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broken valvesprings

D

dustbite

Joined Jun 2007
143 Posts | 0+
Mexilhoeira Grande, Portugal (for US citizens; tha
ola guys,

I run a small business providing enduro fun on two wheels in the south of Portugal.
Since sept-2006 I use Husaberg. I had 1 x 450 fe, 1x 501 fe (both 2004) & 1x 450 + 4x 550 fe (2005)
The 2005 450 & the 4 2005 550s were stolen last febr.

Now I got 3 more 2004 450 and two 2004 501. So I own seven 2004 models at this moment. personally the 501 are my favourites.

But here's my question.
I have experienced broken exhaust spring three times now on the 2004 bikes. I had very little problems with the first seven bikes (untill 5 were stolen) other than the "normal" husaberg stuff like badly fitting exhausts and poor fixings, and three x a loose nut on the crankshaft (primary gear) .
I have read some articles on this website and understood that the conical springs have a rather high pre-tension (if that's the right expression)

- I would like to know if that's the reason why they brake
- would the 2005 mx cylindrical duo valve-springs be a solution?
- do I have just bad luck or a mondaymorning batch of faulty springs?

We do not race with the bikes and I don't think they were overreved.
My experience with valve clearances is that after initial setting of the exhaust valves they change only very little. In this part of the globe dust is my biggest enemy with excessive wear on the intakes only. I had the same problems with 5 ktms EXC that I was running before.
In practice I only check the intakes every 20-30 hrs. The two oldest bikes have done some 400 hrs now and only need new intake valves, cam chain and the seats done. Perhaps I am going to check the piston rings but it's a lot of work because of this stupid design....

Any help would be appreciated a lot.
thanks, Adriaan
 
Hi Adrian,

would be nice to know the location of your business,
mayybe I´ll go there next winter???

But getting back to the (I guess?) right exhaust spring-valve:
It´s an know problem (at least here in Austria),
but I do only know this problem on SuperMotos

Sorry, can´t tell you why they break

maybe you can PM Lineaweaver, he offers a camshaft that reduces the stress on the valves/springs
or ask some of our Roadracers(eg. DR_C), maybe they do know a fix?
 
Hi guys, just stopped by...
The preload is high for a single thread spring design. Not very high for a double spring, in my opinion. The conical shape introduces resonance which can cause reduction in life length for the spring. I have myself not yet had a spring failure on either of my Husaberg 650, 2003 engines. But as soon as I can detect relaxation I change them, mainly because of the larger valves I´m using. I do not know how many hours the 2004-springs lasted for you, dustbite?
 

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I'm also a member of the broken exhaust valve spring club. Nothing bad happened, no bent valve or other damage. Just a loss of compression and party over.

As I understand it the double-spring setup only comes on 'C' competition models with the titanium valves. The single conical valve spring with stainless steel valves are used on the 'E' models.

Can you use the double spring setup on E model stainless steel valve bikes?
 
hi everyone,

I am looking for a cost effective solution but I am also wondering why it only seems to happen on the 450s so far. Perhaps they do rev. higher than the 501, 550, 650?

I know Dale is very knowledgeable and a very good tuner but I don't want to buy a lot of expensive parts. I do have access to the dealer organization so I get my spares for a fair price. That's why I'm asking for the possibility to use the mx springs.
According to the parts manuals it seems possible.

Dr C, how do you detect relaxation on the valves, by dismantling and check the spring tension and length? That would be too much work for me.

Supertireguy and everyone else: these are the symptoms:
different starting habits as if the starter motor cant get through the compression, bad starting in general, once started it seems to run OK (well..)
some backfire on starting.
Supertireguy, what year &model do you have?

O, these bikes have done some 150-170 hrs, I believe thats close to 5000 km/3100 miles

Gokai134, I have a website: www.algarve-offroad.com. we're situated in the south of Portugal, Faro is the nearest airport.

For the rest: I am very pleased with the way these bikes go 'round the corner, a very light feeling and easy handling. And there are not really much lighter, only in the official specs...
 
the cam profiles have been softened since 2003 so i'm disappointed you had trouble my freind. i'm sure that this was all a dodgy batch of springs and once they've run through the system there won't be trouble like it again.

i suggest that if this happens that you replace all four springs on that engine with OEM parts. there is a company called 2S & W" and they do springs. could try racing KTM gear. if it was me though i'd cross my fingers and work my way through this bad batch.

another thing you can do is stop all the bikes on TDC to relax the springs. a lot of effort i know....

regards

Taffy
 
Hi Taffy,

in a way your answer is a comfort. just bad luck and with the replacement of the spring all should be back to normal. Lets hope it's nothing more structural. I am still trying to replace the spring without dismantling the head. it worked for two other springs but they were on the righthand side, this spring is the left one.

thanks, Adriaan
 
Got it sorted out, the bike is running fine again. I checked the maintance book of the bike, it had had a loose cil.head bolt in the past so I guess it's one of those monday morning examples....

Ah, now that I'm at it. With two or three bikes a experienced a damaged mainbearing seal on the clutch side. they do have there little problems, these Bergs.

Well, thanks for all the suggestions, if anyone can say more about why these springs brake » please let me know.

ciau 4 now, Adriaan
 
I´m checking relaxation (free length) to make sure the springs are "fresh". That is not normal to check, but then again, there is not much left that is normal on my engine... :)

For what it is worth, I would place my bets on Taffy´s idea on a dodgy batch.
 
just a thought again: check the rebuild information in the doc: dale kindly offered the spring's compressed length allowance.

me?

i refuse to replace the springs point blank. firstly i don't believe they have any "hours" allocation least not while this pope is still alive! i believe a well run in spring is to be kept and treasured. when they're right you shouldn't "fix 'em till they're broke!"

good luck.

if you want any parts sending over - let me know coz half of portugal now lives in either thetford or soham it seems to me!

regards

Taffy
 
O, these bikes have done some 150-170 hrs, I believe thats close to 5000 km/3100 miles .



i had 13700 klms @ 165 hours , more dirt that road .
 
[/quote]i had 13700 klms @ 165 hours , more dirt that road .
Whosahberg, Australia has only long straights I guess. Here in the Algarve 500 mtr straight is an exception. But I could very well be wrong.

Taffy, I just mentioned the hours to give an idea about the use of the bikes, the're still "new"
And half of England is living here or has a second home and is proud to not speak Portuguese. I get my spares from Holland, but thanks for the offer anyway.

cheers,
Adriaan
Click to expand...
 
Spring Life

All springs of just about any kind do produce less resistance over time. (I would think?)
I have checked a few of the WP springs new before installed and again after a few years.
They do settle and loose resistance on shock springs, so I assume it is all the same?
Just lift an old garage door that has the original springs and you will see what I am talking about.
Metal is Metal and it should be the same?
As for the Ti Valves I have herd it said that 2-2.5 horse is what can be expected.
A guy I ride with has the FE version and after riding myFC he feels as well as myself that it must yeild about that much. The power gain is on top and bottom because you get faster rev and over rev.
The smoke stack also takes a few horse and that is taken into consideration with the above statement. I have also herd that you should see about 30% more life out of SST over Ti. The big names in desert racing do not use them and they can have whatever they want so that should make you think!
 
dustbite said:
ola guys,

I run a small business providing enduro fun on two wheels in the south of Portugal.
Since sept-2006 I use Husaberg. I had 1 x 450 fe, 1x 501 fe (both 2004) & 1x 450 + 4x 550 fe (2005)
The 2005 450 & the 4 2005 550s were stolen last febr.

Now I got 3 more 2004 450 and two 2004 501. So I own seven 2004 models at this moment. personally the 501 are my favourites.

But here's my question.
I have experienced broken exhaust spring three times now on the 2004 bikes. I had very little problems with the first seven bikes (untill 5 were stolen) other than the "normal" husaberg stuff like badly fitting exhausts and poor fixings, and three x a loose nut on the crankshaft (primary gear) .
I have read some articles on this website and understood that the conical springs have a rather high pre-tension (if that's the right expression)

- I would like to know if that's the reason why they brake
- would the 2005 mx cylindrical duo valve-springs be a solution?
- do I have just bad luck or a mondaymorning batch of faulty springs?

We do not race with the bikes and I don't think they were overreved.
My experience with valve clearances is that after initial setting of the exhaust valves they change only very little. In this part of the globe dust is my biggest enemy with excessive wear on the intakes only. I had the same problems with 5 ktms EXC that I was running before.
In practice I only check the intakes every 20-30 hrs. The two oldest bikes have done some 400 hrs now and only need new intake valves, cam chain and the seats done. Perhaps I am going to check the piston rings but it's a lot of work because of this stupid design....

Any help would be appreciated a lot.
thanks, Adriaan
Click to expand...

We have had that problem as well, first we ad a thin washe under the spring, then the problem disapered, but the range of the spring is the shortend, its not a problem if you use a std camshaft, can not see any additional wear on the camshaft or rockerarm roller bearing.
We now use KTM TI valve springs from 450SX, sale at 220E for 4pc complete, and it takes the higher lift that we have on our camshafts.
We belive that they brake due to self vibration, to little tention on the spring.
we have now only cracked one spring in 2 years on our race engine.

We used 14 Husa FE450E at MY Adventure and one FE550, didnt crack one spring. these bikes has now 100-200hrs during 2005-2006, now getting replaced.
I work part time there as an instructor and mechanic.
www.myadventure.se
www.enginehardware.se

Regards
Thomas
 
Feed a few feet of soft cotton rope about 1/4 inch in diameter into the cylinder through the plug hole with the piston slightly downward from tdc compression. Gently rotate the engine to bring the piston upward and the rope will hold the valve up. Change the spring, lower the piston, and pull the rope out.
dan
 
Hello all,

Last race the engine died on me,It was very rainy,so Ithought a water problem somewhere,there was indeed a pearl in the mainjet,so I cleaned the carb rebuild and fired it up again nothing. Elektrical was there also not a problem a clear spark and the plug was also good,I leaved it somedays on the table and.....

Today I opened the engine ,and I had also left broken valve spring.
The engine has 77hours,so far no problems,this is the first problem,there was also nothing dammaged,except the valvespring.
I will replace 4 oem valvesprings,this week.

Greetings Madero
 
Hello

today I will replace the oem valve springs ,to 4 FC valvesprings,also I will change the OEM cam into a HOTCAM that I have changed a bit.

Greetings Madero
 
4 FC valve springs?

what's the idea madero????

most are going to dual valve springs.

regards

Taffy
 

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