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conical springs - time for red alert?

Taffy

Taffy

Joined Nov 2001
17K Posts | 774+
Ely, England
i've had a couple lately, GGRs had one this week, daleo has had it....the conicals do like to break now and again!

i wish they weren't even IN the flaming engine.

so do you think with these regular breaks its a red alert?

i've noticed that if this happens in the old 470s its a major catastrophe! the HC piston and the spring break do not go together!

also, is this age related? 4 years plus and the danger signs are there!

thoughts?

regards

Taffy
 
i dont know why but even the new 2009 motor has conical springs.
maybe they sorted out the material or something?
 
i think joe has had it happen at least once?

oh sorry, real reason=bump!

regards

Taffy
 
What is the material?

What is the diameter?

What is the valve stroke?

Get those numbers, and we can run a fatigue analysis on the springs to see if they come close to breaking after and estimation of total cycles. Maybe DaleEO can recall how many hours he had on them before they broke??

Fatigue analysis is not a perfect/exact calculation, but you can get an idea of how close to the edge the springs are in design.

-Luke
 
Had the broken valve spring myself, and this ruined my engine more or less. When i shopped around to trade in my bike for an other one i noticed that both the Husaberg dealers i visited where very focused on the 120 hours interval of the bike. According to them a Husaberg needs major service around 120 hours on the clock to be on the save side. Mine had 150 on it when the valve spring broke, so i'll definitly change the springs after 120 hours the next time i buy a Husa.
 
so surfdude

you bought the dual valve springs and its they that broke? or what?

can i ask you - DID YOU PUT ANYTHING UNDER THE SPRINGS OTHER THAN THE LITTLE THIN SHEET METAL 1MM WASHER?

regards

Taffy
 
the thing is lads. it's quite clear these things are breaking when people go bye the set hours. so never mind that its the owner's fault (which it is!) this is still a red alert item methinks!

surfdude i trust that at some point you have given the bike a damn good thrashing with those dual valve springs right?

no valve bounce, no weird clack clack!! at high revs?

regards

Taffy
 
I understand that there are cases where we have seen broken valve springs,we now know the immediate signs of such a failure.There is the definite possibility that with enough time and high RPM use the probability of such a failure is more probable ..BUT I am not so sure that a Red alert is in order.
If it means anything there are now about 35 Bergs in my market area and although I stock the springs I have yet to sell any to replace a broken one.
 
No, the conical valve spring was the one that broke. Although everything looked ok at first sight, when the valve hit my piston there was some more damage to the motor as i hoped / thought there would be. This resulted in even more damage lateron when the dual valve springs were already in.

The dual valve springs work great, no complains on them, nor weird sounds at high revs, gave it lots of WOTs in loose sand. I installed them with the plates delivered with the original part, those where 3 0r 4 mm i guess. Only i set the valve clearance at .15 in stead of .12 because it was impossible to get a .12 plate at that time. Tried the 1/6th method, but wasn't comfortable with it.

Did some test driving, and just couldn't find that controllable power of my Husa from way down the low revs. So i would buy another Husa just for that.
 
i forgot - you ordered the cheap ones and got the expensive ones for the same price - a bargain!

so you still haven't told us what happened 'later on'?

i did a job for someone, he had a broken exhaust valve spring. i checked the compression and all was good. a month later, the head snapped off both the exhaust valves. made a right mess....

regards

Taffy
 
The initial damage due to the broken valve spring made the exhaust valve hit the piston. As there was only a slight mark on the piston i didn't look any further, and the engine seemed to run ok, but the damage was already done. While riding with my new bargain valves other problems occurred due to the initial damage. At least that's what the shop told me, but this sounds very logical to me. At first i found some metal scrapings, the second time a little more and the engin began to make a metal scraping noise.
 
that doesn't sound quite right to me? if the valve hit the piston and nothing else happened, you then fit a new valve and valve spring alone then that is that!

nothing else happens. someone is talking bollocks here!

regards

Taffy
 
Valve spring

Taffy said:
so surfdude

you bought the dual valve springs and its they that broke? or what?

can i ask you - DID YOU PUT ANYTHING UNDER THE SPRINGS OTHER THAN THE LITTLE THIN SHEET METAL 1MM WASHER?

regards

Taffy
Click to expand...

There is something to prevent the spring to brake. According to R&D, on occation there is vibration in the spring it self, like inside a old guitar. sorry i dont know the english name for it.
To prevent this you can place a thin washer under the spring to have a bit more tension and the problem goes away.
But it will be harder to press and there will be more wear on the rocker arm roller bearing.

Still the best way is to use dual springs, and it reduces wear on the roller due to its softer.

//Thomas.
(Tested the 700cc engine this weekend)
 
yes i've had 2 x '04 do the same. i reckon it would have been a good year but for the mains. BTW, i think it was simon who said that the '04s never got the axial tolerance right. i believe they left it as .5mm for ball race but went to one ball - one roleer and didn't give them more clearance. doesn't explain why a double ball would go though.....

regards

Taffy
 
Taffy said:
yes i've had 2 x '04 do the same. i reckon it would have been a good year but for the mains. BTW, i think it was simon who said that the '04s never got the axial tolerance right. i believe they left it as .5mm for ball race but went to one ball - one roleer and didn't give them more clearance. doesn't explain why a double ball would go though.....

regards

Taffy
Click to expand...

Taffy,

I am confused about this thread. My 04 came with roller mains from the factory. Are you saying that some of them had 1 roller and 1 ball bearing main?

Joe
 
sorry joe

i'm losing it. do you recall that the australians had a lot of mains go? on 550s mostly. not sure now but i thought it was a lack of axial float? if they were double ball i simply have the year wrong and it's the next year.

regards

Taffy
 
Hi Guys,

Just a thought here, it might be old news, but anyway....

Renewing your springs would not be a big job if you did not have to remove the head..... Being a shipsengineer I have done this many times on big engines by applying compressed air into the cylinder to keep the valve shut. You could do this through plug hole. Have not tried my self on small engines, but would it be possible ????? Would there be room enough for the compression tool with head in place ?????

Anyone tried this ???


Anders, Denmark
 

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