Very good video. I really enjoy the chemistry between you and the mechanic very descriptive. Just a wonderful job. Thank you very much I look forward to new ones.
Excellent video. Probably the best one on the Mk III so far! The RH4 850 heads tend to crack around the intake ports because Norton increased the outside diameter of the valve guides as well as opening up the intake ports. The earlier 750 engines with 32mm intake ports didn't have that issue. Best to try avoiding replacing the intake guides on the 850s with RH4 heads. Worn intake guides can be sleeved. Installing valve guides sleeves is common on auto engines like Chevy Small Block V-8s. The Chevy guides are cast in as part of the cylinder head. Any competent machine shop can sleeve worn intake guides, rather than replacing them. This cracking issue doesn't happen on the exhaust side. Relating to Steve Baron's comments about the intake valve seals below. The original valve seals were made of Nitrile rubber [black]. Norton's improved valve seals are made from Viton [orange]. Viton is only good for 400 F [Nitrile is worse at only 250 F] Norton heads will easily reach 450 F or higher when pushed hard. Who owns a Commando and doesn't run it hard??? This heat will bake the rubber seals in a year or less of every day use. Best to use Teflon valve seals. Kibblewhites and others can supply these. However, you can get the same thing for less money [per seal] from Competition Cams [and others]. Competition Cams P/N 513-12. The original use for this P/N is Chevy 6 cylinder with light weight valves [5/16" stems as opposed to stock 3/8" stems]. I got a deal on these through eBay. So you get 12 seals for a bit more than buying 2 from the motorcycle vendors. Sell a few to your buddies and you'll still have plenty of spares. Best to use a valve seal installation tool to install them. The Teflon seals are stiffer than the Viton and Nitrile rubber seals.
Very nice video, indeed. The rocker shafts were designed to be a tight fit in the head -- in fact, at the factory, the heads were heated to expand the bore so that the rocker shaft would slide in. If they're even the slightest bit cocked to one side, they will gouge the bore in the head and "pick up" circumferential burrs. Once that happens, you'll need to hone the bores but you can't hone out much material without leaving the fit loose. Your installer here has obviously done many and knows exactly how to keep the alignment correct and work the shafts in easily. All his tips about shimming of the rockers and setting the oil cutaways are perfect. I am glad to know about the thicker mushroom-head adjusters -- I've seen too many of the thinner type cracked and I long ago quit using them There's also a process for getting the rockers set to the perfect angle at 0-lift -- this involves slightly shortening the valves (invariably, they're a touch too long) so that the adjuster tip is down in a direct facing position on the end of the valve. Not only does this reduce the wear on both pieces, it prevents side loads on valves in their guides and that's got to be a good thing (note - if your valve seats have been recut or heavily ground, the situation is worse and requires the valve to be shortened more than usual). I've just put a set of J. Schmidt's tubular steel pushrods with Kibblewhites in my 850 PR engine but I haven't had a chance to measure the tip alignment and adjust them yet (I'm also trying his BSA-type lifter blocks for the first time so I'll see how they all fit together; since his products are so perfectly designed and produced, I'm guessing that they'll line up perfectly).
Very good video! Where do you get the parts for this process? The special aftermarket rockers and stainless steel caps and tools like the slide hammer?
The Alen head mushroom head adjusters are somewhat difficult to find british cycle supply seams to always have them They also show up on ebay from time to time www.britcycle.com/products/06/06_7546b.htm The stainless one piece rocker shaft covers are another great product I use on all nortons This guy has a lot of norton stuff and the one piece rocker shaft covers. www.eurojamb.com/collections/norton/products/norton-stainless-rocker-plate-set-750-850-commando-custom They have the slide hammer too www.eurojamb.com/collections/norton/products/triumph-norton-bsa-auto-advance-slidehammer-removal-extractor-tool-60-048-d484 Not sure what other part's or tools your thinking about if there is just ask.
Thank you! It looked like in the video when you opened an Andover Norton package and out popped the stainless cover. I checked with Andover at least on their website and only found the original style ones.??
@@michaelkirby3361 No the only andover bag that is there in the video has the new rocker shims in it. I did have all the stainless bolts copper washers and the new one piece stainless rocker shaft covers still in the seal covers all in a big paper envelope along with the andover bag with shims. The allen head mushroom valve adjusters I had put in the rockers earlier because you can't put them in after the rockers are installed in the head. Sorry for the confusion.
I’ve been going back and watching your videos as I just started a restoration of a ‘71 750 Commando that I have had in a basket for 45 years and I have no good reason why. My excuse has been kids, sports , dance and gymnastics lessons and competitions, college, marriages of 2 girls of the three kids etc. Anyway I’m finding your videos very informative and helpful. I do have another question regarding valve guides . Do I need to have the valve seats re-cut after replacing the guides or is it ok to have just lapp the seats and new valves? I checked the websites you told me about in my first comment and I did find the copper colored valve stem adjusters but not the same stainless rocker spindle plates that you had. They only had the ones that they listed were like the factory original or the ones that Andover sells stainless but segmented. Thank you for responding as you have been doing. Keep up the videos. Mike
If you replace your own guides and install new valves which I would never reuse old valves with new guides. But the seats are always ground slightly to line up the valve surface perfectly then lapped in for a good seal.
You did not show it,,(would have been nice) the intake valve guide seal from Norton is poor quality. They can come off or take as mine did. They make much better seals, CNW Carrie’s them, they have steel bands and springs for a secure fit on the guide and around the valve stem. A failed intake seal will result in smoking and high oil use.
We used the kibblewhite red Viton seal they fit extremely well and have a molded band on the inside that fits the groove on the guide and snaps on tight and we have never had a failure or one fall off they don't shrink crack or get rock hard from heat like the black stock seals do. Kibblewhite also makes a white teflon seal that works well, too, but they are very fragile and can crack installing them and requires a special installation tool.
Excellent, Thank you!
It's like you have to virtually redo the entire engine and gearbox in order to get them in good working order.
Very good video. I really enjoy the chemistry between you and the mechanic very descriptive. Just a wonderful job. Thank you very much I look forward to new ones.
Excellent video. Probably the best one on the Mk III so far! The RH4 850 heads tend to crack around the intake ports because Norton increased the outside diameter of the valve guides as well as opening up the intake ports. The earlier 750 engines with 32mm intake ports didn't have that issue. Best to try avoiding replacing the intake guides on the 850s with RH4 heads. Worn intake guides can be sleeved. Installing valve guides sleeves is common on auto engines like Chevy Small Block V-8s. The Chevy guides are cast in as part of the cylinder head. Any competent machine shop can sleeve worn intake guides, rather than replacing them. This cracking issue doesn't happen on the exhaust side. Relating to Steve Baron's comments about the intake valve seals below. The original valve seals were made of Nitrile rubber [black]. Norton's improved valve seals are made from Viton [orange]. Viton is only good for 400 F [Nitrile is worse at only 250 F] Norton heads will easily reach 450 F or higher when pushed hard. Who owns a Commando and doesn't run it hard??? This heat will bake the rubber seals in a year or less of every day use. Best to use Teflon valve seals. Kibblewhites and others can supply these. However, you can get the same thing for less money [per seal] from Competition Cams [and others]. Competition Cams P/N 513-12. The original use for this P/N is Chevy 6 cylinder with light weight valves [5/16" stems as opposed to stock 3/8" stems]. I got a deal on these through eBay. So you get 12 seals for a bit more than buying 2 from the motorcycle vendors. Sell a few to your buddies and you'll still have plenty of spares. Best to use a valve seal installation tool to install them. The Teflon seals are stiffer than the Viton and Nitrile rubber seals.
Very nice video, indeed. The rocker shafts were designed to be a tight fit in the head -- in fact, at the factory, the heads were heated to expand the bore so that the rocker shaft would slide in. If they're even the slightest bit cocked to one side, they will gouge the bore in the head and "pick up" circumferential burrs. Once that happens, you'll need to hone the bores but you can't hone out much material without leaving the fit loose.
Your installer here has obviously done many and knows exactly how to keep the alignment correct and work the shafts in easily. All his tips about shimming of the rockers and setting the oil cutaways are perfect. I am glad to know about the thicker mushroom-head adjusters -- I've seen too many of the thinner type cracked and I long ago quit using them
There's also a process for getting the rockers set to the perfect angle at 0-lift -- this involves slightly shortening the valves (invariably, they're a touch too long) so that the adjuster tip is down in a direct facing position on the end of the valve. Not only does this reduce the wear on both pieces, it prevents side loads on valves in their guides and that's got to be a good thing (note - if your valve seats have been recut or heavily ground, the situation is worse and requires the valve to be shortened more than usual). I've just put a set of J. Schmidt's tubular steel pushrods with Kibblewhites in my 850 PR engine but I haven't had a chance to measure the tip alignment and adjust them yet (I'm also trying his BSA-type lifter blocks for the first time so I'll see how they all fit together; since his products are so perfectly designed and produced, I'm guessing that they'll line up perfectly).
Thanks for the great comment, I always enjoy your comments on these videos your knowledge is vast and very helpful, thanks
Very good video! Where do you get the parts for this process? The special aftermarket rockers and stainless steel caps and tools like the slide hammer?
The Alen head mushroom head adjusters are somewhat difficult to find british cycle supply seams to always have them
They also show up on ebay from time to time
www.britcycle.com/products/06/06_7546b.htm
The stainless one piece rocker shaft covers are another great product I use on all nortons
This guy has a lot of norton stuff and the one piece rocker shaft covers.
www.eurojamb.com/collections/norton/products/norton-stainless-rocker-plate-set-750-850-commando-custom
They have the slide hammer too
www.eurojamb.com/collections/norton/products/triumph-norton-bsa-auto-advance-slidehammer-removal-extractor-tool-60-048-d484
Not sure what other part's or tools your thinking about if there is just ask.
Thank you! It looked like in the video when you opened an Andover Norton package and out popped the stainless cover. I checked with Andover at least on their website and only found the original style ones.??
@@michaelkirby3361 No the only andover bag that is there in the video has the new rocker shims in it. I did have all the stainless bolts copper washers and the new one piece stainless rocker shaft covers still in the seal covers all in a big paper envelope along with the andover bag with shims. The allen head mushroom valve adjusters I had put in the rockers earlier because you can't put them in after the rockers are installed in the head. Sorry for the confusion.
I’ve been going back and watching your videos as I just started a restoration of a ‘71 750 Commando that I have had in a basket for 45 years and I have no good reason why. My excuse has been kids, sports , dance and gymnastics lessons and competitions, college, marriages of 2 girls of the three kids etc.
Anyway I’m finding your videos very informative and helpful. I do have another question regarding valve guides . Do I need to have the valve seats re-cut after replacing the guides or is it ok to have just lapp the seats and new valves?
I checked the websites you told me about in my first comment and I did find the copper colored valve stem adjusters but not the same stainless rocker spindle plates that you had. They only had the ones that they listed were like the factory original or the ones that Andover sells stainless but segmented.
Thank you for responding as you have been doing.
Keep up the videos.
Mike
If you replace your own guides and install new valves which I would never reuse old valves with new guides.
But the seats are always ground slightly to line up the valve surface perfectly then lapped in for a good seal.
You did not show it,,(would have been nice) the intake valve guide seal from Norton is poor quality. They can come off or take as mine did. They make much better seals, CNW Carrie’s them, they have steel bands and springs for a secure fit on the guide and around the valve stem. A failed intake seal will result in smoking and high oil use.
We used the kibblewhite red Viton seal they fit extremely well and have a molded band on the inside that fits the groove on the guide and snaps on tight and we have never had a failure or one fall off they don't shrink crack or get rock hard from heat like the black stock seals do. Kibblewhite also makes a white teflon seal that works well, too, but they are very fragile and can crack installing them and requires a special installation tool.
each one of those rocker arms cost 120 bucks at Andover ouch. My 69 is missing one, dam