P11 gets the JSM treatment

I’d you didn’t change or raise the needle, I’d look into it.

You’re on the needle when sat at a cruise. When accelerating, the accelerator pumps totally hide the needle jets correctness. But sat at a constant throttle cruise you’re on the needle mostly. If you’re lean there it’s actually hard to tell, and it can cause damage.
 
Last edited:
As they say "it was running great just before it let go"...keep an eye on nice clean plugs
 
Fast Eddie said:
I’d you didn’t change or raise the needle, I’d look into it.

You’re on the needle when sat at a cruise. When accelerating, the accelerator pumps totally hide the needle jets correctness. But sat at a constant throttle cruise you’re on the needle mostly. If you’re lean there it’s actually hard to tell, and it can cause damage.
Click to expand...

Needles were raised, but only a needle shim's worth. Might as well try a full clip position and see if it'll take it without bogging. That might be better for cruising.

The excessive heat I'm talking about is generated at long stop lights idling. Needle is not doing a lot at idle. Slow air jet, idle mixture and pilot jet are.

I have no clue how warm it is or gets at neutral throttle position cruise. This time of year where I am, added ambient heat on the HWY is not a problem yet. Hot days in August might be iffy. I hope to have it under control by then. Either that or have a molten pile of metal in the corner of the garage. ;)

Does a drop of water sit on a Norton head and steam away slowly after a ride when everything is just right? Or does it jump off the surface like water in a hot cast iron frying pan? I never bothered to check it until after this build. The previous build which I also did, did not smell hot after a ride like this motor does. However, it probably was hot being an old air cooled twin.
 
Schwany said:
The excessive heat I'm talking about is generated at long stop lights idling. Needle is not doing a lot at idle. Slow air jet, idle mixture and pilot jet are.
Click to expand...
You might be right. Then again, it might be getting uncomfortably hot on the cruise up to that point, then the idle adds to it and then you notice it…?

Adjusting the air /fuel screw for the idle is fairly straightforward, so you can then rule out incorrect mixture at idle as being your issue. The only way your engine will generate excessive heat at idle is if it’s weak, or the timing is wrong, or if you sit at idles for 6 hours at a time! Not trying to be facetious, just trying to point out that this excess heat at idle does not need to happen and should be easy to eradicate. When it is eradicated from your line of enquiry, you can expose and focus on those that remain.

You’re highly unlikely to damage your engine if it’s weak at idle. Whereas you’re highly likely TO damage your engine if it’s weak at a cruise speed and if you spend time at cruise speeds (race bikes don’t have to worry about it cos they NEVER hold a steady cruise, whereas on the road we do it a lot).
 
Fast Eddie said:
You might be right. Then again, it might be getting uncomfortably hot on the cruise up to that point, then the idle adds to it and then you notice it…?

Adjusting the air /fuel screw for the idle is fairly straightforward, so you can then rule out incorrect mixture at idle as being your issue. The only way your engine will generate excessive heat at idle is if it’s weak, or the timing is wrong, or if you sit at idles for 6 hours at a time! Not trying to be facetious, just trying to point out that this excess heat at idle does not need to happen and should be easy to eradicate. When it is eradicated from your line of enquiry, you can expose and focus on those that remain.

You’re highly unlikely to damage your engine if it’s weak at idle. Whereas you’re highly likely TO damage your engine if it’s weak at a cruise speed and if you spend time at cruise speeds (race bikes don’t have to worry about it cos they NEVER hold a steady cruise, whereas on the road we do it a lot).
Click to expand...
I get it, but 6 hours at a light and my nuts would be roasted. ;)

Yes HWY cruise time to stop certainly is part of it. I didn't mention that, but am aware that is a factor. Same carburetor tune worked on the previous build without excessive heat, so I may have screwed something else up somewhere mechanical in the motor, or just need to drop the clips. Or heaven forbid the straight section of the needles is too thick. The straight section is cruise along with the clip position. Could try larger mains or thinner needles. The list goes on...

I think the as delivered default clip position is at the 5th clip position down, but can't remember or verify it. If anything the timing is currently advanced beyond the recommended TriSpark spec, not retarded. I'll be checking it yet again with the degree wheel when I replace the clutch. I checked to see if I could move the rotor on its center during the build, which would definitely screw up my timing marks, but that may not be possible to do by hand.

Thanks for the thoughts. No need to burn up anymore of your bandwidth. I will eventually figure things out. Or, be pulling the motor apart again this summer instead of riding it. Garage will certainly be warmer.
 
If you know which needle type you have it should be easy to check and buy a couple of the next richest. The needles control very broad band of mixture on these carbs. Highly unlikely to be main jet related unless you’re sustaining WOT.
 
Probably something other than carburetion. I went for a test ride with the clip in the 4th position and the motor got sluggish, the plugs got furry black everywhere but at the electrode, and it made no difference with the heat without getting on the HWY and sitting at cruise. I think it either runs hot in general during the early mileage phase, or some other guess. Here's one: I did not put the oil pressure gauge on it to check and did not replace the oil pump. Oil pressure was OK when I tore it down, and I figured it would be OK when I put it back in. All the oil passages are clear. It is not timing. Timing a Norton twin with TriSpark EI is brain dead simple in my opinion. It would have to be over 12 degrees retarded to make it get warmer than it does, and it would not run worth a poop. Anywho, sun is out and it is what it is. I'm dropping the needle back down and taking it out on a real ride to blow it up. I have towing service. ;)
 
Took off and did 192 miles on the HWY today, NE Seattle to Marbelmount WA and back. Most of it was cruise. Had to do maybe 3 miles at rubbernecking speed between 5 and 10MPH on the HWY and then there was some in town long stop lights. No meltdown, but you could burn your fingers on the head near the plugs when I got back. Ambient air temperature varied between 60-75F. Still have some tuning to do, but it got me there and back without a tow truck.
 
Sounds fun Schwany.

So, now you’ve some miles on it, what’s it like ‘before and after’ engine wise ?
 
Schwany said:
Took off and did 192 miles on the HWY today, NE Seattle to Marbelmount WA and back. Most of it was cruise. Had to do maybe 3 miles at rubbernecking speed between 5 and 10MPH on the HWY and then there was some in town long stop lights. No meltdown, but you could burn your fingers on the head near the plugs when I got back. Ambient air temperature varied between 60-75F. Still have some tuning to do, but it got me there and back without a tow truck.
Click to expand...
Out 20 and back, or 530?

I really liked 20 out that way to the Chelan and back south way. One time on 20 I was on my old mk3 ahead of a mate on a VF750 and he got nabbed by the Snohomish sheriff. Sad part was I was ahead, and I circled back to find him caught 20 over.
 
Fast Eddie said:
Sounds fun Schwany.

So, now you’ve some miles on it, what’s it like ‘before and after’ engine wise ?
Click to expand...
I'll just say it's too early to make a fair assessment in public. I have some things to iron out.

gortnipper said:
Out 20 and back, or 530?

I really liked 20 out that way to the Chelan and back south way. One time on 20 I was on my old mk3 ahead of a mate on a VF750 and he got nabbed by the Snohomish sheriff. Sad part was I was ahead, and I circled back to find him caught 20 over.
Click to expand...
I did the nasty on HWY 5 to the good on 530. I wanted to get some long on and off throttle HWY cruise miles in.

Been there with the ticket. I was the guy that saw the cop in my rear view and slowed down on HWY 9 Skyline in California. Took one for the team that day. Had to go to driving school. That was the last ticket I received. On the P11 I'd be lucky if I could make out a cop car in the rear view. It's a vibrator.
 
Schwany said:
Been there with the ticket. I was the guy that saw the cop in my rear view and slowed down on HWY 9 Skyline in California. Took one for the team that day. Had to go to driving school. That was the last ticket I received. On the P11 I'd be lucky if I could make out a cop car in the rear view. It's a vibrator.
Click to expand...
Hihi .... you need a head-up display and a rear-view camera w/picture stabilising built into your helmet!
 
mdt-son said:
Hihi .... you need a head-up display and a rear-view camera w/picture stabilising built into your helmet!
Click to expand...
That would be nice. My suspension is so darn stiff my head is wobbling like a bobble head toy on any road surface that is not perfectly flat. I can barely see in front of me if the road gets bumpy.
 
Still no commitment from me on performance with these JSM parts. I would like to say I'm not delusional enough to think my thoughts actually matter. Just one more opinion in an ocean of opinions. I will pass along what I think though.

Anywho, I'm still working on the entire motorcycle from stem to stern as a package and it is a work in progress. It does run well, but I know I can get more out of the motor with an improved tune and the bike as a package. It'll never be a Panigale, but it should be a nice ride when I get done, should I live so long. ;)

I'm using colder range plugs now and that seems to be going in the right direction for heat reduction with the higher compression. I had some NGK BPR7ES plugs in it and they run on the hot side with this build. So I grabbed a pair of previously used Autolite 3923 plugs I have on the lots of plugs shelf that should be one step in the colder direction according to my Autolite heat range chart. I will probably end up using an Autolite of that same heat range in a double platinum next.

I also pulled 6 discs out of the SuperTrapp setup I have in my 2 into 1 exhaust to quiet down and restrict the exhaust as well as make it a little richer in the low and midrange of throttle input where the motor will be on cruise for the most part. It's a little quieter, but I have to retune the carburetors a little more. Not yet sure how the exhaust change will impact the top end. Disc count does make a difference up top and everywhere else with SuperTrapp setups. Kind of a fun tuning tool. Overall exhaust length also matters, but you guys know all that. I think my exhaust length is good for a 2 into 1 on a 750.

After making the changes above I went for an around town motor heat test. Most of the ride was in 2nd gear on 25mph streets. Max speed was a blistering 35mph. The motor still got plenty warm but not as hot as it did previously. The air temp is up today, so that is a good sign.

The plugs show what would be a good plug read 45 years ago. So it is running a little richer as I expected it would with the cooler plug and minor exhaust restriction change.

More later. The dinner bell is ringing.
 
Just about sorted. Heat is better controlled with the small change I made to timing, the exhaust, the carburetors, and putting in the coldest plugs I could easily get my hands on 3922 Autolite. Probably too cold for a lower compression motor.

What was taking me so long: I read somewhere on this site (that'll learn me) that too much advanced ignition timing was bad for long rod motors with short skirt pistons, so I kept backing off the timing until things basically turned to shite, plus I got a bad tank of fuel along the way that really did not help at all on a long ride. That all kind of bothered me. So.... Timing is now back where it should be at 29 degrees BTDC static, not strobed, and the motor is easy to start and smooth a silk. That said, I should be happy with the set up as it is. However, I'm getting a summertime itch to dial some advance into the cam timing. Did it on the 2S and it was violent in a good way. This JS2SS cam is pretty tame to me. Then again, maybe I'm a little old for that go fast stuff anymore. Decision decisions... as the wrench turns.
 
Forgot to mention that I ran a separate dedicated ground wire from my battery to one of the pillar posts in the points housing. This may have contributed to a better consistent spark from the TriSpark. In theory this should not have been needed on a solid mount Norton motor, but it seems to have made an improvement. Could just be the timing is perfect now, but I would get a misfire on occasion prior to doing it.
 
Schwany said:
I'm just getting started. Very slow compared to the last time I had the motor out of the frame. Getting older makes me overthink everything. Plus, I forget where I put tools down once in a while and spend 15 minutes looking for a socket. If lucky I find it before I forget I'm looking for a socket.

This JSM stuff is all old, repeated news to most of you guys that have been on this site for years. It's new to me, because I'd never heard of JS Motorsport before signing up as a member.

What I am doing is taking a P11 engine previously modified on the timing side for a 2S cam. Motor also sports a Fred Barlow ported head and a slightly lighter crank that was rebalanced when the 2S cam was installed. Motor has somewhere over 10K miles on it since the 2S was put in there. I'll be putting the following JSM parts in it.

JS2 cam, lifters, pushrods, valves, valve springs, rods, and high CR pistons.

I hope I don't miss that 2S cam.

I'm a shade tree mechanic. Only thing I'm anal about is keeping the parts clean and making sure they spin freely and don't wobble funny.

A few teardown pics so far. Nothing technical will be discussed in this thread. Hence it may not appeal to very many members here.

View attachment 94034
The messy space where I'm doing the work.
View attachment 94035

View attachment 94036
Need a pinion puller. If it isn't one thing it's another.
More to follow.
Click to expand...
You have a nice space to work, you are doing a great job :cool:
 
You must log in or register to reply here.

Similar threads

K
Identifying a Combat motor
Replies
12
Views
427
Karl Johnson
K
Schwany
What did you do with your P11 today. he he
2 3
Replies
44
Views
1,165
Schwany
Schwany
danfr
2S Cam in standard 750
2
Replies
27
Views
1,554
baz
baz
Schwany
Get out the straight jacket
6 7 8 9 10 11
Replies
211
Views
11,650
Schwany
Schwany
N
Where to put the gasket?
Replies
7
Views
500
Dan1950
Dan1950
Back
Top