Cylinder base studs

P

Peter Restaino

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Dec 15, 2024
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Hello everybody. I purchased a basket 1970 Commando with original engine. I tore down the motor completey. I noticed that the cylinder base studs were small diameter on 4 or five locations so I decided to replace all of them with proper andover studs. I removed all the studs by slowly turning them in and out incrementaly and was a slow process but I got em out. Now I think all the threads may be a little compramised because when I screw them in they wiggle a little bit side to side untill they bottom. I do notice some of the first top one or two threads are resesed or gone. In hind sight I should of heated the case before removal. Now Im thinking timeserts. Has anybody ever done all of the base studs with them or just locktight them and press on. I showed some guys with mechanical skills and they said just locktightem but my anal brain says not shure.
 
Peter Restaino said:
Hello everybody. I purchased a basket 1970 Commando with original engine. I tore down the motor completey. I noticed that the cylinder base studs were small diameter on 4 or five locations so I decided to replace all of them with proper andover studs. I removed all the studs by slowly turning them in and out incrementaly and was a slow process but I got em out. Now I think all the threads may be a little compramised because when I screw them in they wiggle a little bit side to side untill they bottom. I do notice some of the first top one or two threads are resesed or gone. In hind sight I should of heated the case before removal. Now Im thinking timeserts. Has anybody ever done all of the base studs with them or just locktight them and press on. I showed some guys with mechanical skills and they said just locktightem but my anal brain says not shure.
Click to expand...
Measure the major thread diameters of old & new studs, report back please.
 
Peter Restaino said:
Hello everybody. I purchased a basket 1970 Commando with original engine. I tore down the motor completey. I noticed that the cylinder base studs were small diameter on 4 or five locations so I decided to replace all of them with proper andover studs. I removed all the studs by slowly turning them in and out incrementaly and was a slow process but I got em out. Now I think all the threads may be a little compramised because when I screw them in they wiggle a little bit side to side untill they bottom. I do notice some of the first top one or two threads are resesed or gone. In hind sight I should of heated the case before removal. Now Im thinking timeserts. Has anybody ever done all of the base studs with them or just locktight them and press on. I showed some guys with mechanical skills and they said just locktightem but my anal brain says not shure.
Click to expand...
I've converted all of the base stud threads in the crankcase using 3/8-16 Timeserts on a couple of engines, both 750 and 850, with no problems. I've also done it to 750 cases using Helicoils, as in the later 750s and all 850s, again with no problems.

Ken
 
lcrken said:
I've converted all of the base stud threads in the crankcase using 3/8-16 Timeserts on a couple of engines, both 750 and 850, with no problems. I've also done it to 750 cases using Helicoils, as in the later 750s and all 850s, again with no problems.

Ken
Click to expand...
When in doubt - re-engineer !
 
I am still running all my original studs and nuts except for the front centre stud, as well all my original head bolt/studs and my engine case bolts since new and even after doing the Featherbed conversion back in 1980/82, seen no reason to replace them, my motor is still oil tight, the slot screw on the timing cover and GB outer cover were replaced with allen ahead screws way back in 1977 and the engineering shop I got them from was under $2 they didn't charge me for them, my Norton/Triumph dealership wanted $35 for the same screws and to this day still using the same AH screws.
In 49+ years of ownership my cylinder barrels have only been off 2 times and my head has only been off 3 times and has only been retorqued maybe 6 times in the 49+ years, my Norton has been an everyday ride for most of its life and was semi-retired in 2013, I think I have been very lucky with my old Norton and giving it a pat on the tank every time I get home from a ride to thank it has done it for me.
Timeserts and Helicoils are strong if done right and have used many when being a T/A in a Fitters maintenance works shop when working at the Tec College (TAFE) for 31 years.

Ashley
 
ashman said:
I am still running all my original studs and nuts except for the front centre stud, as well all my original head bolt/studs and my engine case bolts since new and even after doing the Featherbed conversion back in 1980/82, seen no reason to replace them, my motor is still oil tight, the slot screw on the timing cover and GB outer cover were replaced with allen ahead screws way back in 1977 and the engineering shop I got them from was under $2 they didn't charge me for them, my Norton/Triumph dealership wanted $35 for the same screws and to this day still using the same AH screws.
In 49+ years of ownership my cylinder barrels have only been off 2 times and my head has only been off 3 times and has only been retorqued maybe 6 times in the 49+ years, my Norton has been an everyday ride for most of its life and was semi-retired in 2013, I think I have been very lucky with my old Norton and giving it a pat on the tank every time I get home from a ride to thank it has done it for me.
Timeserts and Helicoils are strong if done right and have used many when being a T/A in a Fitters maintenance works shop when working at the Tec College (TAFE) for 31 years.

Ashley
Click to expand...
I'm with you on this one, Ashley. Our old beaters will generally treat us right, as long as we've been treating them right. I was never able to buy one new, but I've worked on and owned plenty of used ones that were not treated so well by the previous owners. For some of those bikes, repair upgrades like thread inserts were quite useful. My first Norton, a 750 Commando PR, was actually quite dependable and reliable, enough that I commuted to work on it regularly. It was also pretty reliable when I started racing it. But when I started looking for more performance, with higher compression, racier cams, porting and bigger valves, etc., etc., I also found more failure points. That's where modifications for more strength and endurance become more than just a repair resource. You can't make 70 to 80 honest rear wheel horsepower from a 750 Commando and have it live without some serious reliability upgrades, every thing from better fasteners to one piece cranks, stronger rods, lighter pistons, reinforced cases, and so on forever. I've broken my share of crankshafts, crankcases, and connecting rods in learning that lesson.

I quit road racing in 1993, but I still follow some of the habits from building engines and chassis for race track reliability. I don't really need them on a road bike, but once you get in the habit of things like inspecting parts for cracks, updating components, balancing engine components, using safety wire, maybe building for a little more performance from both engine and chassis, you continue to do it, even if it isn't really necessary to have a fun, reasonably reliable road bike.

Ken
 
Ken you can do some good mods to our motors to make them perform better as I have done when building my 850 motor for the Featherbed frame without over doing it and still make it reliable, I built mine back in 1980/82 when doing the conversion, balance crank was the first thing, build up my stock cam to a 2S cam grind profile, 40thu oversize Hepilite flat top pistons and very tight final hone to piston/cylinders, I am still running with my original valves but the ports were ported and polished and head shaved but not by a great deal and my Amals jetted to 270 main jets and of course opened up exhaust system, it made a big performance improvement from stock but still have a very reliable motor, but the whole bike set up is much lighter than when it was a stock Commando which also helps, shorter wheel length and lots of weight savings.
Back in the late 70s early 80s there wasn't the upgrades around that we have on offer these days and things were so much cheaper to do back then, but the last 15+ years was when I did a lot of spending for more better upgrades, but my motor is still the same as when I first built it 44+ years ago, I don't care what most think about the Joe Hunt sticking out the side to be honest it's the best upgrade of my ignition system ever and it works so well with the Amals, my motor has never let me down just things around it that has, my stock GB has only been rebuilt from the dreaded layshaft bearing at 12k mile back in 1979, lucky it blew outside my house when I put it in gear everything in the primary is original except for the chain and still running the stock clutch plates but centre hub and bearing been replaced.
I keep up the maintenance, run good oil with STP mixed with it and is one of the reasons I have had long life out of my motor, so in my opinion it's not snake oil and my motor has proved it, I don't pussy my motor I ride it hard as I do all my bikes, if its not broke I leave it well alone and in my pic you can see I don't pull cases off (I run an auto timing chain adjuster for the last 35 years) or had my motor apart for a long, long time and no oil under it.
My Norton is showing its age, but it keeps going and going, first kick every time as well and has clocked up a lot of hard miles.

Ashley
20230326_161523.jpg
 
Last edited:
lcrken said:
Picture of a Maney crankcase that I fitted with Timeserts for an engine for the infamous Hobot.

Ken,
Click to expand...
Those cases are lovely!What finish is the black and how did you apply it?
Thanks,Mike
 
Ok guys you convinced me my stud holes are slightly fubared so now I have to youtube time serts. so the question is some of the holes are shallow and some are deeper. Do I need two different time serts
 
OEM Nortons had beautifully formed threads and bolts or studs that fit well into the threads in Motor and Trans cases. Today's repro parts ain't what they used to be and there is plenty of slop when you put a new bolt or stud into the OEM casing threads. How do the base nuts fit on the stud threads?
 
Carl H said:
OEM Nortons had beautifully formed threads and bolts or studs that fit well into the threads in Motor and Trans cases. Today's repro parts ain't what they used to be and there is plenty of slop when you put a new bolt or stud into the OEM casing threads. How do the base nuts fit on the stud threads?
Click to expand...
Yes you are right. I took an original cylinder base stud, the large diameter one and original nut, and I feel less wiggle than with Andover stud and nut. But I think the Andover stud ,nut end is slightly off but ok. The Andover nut is the same as the original.
 
Peter Restaino said:
Hello everybody. I purchased a basket 1970 Commando with original engine. I tore down the motor completey. I noticed that the cylinder base studs were small diameter on 4 or five locations so I decided to replace all of them with proper andover studs. I removed all the studs by slowly turning them in and out incrementaly and was a slow process but I got em out. Now I think all the threads may be a little compramised because when I screw them in they wiggle a little bit side to side untill they bottom. I do notice some of the first top one or two threads are resesed or gone. In hind sight I should of heated the case before removal. Now Im thinking timeserts. Has anybody ever done all of the base studs with them or just locktight them and press on. I showed some guys with mechanical skills and they said just locktightem but my anal brain says not shure.
Click to expand...
If
Peter Restaino said:
Hello everybody. I purchased a basket 1970 Commando with original engine. I tore down the motor completey. I noticed that the cylinder base studs were small diameter on 4 or five locations so I decided to replace all of them with proper andover studs. I removed all the studs by slowly turning them in and out incrementaly and was a slow process but I got em out. Now I think all the threads may be a little compramised because when I screw them in they wiggle a little bit side to side untill they bottom. I do notice some of the first top one or two threads are resesed or gone. In hind sight I should of heated the case before removal. Now Im thinking timeserts. Has anybody ever done all of the base studs with them or just locktight them and press on. I showed some guys with mechanical skills and they said just locktightem but my anal brain says not shure.
Click to expand...
You showed the fit to your mechanical friends and they said use them. But now you are asking a group for input on something they can't see, feel, or measure. This makes no sense. Take your stuff to someone you trust and ask them. Otherwise you are just chasing your tail.
 
Stephen Hill said:
If

You showed the fit to your mechanical friends and they said use them. But now you are asking a group for input on something they can't see, feel, or measure. This makes no sense. Take your stuff to someone you trust and ask them. Otherwise you are just chasing your tail.
Click to expand...
I made up my mind after youtubing kindserts so no tail chasing with all the input from you guys. Thanks
 


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