Advice on common sense engine modifications

CNW will rebuild your engine for you for less than 6-grand. I don't think I could spend 5-grand on a rebuild unless I bought a Fullauto head and JS pistons and rods! (Seeing as how we have elimated spending money on anything other than the engine)

I would probably have money enough left over for some titanium valve bling.

Just sayin...But then I am a novice so I suppose I have overlooked a Maney crank or something.

So.........have we given up on the 5k Ducati?

Modern ignition, new Amal Mk 2 tooters, research (here, Access Norton) about balancing, blueprint engine, but with 3 angle valve seats, leave CR standard, set up very thoroughly and away you go.
To me its about careful work, rather than throwing truckloads of money at it.
cheers
wakeup

DITTO :

Cleanliness , deburring etc . Paying attention to anything that will REDUCE the Horsepower FIRST is more profitable than messing about with things .

A deadly accurate ignition system is a First Priority .
as is the OILING System . for prolonged hard use in hotter climates a cooler & /or increaed capacity .

Recessed valves arnt going to do anything for the output . So for the price of a set of oversize valves
( particularly if the originals are past it ) IF this sits them back in the chamber , still on the original
seats , a bit of mild relieveing at the throats isnt going to slow it down .
As opened area is the circumferance x the lift ( this is where recession knocks back he breathing ) .
The contureing there has to be scientific , though . Bigger valves will blanket std. throats .

Reduceing losses means setting up the valve gear accurately . Higher Quality springs ( and fittings )
wont slow it down .

Mufflers wont help a hot cam , use straight through ones . Overlap is what costs mpg , ' off ' the cam .
unless you strike it lucky . With improved breathing a stock cam can go like the wind , and have a
1000 rpm to 7000 rpm + powerband .

Stock magnetic tachos are considered to have about a 200 rpm lag & 200 rpm swing . So arnt as deadly
accurate as a electronic field ' impulse ' Tachometer such as the F-750 Krobers & impulse VDOs .

Its time someone figured out if theres a high strength stock rod bolt replacement , SPS or the like .

OK. So I waited long enough for someone to recommend the obvious. Drum roll please...............
Bolt on a Drouin Supercharger!
Best bang for the buck.

Dances with Shrapnel said:

OK. So I waited long enough for someone to recommend the obvious. Drum roll please...............
Bolt on a Drouin Supercharger!
Best bang for the buck.

Click to expand...

My new toy to play with,

Oh No Dance's, I've refrained dropping the boost bombshell but that's comnoz plan too with his next engine he's been showing us, but he's hung up on his past experience with turbochargers and positive displacement compressors, not driven blowers, which don't have the bottom end limitations of turbos nor the top end limitations of compressors' power character. Boosting don't belong in this thread as there is nothing common sense nor reasonable cost wise nor use wise about boosting a streetable Commando. There's likely 2 dozen Norton configured Drouins left in existence and maybe a handful of those actually working or in process like Brent's luck out ebay find of last latest greatest adjustable belt tension model that weighs about 15 lb in case anyone power to weight concerned. I don't think Brent understand how potent-dangerous 50-60+% more torque on tap means to drive train and frame and rear tire.

Ms Peel a fairly cheap hydrid 2S Combat with accidental intake funneling and streamlined flow turbulence and 2-1-megaphone extraction exhaust and below 350 lb weight with 165 lb rider was strong enough to upset angry SNEERING sports riders and traction reaction enough to shear off gear teeth and fan over sprocket teeth and spin rear at 60 straight up and straight ahead. IF Not for the unbelievable tire traction handling of her unique tri-links that begged for 3x's more power into through and out of severe decreasing radius turns I'd of just put her back to old configuration and not spent 10's of 1000's more to get torque/hp to mass in similar range as elite road racers and drive train to take it. Anyhow now a real mechanic & machinist Brent has one I'm pretty sure we can come up with a way to have a Max Mad lever to engage the blower on the fly to save the belt for just cruising until some whipper snapper on balloon tires thinks he'll show an old clunker what they missing out on. Brent Drouin discussion should be moved to its own thread where we could discuss other boost options for the more crazy to contemplate.

I disagree. Supercharging does belong here. Where else can you nealy double your torque and power for around $2000. You might get close with a conventional build but the high engine speeds eat at reliability. Nitrous is another option but with other drawbacks.

When you step back and consider this thread, although a lot of good ideas have been preseneted, it is nonsense ( no disrespect to the OP and those who have contributed) but the title of the thread lacks a basis or design criteria. By example: engine modifications........for what? Reliability, peak power, durability (hours before rebuild) etc....

I get it, this is a fun thread but generally when you modify something, it is for a purpose.

Cancelled flights, rebooked to get home late if I am lucky. Rant mode off.

Face it we are all addicted to motorcycle joy rides and what ever it takes to get off as much as ya can afford. Real provable Common sense would dictate we not ride or spend on wasteful dangerous things but life's a bitch then ya die so go for it. I know one thing just adding power can make things more scary than fun and more expensive fixing drive train or beefing up plus the spare tires on hand and a decision made ahead of time on what circumstances you may use your extra power in a police chase or not. I've had a couple of chases I didn't even know about on my P!! but was told after wards by on looker of police just pounding and pounding and pounding steering wheel after they had me on their bumper stopped in rush hour traffic, me w/o mirrors as was so much faster than anything around I never ever looked back just nailed it - [short of just smoking in place of course] and leap away like every one else in sludge of slow motion Sci Fi movie. I only know of one ready to go Commando Drouin for $3500, the othersn mostly on museum pieces with one or two needing work popping up yearly luck of the draw and your desire to jump on it in time. Was reflecting today on P!! insane power response and giggling at stunt ridders needing front brake to get rear spinning from a standing or rolling start, hehehe. Dances can explain the many benefits of low draw through blower boost, but my thoughts are drifting towards a 16x5 drag slick for better point and shoot ricochet style. Norton's antique power character is about best there is to me - like the fastest shooting pistola's ain't no fancy modern auto. All in the wrist action...

[video]http://www.youtube.com/watch?v=44Sy3-KKrqc[/video]

If you add the supercharger you should get a magneto just to balance out the ugliness.

Get a belt drive and a good breather and save the rest for gas.

WHOs calling WHAt Ugly !

Trying to look past all the hondyamakawazuki parts, that's a pretty nice bike. Looks better without the Drouin hangin off the front of the primary. Being an Atlas originally it has the magneto on the back of the timing case, no??

Indeed the Drouin is a eye sore tumor and lean fouler, one LH crash loss hazard, but HOT DAM Matt your article has greatly eased my mind by this Hi CR hi boost application - which is why everyone said 'Get Away, It Won't Work!' A *bit* concerning they only said it seemed to have potential and we ain't seen video or ad for it, implies maybe only got it going good before fueling and heat issues set it aside so not any common road sense out of it. Turbo's back pressure so can't leave exht valve open long or flushes exht back out the intake air filter. A short opening early closing exhaust valve ain't a good profile for air cooled head heating. Oh yeah yesterday skewing around THE Grit in my cage I made a decision to slice off the Drouin's ugly lower chin.

Common Sense as modified by this crew is a freaking oxymoron~! In a way though having excess power is safer for me as I tend to slow way up more for the blinds/crests because there ain't much delay to get back to speed once I can see the way, while with lessor power there ain't enough space ahead to hardly get back to speed so common sense dictates just don't slow down going into unknowns.

Boosted benefits most by opening the exhaust flow, so what if water sprayed at end of header into megaphone to lower pressure exhaust see's but still jet out for some vacuum fill in or even some thrust? Warning if ya notice a difference between logical motocycle reasoning and rationalization, ignore it or its the end...

Being the originator of this thread, I have to say I am very impressed that this didn't get derailed until we got into 30-some posts. The supercharger was the culprit! But I am mightily impressed :lol:

I sure appreciate all the comments and it has given me much food for thought. I am actually going to try and condense the replies and do a somewhat informal poll of my own to see what is recommended the most, etc.

In regards to spending the 5k on a Ducati... The only Ducati I am interested in is a 1971-74 GT750. I know a guy who has one, but he doesn't want to sell, and I can't afford to buy!

Dances with Shrapnel; sorry about not having more specific parameters, but I don't know what parameters to set other than price, reliability and the fact that I don't want to lose any of the low to mid range torque, based on my riding. But I do appreciate what you posted, it was very helpful, except I am going to have to pass on the supercharger idea! :wink:

Again, thanks for the replies so far, and feel free to keep 'em coming!

Chris

Larso1 said:

Lots of good responses here. Your self deprecating comment referring to "I'm just a dumb farmer" does not compute for me however, seeing as how my brother-in-law farmer who never went to college has two new airplanes (a Cirrus and a Maule) with fully equipped and heated hanger, well over $1M in John Deere equipment, and has used software for crop management well before I even owned a computer (as an engineer!). It's a noble profession feeding the world and if you inherit a farm, so much the better for you and your family. It's a lot of work and there are a lot of risks as you know, and I salute you for your effort!

Bill

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Well, I guess we do have a couple of green tractors and combines...

I totally agree with your statement. But, let's assume these items have already been addressed.

Typical American way of thinking :
"I like what I have , but I would be happier if I had more of everything " .
If $5k is your budget limit , I would suggest to spend it on suspension , chassis , drivetrain , brakes ..and leave your engine std .
Before searching for more power , try to use whatever you have as efficient as possible ..[/quote]

The only Ducati I am interested in is a 1971-74 GT750. I know a guy who has one, but he doesn't want to sell, and I can't afford to buy!

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l
Amend that's the pick of Italian vintage to me too both beautiful in Norton era style and a great cornering tool i've seen the proof of, if ya can take the rattles and the 'electrics. Most bang for the bux is lighter wheel and the lighter vintage style alloy rims have recently come back in production. I'd allow $400 for rim and $100 spokes and $300 tires, [$800], Rar sets which remove a handful of lb and make C'do more comfy for most, $400ish. JMS pistons/rods ~$2000, then have cast iron crank dyno balanced to 55-65% ~$300. Greth Faults fork kit that lightens with silent stops and easy configure multi rate spring stack and sag height, which I like lifted some for more corner lean fouling angle, which is one the most fun things for me. Rod link head steady $200 and make up a front-breast link $100, then shop for carbs or spiff up the Amals a bit. Then think about rear shocks and nice paint and polish finish and go out and tease the vintage and the moderns up around the ton or so or cruise all day and not end up jangled like the other things out there folks hardly look at twice if a Norton Commando around.

I hate to tell you this, but a Ducati 750 GT is potentialy slower than a Commando, and is not a good choice for roads with tight turns.

Basket case 750 GTs are pushing $8K now :cry:

$3000-$5000 will get you a low mileage Monster with all the good mods (airbox, pipes, carb/injection) done by the PO.

Yep ya preaching to me already in the Commando choir so mostly me being polite to a foreign funny looking cycle that still shares lots of genetics from the era wheels to frame contructions power bands and sounds and similar fairings and colors. First late GT750 I saw had pulled in a few minutes ahead of a new GXSR600 with RH all scrapped and soon after asked Duci pilot HoW can that thing go around corners so fast! That's almost a routine scenario at my little village square, a ground zero for testing flings into faith and fate on 2 or less tires. Like IOM extended a 150-200 miles in all directions so keep that in mind when I keep repeating my suggestions on sensible modifications that allowed a sneer whipping sideline hobby that within 2 seasons squadrons of hot shots near and far came looking for the Norton Nut in Kingston. There's at least 70 hp lurking in Combat spec 2S and std head/valves and with a good bit of weight loss most bikes will be wheelie limited to up over 60 and then neck and neck to 90 before they can out power/wt/drag ya, but then must slow up so much ahead of turns and wait so long to get on power its like shooting birds in a cage. I've had good hunks of common sense guidence and a logic and rule disciplined lifestyle behavior so all's I can say is if ya only live once make it the best fantasy ya can. You know my road orgasm tool of choice.

norton73 said:

I hate to tell you this, but a Ducati 750 GT is potentialy slower than a Commando, and is not a good choice for roads with tight turns.

Basket case 750 GTs are pushing $8K now :cry:

$3000-$5000 will get you a low mileage Monster with all the good mods (airbox, pipes, carb/injection) done by the PO.

Click to expand...

Ducatis are a different style of bike from a commando. They are usually more suited to situations where there a long sweeping bumpy high speed bends. Could be good on American freeways where you don't really need to exert yourself. The 900 I rode felt so stable that you could almost jump up and down on it while it was laid over in a bend. The optimum motor characteristics and gearing are also different for such a bike. A friend has modified the steering geometry on an old 860 Ducati, and it is OK around our local race circuit which has half tight twisty stuff on it. To my mind, I wouldn't go that way, it destroys the character of the bike. If I owned a Ducati it would be partly because I wanted the original sort of handling and power delivery. A Monster could be good on public roads, it doesn't seem to be a derivative of a racing bike. I think the Ducati exercise could end up being expensive. I suggest the commando is more of a 'scratchers' bike, you can actually fight a battle with it.

http://www.motorcycleclassics.com/class ... azbea.aspx