961 Birthday

ntst8 · Jul 12, 2021

Valve guides are cast iron, no appreciable wear on them or the valve stems.
Rocker bushes - these were easily removed, and i am told could be reinserted with hand pressure

. Must have been very close to the rockers turning on the bushes rather than the bushes turning on the spindles. Ollie is making new ones this week.
Throttle body - idle air intake plugged and ready to go.

gortnipper · Jul 13, 2021

ntst8 said:
Valve guides are cast iron, no appreciable wear on them or the valve stems.
Rocker bushes - these were easily removed, and i am told could be reinserted with hand pressure . Must have been very close to the rockers turning on the bushes rather than the bushes turning on the spindles. Ollie is making new ones this week.
Throttle body - idle air intake plugged and ready to go.

The Norton assembly line build legacy is unbroken.

ntst8 · Jul 21, 2021

Crankshaft trued and ready to refit.
Crank oiling - Richard 7's Oil Route guide covers it well but doesn't mention the small holes in the top of the crank centre plate (pic below) - these seem aimed to squirt the underside of the pistons.
Also the page 6 of the guide shows the side squirters - it seems that these align with the open side of the hollow big ends (the cap on the outside face can be seen below), and rotational forces then force the oil into the big ends with drainage out via the grooves arrowed in the guide.
Bearings are all marked Koyo Japan and look/feel to be in good nick, no plans to change those.

ntst8 · Jul 24, 2021

The engine is nicely thought out for dismantling in the frame, the crankcase split allows one section to remain in place.
Next step, re-assemble the jigsaw once the bits which are in transit get here.

cliffa · Jul 24, 2021

Thanks for the continual updates and pics Iain, a valuable insight into the 961 engine. When you mentioned "We have now relieved the holes in the cases as in Richard7's guide" can you explain further please?

ntst8 · Jul 24, 2021

Thanks Cliffa.
The bolts which mount the crank centre plate to the crankcase have a plain shank, then a threaded portion. According to Richard-7 some bikes (including mine it turns out) in the 2013 - 2015 range suffer from the unthreaded portion of the bolt projecting through the plate so that when you torque the plate in the place the unthreaded shank is forcing its way into the threaded hole in the crankcase. This gives a torque reading without necessarily clamping the plate tightly. Drilling out the first few mm of the hole in the crankcase provides clearance to allow the bolts to be tightened correctly. There looks to be plenty length of thread left after the modification.

cliffa · Jul 24, 2021

ntst8 said:
Thanks Cliffa.
The bolts which mount the crank centre plate to the crankcase have a plain shank, then a threaded portion. According to Richard-7 some bikes (including mine it turns out) in the 2013 - 2015 range suffer from the unthreaded portion of the bolt projecting through the plate so that when you torque the plate in the place the unthreaded shank is forcing its way into the threaded hole in the crankcase. This gives a torque reading without necessarily clamping the plate tightly. Drilling out the first few mm of the hole in the crankcase provides clearance to allow the bolts to be tightened correctly. There looks to be plenty length of thread left after the modification.

Ah, I see. Thanks for clarifying Iain.

grandpaul · Jul 24, 2021

KOYO are good bearings.

ntst8 · Aug 2, 2021

For any with older oil pumps Ollie offers a retrofit non return valve, allegedly can be fitted with the cases in place.
Is larger and so less restrictive on the pumped flow than the one the factory offered as a press fit into the pump.

ntst8 · Sep 1, 2021

Happy Days.
Bottom right - Ollies oil non return valve sits next to the factory one.

cliffa · Sep 2, 2021

ntst8 said:
Happy Days.
Bottom right - Ollies oil non return valve sits next to the factory one.
View attachment 81688

Hi Iain,

Glad you got the bits. I have a few questions if you don't mind..

Were the pictures you posted before of the return valve of another bike ? If so how do you fit the new valve into your bike?

I want to take a look at my clutch soon and was thinking about the pinning of the ring gear, but I wondered if the same could be achieved by fitting slightly longer shouldered bolts and recessing the threads so the joint is bridged by the shoulder rather than relying on the threaded section only which is obviously weaker.

Cheers,

cliffa.

ntst8 · Sep 2, 2021

Hi Cliffa - the earlier valve pics were the sales photo's from Ollie, i'll comment on how easy the install was once we have had a go.

The bike is at a friends place, i have been spannering under his more educated supervision, but we will not be allowed to mingle again until the current covid lockdown drops a level, hopefully next week.
Below is a pic of a new ring gear mounting bolt, the plain shank half protrudes through the ring gear but is a slightly loose fit. I don't yet know whether that is the same as the originals, the old ring gear is still fitted, but it does look that these are intended to act as shear pins. Maybe if Stu B sees this post he might offer a comment.

cliffa · Sep 2, 2021

Aha, maybe it's the looseness which causes the bolt failure, in which case I guess pinning it the best option.

ntst8 · Sep 3, 2021

Feedback from Ollie is that pinning is "never wrong", so i will be going there.

ntst8 · Sep 9, 2021

The good news - the replacement starter ring gear is fitted and pinned.
The not so good - the HD starter motor is in the Covid maelstrom, at least another month away still, the clutch basket will mask the mouting bolts so can't rebuild the primary side until the starter is here

.
Decisions made on the breather system - i like the set up on my 850 so have copied that, despite iwilson and others success with the original system. Crankcase breather, with inline reed valve, will go to the oil tank instead of the airbox. We have drilled and tapped the oil filler tower for 6mm push fit air line breather, similar to the cNw breather on the primary/gearbox. All 3 vents on the rocker box will be blanked off.
Shock Mounts - we tried to remove the shock bolts to fit Ollies much nicer mounts. The allen key is rounding out the hex, cheesey grade stainless combined with permanent grade loctie on the threads it seems. Work continues.

cliffa · Sep 9, 2021

Hi Iain, how did you pin the ring gear ?

ntst8 · Sep 9, 2021

With my wallet

. I took it to a local machine shop along with a print out of Richard7’s how to info.

ntst8 · Sep 11, 2021

Cliffa - following up on your query on the non return valve installation, i have been in touch with Ollie and no surprise but it is not for the faint hearted.
22mm x 1.5mm taps need to be shortened, a guide made to attach to the leading end of the taps, and then a careful but firm hand for the thead cutting. So access to someone with the skills and equipment to make the tools is important, if in Europe a visit to Ollie might be easier.

Stu Bodycote · Sep 12, 2021

ntst8 said:
Hi Cliffa - the earlier valve pics were the sales photo's from Ollie, i'll comment on how easy the install was once we have had a go.
The bike is at a friends place, i have been spannering under his more educated supervision, but we will not be allowed to mingle again until the current covid lockdown drops a level, hopefully next week.
Below is a pic of a new ring gear mounting bolt, the plain shank half protrudes through the ring gear but is a slightly loose fit. I don't yet know whether that is the same as the originals, the old ring gear is still fitted, but it does look that these are intended to act as shear pins. Maybe if Stu B sees this post he might offer a comment.
View attachment 81694

Sorry, I missed this.
Ive just reassembled one, and yes the bolts machined shank is a little baggy in the ring gear etc. That little bit of movement is probably what was causing the failures, as the minimal clamping force from the bolt its self is just there to hold the five pins in place....so any movement between the shank and drilling would allow the starter ring gear to slip. Wouldnt take much of that back lash / hammer effect to shear the threaded part. Nortons answer was to lather the bolt shank and thread in green thread lock (ThreeBond 1305), and to be honest I dont think Ive seen a failure since that became the standard way to go......anyone know different, loose starter ring gears build 2016- ?
Ive measured protrusion on one Ive got in bits right now, and I got approx 5.6-5.7mm bolt shank protrusion from the starter ring gear, and a drilling depth on the sprung gear thingy (memory blank, cant remember the name) of approx 6.0mm. I say approx as my digital vernier at home right now is crap....took my good one to work the other day. So there's a decent clearance there....on the one Ive got here at least.

ntst8 · Sep 13, 2021

Thanks Stu, my 2014 model was bathed in threadlocker, probably for the best it sounds. I have had to spend plenty of time cleaning the flakes of the stuff out of the cases/rocker box as we have pulled things down. Definitely sounds that pinning is the best thing to do.

961 Birthday

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