Photo Contest - Commando Engines in Other Chassis - Race Bikes

Whats the total length from the head to the end of the Velocity stack? And what's that connected to the bottom of the carb bowls?

Same question to you Ken - referring to the Vendetta

jseng1 said:

Whats the total length from the head to the end of the Velocity stack? And what's that connected to the bottom of the carb bowls?

Same question to you Ken - referring to the Vendetta

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Sorry Jim, but I don't have that information. You can probably estimate it pretty accurately from some more detailed pictures. I don't want to post them on this thread, because they will end up in the contest automatically. But I'll email some of them to you.

Ken

jseng1 said:

Whats the total length from the head to the end of the Velocity stack? And what's that connected to the bottom of the carb bowls?

Same question to you Ken - referring to the Vendetta

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9 3/4 from head flange to end of stack. The large anodized tank is added float bowl capacity which ties the two float bowls to lower tank reservoir. They ran Alcohol with big needle and seat, they felt it was running out of fuel on the long straights so they made jet extensions that run into the reservoir.

lcrken said:

Sorry Jim, but I don't have that information. You can probably estimate it pretty accurately from some more detailed pictures. I don't want to post them on this thread, because they will end up in the contest automatically. But I'll email some of them to you.

Ken

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Damn, there I go getting in trouble again, sorry for posting the pic here.

Son of Siredward said:

Damn, there I go getting in trouble again, sorry for posting the pic here.

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Hey Paul, I was deliberately not picking on you. I almost did the same thing on another photo contest thread. And you weren't the only one. Easy mistake to make.

Ken

Ken, I am extremely grateful to you fir initiating this thread. I only ever access this forum because I desperately seek inspiration. I have not raced for about the past 6 years. In that time two of my close motor sport friends and a few rellies have died. For me, road racing is more about improving the bike than it is about winning races. My whole professional life has been about technical development. Because of this thread, I now feel a bit more motivated to do what needs to be done. I believe my Seeley 850 can be good enough to win convincingly in Period 4 Historic.

storm42 said:

I suppose I should make my statement about too much front brake clear.

I have bikes with stronger brakes than I fitted to the Seeley (320mm discs with radial Brembo 4 pots) but the Seeley brake was vicious, It was a one finger max brake, but even that was on the edge. I had those GP Fax pads in and they are just so powerful with zero feel on those discs. Just blipping the throttle with a finger on the brake would lock the wheel, I guess I could have got used to it but it was just about uncontrollable, the brakes on my Turbo by contrast, are still a one finger brake, but with so much feel and control.

Bottom line is that brake on the Seeley was badly setup and I guess I could have sorted it with different pads or master cylinder or whatever, but, going down to one disc on that bike saved a load of unsprung weight and i can still lift the back wheel off the floor.

It might make sense when I say the master cylinder for the single disk is the same one I used for the twin setup, it was just all wrong. So I still say you can have too much brake, if it is badly setup.

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My Seeley has the same setup for the front brake - single calliper lever operating two callipers. I had trouble getting the right pads for the Lockheed callipers so I went back to asbestos pads which are about 50 years old. I tried carbon race pads and had no brakes. I don't race often enough to wear out the disc pads - but if I did, I would be stuffed.

acotrel said:

Ken, I am extremely grateful to you fir initiating this thread. I only ever access this forum because I desperately seek inspiration. I have not raced for about the past 6 years. In that time two of my close motor sport friends and a few rellies have died. For me, road racing is more about improving the bike than it is about winning races. My whole professional life has been about technical development. Because of this thread, I now feel a bit more motivated to do what needs to be done. I believe my Seeley 850 can be good enough to win convincingly in Period 4 Historic.

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Thanks for the kind words, Alan. My predilection is much more towards improvements, innovation, and technical details than towards restoration, and I really enjoy seeing what others are doing in the way of interesting builds and applying modern technologies. Still, I enjoy the beauty of a good restoration as much as anyone. It's just not what I do. I'm still not sure how much this photo contest format was intended to value the photographic quality vs. the content, but I thought it would be interesting to give it a try and see how it works out. I think we're still experimenting with the idea, and learning how to write contest rules that work, but so far it seems to be a reasonably popular activity. As long as Jerry is happy with where it's going, I'll see if I can put up a couple more interesting subjects for contests.

Ken

Son of Siredward said:

9 3/4 from head flange to end of stack. The large anodized tank is added float bowl capacity which ties the two float bowls to lower tank reservoir. They ran Alcohol with big needle and seat, they felt it was running out of fuel on the long straights so they made jet extensions that run into the reservoir.

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I tried Alcohol for a short time because my race engine was overheating. Straight methanol has problems - its invisible and dangerous when burning. It corrodes aluminum etc. I found that these problems went away by mixing 25% race fuel with the methanol. You can't add more than 25% because then the gas falls out of suspension. But you can see it burn and it no longer corrodes everything. Something to consider if its still on Alky. The ideal race fuel as far as I'm concerned. Too bad its illegal on most tracks.

PS
The overall intake length from the head to the end of the velo stack looks like more than 8.5"

jseng1 said:

I tried Alcohol for a short time because my race engine was overheating. Straight methanol has problems - its invisible and dangerous when burning. It corrodes aluminum etc. I found that these problems went away by mixing 25% race fuel with the methanol. You can't add more than 25% because then the gas falls out of suspension. But you can see it burn and it no longer corrodes everything. Something to consider if its still on Alky. The ideal race fuel as far as I'm concerned. Too bad its illegal on most tracks.

PS
The overall intake length from the head to the end of the velo stack looks like more than 8.5"

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In the old days the race fuel was often a benzene / methanol blend. The blending was achieved by adding acetone. In our pre-72 bikes methanol is legal. My motor is 1973, so I can be pinged. I have a nice new Elf racing fuel drum in my shed, just in case. They never do fuel checks at historic meetings, or most open meetings and certainly not at seniors' meetings.
If you use methanol, it is essential to drain the carbs as soon as you get home from any race meeting, otherwise the white crap will form and block up the internal passage ways. I simply remove the jet covers and put them on a shelf. The only flammability problem with methanol is the flame is not visible when it burns. Otherwise it's flash point is lower than that of petrol.
I use methanol at 9 to 1 compression and it is still lovely - much easier on the motor when you don't get that heat build-up, and easier to get the jetting right.
If you use a blend which is not factory prepared, you can end up using large quantities of solvent so that the fuel does not change and affect your jetting. If I was going to do that I would blend 60% methanol with toluene and add acetone until there was only one layer. You don't need much methanol to get the supercharging effect, and toluene has a higher calorific value - so more energy to be released. Toluene has low toxicity.

grandpaul said:

Your memory is a lot better than mine! I met a hundred people in 2 days, and that was 12 years ago...

Is that you without the hat? What is YOUR name, anyway? (as if I will remember it)

(At least I got the Commando engine part right)

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I´m not on the picture as I was busy preparing the Lambky Vincent streamliner for my next run.

lcrken said:

Thanks for the kind words, Alan. My predilection is much more towards improvements, innovation, and technical details than towards restoration, and I really enjoy seeing what others are doing in the way of interesting builds and applying modern technologies. Still, I enjoy the beauty of a good restoration as much as anyone. It's just not what I do. I'm still not sure how much this photo contest format was intended to value the photographic quality vs. the content, but I thought it would be interesting to give it a try and see how it works out. I think we're still experimenting with the idea, and learning how to write contest rules that work, but so far it seems to be a reasonably popular activity. As long as Jerry is happy with where it's going, I'll see if I can put up a couple more interesting subjects for contests.

Ken

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I really like the thought of the Rob North Commando. That is a really good looking frame. I think the problem with many hybrids is the motor is often not far enough forward. As you accelerate, where the motor is affects how fast the front of the bike rises and changes the head angle - thus the way the bike self-steers, if it does.

WEAL Norton said:

I´m not on the picture as I was busy preparing the Lambky Vincent streamliner for my next run.

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I saw (and HEARD) that bike! What a beauty. I spent 20 minutes taking pictures of it...

I left just after the guy died on that lay-down bike. I only made one of 2 passes we ere allotted, as I was just there for fun before roadracing at Miller & Sandia on back-to-back weekends, and needed to "save" my bike/engine to finish the season.

Yep, that Vincent double engined liner kept us busy but I had a lot of special experiences in it during my runs.

I make no excuses!
I have done this purely
To keep race bikes at the top of the page. Lol
My Seeley MK4 as first built. Strengthened Maney cases. (Welded plate!) Steel flywheel, Maney cam, 34mm Smoothbores. Joy

Chris said:

I make no excuses!
I have done this purely
To keep race bikes at the top of the page. Lol
My Seeley MK4 as first built. Strengthened Maney cases. (Welded plate!) Steel flywheel, Maney cam, 34mm Smoothbores. JoyView attachment 17076

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I think that bike needs two discs on the front, if it goes as fast as it looks. Or are all your race circuits fast and flowing with no sudden stops ?

That disc was good enough for Peter Williams et al...

Fast Eddie said:

That disc was good enough for Peter Williams et al...

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OK, I apologize in advance as this is slightly off subject, but N- V were more than daft not to put that setup on the JPN replica ( and 5 spoke wagon wheels) they would have sold many, many more in my opinion.

Chris said:

I make no excuses!
I have done this purely
To keep race bikes at the top of the page. Lol
My Seeley MK4 as first built. Strengthened Maney cases. (Welded plate!) Steel flywheel, Maney cam, 34mm Smoothbores. JoyView attachment 17076

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No excuses required Chris, that is beautiful, and the zorst is a piece of art. I've never seen one that followed the contours of the engine so closely and accurately.

Fast Eddie said:

That disc was good enough for Peter Williams et al...

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What was good enough back then. might not have been really good enough. You can only go as fast as you can stop. A Seeley Commando still has significant weight. Try it yourself - how fast can you stop your bike when it is in full flight, especially when something gets within your braking distance when you are travelling in the same direction. If he stops suddenly and you crash - who wins ? At least the disc on the bike in the picture is not chromed. The brake on the Mk3 Commando is an insult.
I raced at about the time PW was racing, it was just after pudding basin helmets were banned - most bikes still had drum brakes, so even a mediocre disc was excellent.