750 Inner valve springs

[LaverdaSoren]

On my 750SF cylinder head the new inner valve springs are interfering with the outer valve springs. When I turn the camshaft the valves hangs up for a moment and then comes banging down into the seats!
I have a set of old inner springs but does anybody know where I can find new wich have the right outer diameter? (Wolfgang only have a few that he needs for himself).

 

[Tippie]

Laverdaparadies, OCT?

 

[LaverdaSoren]

The too big inner springs came from Laverdaparadies. I,ll check with OCT.

 

[piranha-bro2]

i'd probably risk refitting the original inner springs - unless you plan revving the bags out of it, they should be fine.

 

[Exmoor beast]

What else have you done to the head? Reason I ask is lots of modern valve springs have a “touch fit“inner to outer spring to damp resonannce but I can’t see how the springs touching would hold a valve open- even momentarily.

 

[Paul Marx]

How is the valve gear? How are the guides?
Paul

 

[piranha-bro2]

My Todd SFC valve springs touch inner-outer but no binding. Valves close without drama.

 

[LaverdaSoren]

The cylinder head has new guides, the valve gear is all new parts, the inner and outer valve springs are new from the same dealer and the only reason I can think of is that the springs are momentarily binding.

 

[Rob]

Is the valve/guide clearance correct? The need for honing new guides is often overlooked.

 

[Exmoor beast]

I don’t know if you assembled the head but if guides were tight enough to hold open valve they would be a hammer fit.
Grinding paste residue could do it but unlikely to be repeatable, I would look closely at rocker spindle binding or something just Fouling the head casting and causing the valve to stick. Is it both valves/ one valve/both sides? Is the Tappet foot going past the valve head and catching on the collet?

 

[LaverdaSoren]

Sorry guys, I WAS WRONG!
I have made an adjustable camwheel and I had not tightened it enough to the camshaft before I made the first turns.
The bangs came when the camwheel let go after the camtop passed maximum lift....
From now I will try to not draw fast conclusions.

 

[The Sock]

My daughter had a Primary Scool Teacher, who drummed into the class,
"MISTAKES ARE GOOD!
If you learn from them"