Where would you spend your money?

The Maney crank ain't gonna give you much (any?) more go in itself.

The FCRs along with a hotter cam and hike in compression ratio will achieve what you're after.

Yes, the PW3 cam with the other bits must be part of the equation. The cam in my 70 is standard as far as I know.

freefly,
you didn't tell us that the engine had new pistons, a rebuilt head and a E.I.
Those little details are kinda important. :lol:

But, I still have the same advice....... carbs, ignition, tune up.

It sounds like you have a pretty complete package already and it just needs carbs and dialed in.

I rode a super nice hotrod one time that had all the mods and still couldn't keep up.
the reason? the chutch was slippin'.
Point being - it's all gotta work together to make it a fast bike. (of course :roll: )

If you just have to tear it apart, then a cam.

Got any Pics ???????

OK you probably don't need a leakdown tester. Since you already have a good running full compression motor and want more power, (presumably lots more) there is no inexpensive way forward that I'm aware of.

Glen

worntorn said:

OK you probably don't need a leakdown tester. Since you already have a good running full compression motor and want more power, (presumably lots more) there is no inexpensive way forward that I'm aware of.

Glen

Click to expand...

I get the feeling someone is doing a lot of talking and not much listening. I'm not referring to you, Glen.

I have a '70 commando myself, so I am familiar with that year's weaknesses.

the obvious:
superblend main bearings IF you are going to tear your cases apart and your bike still has the original roller on the drive side and ball bearing on the timing side.

yes, the camshaft breather is insufficient. I added a reed breather on my timing side blanking plate, and left the cam breather operational too with no bad results from having both work together.


Brakes, as you said you can always do them later. My '70 has a '73 disc brake front end which is an improvement over the front drum that was stock in '70.

The less obvious:

The swingarm tube on a '70 engine cradle has a single bolt to fix the swingarm shaft in place. This tube developes a lot of play that is felt as sloppy swingarm play regardless of whether you have good swingarm bushings. There's a simple modification called the kegler modification that fixes this play between the shaft and the tube. Later commando's had a different swingarm tube design with 2 bolts to fix this issue, but the '70 model year has poor handling without this modification.

The '70 doesn't have a disposable oil filter. I have yet to add that modification to my bike, but having a way to filter particles out of oil has to be a good thing if it doesn't restrict oiling. Their are kits to add a filter and the extra plumbing.

Rear brake return spring. If your rear brake cable snaps, the foot lever can drop and hit the pavement, launching you off the bike. There's a safety spring you can add to the lever that holds the lever up so this can't happen if the cable breaks...

Get a metal gas tank... Fiberglass tanks... suck.

Get a metal gas tank... Fiberglass tanks... suck.

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So do sealants.

'Go first, handle second, stop third. If it doesn't go, no need to make it stop better.'

I'm an OLD rider and I used to have that philosophy. I can still feel the pain. If you cannot stop, you cannot go fast. There is nothing worse than finding yourself doing the death-dive into a corner with white knuckles on the brakes, and then the brake locks and launches you. The next thing is the handling - steering geometry and to a lesser extent suspension. If your bike tightens it's line in corners, you can ride under many other riders and get on the gas earlier. I don't know how you do that with a standard type Commando. The 'go' thing is pretty much irrelevant, you will always be unlikely to out-power a modern superbike in a straight line blast. Always work within and exploit the design strengths of your machine.
I don't ride motorcycles on public roads - so what would I know ? However I love your philosophy - Oh, to be young again !
Get rid of your drum brakes and at least fit two discs on the front. Most of my race crashes have been caused by the front brake being inadequate/dangerous.

If you are ever building a classic racer, always choose a bike to start with for which you can easily get a six speed gear-box and a decent front brake. A good drum brake for the front of a Period 3 Australian historic racer costs at least $3000 - a Grimeca almost gets there - an Oldani or Fontana is better. And a 6 speed TTI box costs about $6000. Without those two things, you are usually beaten before you start. The replica featherbed frame costs about $3000. - Why would you bother ?

When I first started racing, one of the older riders said to me ' the bike has to do something for you and you need a lot of racing miles under your belt'. It took me a lot of years and a lot of crashes to learn how to stay upright. My Seeley is extremely direct steering and tightens it's line in corners. It means that where you put your head, that is where it goes. I never have to reverse steer it, in fact I think I would crash if I tried that. The front brake is one finger operation and I can lock the front wheel. It takes experience to get your bike to handle and stop like that, however once it is safe it inspires confidence. If I am on a circuit with other riders all trying hard, I always know if and when and where I can beat them. If they hose you off in a straight line, you have to make up under brakes and around and out of the corners. There is nothing more disheartening than when the opposition proves they have 10 horsepower more than you by hosing you off, however patience is a virtue.

freefly103 said:

Brakes are phase 2.

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Yeah you don't need to stop...especially with all those engine performance enhancements.

Brakes and suspension should be first IMO...but in reality you have to do it all to have a decent bike in the end. I like to be able to stop and can't stand the wooden feel of stock Norton brakes. Even with sleeved master...still not good enough IMO.

dennisgb said:

freefly103 said:

Brakes are phase 2.

Click to expand...

Yeah you don't need to stop...especially with all those engine performance enhancements.

Brakes and suspension should be first IMO...but in reality you have to do it all to have a decent bike in the end. I like to be able to stop and can't stand the wooden feel of stock Norton brakes. Even with sleeved master...still not good enough IMO.

Click to expand...

+1 on the brake. Even without building a hot rod, the issue is that everyone else has such good brakes these days... And a massive lack of concentration!

So, mums in ABS equipped SUVs full of screaming kids can stop in a nano second. When you're behind them, can you?

Braking performance of general traffic has increased tremendously since our old bangers were nailed together. Fast riding in busy traffic needs brake upgrades before anything else IMHO.

If you are on a budget, do combat engine upgrades just like Norton did but don't forget the superblends.

I also added a front drum brake stiffening kit which helps.

Brakes. Brakes. Brakes. Good carburation. Then the never ending list of need this and need that

I went through this same dilemma about six years ago. I had bought a nice complete but tired 73 850. I had the crank rebalanced, journals polished new rod bearings, Superblends, cam bearings (cam looked new), 10 over bore, and had the head rebuilt to stock specs. I reused the stock Amals . The motor ran awesome. Once the wallet refilled a bit I had the front master cylinder re-sleeved, rebuilt the front forks and replaced the rear shocks with some new OEM Girlings that I had in my parts stash for about 30 years.The bike runs sweet and is plenty fast for me. If and when I have a real need for speed my BMW S1000RR satisfies it very well. I've owned hot rod Nortons in the past including a Drouin supercharged unit with a Quaiffe 5 speed. That one was crazy fast but not something that a 25 year old should own. Blew up the gear box first so I put a used 4 speed back in. That allowed me another couple of months of riding until I busted the crank clean in two while racing a Z1. I had him until it all came apart. Now I build close to stock for reliability.

A sharp engine is nice to have, but expensive to obtain with reliability.
My bike has three discs, so once you make sure they are all working, "better" pads are cheap enough for a little experiment.

The best money spent was optimising the suspension for *me*. Now with crap knees and hips, poorly back with a touch of spondylitis, that it still paying dividends. Forks are supple enough not to jar, but very controlled. The rears always feel a tad soft (or should that be plush?), but never get out of control. Its like the councils spent some money on roads.
Without stressing the mechanicals more, you can ride faster because you can maintain speed, more bends become sweepers - you just swoosh along.

Older bikes tend to have the suspension set too hard, because back then, damping was mostly rubbish - if not now then very soon.
Decent modern damping is vastly better and more durable (and more comfortable if you have old bones and crap roads). Better damping will control the wheel so much better, allowing softer springs to absorb shock rather than pass it on to your wrists/arse.

Have fun

The posters who have commented brakes first are correct.
Slow bike or fast, sixty MPH is sixty MPH when a car driver doesn't see you and pulls out from a side road.
The only difference is, if the fast bike has proper brakes, the rider has a chance, whereas the rider of the slow bike with crap brakes has none.
I was reminded of this recently when riding my new-to-me 1963 BSA Super Rocket. It is not a fast bike but it still gets ridden at mostly the same speeds as the more powerful bikes. The brakes on it were very poor and I had one very close call as a result of this.
It now has a 2 ls unit from the later a65 s or 69 Bonneville. At least now there is a chance of avoiding immovable objects that suddenly appear in my line of travel.

Glen

worntorn said:

The posters who have commented brakes first are correct.
Slow bike or fast, sixty MPH is sixty MPH when a car driver doesn't see you and pulls out from a side road.
The only difference is, if the fast bike has proper brakes, the rider has a chance, whereas the rider of the slow bike with crap brakes has none.
I was reminded of this recently when riding my new-to-me 1963 BSA Super Rocket. It is not a fast bike but it still gets ridden at mostly the same speeds as the more powerful bikes. The brakes on it were very poor and I had one very close call as a result of this.
It now has a 2 ls unit from the later a65 s or 69 Bonneville. At least now there is a chance of avoiding immovable objects that suddenly appear in my line of travel.

Glen

Click to expand...

Some are old, some are smart, some are old and smart. Some never attain either.

Thanks for the comments re brakes and handling. My mother will agree with all that you've said before making the bike go faster.

I'm just trying to isolate where relative performance gains come from i.e cam + compression, then carbs, then head, then lighter crank, then ???

They're all pieces of a joined puzzle and not mutually exclusive, but while I have the bike apart to sort the cases with a breather, I'm inclined to change the cam for a hotter one and maybe also the crank. I think twin carbs are the way to go after that. Fullauto head can wait since the Jim Comstock refurb'd head will do to the job for now.

Good tires, better brakes, what else?.
Ciao
Piero

The good brakes are needed to make anything else effective. It all depends on how you intend to use the bike. If you are riding on public roads, you don't usually have the advantage of practising riding through each of the corners. So if you go in too hot, there is sometimes no way to recover safely. It only has to happen once to end your career, if you are unlucky. My advice is that if you really want to play - go road racing on properly controlled circuits. You will live longer. As far as tyres are concerned, most riders push them until they get the bad scare. Good tyres are essential for racing unless you grew up with the old compound racing tyres and rode often in the rain. I find my Bridgestone Battle Axe tyres are more that I ever need and I have even won in the wet with them. When I started racing, with tyres we had you only needed the slightest change of mind to had a crash. If it rains when I am racing, I always know I am in with a chance and so I ride quicker. The other thing is, if you fall off in the rain you usually slide, so it doesn't hurt as much.