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new decomp lobe v old

Joined Nov 2001
17K Posts | 774+
Ely, England
i have the two here so i may as well let you know the difference between them to look at?

the OLD one i have has the end profile of an iron for ironing clothes, it is symmetrical. has a flat face in profile at the end and a 'D' profile where the spring will slip onto.

the NEW one has the end profile of a dutch clog. there is a single hole in the end profile.the spring sits in a gulley in the arm where the base of which is still a letter 'D'. the point isn't symettrical but instead curves around one way to give the appearance of a dutch clog!

the counterweight designs do differ but is too hard to explain!

regards

Taffy
 
my camera won't take a nice photo close-up. anyone else able to capture that end profile?

regards

Taffy
 
i've got pics of them in situ but only the old style is out at the moment.
 

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  • berg 04 cam (2).JPG
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  • berg 650 decomp.JPG
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... and the other two '02 650 pics
 

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  • berg 650 decomp (1).JPG
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  • berg 650 decomp (2).JPG
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.....and two different styles of decomp spring as well. i have been sent what i thought was the latest that is profiled also like a D. this was sent to replace the spring you have in the top photo that goes round the corners.

i will try again.

regards

Taffy
 
i used the newer spring (you can see in the 04 cam (1) pic) when i replaced the knackered decomp on the 02 650 and it ended up coming loose on me, so i reused the old one after tightening the bends a bit and its holding up ok.
and after i wrote this i went to look at that "newer style" spring and it looks to me to be the older style as well??? what do you think?
 

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seems to have lost it's shape a little ned?

i agree that by the time they're fitted they seem to be half knackered already!

i'll get right up close to your '04 decomp and it will appear in the doc....so thanks mate.

regards

Taffy
 
auto decomp

i would like to remove the auto decomp and run just the 2 others, manual and kick starter. I ride the bike most of the time in a hi gear at low res,the auto will open killing the power at the worst time.

So will the rocker arm roller be damaged or damage the exhaust lobe with out the auto decomp in place? The roller still has 50% of the lobe to ride on with out the auto decomp in place.

Mars
 
RE: auto decomp

you'll be fine if you remove the lobe and spring.

as for the decomp opening and killing power i am dubious of this!

i am about to go the other way and am going from manual decomp only to auto decomp only...

regards

Taffy
 
RE: auto decomp

WELL WHAT SHOCK!

i have just started the engine with the new decomp lobe. the ONLY changes i made were to fit the modern decomp lobe (dutch clog) and the dual valve springs.

i went up to the bike and sat on it for the first time and went to kick it through to TDC and then operate the manual decomp IF NEEDS BE.

I KICKED A 2-STROKE!!!!!

that's the only way i can describe it! my foot fell through each stroke of the kickstarter. from now on lizard killer has no excuse! she could ride the force!

bike started second prod (i can no longer use the term "kickstart").

regards

Taffy
 
my 650 was the same. with the knackered autodecomp, you started it like a 4 stroke, finding tdc, etc. with the new auto d, it kicks right thru, but a 650 has such a long stroke, you can't compare it to a 2t, but still starts quite easily. the other thread about the starter motor http://www.husaberg.org/index.php?name= ... 1265#71265 was to show the differences in the 2 starters. even with the new auto d, the honda wouldn't spin it fast enough.[/quote]
 
just done a 650 with the dual springs, new decomp and spring so i was simular to you ned and it kicks very easily, as you say not so much hard as slow! you can start it sat down.

regards

Taffy
 

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