It's a long way to 920 type(rary)

The guy goes thru hell to get 70 HP and needs 100 right away!
Gotta admire the spirit!

Since you aren't concerned about using original Norton parts, I can think of a couple of choices for the desired output. Both only require Norton tank decals

Glen

Well, when I see what you have to do to find 30 HP more, I will not do it, first I don't have the skills, I think only a few genius in the world can do the job.
IF I can find 5HP more I will be very happy
And more: to me the Seeley frame reach is limits with 70 or 75 HP, at least on the roads here in Belgium, you have always a holl or a bumb in the corner and this make a hard work for the Seeley to stay on the road when in full acceleration at least for me at 68 years old, don't misunderstand me, it stay sano, but the bike says don't go any farther, you are close to the limits...
And I wish to keep the engine in one piece, the final goal is not to work a few hunderd hours to ride 10 minutes and to find conrods salade on the road
Yves

At some point you have to say it's developed as far as reasonably possible, I think you are there Yves , good job.
Now it will be interesting to see how the durability is.

Glen

worntorn said:

At some point you have to say it's developed as far as reasonably possible, I think you are there Yves , good job.
Now it will be interesting to see how the durability is.

Glen

Click to expand...

+1 !!

Also Yves, we should all remember ‘relativity’ here.

A lot of bhp figures are pure nonsense.

Even the factory figures were, shall we say, extremely optimistic.

Many of us amateurs use dynos and have no base line calibration to work to.

Then there are ‘rogue’ dynos out there too.

Then there are the ‘estimaters’ Who think that the stock bike had 65bhp, and they have added a few tweaks, so they must be over 70bhp right? Wrong!

At the end of all the talk, a stock road going 850 is probably circa low 40s rwhp. Add a single carb and you’re into the mid to high 30s.

So, if you can creep over 70, you will be in the ball park of double the rwhp of most real life road going Cdos you’re ever likely to come across.

And, the vast majority of their owners (understandably) don’t want to thrash a 40-50 year old bike. So in reality, they never even see the 35-40 rwhp that they have.

So, as Glen says, durability is probably your main priority now IMHO, meaning, having the confidence to fully utilise all 70 horses wherever and whenever you want to, without worry.

Because then, all BS aside, apart from a very few well built big Vin specials and / or big triples or Cdos, you are unlikely to meet any old Brit bike on the road who will see anything other than your disappearing rear wheel!

You’ll meet them in the bars of course... but that’s another topic entirely ...!

Fast Eddie said:

Also Yves, we should all remember ‘relativity’ here.

A lot of bhp figures are pure nonsense.

Even the factory figures were, shall we say, extremely optimistic.

Many of us amateurs use dynos and have no base line calibration to work to.

Then there are ‘rogue’ dynos out there too.

Then there are the ‘estimaters’ Who think that the stock bike had 65bhp, and they have added a few tweaks, so they must be over 70bhp right? Wrong!

At the end of all the talk, a stock road going 850 is probably circa low 40s rwhp. Add a single carb and you’re into the mid to high 30s.

So, if you can creep over 70, you will be in the ball park of double the rwhp of most real life road going Cdos you’re ever likely to come across.

And, the vast majority of their owners (understandably) don’t want to thrash a 40-50 year old bike. So in reality, they never even see the 35-40 rwhp that they have.

So, as Glen says, durability is probably your main priority now IMHO, meaning, having the confidence to fully utilise all 70 horses wherever and whenever you want to, without worry.

Because then, all BS aside, apart from a very few well built big Vin specials and / or big triples or Cdos, you are unlikely to meet any old Brit bike on the road who will see anything other than your disappearing rear wheel!

You’ll meet them in the bars of course... but that’s another topic entirely ...!

Click to expand...

Hi Nigel and Glen, of course, I can not say anything about durability yet, but I am confident, I use the best components on the market and I will try to keep the engine in good shape
There are still steps in the unknow like using Nicasil on cast iron sleeves, not many Codo owners did it before so far I know, but who not dear not win...
A few words about Alton, I discover yesterday that the alternator was dead, wel, the new parts will be there tomorow, what a service, thanks Paul!
Once the new alternator will be fitted I will try to find the perfect carburation on the FCR, but Frank MX parts, my suplier for FCR parts don't antsword the last two days.
It will be raining the entire WE here in Belgium so I don't worry to match if I can not do any road test this WE
Yves

jseng1 said:

See the 84ok links in the above post and note what's already been achieved by Herb Becker. Beyond that - To get another 30 HP you might have to copy the characteristics of the Harley XR 750 because that's the most powerful pushrod twin valve. They get 90 to 100 hp out of a 750cc. For starters you have to move the valves so they are further apart (not just re-angle). You need .250" between the valves when they are on their seats and that means welding up the port bowls and re-shaping everything. When you get .250" between the valves then you can use wild cams with 100 deg lobe centers (the only way to realize a Nortons full potential). Then you need longer rocker arms to fit the new valve locations and to give you more lift (increased rocker arm ratio) with the available Norton cams. The longer rocker arm is available but that's another story.

You'll have to go to a JS3 or Sifton 480 cam and twin free breathing exhaust pipes. You'll need 10-1/2" length from the end of the velocity stack to the head.

It won't be cheap and it will take lots of time and development - but the technology exists - it just needs to be applied. Most of it is already laid out with the "Narley ports". This would be breaking new ground as no one has taken a Norton this far. The head would be very expensive with many hours of "Cobrahead" port shaping and the installation of huge valves. There would be so much modification that you may as well start with a stock 750 head.

Click to expand...

Hi Jim thanks for your very good parts and advises. I wish to try different lenght of intake manifolds, can you make a drawing?
The problem is that I use K&N filters and there is no place to use longer inlets on the Seeley MK 3 frame, or I have to find other kind of air filters
Thanks Yves

yves norton seeley said:

Hi Jim thanks for your very good parts and advises. I wish to try different lenght of intake manifolds, can you make a drawing?
The problem is that I use K&N filters and there is no place to use longer inlets on the Seeley MK 3 frame, or I have to find other kind of air filters
Thanks Yves

Click to expand...

If you are out of room then you are stuck with the intake length that you have.

On a race bike without airfilters you can use longer intake velocity stacks or extended intake manifolds.

Measuring from the head (where the manifolds bolt on) to the end of the velocity stack - aim for 10-1/2" That's a lot longer than usual. But this may only be good for race bikes - you will have to test it.

See Ron Woods 84 HP 750 short stroke and the long intake length.

yves norton seeley said:

At the moment I have a question, some persons claim to find 100HP on a Codo engine without turbo or blower, if I see what you need to do to find 70HP, I am asking my self
what to do to find the 30 Hp left ???
Yves

Click to expand...

Regarding 100 hp claims, there might be some confusion between rear wheel and crankshaft horsepower. The best 920 engine I've seen made 88 hp (at a bit over 7,000 rpm) at the rear wheel (and 94 ft-lbs of torque), and a correction factor was used for the drivetrain loss that gave just over 100 hp at the crankshaft. That was a full on Steve Maney race engine, so 70 or so hp at the rear wheel for a street bike is actually quite respectable. Eldo, here on the forum mentioned that his Herb Becker built 920 made 90 hp at the rear wheel, but that was a very highly tuned engine, built to make maximum top end horsepower for land speed racing, and probably would be terrible in a street bike.

Yves, I'm sure you'll find a few more ponies with some more tuning, but like fast eddy said, if you made the more extreme mods to get to the 85 or 90 hp range, you might find the bike much less fun to ride.

Ken

yves norton seeley said:

Hi Nigel and Glen, of course, I can not say anything about durability yet, but I am confident, I use the best components on the market and I will try to keep the engine in good shape
There are still steps in the unknow like using Nicasil on cast iron sleeves, not many Codo owners did it before so far I know, but who not dear not win...
A few words about Alton, I discover yesterday that the alternator was dead, wel, the new parts will be there tomorow, what a service, thanks Paul!
Once the new alternator will be fitted I will try to find the perfect carburation on the FCR, but Frank MX parts, my suplier for FCR parts don't antsword the last two days.
It will be raining the entire WE here in Belgium so I don't worry to match if I can not do any road test this WE
Yves

Click to expand...

About durability: My 850 engine with the Jim Schmidt crank, rods, pistons and camshaft / followers dont need to be open in 30.000 kms
Yves

lcrken said:

Regarding 100 hp claims, there might be some confusion between rear wheel and crankshaft horsepower. The best 920 engine I've seen made 88 hp (at a bit over 7,000 rpm) at the rear wheel (and 94 ft-lbs of torque), and a correction factor was used for the drivetrain loss that gave just over 100 hp at the crankshaft. That was a full on Steve Maney race engine, so 70 or so hp at the rear wheel for a street bike is actually quite respectable. Eldo, here on the forum mentioned that his Herb Becker built 920 made 90 hp at the rear wheel, but that was a very highly tuned engine, built to make maximum top end horsepower for land speed racing, and probably would be terrible in a street bike.

Yves, I'm sure you'll find a few more ponies with some more tuning, but like fast eddy said, if you made the more extreme mods to get to the 85 or 90 hp range, you might find the bike much less fun to ride.

Ken

Click to expand...

Good points Ken.

The most I’ve seen on the dyno with my old Brit stuff is around 87rwhp out of my old 900 Dresda Nourish. But I ran it at around 84, I ‘gave away’ 3 peak hp for a better overall curve. That was a light bike, and that bhp made it really quite quick.

That was on the same dyno I still use, the one that shows I’m at 65rwhp on the Trident Hunter.

So I only need another 20 out of that to match the Nourish !!

Like Yves, I’m also building a 920 motor (but far more slowly), and am also hoping it lands somewhere in the low 70s rwhp whilst still being ‘streetable’.

It’s all good fun though isn’t it?

Isn’t it ?!

One day I'll put my stock MK3 on a dyno just for fun.
It certainly acts like it has a bit more than low40s
It always surprised me that it feels decent even after spending time on the modern high powered bikes. I think it is because the peak number everyone looks at is not actually in use on the road, or at best just for a split second before a shift.

Maybe best not to put a number to it!

Glen

I friend of mine has got a low mileage MK111, stock apart from peashooters, ham can and Boyer.

I will try VERY hard to get him to accompany me and put his on the dyno next time I go.

Hi there,
I agree with Nigel about the relativity of a dyno run, but every year there is a drag race here in Belgium and I participed every year, this will be the judge!
I still have the records from my time on the 1/8 mile track wit the 820, so I will do it with the 920 in september... and see!
The problem is my weight: 0.1 ton, of course I can put another rider on my bike, but if we want to have a comparaison I need to do it my self.
My weight is a real problem, if I wish to see my dick, I must put motorcycle mirrors on my knees
The problem with the Alton stator and rotor is fixed with new parts, so I hope it will not rain tomorow so Bruno can test the Seeley and give you is impresions
Keep you posted
Yves

Yves / Bruno,

You seem like nice guys... And you seem like you use your bikes properly... So the serious question is...

When are you going to bring your fabulous classic English bikes over here to one of the fabulous classic track events that we have in England ?

The Festival of 1000 bikes at the iconic Mallory Park, which is the only event when that allows the track to be used in its original layout without all the stupid modern chicanes.

Or the Beezumoh festival put on by the TR3OC. If you boys came with me to that we could set up our own Trident Hunters Club...!

Let me know, and I’ll send out Trident Hunters Club membership forms to you...

Can I bring my Tridents as well.lol

Chris

Fast Eddie said:

Yves / Bruno,

You seem like nice guys... And you seem like you use your bikes properly... So the serious question is...

When are you going to bring your fabulous classic English bikes over here to one of the fabulous classic track events that we have in England ?

The Festival of 1000 bikes at the iconic Mallory Park, which is the only event when that allows the track to be used in its original layout without all the stupid modern chicanes.

Or the Beezumoh festival put on by the TR3OC. If you boys came with me to that we could set up our own Trident Hunters Club...!

Let me know, and I’ll send out Trident Hunters Club membership forms to you...

Click to expand...

Hi Nigel,
Thanks for the invitation, but I have two problems: my dear Marina is disabled and I can not leave here alone more as one day, the second problem is: if I go on the track, I have no limits and for sure I will put the Seeley on the ground and maybe hurt my self, you imagine if I broke a leg or so, how can I take care for Marina?
I will speak with Bruno and try to find a solution.
I am more intrested in a drag event over 1/4 mile, if you can find one I will be glad to come over
But we will meet us in Belgium at Chimay or Gedinne or not?
Thanks
Yves

I definitely want to attend Chimay one day. No chance this year though as my ‘bike calendar’ is too full already.

We all have to balance our bike calendars with our family life. And despite how committed we may sometimes appear to our funny old bikes, family must come first. And that includes Marina, who sounds like and unbelievably tolerant and understanding wife Yves!

Maybe we can have the Trident Hunters Club meet at Chimay next year?

Fast Eddie said:

I definitely want to attend Chimay one day. No chance this year though as my ‘bike calendar’ is too full already.

We all have to balance our bike calendars with our family life. And despite how committed we may sometimes appear to our funny old bikes, family must come first. And that includes Marina, who sounds like and unbelievably tolerant and understanding wife Yves!

Maybe we can have the Trident Hunters Club meet at Chimay next year?

Click to expand...

Yes Nigel, Marina is a fantastic women, 30 years with Multiple sclerose and she NEVER complain!
Bruno did a test ride from the 920 Seeley to day, he wil do his test report soon
I was watching him a long the road, and I was impressed my self to see my own bike on the road
If some member can keep me posted about drag races in the UK, I will be very tankfull
Yves

Well guys, not sure where to start...
I did try Yves' 920cc Seeley this afternoon. I started very conservatively because I had never ridden a Seeley and I wanted to get the grasp of the bike as a whole, not just its engine.
What an incredible job Yves has done with this bike! Even though I am about 10cm taller and 25kg lighter than him, it took me just about 4 seconds to feel completely at home on his Seeley. All the controls are exactly where you expect them to be and everything went completely flawlessly during the 30 minutes or so I was on the bike.
The bike feels very light, and lower than my Slimline Commando. The clutch action is smooth and easy, a gentle push on the gear lever and of I went...slowly at first, as I didn't know what to expect. Even at 1/3 throttle, the engine feels full and lively, the TTI 5 speed gearbox is an absolute revelation, silky smooth, perfect ratios, I am seriously thinking about selling my left kidney to buy one asap.
The front 4LS 260mm magnesium Fontana brake is nothing short of incredible, progressive, powerful and immensely precise, much better than most modern disk set ups,the rear 2LS 230mm magnesium Fontana is probably a bit too powerful for this very light motorcycle yet perfectly precise and safe to use. Actually on a couple of'occasions I used only the the rear brake without even touching the front to slowdown Yves' rocket before a roundabout and it was not a problem at all, quite incredible in fact!! The Mk3 Seeley steers precisely, goes exactly where you want it to go at any speed, thanks to Ceriani GP forks and Öhlins rear shocks.
If it was my bike (dream on, Bruno!) I would probably adjust the rear shocks to be a bit harder considering the brute power delivery of Yves' mighty engine.

Yes, I know, I know, I haven't said anything about the engine yet.
Well, it starts on the Alton starter button, idles with the precision of an atomic clock, and is suprisingly vibration free, even at low rpm. At first, I wanted to remain very cautious and kept my right hand below half throttle. In those conditions, the engine feels full and responsive under 4500 rpm, not so different (I naively thought) from my own 828cc PW3.
But after a couple of minutes, Yves, who was standing by on the side of the road, started to make big gestures telling me to give his 'Big Spender' a real go.

So I did.

Should you decide to twist your right wrist on Yves bike, here is what happens: with a otherworldly roar from the Maney exhaust, Yves bike suddenly morphs into Maverick's Tomcat on afterburners being launched from its carrier, the front of the bike starts to feel very light, click, second gear front still feels very light at 7000rpm, click, third gear front still feels very light at 7000rpm, click, fourth gear what 7000rpm already?, click fifth gear oh shit this thing is really moving, time to leave Warp 8 acceleration, Scotty Bruno reporting serious facial grinnage inside space helmet as he flies right by Captain Yves Kirk on the deck. Looking on the rearview mirror for Thor's hammer which, I am sure of it, just kicked me on the backside, I see nothing but an empty stretch of road.
As I am a lifelong epicurian, I decide to go for it again.
And again.
And again.
After all, Yves has asked me to try his bike out and encouraged me in no uncertain terms to 'test-osterone' it.

So I did.

The engine pulls like Saturn V from 2500rpm until Mjölnir (the aforementionned Thor's hammer) hits you squarely in the backside from 4500 to 7000rpm. Vibration free, the engine feels free and open, completely quiet mechanically at all revs, torque and power galore. As I write this report, I am trying very hard to find something wrong to Yves' bike and incredible engine.Yet I just can't find anything less than perfect on his bike.
His 920cc Seeley is the stuff normal people's dreams are made of.

After some debriefing and (many) compliments, I said goodbye to my friend Yves after thanking him for the privilege bestowed upon me etc., ...one good kick started my PW3 Featherbed Commando and off I went for a happy ride in the Belgian countryside. Or so I thought.

Bruno was not happy at all by now.
Quite pissed off even.
My mighty 828cc PW3 engine now feels like a mere glorified moped after trying out Yves' spaceship.
Oh, do I hate Yves now.
One cannot do to a friend what he did to me this afternoon. It's not fair.

Just not fair.

I need a drink. Or a few.