West Auckland Engine Reconditioners http://www.waer.co.nz/ Heard mixed reviews about their work but went to them for the machining cos they're just around the corner... Brought them the XS head and they diagnosed: valve guides OK IN valve seats OK EX seats need re-cut Got the head back today. The two EX valves (where they cut the seats) now have (side) play in them where there was none previously and the guides are looking damaged (they have like a step on the inside, towards the inner end of the guide), this is visible to the naked eye. I'll go back to them to ask questions but it would be good to know what exactly may have happened, what they actually did. I don't know how the seats are re-cut. Can anyone enlighten me? Is there a fitting that you put inside the valve guide when machining the seats maybe? Cheers for any help
They've done something very bad. Re-cutting the seats is all done form the face side so no need for anything up the guide itself.to pop the guides and put new ones in doesn't take long and aint expensive.Give em Shit psy, hope you have not paid them yet cause I most certainly would not. Should have gone to the BFTP's universally approved moto engine reckoner Taylor's Automotive, sad but true.
Ask Max...he knows stuff.... +1 for Taylors.
so no need for anything up the guide itself would they not use something up the guide to centre the tool that cuts the seats?
yeah I think them must, although the web shows some that don't...
Seats can't be accurately recut without using the valve guide as a pilot. The method may change, for example from a hand-held assembly to a clamped jig on something that looks like a milling machine, but the process is essentially the same and the result is similar. I seem to recall Dodgy saying that he wouldn't take a wheelbarrow to West City Reconditioners. Just saying . . .
Just doing seat work would've cleaned the guides....and so they will have more clearance than the dirty stems and guides you checked. A lot of guides also have a step at the port end....cleaning may have exposed that where it wasn't obvious before. Westies only know about V8's, precision engines are unknown out there.
C'mon...us keyboard experts need piccys...before erroneous conclusions are jumped too.
What Motu said will be correct. Never clean your guide bores, or you'll need to fit new ones. I would have fitted new seats . Any exhaust seats that are pitted enough to require re-cutting, will end up pocketing the valve head causing inferior gas flow, and an increase in chamber volume. I wouldn't entertain the idea of cutting seats without using the guide as a centering device.
Thanks for the input guys. Let me clarify it: I inspected the guides and valve stems fitting together AFTER the vapour blasting so they were clean as. There was no play between any of the valve stems/guides. Now there is. I'm going there on Mon to have a wee chat but it would be good to know my facts beforehand.
I just took apart the spare head i have and there does seem to be a difference between the IN and EX guides in that the EX do have a step but the IN don't (like on the pics above)... Now I'm even more confused...
Some valve guides have the inner step, which is intended to act as a carbon trap. It's doubtful as to how effective it is. DD, I recut exhaust seats with good success, and have done so for many years. The majority of older engins can tolerate seat cutting with no issues as long as the seats are in reasonably good condition, and little metal removal is required. It's not unusual to see seats which have been molested beyond redemption, in which case replacement is the only remaining option.
The XS650 has a skull cap, I'm not sure if the seats are replaceable. I seem to remember there were some exhaust seat issues when I got Graham to do some work on my XS650 head, it ended up with the stem height on one valve wrong. Rather than complain about my worn out parts not coming up to spec, I managed to find some other valves in my collection which gave me the right height....maybe after some modification too.
funny. went to the kumeu show today and run into the machinist... they have a stall there. talked to him and he agreed to re-inspect if the EX stems/guides are still in spec. one thing that have come out of the conversation was that i checked the fitting with stems/guides while thoroughly oiled (heavy oil, too) and they're now dry and that that may be making the before/after difference. i kinda hope that this is the case. it would make me look silly but would indemnify them from any fault. will know on Monday.
Yep, that would do it.
