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Message started by Savage_Greg on 10/15/07 at 08:44:29

Title: Head Cover and Head Alignment...
Post by Savage_Greg on 10/15/07 at 08:44:29

I notice that scored cam bearing journals were mentioned in the "What a Stud" topic, but rather than hijack that topic, I'll start here...

This subject is inspired by the VTR engine in my shop (not finished yet, but that's a story itself)...

Anyway, the VTR manual specifically states that the cam shaft holders are "matched" to the heads and must be replaced as a set.  You can not swap the 4 of them around, and if there is any damage you need a new head.  That's because the cam journals are line bored as a set...

However, I don't recall reading or anyone else mentioning this subject with the Savage head and headcover (cam holder).  A check with Ron Ayers also shows that the 2 parts listed as item #1, as an assembly.  But that is the only hint that I've seen about this subject...

As a suggestion to anyone that might consider mixing these 2 parts for whatever reason, I am certain that the Savage head and headcover are also line bored for the cam journals.  If you need either part, you need both.  After all, that is why the head has dowel pins to keep them aligned.  

Don't be drawn to buy either part from eBay or anywhere else unless they are an original set.  The journals won't match and you could screw up all 3 of the parts...



Title: Re: Head Cover and Head Alignment...
Post by LANCER on 10/15/07 at 09:56:05

UH-OH   :-X

Title: Re: Head Cover and Head Alignment...
Post by Max_Morley on 10/15/07 at 10:06:18

Greg, I believe you are correct and this is important information for folks. One could check and if there is no lip at the parting edge on either side of the cover/head journal it should be usable, they may be holding the tolerances very close. certainly I would be very careful between the mid 80's and later ones. I know on a Honda XR230F we did, we were able to order just one side of the crankcase set and it works fine so far. Max

Title: Re: Head Cover and Head Alignment...
Post by Savage_Greg on 10/17/07 at 07:35:25


Max_Morley wrote:
Greg, I believe you are correct and this is important information for folks. One could check and if there is no lip at the parting edge on either side of the cover/head journal it should be usable, they may be holding the tolerances very close. certainly I would be very careful between the mid 80's and later ones. I know on a Honda XR230F we did, we were able to order just one side of the crankcase set and it works fine so far. Max

Right...if you were determined enough to remount the headcover and go in through the cam shaft plug hole to check...

...and you could also double check by using plastigage, but once again...

...I'm sure there is tolerance on the line bore center, and if you have +.002" on one part and -.002" on the other, there goes your oil clearance...

...and that doesn't count for wear on used parts...or whether the parts were manufactured on Friday night :P

Title: Re: Head Cover and Head Alignment...
Post by smokin_blue on 10/17/07 at 09:54:30

I can not speak specifically about the Savage head but I would second Greg on the need to keep them together.  Historically Suzuki line bored all their GS and old oil cooled GSX-R's with the little keepers bolted down in place.  Hence the standard practice in the shop that no way do you ever mix and match keepers with in a head much less across to a different head.

My assumption was that the Savage head was done the same way.  I don't see how they could do it any other way and hold the kind of tolerances they need.

Now that's not so say someone couldn't get away with it and not destroy something.  The Japanese are very good at what they do.  However, as a practice don't count on luck when rebuilding a head. :-/

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