Get out the straight jacket

Your carbs are rubber mounted. So you don’t need no stinkin’ heat insulators …

mean gene said:

Haven't looked at your post for a while. ....., Is that an aluminum transmission cradle. How thick is the material. Please let us know it it is stiff enough.

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Loads on engine plates are
* weight load
* torque load (from the drivetrain)

Weight load distributes equally into the plates when bike is vertical. The load acts as shear load and the maximum is at the frame mounts due to the least cross section, fore and aft.
There is also some in-plane bending/tensile load, more so aft than fore.

Drive train torque load acts as an in-plane force couple of tensile loads top/bottom at each rear engine plate. On the P11 there are 2 bolts upper/rear and two small bolts at the frame rails cross tubes counteracting these loads.
On the G15, torque loads are counteracted by 2 bolts upper/rear and the large centre stand bolt which crosses the lower rails.
Due to the vertical distance between these bolts, and torque loads split on 2 plates, the resulting tensile load is small.

Obviously the engine plates need tensile and shear stiffness primarily. This is assured by plate thickness x necessary height at the frame joints. Even the alloy plates can cope with these requirements, as they were given increased thickness over the G15 plates,
compensationg for loss of tensile and shear moduli.

Weakness of plates is primarily seen as creep (material flow) at the engine bolt holes due to high contact pressure caused by small diameter bolts, and also by twisting/tilting/vibration of the engine itself.
Strangely, my G15 rear engine plates also shows ovalization of the gearbox adjuster hole. Obviously the gearbox tries to twist a great deal. Reason enough to take corrective action minimizing the gearbox bolt/plate clearance.
The Commando has a similar arrangement, but torque reaction loads are cushioned, so there is less likelihood of material creep at the engine and adjuster bolt holes.

Fast Eddie said:

Your carbs are rubber mounted. So you don’t need no stinkin’ heat insulators …

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True

I was using them to space the intake manifolds back a little. I didn't put enough effort into it. I also didn't think it would be as bad as it was being only .5mm smaller in radius, or 1mm in diameter. Just as well, the filters are easier to get off and on without the spacer.

I joined up to tell a P11 modification story, and it's basically done. Well, I'm done for sure.

I'm checking out until I get in a dyno run and have something to add. Somebody might want to know if all the parts I used really make any difference. I don't need a dyno to know I'm making more HP than a stock P11 ever could, but that isn't saying much. Besides I am curious myself.

Unsolicited harsh advice section:

If you get an itch to install a JSM cam kit in a street motor, make sure before you lay your money down you are going to get BSA lifters, and not Triumph lifters. There is a significant difference. My advice is get the stock tappets radiused for use with a JSM cam on a street bike. You won't notice any big difference with the lighter lifters riding around on the street. The bronze blocks are a tedious job to install. Looks easy in the JSM video that covers the install, but the install has to be perfect to stop rapid wear of the bronze lifter blocks. The stock tappets are a piece of cake to work with.

Be well and prosper.

So the bronze flecks in your oil came from the cam followers?

Glen

Bronze in the oil was from the previous build. My bad on when I saw it. Brain malfunction.

Overly sharp edges on the smaller Triumph lifters I received last year (surprise) from JSM when I ordered BSA lifters.

Long story involved, here is the short version:

I didn‘t know JS was using Triumph lifters these days.

In fairness, there are many, many Triumph lifters in service. Many using light alloy lifter blocks. I suspect misalignment was the root cause here unfortunately.

Fast Eddie said:

I didn‘t know JS was using Triumph lifters these days.

In fairness, there are many, many Triumph lifters in service. Many using light alloy lifter blocks. I suspect misalignment was the root cause here unfortunately.

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Right on cue.

Have you ever installed and used JSM Triumph lifter blocks and little Triumph lifters in a Norton?

Far as I'm concerned I got the very short straw with these. He ran out of BSA lifters last year and sent me the Triumph lifters without telling me that is what he was doing. To get BSA lifters now to replace the Triumph lifters I have to buy a complete cam kit. Tis BS all things considered.

Changes were made to the Triumph lifter blocks he still had after I showed the image to Jim. I'm not sure if he decided to fully dress out the lifters in the future, but he should if he is still going to sell them.

Hard to misalign the blocks with the tab there. All of the lifters would have made a mess if the blocks were misaligned. The other block looked the same with only 1 lifter digging in. The lifters were incredibly sharp on the edge that was responsible for the problem. I dressed the lifters out on all edges for the engine rebuild this thread is about, and put in new lifter blocks. Nutts to do so really. I should have had him radius my stock lifters. Never would have had an issue at all with the stock lifters.

Good alloy is harder than bronze, and if I'm not mistaken Triumph and BSA used iron blocks in the bikes they built with old pushrod technology. Whatever the case, if a person had to have a JSM cam and JSM lifters and lifter blocks, I'd still make sure they were the BSA lifters that have more face surface area and larger stems.

I'm surprised you didn't say I must not be using a top-rated oil in the Comnoz oil data base.

Schwany said:

Right on cue.

Have you ever installed and used JSM Triumph lifter blocks and little Triumph lifters in a Norton?

Far as I'm concerned I got the very short straw with these. He ran out of BSA lifters last year and sent me the Triumph lifters without telling me that is what he was doing. To get BSA lifters now to replace the Triumph lifters I have to buy a complete cam kit. Tis BS all things considered.

Changes were made to the Triumph lifter blocks he still had after I showed the image to Jim. I'm not sure if he decided to fully dress out the lifters in the future, but he should if he is still going to sell them.

Hard to misalign the blocks with the tab there. All of the lifters would have made a mess if the blocks were misaligned. The other block looked the same with only 1 lifter digging in. The lifters were incredibly sharp on the edge that was responsible for the problem. I dressed the lifters out on all edges for the engine rebuild this thread is about, and put in new lifter blocks. Nutts to do so really. I should have had him radius my stock lifters. Never would have had an issue at all with the stock lifters.

Good alloy is harder than bronze, and if I'm not mistaken Triumph and BSA used iron blocks in the bikes they built with old pushrod technology. Whatever the case, if a person had to have a JSM cam and JSM lifters and lifter blocks, I'd still make sure they were the BSA lifters that have more face surface area and larger stems.

I'm surprised you didn't say I must not be using a top-rated oil in the Comnoz oil data base.

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Just trying to offer some perspective (it’s usually helpful when problem solving).

I’ll leave you to it.

Schwany said:

I joined up to tell a P11 modification story, and it's basically done. Well, I'm done for sure.

I'm checking out until I get in a dyno run and have something to add. Somebody might want to know if all the parts I used really make any difference. I don't need a dyno to know I'm making more HP than a stock P11 ever could, but that isn't saying much. Besides I am curious myself.

Unsolicited harsh advice section:

If you get an itch to install a JSM cam kit in a street motor, make sure before you lay your money down you are going to get BSA lifters, and not Triumph lifters. There is a significant difference. My advice is get the stock tappets radiused for use with a JSM cam on a street bike. You won't notice any big difference with the lighter lifters riding around on the street. The bronze blocks are a tedious job to install. Looks easy in the JSM video that covers the install, but the install has to be perfect to stop rapid wear of the bronze lifter blocks. The stock tappets are a piece of cake to work with.

Be well and prosper.

Click to expand...

I'm currently putting together a Commando engined special, so just lurking on here mainly. However I've just taken delivery of a JSM cam kit, so if you wouldn't mind, what are the differences?

Schwany said:

Right on cue.

Have you ever installed and used JSM Triumph lifter blocks and little Triumph lifters in a Norton?

Far as I'm concerned I got the very short straw with these. He ran out of BSA lifters last year and sent me the Triumph lifters without telling me that is what he was doing. To get BSA lifters now to replace the Triumph lifters I have to buy a complete cam kit. Tis BS all things considered.

Changes were made to the Triumph lifter blocks he still had after I showed the image to Jim. I'm not sure if he decided to fully dress out the lifters in the future, but he should if he is still going to sell them.

Hard to misalign the blocks with the tab there. All of the lifters would have made a mess if the blocks were misaligned. The other block looked the same with only 1 lifter digging in. The lifters were incredibly sharp on the edge that was responsible for the problem. I dressed the lifters out on all edges for the engine rebuild this thread is about, and put in new lifter blocks. Nutts to do so really. I should have had him radius my stock lifters. Never would have had an issue at all with the stock lifters.

Good alloy is harder than bronze, and if I'm not mistaken Triumph and BSA used iron blocks in the bikes they built with old pushrod technology. Whatever the case, if a person had to have a JSM cam and JSM lifters and lifter blocks, I'd still make sure they were the BSA lifters that have more face surface area and larger stems.

I'm surprised you didn't say I must not be using a top-rated oil in the Comnoz oil data base.

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Pretty sure I commented on the fitting of the bronze block difficulties.

I was subtle.

Pretty sure most didn't understand it.

Pretty sure it was glazed over/ignored.


Maybe I can find it later.

JMWO

concours said:

Pretty sure I commented on the fitting of the bronze block difficulties.

I was subtle.

Pretty sure most didn't understand it.

Pretty sure it was glazed over/ignored.


Maybe I can find it later.

JMWO

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Go for it. I ignore most of what I'm told here, so will be a waste of your time if trying to enlighten me specifically. lol

Maybe Paul will get something out of it.

Paul (850 Commando.) said:

I'm currently putting together a Commando engined special, so just lurking on here mainly. However I've just taken delivery of a JSM cam kit, so if you wouldn't mind, what are the differences?

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Did you get the Triumph lifters? If not, I would not worry about it. If you did, good luck. I have not had the two lifter types in my hands. I have only had the Triumph lifters, Triumph lifter blocks, and BSA lifter blocks in my hands. I did not measure any of them. Didn't think I'd have to.

Here's a pic I took of one of the Triumph lifters I have in a BSA lifter block. I ordered a set of BSA lifter blocks after I removed the messed up Triumph blocks because BSA lifters were what I thought I received. Litte did I know they were the Triumph lifters, and Triumph lifter blocks. Anyway it is easy to tell the Triumph lifter has a much smaller stem. The end of the follower is also wider on a BSA lifter and the followers travel up and down closer together in the center of the block, so are less likely to turn and dig into the block.



Second pic shows how much smaller the follower is on a Triumph lifter in the BSA block.

Just some observations for general consumptions here:

Looking at the wear pattern on the Triumph lifter, it seems to show that it’s working with the cam, as the wear is not right up to the edge (I won’t comment on the wear line in the centre as that has been discussed already). Which is what I’d expect as these lifters are used in Triumphs and even NRE engines.

But looking at the pictures, the BSA lifter does look preferable to me given the bigger foot and stem.

It is crucial when using the JS kit to set up the lifter blocks in a case half and basically mount them as low down, ie as close to the cam as you can, in order to support the lifter as much as possible, whilst also ensuring the lifter block does not touch the cam and that the lifter does not hit the roof of the lifter block at full lift.

Norton lifter design means you don’t have to check any of this, but with BSA / Triumph suff you do, especially when playing with higher lifter cams etc as there’s not a lot of spare support area, so you can’t afford to lose any.

I don’t know what Triumph lifters look like in a JS lifter block, that would be good to see.

I have only ever run a JS#1 cam and the wear on cam / lifters / lifter blocks is practically zero. In this run time I got through 2 sets of pistons and the crank needed a regrind… so the motor wasn’t exactly mollycoddled. I mocked up a JS#2 but decided to keep the #1. The above points about careful checking when installing lifter blocks are actually way more crucial with a JS#2 than a JS#1.

I used 16 penny nails and duck tape.

The Triumph lifters needed to be deburred and dressed. I did not do that when I installed them the first time thinking all that would have been taken care for the price. I did do it for this build.

The installation instructions are very clear and were followed. It is however a tedious exercise and not particularly worth doing on a street motor in my opinion.

The incorrect installation theory was fully expected from JS fans, but all the lifters would have been a problem if the blocks were installed incorrectly. One exhaust lifter and one intake lifter had issues, I believe. I'll go check the old blocks later.

The JS2 cam just clears the block by the spec provided in the instructions and is right on the money pushed up as far as they will go in the Molnar barrels.

Triumph lifters in the worst worn Triumph block. You can see how much the lifter dug out looking at the top of the lifter on the left. Other than that it looks like they should work fine, and might have in somebody else's magic engine.

Schwany said:

Did you get the Triumph lifters? If not, I would not worry about it. If you did, good luck. I have not had the two lifter types in my hands. I have only had the Triumph lifters, Triumph lifter blocks, and BSA lifter blocks in my hands. I did not measure any of them. Didn't think I'd have to.

Here's a pic I took of one of the Triumph lifters I have in a BSA lifter block. I ordered a set of BSA lifter blocks after I removed the messed up Triumph blocks because BSA lifters were what I thought I received. Litte did I know they were the Triumph lifters, and Triumph lifter blocks. Anyway it is easy to tell the Triumph lifter has a much smaller stem. The end of the follower is also wider on a BSA lifter and the followers travel up and down closer together in the center of the block, so are less likely to turn and dig into the block.

Second pic shows how much smaller the follower is on a Triumph lifter in the BSA block.

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Thanks for posting the pic's.
There's a large difference in size isn't there?
I've got some Triumph and NRE lifters, so I can compare them to see what I have got.

Haven't got beyond opening the box it came in TBH, stripping an NRE engine/Quaife 'box etc and sorting bits out prior to sale.
This Norton's turning into a real money-pit!!!

Welcome to the Norton money pit!

Paul (850 Commando.) said:

Thanks for posting the pic's.
There's a large difference in size isn't there?
I've got some Triumph and NRE lifters, so I can compare them to see what I have got.

Haven't got beyond opening the box it came in TBH, stripping an NRE engine/Quaife 'box etc and sorting bits out prior to sale.
This Norton's turning into a real money-pit!!!

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Could be worse
Could be a boat!

Paul (850 Commando.) said:

Thanks for posting the pic's.
There's a large difference in size isn't there?
I've got some Triumph and NRE lifters, so I can compare them to see what I have got.

Haven't got beyond opening the box it came in TBH, stripping an NRE engine/Quaife 'box etc and sorting bits out prior to sale.
This Norton's turning into a real money-pit!!!

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Indeed, they are not even close to the same lifters.

If you got Triumph lifters, and I doubt you did, just check all the edges and if sharp run some emery cloth or a small file over them until they don't cut your fingers. The alternative is send the Triumph lifters and blocks back for an exchange for the BSA lifters and blocks. Jim will or should take them back if not installed. I sure would not use Triumph lifters if I could exchange them for the BSA lifters. I don't care who has had no problems with the Triumph lifters.

Yep, Nortons are spensive, but not so much if left closer to stock and reusing parts that are fully serviceable.

It seems that an extra few hp can be very costly to find, even more costly to keep!

Ive got standard lifters in an alloy barrel for the 920. A standard but nitrided nos stock cam is lifting them.
Cost was very low, but I wonder if the alloy tunnels will hold up. I guess you have that concern too.


I recall that G81 was investigating this, not sure if he came to a conclusion or just dropped the plan to build alloy cylinders and left that with Andy Molnar.

Glen