Slipper tensioner AKA timing chain adjuster.

[Schwany]

I replaced the original timing chain adjuster with the newer rubber coated adjuster. On the P11 the adjuster called a slipper tensioner in the P11 Red book has a curve ground on the left side edge to provide clearance for the intermediate gear. The new timing chain tensioner AN sells is straight on the left side does not have the curve shape. The curve should be there to get clearance. Easily done on a grinder. That said my P11 could be different. Anyway, it is something to check if replacing the original slipper tensioner with the newer part. May also apply to other pre-Commando 750 twin engines.

Also went to the bother of making an intermediate gear spindle holder tool. Did not need it though. That spindle is not wiggling in my case.

 

[robs ss]

That spindle is not wiggling in my case.

If it's "wiggling" it's too late!
Always use a support tool- I use a cut down scrap timing cover (fits all dommie's/commandos)

Post in thread 'Repairing a Loose Timing Gear Spindle in Case'

Mar 6, 2023

Andover & RGM make the intermediate shaft support tool - but 20GBP plus shipping.

INTERMEDIATE SHAFT SUPPORT PLATE TOOL (SUITABLE FOR NORTON TWINS 500CC TO 850CC)

RGM NORTON 067325 INTERMEDIATE SHAFT SUPPORT PLATE

www.rgmnorton.co.uk

I thought I would show a little more detail on my "modded" timing cover tool for some who have not seen one. Damaged timing covers can be found quite cheaply at swap meets, etc.
I have only used a hacksaw, some files and sandpaper to get this shape. You'll note it picks up the dowel at the lower/front (lower left on first photo) and that the support gussets around the spindle boss have...

• robs ss

• 

Cheers

 

[Schwany]

Having rebuilt the engine 5 times trying out different performance stuff without the intermediate shaft support tool and never having an issue I think mine is in there really tight. I have the original P11 timing cover I could have hacked up, but I'm saving it for the next individual that might end up with my Norton if I remember to sell it before I forget I have it. I didn't actually use the tool I made. I tested it though. If that tool is really "must use" required, I'd have to say my timing chain has always been a little loose and still is today. Not going to worry about it.

Below is the original slipper with the curve on the left that is not cut in on the part AN sells. The curve was ground into the original part after it was stamped out. Easy to tell by the grinder witness marks on the curve.

 

[Ron L]

Never seen one with a curve ground in. That goes for a couple dozen P11, N15, and Commando engines.

 

[Schwany]

Never seen one with a curve ground in. That goes for a couple dozen P11, N15, and Commando engines.

Well shucks. I am the worst of the worst.

Doesn't surprise me. I did mention that my P11 might be different, and it is something to check. Apparently, the curve is not necessary.

On my engine the new AN slipper touches the intermediate gear without the curve ground in it. The outer plate also has a curve in it. The plate behind the slipper is straight. With the curve in those parts, it is very easy to install the slipper hardware with the gears and chain in place. Maybe that is why the curve was ground in there. I'm not the first owner. When I got the basket case in the 70's the engine had a K2F. I rode it off and on about 20 years with the magneto setup. I later had the timing side modified for using Commando cams that support points in the timing cover. It is different. I'm not sure when the curves were ground into those parts.

 

[o0norton0o]

I just did the same swap of the original tensioner on my '70 commando for the new style rubberized tensioner. I also changed to the heavy duty timing chain. My intermediate gear stud was also absolutely rock solid and I didn't use any sort of cutaway timing cover to adjust the chain. My intermediate gear stud was rock solid, so I'm not worrying about it. I just worry about earthquakes and asteroid strikes...

 

[hybridracer]

Well shucks. I am the worst of the worst.

Doesn't surprise me. I did mention that my P11 might be different, and it is something to check. Apparently, the curve is not necessary.

On my engine the new AN slipper touches the intermediate gear without the curve ground in it. The outer plate also has a curve in it. The plate behind the slipper is straight. With the curve in those parts, it is very easy to install the slipper hardware with the gears and chain in place. Maybe that is why the curve was ground in there. I'm not the first owner. When I got the basket case in the 70's the engine had a K2F. I rode it off and on about 20 years with the magneto setup. I later had the timing side modified for using Commando cams that support points in the timing cover. It is different. I'm not sure when the curves were ground into those parts.

I also fitted a later Commando cam (4S) , timing cover and intermediate gear to my Domi 88 engine. The original tensioner did not fit so I turned the tensioner upside down and used longer studs and a spacer block under the tensioner. That solved it without having to alter the tensioner.

 

[Schwany]

I also fitted a later Commando cam (4S) , timing cover and intermediate gear to my Domi 88 engine. The original tensioner did not fit so I turned the tensioner upside down and used longer studs and a spacer block under the tensioner. That solved it without having to alter the tensioner.

2S in my case. It now has a JS02 in it and all the JSM valve train parts and a lot of other goodies.

I ordered the rubberized tensioner for a Commando initially a couple years back. The Commando tensioner does not fit because the slot is too far to the right and at the wrong angle. I still have it for no good reason other than shipping it back costs more than the part.

 

[Schwany]

I just did the same swap of the original tensioner on my '70 commando for the new style rubberized tensioner. I also changed to the heavy duty timing chain. My intermediate gear stud was also absolutely rock solid and I didn't use any sort of cutaway timing cover to adjust the chain. My intermediate gear stud was rock solid, so I'm not worrying about it. I just worry about earthquakes and asteroid strikes...

Read your post about that and participated a little.

The rubberized slipper didn't make a farts worth of difference engine sound wise for me. My engine still sounds like an old solid lifter push rod Norton at idle. Timing after removing and replacing the TriSpark ignition might have ended up a degree closer to where it belongs, because my idle improved. I do not check it with a strobe. No tach.

 

[o0norton0o]

The tach speed part is easy to check at idle since a 360 twin fires a cylinder on every full rotation. I use a metronome off of youtube to set my rpm
Here's 1000 rpm. As much as people say they set their bike up for 1000 rpms, I don't know many norton owners who's bike idles this fast



***********************************************************************************************************************
Here's 800 rpms. It sounds like some of the common norton idle candence that I've heard.



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Lastly, I hear plenty of Nortons that sound like this and it's 600 rpm, which is probably not good for the cam, but it makes your bike sound cool at idle



I just bring the laptop outside and try to get the engine in sync with the metronome

At some point if you wanted to time your bike you could use my cheapo 50 year old craftsman timing light. I have a boyer microdigital igntion and I actually liked 30 degrees full advanced better than the 31 degrees that is recommended. I think the bike starts easier and I don't think it makes all that much difference at full throttle.

 

[Schwany]

At some point if you wanted to time your bike you could use my cheapo 50 year old craftsman timing light. I have a boyer microdigital igntion and I actually liked 30 degrees full advanced better than the 31 degrees that is recommended. I think the bike starts easier and I don't think it makes all that much difference at full throttle.

Music to your ears with the metronome.

I have a couple of timing lights, but the TriSpark is real easy to get close enough static using the LED static timing feature and a degree wheel. I might have moved the TriSpark stator plate 1/64th of an inch counterclockwise (retarding direction) from where my previous marks were. Not necessarily intentionally, I just didn't feel like messing with it once I got it all in there. Turned out to be a hair better. I suspect it is closer to 29 degrees BTDC than it was previously. 29 degrees is what TriSpark says is good for a Norton, and it is for my engine

 

[gpzkat]

I've only worked on one Norton (my '66 but really '67 N15) and that tensioner is one thing that struck me. Just metal? Well, seemed like that's how they rolled back then, and since my engine had 10K on the clock and the thing looked perfect, that's what I'm running. I got AN's tool, which I felt was a good thing to set the tension, it helped for me anyway. It seemed very important to do that as accurately as possible on both the magneto (now EI) and cam chains. Not sure I'm adding anything but it's an area I always thought hmmm.... but all's well. Interesting to read about all the different approaches/issues.

 

[Schwany]

I've only worked on one Norton (my '66 but really '67 N15) and that tensioner is one thing that struck me. Just metal? Well, seemed like that's how they rolled back then, and since my engine had 10K on the clock and the thing looked perfect, that's what I'm running. I got AN's tool, which I felt was a good thing to set the tension, it helped for me anyway. It seemed very important to do that as accurately as possible on both the magneto (now EI) and cam chains. Not sure I'm adding anything but it's an area I always thought hmmm.... but all's well. Interesting to read about all the different approaches/issues.

I personally think 1 Norton is more than enough Norton.

My original tensioner has some witness wear on it, but nothing dramatic. I changed it because I wanted to take a look inside the timing chest, and I wanted to find out if the hard rubber coating made any difference in old engine sound. It doesn't. Properly adjusted the chain isn't flopping around in there, it's sliding along on the tensioner. I'll take a look in there after a couple thousand miles. If the rubber shows wear and the bottom of the timing chest is layered with black rubber film, I'll put the old tensioner back in and not think about it wearing out anytime soon. The old all metal tensioner is not an ideal design, but good enough for an old Norton.

 

[Schwany]

The original (but modified with the curve) all metal P11 tensioner and the Commando rubberized tensioner side by side. Exciting not

My next post will be about using the JSM offset key to get 2 degrees of cam advance. I'm curious to see how or if it changes the power band and how much tuning might be required to take advantage of the change. None of it will apply to a stock Norton. It might apply to some of the Nortons with FCRs, modified heads, 2 into 1 exhaust, lighter fly wheels, bigger cams, and the list goes on.

 

[gpzkat]

The original (but modified with the curve)

I was wondering what the curve meant so I dug up a photo of mine and can see that it has a flatter center section. Does the curve help, and if so how? I'm ignorant of such things but maybe the flatter area is to spread the load along more links? By ignorant I mean in the truthful sense - I have no idea what I'm talking about. I read your first post explaining why, but can't quite understand. Maybe it's the bourbon, so will try re-reading tomorrow, ha!

 

[Schwany]

I was wondering what the curve meant so I dug up a photo of mine and can see that it has a flatter center section. Does the curve help, and if so how? I'm ignorant of such things but maybe the flatter area is to spread the load along more links? By ignorant I mean in the truthful sense - I have no idea what I'm talking about. I read your first post explaining why, but can't quite understand. Maybe it's the bourbon, so will try re-reading tomorrow, ha!

Re-reading won't clarify anything. My advice is ignore it.

I built a stock version of this P11 engine the first time with zero documentation 25 years before Google existed. I may have put the curve in there because I thought the tensioner assembly was too close to the intermediate gear. I forgot if I did or did not grind the curve, so thought the factory did it. Wrong Not necessary.

What the curve does for me and me only apparently is make installing the tensioner easier if the sprockets and timing chain are installed first, or installing the chain and sprockets if the tensioner is installed loosely first. To me there is no engineering advantage with or without the curve.

 

[Schwany]

My Norton engineering acumen ends with righty tighty lefty loosey. Blame it on the Bourbon and the 60's.

 

[gpzkat]

My Norton engineering acumen ends with righty tighty lefty loosey. Blame it on the Bourbon and the 60's.

Dude, I hear you. Garage zen time for me is some good old 60's music and bourbon (easy does it), working on my bikes.