XR650-valve grind


10 replies to this topic
  • iestrada

Posted January 21, 2005 - 12:12 PM

#1

A friend of mine make his 650 big bore, on the bill there was a charge for "3 valve grind 4 valve" Any one knows what it is that job :cry: ?

  • brrpr

Posted January 21, 2005 - 12:27 PM

#2

just a guess.

he needed three valves ground. the fourth didnt need anything?

is there good riding in Moldova?

  • qadsan

Posted January 21, 2005 - 12:46 PM

#3

It's probably supposed to be a 3 angle valve grind on all four valve seats. Now days, it's more common for higher end shops to use a Serdi multi-angle machine or something similar to accurately cut the seats with carbide tooling instead of grinding them, but grnding still works well when done properly.

  • XRMANU

Posted January 21, 2005 - 12:49 PM

#4

A friend of mine make his 650 big bore, on the bill there was a charge for "3 valve grind 4 valve" Any one knows what it is that job :cry: ?


Maybe a 3 ANGLE grind job on the 4 valveseats :cry:

  • frankstr

Posted January 21, 2005 - 12:58 PM

#5

I've been doing mach. work over 25 years, IMO you are not doing a valve job,seat grind,whatever ya wanta call it,unless there is 3 or more angles on the seat.... :cry:

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  • BigIvyI

Posted January 21, 2005 - 01:37 PM

#6

Sorry I'm a newbe to valve work, but what are the angles in the seat? It seems like it would just be one slanted angle to match the face of the valve.

  • qadsan

Posted January 21, 2005 - 01:53 PM

#7

The angles are important for good seating, but mostly important for air flow (improved efficiency, especially during low and medium valve lift). Even the stem size of the valve is vital in regards to air flow.

  • qadsan

Posted January 21, 2005 - 01:58 PM

#8

Here's an interesting link I've kept the link to which shows a picture of a Serdi machine and talks a bit about valve grinding & cutting.

http://www.d.umn.edu...SerdiReport.PDF

Here's another interesting article that talks about the importance of multi-angles.

http://www.chevyhipe...articles/89678/

  • BigIvyI

Posted January 21, 2005 - 04:19 PM

#9

nice articles :cry:

  • brrpr

Posted January 21, 2005 - 05:09 PM

#10

ya gotta wonder just how often most guys have their grinders re-calibrated to 30/45/60 degrees?

with all these new 4 smokes coming out...theres going to me a lot more interest in the subject...

thanks for the articles. great reading.

  • bootlegger2

Posted January 22, 2005 - 05:02 AM

#11

i run a automotive machine shop and do the valve jobs for most every repair shop in town you can do a valve job or valve grind with just about any angle you want but you must go by what the valve face has it is most of the time a 45 and that will be your seal surface the 30 and the 60 are used for how wide you want that sealing surface 2mm,3mm,1mm what ever your application the intake side is usualy set narrow like 1mm the exhaust needs to be a little wide because it has to get rid of the heat the 30 and the 60 are also used to move the sealing surface up and down the valve face like closer to the outside edge of the valve face which is good on the intake side the exhaust needs to be closer to the middle because of the heat transfer you could even have 5 angles if felt it needed it i dont realy see any gains from it though
hope this wasnt more than you wanted to know





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