford to be down...

Once I get the bike apart and have alook I'll post what I find (torque capabilities etc) because from what I am hearing it is unusual for the later edition bikes with the upgraded starter parts to have this kind of failure.

Cheers

Mark

chilledspode said:

Sparks recent comment on the noise differences between the two is really what forced me to rethink things - that little gem of info should get added to the Doc under the e-start issues.

Without the noise trick, I don't know if there is any other way to tell which of the two (limiter or sprague) has given up.

I will order up both just to be sure - like the member from Iceland, I only have a 3 month riding season so I can't afford to be down...

Once I get the bike apart and have alook I'll post what I find (torque capabilities etc) because from what I am hearing it is unusual for the later edition bikes with the upgraded starter parts to have this kind of failure.

Cheers

Mark

Click to expand...

The other way you can test to see which part is failing is to remove the torque limiter as this can be done without removing the clutch. Lightly nip it in a vice that has soft jaws with a torque wrench set it to 11Nm if the wrench wont click off then it's your limiter.
The one that went on mine clicked off at 5Nm.
But like I described before this can be easily resolved by reshiming.
But more often than not it is the roller sprague that goes.

Regards

Saprks.

The other way you can test to see which part is failing is to remove the torque limiter as this can be done without removing the clutch. Lightly nip it in a vice that has soft jaws with a torque wrench set it to 11Nm if the wrench wont click off then it's your limiter.
The one that went on mine clicked off at 5Nm.
But like I described before this can be easily resolved by reshiming.
But more often than not it is the roller sprague that goes.

Regards

Saprks.

Click to expand...

It seems that I had both failing at the same time. Limiter was really loose and the friction spacers were worn. Replaced the limiter and cleaned the sprague and changed the spring. Still slipping. Have to try shortening the spring. Still wondering what causes them to fail.

regards,

Hannu

Hannu said:

The other way you can test to see which part is failing is to remove the torque limiter as this can be done without removing the clutch. Lightly nip it in a vice that has soft jaws with a torque wrench set it to 11Nm if the wrench wont click off then it's your limiter.
The one that went on mine clicked off at 5Nm.
But like I described before this can be easily resolved by reshiming.
But more often than not it is the roller sprague that goes.

Regards

Saprks.

Click to expand...

Click to expand...

It seems that I had both failing at the same time. Limiter was really loose and the friction spacers were worn. Replaced the limiter and cleaned the sprague and changed the spring. Still slipping. Have to try shortening the spring. Still wondering what causes them to fail.

regards,

Hannu[/quote

Use and abuse my friend.

Regards

Sparks.

Let me throw this out, as Hannu has raised the question about why they failed, and I interested in the answer as well.

Certainly, Sparks you are correct on the use and abuse statement but in my case there is little of either...

The failure of the sprague/freewheel - is it a wear issue or a case of if over loaded it strips out? Where I am headed is, is the sprague more prone to failure from repeated use or more from peak loads/applied torque.

My theory is this: the e-start as long been called a re-starter and in the past has clearly had some weak points and since 05? the e-start system has been pretty reliable by all accounts. Boss and others still advocate kicking from cold then using the happy button, which suggests there are still concerns with cold starting.

The only significant issue I see with cold starting that is different from hot starting is viscosity and drag related to the oil. Up here we all run very light 0W-40 full synthetics in vehicles to reduce cold starting issues and I am wondering whether a 0W-40 or 5W-50 oil in the Hbgs would reduce the e-start cranking loads on the sprague/freewheel.

Anyone see a down side to running the light oil? assuming is suitable for wet clutches. For example Shell Rotella is available in a 0W-40 and since I am not racing and not running in high ambient temperatures, I don't feel I need the protection offered by the **-50 oils.

Cheers

Mark

hello i wanted to mention that i have the same problem as hannu. But only after the bike has been towed on a bike trailer but not when i take the bike straight out of the garage and E start it or when the bike is warm after riding (I'm guessing it has something to do with oil temperature/viscosity).

Hannu said:

I checked the almighty Google and found an interesting way to repair the sprague by shortening the spring. Very simple and it works(tried the shortening).. http://www.mad-ducati.com/Technical/Sta ... lutch.html
Has anyone tried it in practise?

- Hannu

Click to expand...

Wow, that is some fine Google work with a very interesting article Hannu! The symptoms for the Ducati are the same for many Husabergs and the sprague clutch in the article looks identical. Who's going to be the first to try this spring shortening mod? Could this be a cure from the damned sprague slipping?

I encourage all Husaberg dudes to take a quick look at the Ducati sprague clutch link that Hannu found!

log

this is where the real action is!

http://www-ccrma.stanford.edu/~peer/Duc ... pring.html

i have an engine in right now and i may well try it. however as we all know, the auto decomp, battery, connections and so forth are still a part of the overall answer!

regards

Taffy

Sprag clutches are very neat devices. They have been around for years. They are standard equipment on the packaging machines I work on. They are filled with light grease and I eventually have to take them apart, clean them out and replace the grease. The individual "sprags" stop swiveling when the grease dries out. The sprags are like little hula dancers that sway back and forth depending on the direction of rotation. Each sprag is ground so that in one direction it runs free. In the other direction it cams out and drives. They must all face in the same direction. The actual change in their profile is very slight. When they "run free", they still drag on their contact surfaces. There must be some friction to get them to swivel when the rotation reverses, hence the spring requirement. In the Husaberg motor the sprag clutch functions as an over-running device. When the starter cranks, the sprags are pushed to cam out and grab. When the engine is running they swivel back into a free condition. The actual amount they move is extremely small.
I had my engine fail to crank once in cold weather. Perhaps the thick oil prevented them from grabbing or the torque limiter released from engine oil friction. The starter spun up with no cranking occuring. I don't remember any sort of squawking sound so maybe it was the sprag clutch.

Hi Neil,

Thanks for that - I am starting to get a better understanding of how this odd little part works and how it might be affected by stiff oil.

Cheers

Mark