What is this sound ?

[Tsunamix]

At the top of the rev range, just on gearchange I am hearing this noise.

I have just put in a new tune, with a shift in change points and rev limiter.

i thought at first that it might be touching the rev limiter, but I have become suspicious that what I am hearing is valve bounce...

I would like peoples opinions.....

Cheers...

http://users.tpg.com.au/ashnak68/memo.m4a

 

[cds]

Dosent play.. i think im missing codec for it can you maybe put it up as .wav or .mp3?

 

[Tsunamix]

Dosent play.. i think im missing codec for it can you maybe put it up as .wav or .mp3?

Can't - it's proprietary quicktime from my iphone.

 

[Tsunamix]

bump - Will play on any quicktime player

 

[Jesterarts]

Yeah, that doesn't sound like hitting rev limiter.

I'd say value float... new springs should cure it....

 

[Tsunamix]

If it is valve bounce.... Ive changed valve springs with the heads off, can it be done without much risk with the heads on ?

COncerned about droppoing a valve into a pot of course.

 

[Not_An_Abba_Fan]

It can be done. There are a couple of ways to do it. One is to get an attachment that screws into the spark plug hole with an air valve on it. You pump compressed air into the cylinder to hold the valves closed. Another way is to feed a piece of rope in through the spark plug hole and this will hold the valve up.

 

[greenfoam]

See how you go with the other tune, the shifts are a little lower then you will know if it's the limiter or not. I can't get the file so I dunno. But I wouldn't be at all suprised since you have those big ratio rockers. I've allways thought they had no chance of hanging on at any kind of decent rpm on the standard springs. I used rope fed into the bore to change mine, takes a while but works well

 

[greenfoam]

Edit: Heard a VT on the limiter on youtube, it's not that even thos the limiter will be faster, I don't think THAT fast. Sure doesn't sound like pinging either so it's got me beat, doesn't leave many options

 

[burnz]

to change valve spring/collet place cylinder at top dead centre.
remove sparkplug and compresse with air and change collet/spring.
the compressed air will hold the valve up quiet easly while you do the work.