Valves still hitting piston, time for new springs?

[stng_96]

Ok guys, here is where I am now. Ive got the 11:1 426 wiseco in my bike, with a stage two cam. I have been fighting intake valve/piston contact for some time now. I know the timing is dead on, but I am not sure about the lash. I have read in multiple places that a hotcam just takes stock lash, but I have also seen where people lash them out much farther, so whats the deal there? Also, I am worried that the valve springs are worn, and its floating the valves, anyone else think this is a possibility?

I put a crf timing chain in it, and clayed it last week, and there was no contact, which leads me to believe the floating issue.

Please help

[rubbersdown]

.005 (.13mm) Intake and .006 (.15mm) Exhaust is what your valve clearance should be set at. Your springs could be bad, are they stock? Just take them out and measure them with a caliper set, the inner springs service limit is 1.43", the bigger outer spring service limit is 1.70"

[stng_96]

My springs are stock yes, so Ill take them out and measure them. That being said, would a new set of stock springs be fine? I have read a lot of people using them, and my local dealer actually has a set in stock for 48 bucks, which is a lot better then the aftermarket ones I have looked at.

And that is what I had it lashed to, so I guess Ill leave that alone.

[CJM]

Im actually running it the stock lash after I did about 20 hours break in Im not sure it makes much of a difference but it did quiet the ticking.

[rubbersdown]

stock springs will be fine as long as you have oem style valves. Its when you change the material the valves are made of that you sometimes need to run different springs.

[sixer3]

have you verified that the noise you are hearing is indeed the valve hitting the top of the piston?

[stng_96]

Haha, yeah, took the head off again, it was not a question of whether or not they were makin contact.


So the update is that I got the old springs out and measured them, the were all a good 50 thousands to short as far as expected length, and also all about 10 thousands below the service limit, so I got the new springs and put them in, and now she is purring like a kitten.:D :D :D

[hiway6969]

the arrow on the piston points towards the exhaust side...............
had a guy bring me a bike making noise like that, he had put his poiston in backwards lol just a thought

[09RappySe]

I am no expert, but it seems to me you have piston to valve clearence issues....have you clayed it up to see what the clearence is? maybe you need to either run a thicker head gasket or fly cut your piston. If it was a valve spring issue it seems like it would only happen at high revs due to valve float. I don't know what the clearence should be on the 400, but I would clay it up and go from there.

[stng_96]

Originally posted by 09RappySe
I am no expert, but it seems to me you have piston to valve clearence issues....have you clayed it up to see what the clearence is? maybe you need to either run a thicker head gasket or fly cut your piston. If it was a valve spring issue it seems like it would only happen at high revs due to valve float. I don't know what the clearence should be on the 400, but I would clay it up and go from there.

refer to first post, specifically the last part wherer it says I clayed it last week

[09RappySe]

Originally posted by stng_96
refer to first post, specifically the last part wherer it says I clayed it last week

I don't know how I missed that.....I guess I am blind.

[stng_96]

Lol, happens to the best of us