Rocket Racer Project - Plan 6 or is it 7?

phil yates · Jun 15, 2014

The machine selected for the project is a Candy Apple MkIII Roadster. I had forgotten how much I liked the look of a Roadster. In fact, every version of the Commando ever made was a handsome brute and the only one I wouldn't fancy in the shed is the Hi-Rider. But some loved it too.

The motor in this machine was re built in the USA only 2000 miles back, complete with a new camshaft. So I did my sixth or seventh reverse hobot snap roll. Last plan, I was going to send an entire motor to Jim Comstock, so he could fit a webcam #12 camshaft. Jim advised anything much beyond the # 12 would be a negative when running a single carburettor. And others had reported how strongly the MkIII pulled simply with the Fullauto head and Jim's input to it. So, saving all the trouble and expense, I'm back to sending just the Fullauto head to Jim who will install larger valves etc and hit it with the razor, probably about .040.

I will up the Mikuni to 36mm as per Jim's advice. With all the money saved in the exercise, I can afford another Fullauto, again to be worked by Jim and returned to Oz to be fitted to my Fastback. Seems now pretty easy and relatively cheap to make endless Rocket Racers.

All was starting to sound finalised and clear until hobot had to jump in with Drouin Super Charger tantalisers. My head is spinning again. But that one can wait. I'm thinking beyond here, Norton side car outfit with Drouin Super Charger will really turns heads. They'll have to turn them pretty fast to even see it go past, leaving a trail of unopened mail from here to MossVale.

BTW, those bean cans will be the first to go. I think those things in the back are corks. Feels like it when accelerating, or trying to would be a better description.

Comments, suggestions, criticisms and abuse all welcome.

Phil

Hobot · Jun 15, 2014

Philis might think=feel like hobot and your thoughts barn storming below electric lines and with Jenny, so better jump on opportunity Now than reflect later as so so many have on I wish I had or hadn't gotten it or lost it on some rare desirable object. My dreams from friends, women, aircraft, boats and cycles have too often got wiped out or lost so on my last legs of last dream machine to do me a life time. Blower on Commando side car rig is what I expect to end up with on life's last legs. May have to ask someone to kick it off but expect more to beat off the crowds wanting too but filtered to the ones in hot shorts as Peel may have worlds first only Commando compression release dream catchers installed by then.

pete.v · Jun 15, 2014

phil yates said:
All was starting to sound finalised and clear until hobot has to jump in with Drouin Super Charger tantalisers. My head is spinning again. But that one can wait. I'm thinking beyond here, Norton side car outfit with Drouin Super Charger will really turns heads. They'll have to turn them pretty fast to even see it go past, leaving a trail of unopened mail from here to MossVale.

Abuse welcome.

Phil

No room for E-start.

phil yates · Jun 15, 2014

pete.v said:
phil yates said:

All was starting to sound finalised and clear until hobot has to jump in with Drouin Super Charger tantalisers. My head is spinning again. But that one can wait. I'm thinking beyond here, Norton side car outfit with Drouin Super Charger will really turns heads. They'll have to turn them pretty fast to even see it go past, leaving a trail of unopened mail from here to MossVale.

Abuse welcome.

Phil

Click to expand...

No room for E-start.

No pete, no room. But the side car will act as a stabiliser. The real reason I went MkIII as opposed to a real Commando, is that I (and the bike) fall over every time I try the kick starter. Very embarrassing at the traffic lights. And there is in fact a very real story behind that which I will tell you one day.

Phil

phil yates · Jun 16, 2014

That nice chappy from LA told me you keep your topic alive by adding posts, even about nothing. Les' machinery can't tell the difference, apparently.

Single Mikuni has gone to twin Amal Premiums to now possibly twin FCR's, compliments of eddie's advice. I'll ask Matt at CNW about those.
pete.v has convinced me to chuck the E-start. He'll even dive the Wingercarribee river to retrieve my old Amals for me.

Les, I want this permanently up the top like your bucket photo topic always is. I know why that's always up there, no poor bastard can understand it, me included. It was easier to just become a VIP member. A DUMB VIP member at that!!

Phil

phil yates · Jun 16, 2014

And look at that!!
One post and I'm right up under Bucket Photos.

That's serious promotion!!

Phil

dennisgb · Jun 16, 2014

Nice Bike Phil...I just asked about it. Was wondering if you got it home.

Now the fun starts

pete.v · Jun 16, 2014

phil yates said:
And look at that!!
One post and I'm right up under Bucket Photos.

That's serious promotion!!

Phil

Let me help phil, and give you a bump up to the top where you surely belong.

You have really out done yourself this time. I have never been so frozen to the thread before.

As always phil, keep up the phenominally wonderful and interesting posts.
Well done to say the least. Awesome!

your top admirer,
Pete (mr. happy)

Opps, I just soiled myself. I owe it to you, phil.

phil yates · Jun 16, 2014

pete.v said:
phil yates said:

And look at that!!
One post and I'm right up under Bucket Photos.

That's serious promotion!!

Phil

Click to expand...

Let me help phil, and give you a bump up to the top where you surely belong.

You have really out done yourself this time. I have never been so frozen to the thread before.

As always phil, keep up the phenominally wonderful and interesting posts.
Well done to say the least. Awesome!

your top admirer,
Pete (mr. happy)

Opps, I just soiled myself. I owe it to you, phil.

Thanks pete.
I'm just waiting on some info back from CNW about FCR carburettors. Are these the ones you use? I remember you mentioning carbi's in a topic a while back. If so, I'd be interested in your opinion. Or your opinion on what you are using if not FCR's. The more information the better in determining the best way to go.

Phil

phil yates · Jun 16, 2014

dennisgb said:
Nice Bike Phil...I just asked about it. Was wondering if you got it home.

Now the fun starts

Owner due to deliver it this weekend den.
Yes, the fun starts here. And the bank account goes down, RAPIDLY, if you're not careful.

Phil

pete.v · Jun 17, 2014

phil yates said:
Thanks pete.
I'm just waiting on some info back from CNW about FCR carburettors. Are these the ones you use? I remember you mentioning carbi's in a topic a while back. If so, I'd be interested in your opinion. Or your opinion on what you are using if not FCR's. The more information the better in determining the best way to go.

Phil

Here is another bump to the top for ya.

Read through this.
40mm-flatside-pumper-t13023.html?hilit=tm40#p153742

I guess it would be possible to put as big single FCR (say 41mm), if you want to go single that is.

phil yates · Jun 17, 2014

pete.v said:
phil yates said:

Thanks pete.
I'm just waiting on some info back from CNW about FCR carburettors. Are these the ones you use? I remember you mentioning carbi's in a topic a while back. If so, I'd be interested in your opinion. Or your opinion on what you are using if not FCR's. The more information the better in determining the best way to go.

Phil

Click to expand...

Here is another bump to the top for ya.

Read through this.
40mm-flatside-pumper-t13023.html?hilit=tm40#p153742

I guess it would be possible to put as big single FCR (say 41mm), if you want to go single that is.

Thanks pete.
A lot of advantages just running a single carb, but as you know the twin FDC's are link connected so balancing (which annoys me) is pretty much eliminated. I love the idea of a pump squirting fuel in for quick response, so obviously do you. Just been speaking to Matt at CNW and Jim certainly likes them, so have decided to order a twin set of FDC's. I won't change my single VM Mikuni on the Fastback, that does a very good job for general riding purposes. I know it's all a lot of money, but as you said in your post, we're all insane anyway and it beats the alternative, cutting out paper dolls in the nut house.

Phil
ps I'll keep you posted.

pete.v · Jun 17, 2014

phil yates said:
Thanks pete.
A lot of advantages just running a single carb, but as you know the twin FDC's are link connected so balancing (which annoys me) is pretty much eliminated.
Phil
ps I'll keep you posted.

I'm not so sure about that. Maybe reduced, but I doubt eliminated. As long as both cylinder are "perfectly" equal, maybe, but there are too many variable and thing change over time to think that this perfect senerio to last with such delicate jetting.

A batch of bad gas, a weak gasket, a loose head, a little carbon build up, a valve a little out of adjustment, a slight kink in the fuel feed line, on and on and on.

Sure this will happen with a single carb also, but there will be a lot less head scratching. And for a guy like you, a little head scratchcing may cause some brain matter to leak out and you need all you got left.

phil yates · Jun 17, 2014

pete.v said:
phil yates said:

Thanks pete.
A lot of advantages just running a single carb, but as you know the twin FDC's are link connected so balancing (which annoys me) is pretty much eliminated.
Phil
ps I'll keep you posted.

Click to expand...

I'm not so sure about that. Maybe reduced, but I doubt eliminated. As long as both cylinder are "perfectly" equal, maybe, but there are too many variable and thing change over time to think that this perfect senerio to last with such delicate jetting.

A batch of bad gas, a weak gasket, a loose head, a little carbon build up, a valve a little out of adjustment, a slight kink in the fuel feed line, on and on and on.

Sure this will happen with a single carb also, but there will be a lot less head scratching. And for a guy like you, a little head scratchcing may cause some brain matter to leak out and you need all you got left.

Yes I agree, nothing is set and forget. But what used to drive me nuts was cable stretching which was always causing my original twin Amals to get out of balance far too regularly. I think the best balancing method we used to use was dropping the float bowls off and watching the needles lift, then adjusting the cables to get the needle movement simultaneous. That worked fine, then some days later (as I remember) you were at it again. When the Honda 4 came out, I shuddered at the thought of balancing four carburettors before I looked and saw they were linked. I thought, those bloody clever bastards!!

Brain matter leaking out? I thought that was just oil stains on the garage floor. Time for a bit more head silicone I think. Thanks for the tip pete.

Phil

baz · Jun 17, 2014

phil yates said:
pete.v said:

phil yates said:

you can keep the amals in balance a little longer if you cable tie the splitter box too the frame so only the section of cable to the twist grip moves from side to side but like you say amals always need balancing ,the gantry idea that the honda 4 and triumph trident etc had was a much better idea but as you know you really need a set of vacuum gauges to get them right
Thanks pete.
A lot of advantages just running a single carb, but as you know the twin FDC's are link connected so balancing (which annoys me) is pretty much eliminated.
Phil
ps I'll keep you posted.

Click to expand...

I'm not so sure about that. Maybe reduced, but I doubt eliminated. As long as both cylinder are "perfectly" equal, maybe, but there are too many variable and thing change over time to think that this perfect senerio to last with such delicate jetting.

A batch of bad gas, a weak gasket, a loose head, a little carbon build up, a valve a little out of adjustment, a slight kink in the fuel feed line, on and on and on.

Sure this will happen with a single carb also, but there will be a lot less head scratching. And for a guy like you, a little head scratchcing may cause some brain matter to leak out and you need all you got left.

Click to expand...

Yes I agree, nothing is set and forget. But what used to drive me nuts was cable stretching which was always causing my original twin Amals to get out of balance far too regularly. I think the best balancing method we used to use was dropping the float bowls off and watching the needles lift, then adjusting the cables to get the needle movement simultaneous. That worked fine, then some days later (as I remember) you were at it again. When the Honda 4 came out, I shuddered at the thought of balancing four carburettors before I looked and saw they were linked. I thought, those bloody clever bastards!!

Brain matter leaking out? I thought that was just oil stains on the garage floor. Time for a bit more head silicone I think. Thanks for the tip pete.

Phil

phil yates · Jun 17, 2014

phil yates said:
you can keep the amals in balance a little longer if you cable tie the splitter box too the frame so only the section of cable to the twist grip moves from side to side but like you say amals always need balancing ,the gantry idea that the honda 4 and triumph trident etc had was a much better idea but as you know you really need a set of vacuum gauges to get them right
Thanks pete.
A lot of advantages just running a single carb, but as you know the twin FDC's are link connected so balancing (which annoys me) is pretty much eliminated.
Phil
ps I'll keep you posted.

I'm not so sure about that. Maybe reduced, but I doubt eliminated. As long as both cylinder are "perfectly" equal, maybe, but there are too many variable and thing change over time to think that this perfect senerio to last with such delicate jetting.

A batch of bad gas, a weak gasket, a loose head, a little carbon build up, a valve a little out of adjustment, a slight kink in the fuel feed line, on and on and on.

Sure this will happen with a single carb also, but there will be a lot less head scratching. And for a guy like you, a little head scratchcing may cause some brain matter to leak out and you need all you got left.[/quote]

Yes I agree, nothing is set and forget. But what used to drive me nuts was cable stretching which was always causing my original twin Amals to get out of balance far too regularly. I think the best balancing method we used to use was dropping the float bowls off and watching the needles lift, then adjusting the cables to get the needle movement simultaneous. That worked fine, then some days later (as I remember) you were at it again. When the Honda 4 came out, I shuddered at the thought of balancing four carburettors before I looked and saw they were linked. I thought, those bloody clever bastards!!

Brain matter leaking out? I thought that was just oil stains on the garage floor. Time for a bit more head silicone I think. Thanks for the tip pete.

Phil[/quote][/quote]

Yes baz
I guess I'll be buying vacuum gauges as well. In for a penny, in for a pound. I had forgotten about the Trident set up. Rarely saw one and never looked closely anyway. I tried splitter box and twin cable. I think I settled on the splitter box as preference. Some guys didn't seem to care much about the idle but I wanted it spot on all the time. Mum's crappy old Hillman idled okay, why wouldn't my Commando!! I came close to fitting a Zennith carburettor, but thought better of it. The Hillman didn't go anything like my combat!!

Phil

baz · Jun 17, 2014

no you have missed my point i cable tie the splitter box to the frame to hold it rigged !,if you have the engine running and the the throttle open no slack in the cable ie pulling away etc and the cable splitter box is able to move about when you turn the bars it will pull one carb more open than the other ,i have proven this to a mate by connecting a vacuum gauge and turning the bars from side to side and seeing the vacuum go up and down,i found just moving the splitter by hand had an effect on the carb balance so ever since then on a twin carb bike i cable tie the splitter so it can not move ,this is just my opinion,,,,,,,,baz

Fast Eddie · Jun 17, 2014

baz said:
no you have missed my point i cable tie the splitter box to the frame to hold it rigged !,if you have the engine running and the the throttle open no slack in the cable ie pulling away etc and the cable splitter box is able to move about when you turn the bars it will pull one carb more open than the other ,i have proven this to a mate by connecting a vacuum gauge and turning the bars from side to side and seeing the vacuum go up and down,i found just moving the splitter by hand had an effect on the carb balance so ever since then on a twin carb bike i cable tie the splitter so it can not move ,this is just my opinion,,,,,,,,baz

I agree Baz. That's why twin pull throttles are not good, just moving the bars effects the balance!

Keep the cables from carb to junction box as short as possible and cable tie the junction box and things stay good!

phil yates · Jun 17, 2014

baz said:
no you have missed my point i cable tie the splitter box to the frame to hold it rigged !,if you have the engine running and the the throttle open no slack in the cable ie pulling away etc and the cable splitter box is able to move about when you turn the bars it will pull one carb more open than the other ,i have proven this to a mate by connecting a vacuum gauge and turning the bars from side to side and seeing the vacuum go up and down,i found just moving the splitter by hand had an effect on the carb balance so ever since then on a twin carb bike i cable tie the splitter so it can not move ,this is just my opinion,,,,,,,,baz

I think you might have missed my point baz, I was talking about cable stretching, not individual movement. Just the same as a single carb/ cable arrangement requires the slack taken up from time to time using the adjuster. This is what we assumed was causing such frequent out of balance of the carbi's, one cable stretching a little bit more than the other, nothing to do with splitter box movement. I didn't like the extra size of the dual cable twist grip so preferred the splitter box. Neither made any difference to the carb balancing requirement. Either system is prehistoric in my view, depending on two individual cables to maintain precise simultaneous movement. A cross connected link arrangement between the carbi's makes so much more sense, with a rotating wheel actuated by one cable only.

Apart from erratic idling, the out of balance slides used to cause surging at low throttle opening, such as in traffic at low speed. When I think of all the little and not so little issues that used to plague us, it's no wonder the Japanese machinery seemed to do everything better, except be light and handle well. You almost had to be a masochist to stay faithfully with English machinery. But nowadays we've been able to improve so much on our Commando's, it leaves us a lot freer to enjoy the good things about them. Well that's how I see it. And it's interesting how people who know nothing about motorcycles will look at it and say, what a beautiful bike. Not all but most. So aesthetically it is very impressive as well, not just to us. Even my mate Sandy, owner of Staintune walked around it looking decidedly clinical and commenting about Commando oil leaks, fractured exhaust pipes and no end of vibration related problems finally said, if the cops pull you over it will be only to look at your beautiful bike. Prior to that comment, I was thinking he's probably just seen one too many Brit bikes. He's a bit of a Beemer man these days, but barely rides anyway, like so many long in the tooth bikers, which most of us are.

Getting way off beam, it also amuses me how there are so many non riding experts out there. Especially at the pub after a few beers. One guy was tearing strips off me for riding in shorts, told me all the terrible injuries he'd had, torn ligaments, broken bones etc. So I asked, how would wearing long pants save me from doing that? He just looked at me blankly, couldn't answer so had another beer instead. I'm not suggesting good riding gear is not necessary, but it won't save you breaking a leg etc.

Getting back to the Rocket Racer, twin FCD's are going on it and I'm expecting a very good result. They certainly aren't the cheapest carburettors.

Phil

Fast Eddie · Jun 17, 2014

phil yates said:
baz said:

no you have missed my point i cable tie the splitter box to the frame to hold it rigged !,if you have the engine running and the the throttle open no slack in the cable ie pulling away etc and the cable splitter box is able to move about when you turn the bars it will pull one carb more open than the other ,i have proven this to a mate by connecting a vacuum gauge and turning the bars from side to side and seeing the vacuum go up and down,i found just moving the splitter by hand had an effect on the carb balance so ever since then on a twin carb bike i cable tie the splitter so it can not move ,this is just my opinion,,,,,,,,baz

Click to expand...

I think you might have missed my point baz, I was talking about cable stretching, not individual movement. Just the same as a single carb/ cable arrangement requires the slack taken up from time to time using the adjuster. This is what we assumed was causing such frequent out of balance of the carbi's, one cable stretching a little bit more than the other, nothing to do with splitter box movement. I didn't like the extra size of the dual cable twist grip so preferred the splitter box. Neither made any difference to the carb balancing requirement. Either system is prehistoric in my view, depending on two individual cables to maintain precise simultaneous movement. A cross connected link arrangement between the carbi's makes so much more sense, with a rotating wheel actuated by one cable only.

Apart from erratic idling, the out of balance slides used to cause surging at low throttle opening, such as in traffic at low speed. When I think of all the little and not so little issues that used to plague us, it's no wonder the Japanese machinery seemed to do everything better, except be light and handle well. You almost had to be a masochist to stay faithfully with English machinery. But nowadays we've been able to improve so much on our Commando's, it leaves us a lot freer to enjoy the good things about them. Well that's how I see it. And it's interesting how people who know nothing about motorcycles will look at it and say, what a beautiful bike. Not all but most. So aesthetically it is very impressive as well, not just to us. Even my mate Sandy, owner of Staintune walked around it looking decidedly clinical and commenting about Commando oil leaks, fractured exhaust pipes and no end of vibration related problems finally said, if the cops pull you over it will be only to look at your beautiful bike. Prior to that comment, I was thinking he's probably just seen one too many Brit bikes. He's a bit of a Beemer man these days, but barely rides anyway, like so many long in the tooth bikers, which most of us are.

Getting way off beam, it also amuses me how there are so many non riding experts out there. Especially at the pub after a few beers. One guy was tearing strips off me for riding in shorts, told me all the terrible injuries he'd had, torn ligaments, broken bones etc. So I asked, how would wearing long pants save me from doing that? He just looked at me blankly, couldn't answer so had another beer instead. I'm not suggesting good riding gear is not necessary, but it won't save you breaking a leg etc.

Getting back to the Rocket Racer, twin FCD's are going on it and I'm expecting a very good result. They certainly aren't the cheapest carburettors.

Phil

Indeed, no one could accuse the FCRs as being cheap Phil! But they are SO nice, almost a shame to fit them to the bike, especially with Matts intake manifold too!

At present though, all I can confirm is their very fine build quality (based on looks) and how light and quick the throttle action is. I'll report more as soon as my bike is running. Just don't hold your breath while you're waiting !!

Rocket Racer Project - Plan 6 or is it 7?

phil yates

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