Will it take the load?

[roadrocket]

Hello

On a more general note, I am wondering a bit how much thrashing the Rocket will take... I have pretty much rebuilt the bike all over now, bought as a running wreck in 2000. All bearings are new, journals reground, new pistons, rebore, new valves and guides etc. Gearbox has new bearings and bushes. Exhausts are new, as are the wheels, even the steering head bearings are new. When I ride, I usually go about 55-60, with occasional bursts to 65-70. But reaching 70, I feel that the bike is really buzzing. It does not sound bad in any way, but seem very busy and not well at ease. The bike should be good for just over 100 mph, but that must really be setting all systems into maximum buzz mode. I have no tachometer fitted, so don't know how many revs I am doing. My gearbox is standard, as are gearbox and rear sprockets. Now, should I stop worrying and roll up to 80 and smile, or stay within safer margins? I am going to the International in Norway, and will be doing some motorway stretches. I have done motorways many times, but at around 65-70. If I could be confident doing 70 all the way, it would whizz me up there quicker, and keep me more in pace with traffic. What speeds are you chaps doing?

Cheers, Otto in Denmark

[cus]

G'day Otto,
I've owned 2 Super Rockets, from my experience they both behaved a bit differently even though they were set up the same, accept one had a h/duty crank off a '56 rocket I think.
Like yourself I used to ride around 55-60, but my '63 really smoothed out around 70 & wanted to get cracking, my '61 with the h/d crank was a noisier engine, even though it was re-built
& sounded busier as you describe, always making me feel like I should back off a bit. My only criticism is that they both died on steep hills, I live in a fairly hilly area & found I had to
gear down a lot & retard on hills, probably got a bit to do with the fairly small standard rear sprocket. I now ride a '77 Triumph Tiger that eats the hills & is also good on the flats. Both my bikes
have now been sold to guys over west & up north, where it's mostly flat & more suited for them. I've decided to restore my '56 Flash, which will be good as a club bike.
I'm sure others will have different experiences, the longest motorway run I went on would of been for about 1 1/2 hours, doing about 110 k's, it was nice & flat & the '63 settled right in &
still had heaps to pass the odd car.

regards, Cus

[fido]

These engines are not fragile and there would not be so many still around if they were in the habit of throwing a rod every time you went fast. Remember that they all survived the rocker era and many were owned by teenagers. When I had my A7SS I rode with the Coventry Polytechnic bike club. They were on modern bikes and went everywhere at 80mph so I had to do the same to keep up.

[KiwiGF]

They do sound like they are revving surprisingly high, compared to what I'm used too anyway, mine starts to vibrate at about 60 odd, and I keep to 70mph cruising for that reason, as the buzz is still ok at that speed, engine wear will faster at higher rpm I reckon but I dont think it will blow up! My engine has pretty much std balance factor, for a sj crank.

In NZ the limit is 100km ph, 62mph, so the A10 can keep up even with fast moving traffic on main roads just fine, but the brakes are another thing altogether.........one needs to keep at the braking distance at all times......

Ive bought an engine sprocket with an extra tooth but not got around to fitting it yet, that should make a little more relaxed at 70.

[Brian]

I live in the country so nearly all my riding is at highway speeds. I dont have a SR just a iron headed Flash with a 357 cam and 8.5-1 pistons. I run std gearing.

My bike will cruise all day everyday at 65-70 mph. With the std gearing it will still cope well with hills or head winds.

So, your bike is well capable of sitting on 70 mph without stressing it. Just enjoy the ride.

[muskrat]

Yep, even my '51 A7 will do 70 all day, most decent hills see her drop to 50 where I throw her back to 3rd.
Cheers

[Billybream]

Hi Otto.
Had my super Rocket since 1966, never held back then, 100mph+ was possible with the right conditions, but now stay @ 50 to 60 mph which is 3000rpm. Sign of me and the bike getting old. My opinion is that you can replace all major parts, but what,s the ageing effect on castings etc, and they could be expensive and difficult to replace upon failure. So be careful and enjoy.

[Topdad]

Hi Otto, for my tupenny worth, when I rebuilt mine ,I went for 8.25 pistons and sports cam/followers with s/rocket inlet valves. First runs were fine ,good power and quite smooth but very buzzy .It was on std engine sprocket so reduced down by degrees and ended up with 19 ,which initally was a bit much ie anything not flat , down to 3rd ,however given a bit of mileage it's improved no end and now pulls like a train with the advantage of being easier on my ear/imagination plus seat of pants etc. Still don't like motorways though, purely my own conviction. However remembering, as someone previously mentioned ,the amount of abuse my first A's endured when I was 16 onwards and friends bikes as well with only one blow up between us ,which was completely my fault as well ,I have to agree that they are stronger than we give them credit for. Maybe a case of get yours to where it feels comfortable and take "comfort breaks " often! Best of luck, BobH.

[Greybeard]

I'm finding the same as RoadRocket; at 60mph I keep trying to find another gear! (I saw this five speed box on Ebay the other day - http://goo.gl/KnHym)

My bikes, (1955 Plunger GF) rear sprocket has 42 teeth; I think the gearbox sprocket has 18 teeth. I hope that is the standard solo setup.

I find it hard to imagine my bike struggling on hills; it seems to pull like a train! I'll let you know after I've visited my son in Wales.

[Stephen Foster]

"Brian" , what is the comfortable cruising speed of the "Star Twin" please ?

Steve ...

[Brian]

I havent ridden my Star Twin for about two years but as I recall it would sit comfortably on 60-65mph. I must get it out again oneday.

[jfligg]

Hi guys
     When I was riding my 49 Star Twin I found its sweet spot was 55 - 60.  I run my 61 SR at 60 but she wants to go faster.  Jeff

[Stephen Foster]

Thanks for that .
Plenty fast enough for Me !