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R1 cam change
Yazza54 - 25/2/11 at 06:26 PM

As I'm now keeping the fury I want to fit the Kent cams I have... Am intending to raise the compression slightly at the same time. I'm not particularly worried about timing etc but should I be worried about piston valve contact? Anyone done this or anything similar have any tips?

Engine is a STD 5pw r1

A1 - 25/2/11 at 06:59 PM

can you measure it up to see? like cam lift vs height above piston...

Yazza54 - 26/2/11 at 11:21 AM

Probably but surely someones done it before

Major Stare - 26/2/11 at 07:58 PM

quote:
Originally posted by Yazza54
Probably but surely someones done it before


Yes they have........ and stop calling me Shirly

Yazza54 - 26/2/11 at 08:00 PM

Help pls

matt_gsxr - 26/2/11 at 09:54 PM

Isn't this the old "rebuild with thin layer of plasticine on the piston top".

Then reassemble and turn over by hand (super carefully no spark plug), take apart and see what the plasticine looks like.
Worth getting the plasticine reasonably warm (softer) and spraying with wd40 so it doesn't stick to the valve and piston.
Not sure how much valve to piston clearance you need, but I am sure Adi (fount of all R1 knowledge) will be on for that.


The other thing to look out for is the piston walloping the end of the plug. You can space the plug back with m10 copper banjo bolt washers if that is too close.

adithorp - 26/2/11 at 10:22 PM

quote:
Originally posted by matt_gsxr
...I am sure Adi (fount of all R1 knowledge) will be on for that...


Don't drag me into this. I was just reading it hoping to learn something.

matt_gsxr - 26/2/11 at 10:42 PM

quote:
Originally posted by adithorp
quote:
Originally posted by matt_gsxr
...I am sure Adi (fount of all R1 knowledge) will be on for that...


Don't drag me into this. I was just reading it hoping to learn something.


sorry, you aren't going to learn anything from me (except bad habits)

The Graham Bell book suggests clearance of 60thou (1.5mm), my attitude is that a miss is as good as a mile! But I treat engines as disposable learning tools.

Graham Bell excerpt

The link describes the process that I tried to, and another method.

Matt

mikemph - 27/2/11 at 08:27 AM

I am pretty sure the 1.5mm is to allow for rod stretch at high rpm and expansion as things warm up.

Big CC Racing - 27/2/11 at 11:50 AM

quote:
Originally posted by Yazza54
As I'm now keeping the fury I want to fit the Kent cams I have... Am intending to raise the compression slightly at the same time. I'm not particularly worried about timing etc but should I be worried about piston valve contact? Anyone done this or anything similar have any tips?

Engine is a STD 5pw r1



If your intending to skim the head & fit race camshafts you should be worried about the cam timing as it will affect the piston to valve contact.