Valves, Springs, and Guides questions

[MarsN]

Hello boys and girls. Long time reader, first time poster. Love the site, hoping for a little experienced feedback....

 

Finally starting my engine rebuild during the long Canadian winter, gathering parts. Plan: 1216, 11:1, port, 30/26 valves, stock 86-88 1100 gix cams, 38CV's(with Lee's stepped jet-needle washers, thank you), Hindle 4-2-1.

My questions are:

- Regarding the increased weight of oversized stainless steel valves over oem, is it enough to warrant stiffer than oem valve springs? I'm thinking if I use titanium retainers this may keep the valve train weight close to oem so that oem springs are sufficient? stock cams/lift.
Anyone know the difference in weight between a 30mm or 26mm ss valve vs the oem 28.5mm, 25mm? 

(I want to avoid using heavier springs if not absolutely necessary to avoid the increased wear on the cams, rockers etc.)

- I have yet to pull my head and measure the valve guide slop, if any, but assuming I go with new guides, any opinions on best re-fittment? I am thinking bronze guides from APE or Kibblewhite which don't require re-boring the head. The other option is using new cast oem guides which requires re-boring the head I believe. Having a shop do it either way so mainly wondering which guides are better for longevity assuming they both seal equally well. Also, can I even use oem cast guides with stainless valves?

Thanks for any opinions/feedback!

Neal

 

I've attached a pic of my bike. It's a '91 with 2011 gsxr1000 front end I put on, Robby Moto triples.

 

[Gixer1460]

IMO - valve weight difference is negligible especially if you use Ti retainers. Most spring changes required due to cam profiles or higher rpm limits - keep those in order, no change required - check spec's though, they do sag with use / age!

Are OEM guides even available? I would guess anything whether steel or bronze will be aftermarket pattern parts. So if the old ones can be pressed out, there is no reason that either material couldn't be shrink fitted as replacement. Its fairly involved as guide bores should be honed to valve stems then v. seats and spring seats cut / ground to match new guides and obvs x16 its not cheap job! And I don't think i've ever heard anyone say no to SS valves in OEM guides!

[MarsN]

That sounds right, cant be too much extra weight with 1.5mm larger diamer valve. Oem are probably hardened steel which shouldnt be much lighter, if at all, than SS. Planning on using new oem springs, so no worries about sag/lost temper etc.

Oem guides are available from places in Japan that sell new old stock. Am I allowed to state a vendor?...rhymes with "me bike". Only $5 too! hence my curiosity vs bronze. Think i'll go with bronze though(if needed at all), lots of positive testimonials.

thanks for the input.

[george 1100]

I run 750 springs in one of my engines with oversized valves, oem retainers and 9.2mm lift intake cams

[MarsN]

Ok that’s good to know. Sounds like OEM springs can handle a little more weight and lift than OEM specs.  
 

btw, the reason I was wondering about SS valves in OEM guides is that I read a couple articles that mentioned stainless steel needing bronze guides as ss can have friction issues with other metals. However, the ss valves sold for our bikes at least, have either chromed, or nitrided stems. I assume this is for friction reduction so makes the guide material less significant. 

[Cunnerz77]

On 10/14/2022 at 9:03 PM, MarsN said:

Ok that’s good to know. Sounds like OEM springs can handle a little more weight and lift than OEM specs.  
 

btw, the reason I was wondering about SS valves in OEM guides is that I read a couple articles that mentioned stainless steel needing bronze guides as ss can have friction issues with other metals. However, the ss valves sold for our bikes at least, have either chromed, or nitrided stems. I assume this is for friction reduction so makes the guide material less significant. 

Nitriding is just for surface hardening and reducing wear.