FE501 top end refresment

bushmechanic · Sep 8, 2014

Hi Kli Im very happy you found some good valves

you should be able to just install the KTM duals as long as possible in the head, I have the exact numbers at work and will post them tomorrow night but usually unless you machine the head like i did to get more room ( http://husaberg.org/mechanical/17998-bushmechanic-mongrel-628-trailbike.html ) you are guaranteed to have enough seated force. it should end up at about 70-75 lbs without machining, i went for 65 lbs.

the head in the pic was set up at one time with 98mm long valves, it is now set up with 97mm long valves, just showing that it can be done.

kli · Sep 8, 2014

Perfect,

thanks.

bushmechanic · Sep 9, 2014

No worries Goran!

there are a few variations in the thickness of the lower spring seat and also there are 2 slightly different types of inner spring that I have seen

so to keep it simple a preload of 5.6mm on the ktm DVSK results in approx 66lbs, safe to say you will have more preload and more force than that.

I think 65lbs is a good minimum value.. i found some valve float at 60lbs near 8000rpm and the 08 profile cam.

FWIW the KTM RFS "spec" is 80lbs

kli · Sep 30, 2014

Hi all,

Received new valves and other stuff.
Here is couple of pictures from old and new things.

Old inlet valve

Old and new inlet valve

Cracked inlet vealve seat

kli · Sep 30, 2014

New valves, guides, steams fitted in head

New exhaust seats

New inlet seats

kli · Sep 30, 2014

Here start the throuble.
Today my mechanic call me that he have problems with fitting the springs.
Instead conicals I buy KTM DVSK ATV kit.

I found out that lower shim is not seating nice in head, there is a inner hole of 12mm which is for new stainless steel guides, I have old bronze which are smaller in diameter, also outer diameter is smaller, so they can be moved easy, is this a problem or when the spring it's fitted preload keep it in place firmly?

Another problem is that one of springs can't be fitted because it's touching side of the head.
I think that if I grind a bit of head it will go in place, can this be done?
It will be just a smaller place to put sealant.

Right inlet valve touching head

Does any of you have had similar problems during upgrade to DVSK?

BR
Goran

kli · Sep 30, 2014

I'm too fast

I found that side of the head can be milled in one of Bushie's post - Mongrel 628 trail bike.

Kayeffess · Sep 30, 2014

Yup, I used a dremel tool to remove the material to clearance the valve spring.

bushmechanic · Sep 30, 2014

the seats are also loose with the steel guides .. it doesn't seem to be a problem as long as the seat is thick enough to spread the load of the spring

i went for 1,5mm clearance on the springs, had to also dremel the rocker cover, in particular the LH intake

kli · Nov 12, 2014

Finally I catch some time to play around bike.

Milled head to fit springs, also needed to grind valve cover, worst situation was on right inlet valve.
Now I have clearance 1 mm on right inlet valve from spring to head and only 0,3 mm from spring to valve cover.
Also I needed to mill collar head screws, newer screws (58036099100) can't fit directly to older head, they have bigger diameter of nut.

Milled around left inlet valve

Milled around left inlet valve

Grinded valve cover

Right inlet valve, very close with fitted valve cover.

Left inlet valve

Exhaust are fine

Wide nuts on head screws

bushmechanic · Nov 13, 2014

nice pics Kli ... you're getting there!

kli · Nov 17, 2014

Finally sorted out everything.

FE501 top end refresment

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