Favorite Motorcycle Engines . . . and why?

[Aaron D.]

An engine that's slipped from memory because not many have experience of it is MV's 750cc across-the-frame four  (..and I don't mean Cagiva's modern-day offering!). 

Designed half a century ago, and still unmatched for sheer machismo, this engine makes most modern powerplants look, sound and feel powder-puff.  With gear-driven cams, proper open-bellmouth DellOrto carbs and open race pipes, it sounds like rolling thunder from idling to peak revs (..it's way more spine-chilling than even Ducatis with Termignonis).  It has roller-bearings everywhere, it's got horizontally-split sandcast casings enabling easy removal of the crank, and an automotive-style distributor for easy timing checks. 

Completely free of vibration on the road; it needs no rubber-mounts whatever, anywhere ~ even the footpegs are plain turned steel and bolted directly to the frame.  It makes power from idle to max revs (..it's quicker than a Mk1 Le Mans) and it has the kind of 'real world / on-the-road' flexibility you would hardly believe from a motor that brought MV Agusta 37 World Championship titles (..the race engine had magnesium casings, but was of the same design).

No engine is more handsome, IMHO: it looks like it's been carved from rock ~ and it can be stripped down at the roadside with barely any more than two spanners and a screwdriver!  It has to be a contender for 'best ever'.

This audio hardly does it justice.  Turn up your speakers: https://www.youtube.com/watch?v=fImkF4zafXQ     


   

I like them a lot, but even when they were "new" they were old. The 350 version couldn't touch the Guzzi 350 single. At heart it is a '30s design.

[Fontain25]

One of my favorite motorcycle engines was a Triumph 750 Bonneville that I rebuilt. Found the bike in a garage with very low mileage and a locked up engine. Upon disassembly found that roller main bearing had failed and loose balls were locking motor . My boss showed me the difference between the O.E. Triumph bearing as compared to same size Japanese bearing - with 10X magnifying glass the surface of the balls on Triumph bearing looked like the surface of Mars - while the Japanese bearings balls were very smooth and it didn't have any sideways play. Using the Japanese bearings was a no brainer. Also bored cylinders .010" over and fitted them at half of what factory piston to cylinder clearance was recommended after relieving exhaust side of piston just below bottom ring by .002". Then sent crank assembly to be balanced to a factor of 70 [still don't really understand terminology]. When finished the Triumph was just as smooth as my BMW R100S engine and was exceptionally fast ! Later I bought a new house and decided the Triumph had to go so I sold it. 15 years later I ran into the guy I sold it to and he said he had NEVER had to do any repairs to it and with his wife on back it would beat any Harley he ever raced ! I liked that bike but  just have a soft spot for Guzzis.

[drbone641]

One for it's torque and simplicity, the other for it's raw visceral appeal. IMHO, nothing sounds like a CBX with the optional 6 into 2 exhaust. Except a few Formula 1 / Indy engines.

[tetarabra]

Really like the "push in your back" mode of my 900 SS bevel drive even at slow speed. Engine and cycle part are so rewarding.  Love it .
And sitting at terrasse of a bar after a ride and admiring the beauty of the engine while  hearing the "kling,kling " of the engine cooling down ... 

[MotoChuck250]

From the single Guzzis, Ducatis & Aermacchis to the twins of Ducati and Guzzi to the multis of MV Agusta, it is amazing to think of all the beautiful engines that Italy has given us. The Brits, Germans, Japanese and Americans all have produced great engines but the Italians have been special to me.

Chuck

[nighthawk]

VMAX!

[Toecutter]

The SOHC CB750.

Why? Presence. Sound. Feel. I love the look of it, that big chunk of aluminum dominating the frame. The sound of it when you hit 4000 rpm. And just the feel of the bike when you're cruising down the road. They're simple to work on, easy to tweak. And they "fit" in almost anything. Stock, chopper, "café"... I just find them really pretty. Which is whay I own so many of 'em I guess.

[wymple]

I had a SOHC 750. There is still one sitting in my garage belonging to someone else. I don't see the charm.

[geodoc]

[jas67]

The round case bevel twin is definitely one of the best looking engines ever made!

[nortryder]

I don't remember too many that I didn't like but one of my absolute favorites to ride hard was an early Laverda triple that Eraldo Ferracci or someone had waved their wand over. It had cams etc, And torque. Boy was it fun to hammer on. I owned a round case Ducati 750. It was nice to look at but always sounded like it wanted to explode. Kawasaki turbos and Yamaha RD500lc were fun too.

[geodoc]

Austere, yet voluptuous.

The round case bevel twin is definitely one of the best looking engines ever made!

[pressureangle]

Vincent 1000cc twins. Because Vincent.

Panther singles, as above. Because you haven't ever seen one.

Ducati bevel twins. 'Nuff said.

Norton Commando. Any questions?

Big Block Moto Guzzi. Because it's in there.

[Arizona Wayne]

My favorite MC engine I've owned so far is the 805cc V-twin on my Suzuki `91 VX800.  It has very linear power....no vibration issues.....bike handles good with superbike handlebar(not original HB).....sound isn't bad......low maintenance....127 mph top speed.....most trouble free bike I've ever owned(sorry Moto Guzzi). 

[oldbike54]

My favorite MC engine I've owned so far is the 805cc V-twin on my Suzuki `91 VX800.  It has very linear power....no vibration issues.....bike handles good with superbike handlebar(not original HB).....sound isn't bad......low maintenance....127 mph top speed.....most trouble free bike I've ever owned(sorry Moto Guzzi). 

 The specs say top speed just short of 117 , which seems more likely for a 520 lb motorbike with a claimed 62 HP .

 Dusty

[ramarren]

My favorite motorcycle engines:

Ducati 750GT ... The 1975 version with screw and locknut tappets. Beautiful engine, easy to maintain, superb power delivery, incredibly smooth, and wonderful broad, useful power band. Uprated it to Sport specs with 9.2:1 pistons (originally 8.4:1) and 32mm carbs ... perfect.

Moto Guzzi 850T ... The archetype of the big block Guzzis. Solid, reliable, easy to maintain, easy to rebuild when needed, wonderful power delivery, everything. It took until the T3 model for a full-flow paper oil filter and of course there were detail improvements in subsequent LeMans and T series model engines for years, but this engine is timeless. The square-fin version in my LeMans V was outstanding, albeit those huge, heavy valves could wear the relatively short valve guides a bit quickly compared to the more pedestrian models.

Honda Intercepter v700-750 ca 1987 ... My favorite version of the Honda V4. A little densely packed in the frame and thereby a bit more work to service and maintain, and a little heavy, but outstanding power band, wonderful sounds, and again that wonderful, broad, easy to ride power band.

Ducati 907IE ... Having had three of the early '90s Ducatis (907IE, 900SS, E900), this engine was my favorite. The water cooling added some complexity but it remained relatively easy to service with decent access to valves, easy access to clutch and clutch lifter pieces, and proved very reliable. The EFI gave it more power and a broader power band than the 900SS or E900; coupled with the all inclusive fairing and the very robust frame and suspension, it was a warp speed bullet of a sports tourer.

Moto Guzzi V7III ... I was never partial to the Guzzi small block engines' heron head design, it simply placed too low a limit on the power that could be achieved, but otherwise their light weight and compact size was always appealing to me. The re-work that the V7III and V9 motors received, both the improved bottom end and the new hemi heads, now puts this engine on rank with the big blocks that I loved. Like the big blocks, it's easy to maintain, produces a wonderfully broad and flexible power band, and should be nicely durable (too early to tell; I'll let y'all know when I hit 100,000 miles... :)). The hemi heads respond to minor tuning efforts (better mufflers, engine map update) with a bit more return than the heron head models could, and have more potential for improved power if I want to dig deeper into the engine.

I owned a couple of inline fours, mostly Hondas (400-4, later twin-cam 750-4) ... they were nice but heavy. I also owned a BMW R75/5 (a nice bike but compared to the Guzzi and Ducati twins a bit of a clunky engine), a Norton Atlas and Triumph Bonneville, 1960s vintages (liked the Norton, fought bitterly with the Triumph), and a few classic Ducati singles (those engines were like jewelry and timepieces--beautiful if not particularly robust or durable--but a pleasure to ride).

[Tusayan]

Hello G 

The 907ie engine was carried over at 944 cc to the ST2, and I agree it's a sweet engine.  I'm about to move from mine to a low mileage ST4 and the change is making me nervous.

[Arizona Wayne]

The specs say top speed just short of 117 , which seems more likely for a 520 lb motorbike with a claimed 62 HP .

 Dusty

Mag. road tests verified 127 mph and that's what I got w/a 130/90 rear tire instead a 150/70 that it came with.  I never knew it's rated hp because back then they wouldn't tell you.

Where did you get 62hp?   BTW, I had my '87 LM IV dyno tested @ 61hp and it got up to 139 mph even tho a book claimed it would do 145 mph.  I raced a brand new Camaro with it once that had 140mph top speed (Road & Track) and it barely beat me, so I drafted it.

[Testarossa]

Twins, especially Italian twins. Fours feel like electric appliances, Agusta notwithstanding. Singles buzzy at speed.

I liked the VX800 engine -- very usable flat torque curve, and the CV carbs are sort of miraculous going over high mountain passes. Didn't like the top-heavy feel of the frame.

Liked the Laverda twin but mine kept breaking the woodruff key in the camshaft.

Like my Triumph but haven't yet solved the wet-sumping issue.

A Ducati 750SS opened my eyes about Italian V-twins -- what a locomotive! That led directly to acquisition of the 850T, still my favorite engine. Smoother than the Mille, and the bike handles better. If it had an oil filter it would be perfect.

[Steph]

An engine that's slipped from memory because not many have experience of it is MV's 750cc across-the-frame four  (..and I don't mean Cagiva's modern-day offering!). 

Designed half a century ago, and still unmatched for sheer machismo, this engine makes most modern powerplants look, sound and feel powder-puff.  With gear-driven cams, proper open-bellmouth DellOrto carbs and open race pipes, it sounds like rolling thunder from idling to peak revs (..it's way more spine-chilling than even Ducatis with Termignonis).  It has roller-bearings everywhere, it's got horizontally-split sandcast casings enabling easy removal of the crank, and an automotive-style distributor for easy timing checks. 

Completely free of vibration on the road; it needs no rubber-mounts whatever, anywhere ~ even the footpegs are plain turned steel and bolted directly to the frame.  It makes power from idle to max revs (..it's quicker than a Mk1 Le Mans) and it has the kind of 'real world / on-the-road' flexibility you would hardly believe from a motor that brought MV Agusta 37 World Championship titles (..the race engine had magnesium casings, but was of the same design).

No engine is more handsome, IMHO: it looks like it's been carved from rock ~ and it can be stripped down at the roadside with barely any more than two spanners and a screwdriver!  It has to be a contender for 'best ever'.

This audio hardly does it justice.  Turn up your speakers: https://www.youtube.com/watch?v=fImkF4zafXQ     


   

However attractive the Agusta 750/850 were, I can’t help remembering the write- up from a French Canadian journo of that era, went something like this: ‘ even though I get along well with the importer and he has lend me his 750 America, it’s a fine motorcycle but can’t help thinking the weight of the machine spoils everything’

Personally, in terms of power to weight ratio with that special character, I’d go for the very underrated KH400. More or less the same fun as a modern V750III.

But you can’t beat a big block Guzzi for a long term relationship

[Arizona Wayne]

The specs say top speed just short of 117 , which seems more likely for a 520 lb motorbike with a claimed 62 HP .

 Dusty

OK, it's been years since I looked @ my VX800 mag. articles and this is what I found....62hp @ crankshaft,  52.8 bhp.  Weight-520.5# w/5 gal. fuel, 470# dry weight.

[weevee]

However attractive the Agusta 750/850 were, I can�t help remembering the write- up from a French Canadian journo of that era, went something like this: � even though I get along well with the importer and he has lend me his 750 America, it�s a fine motorcycle but can�t help thinking the weight of the machine spoils everything�

Yes, weight is the Achilles Heel of these MVs, and back in the day it mattered.  Rumour has it that the Count didn't want privateers on MVs competing with the works bikes so added weight/shaft drive etc to discourage it.  Today, it doesn't have to compete: its a classic for a Sunday run.

My post wasn't about the bike though; it was about the engine.  The engine's a real cracker, and way better (in all respects) than you'd imagine - or any contemporary figures suggest.

Of more modern-day engines, I'd have to agree with someone else's suggestion: Honda's V-4.  The 750cc (RC) engine will pull top gear from idle to 12,000rpm, and respond in an instant at any point in the rev-range.  Nothing I've ridden matches it for real-world usability.  Filled with drive-gears, roller-bearings, titanium rods & magnesium fittings, etc, it's a real jewel.             

Steve

[Steph]

Yes, weight is the Achilles Heel of these MVs, and back in the day it mattered.  Rumour has it that the Count didn't want privateers on MVs competing with the works bikes so added weight/shaft drive etc to discourage it.  Today, it doesn't have to compete: its a classic for a Sunday run.

My post wasn't about the bike though; it was about the engine.  The engine's a real cracker, and way better (in all respects) than you'd imagine - or any contemporary figures suggest.

Of more modern-day engines, I'd have to agree with someone else's suggestion: Honda's V-4.  The 750cc (RC) engine will pull top gear from idle to 12,000rpm, and respond in an instant at any point in the rev-range.  Nothing I've ridden matches it for real-world usability.  Filled with drive-gears, roller-bearings, titanium rods & magnesium fittings, etc, it's a real jewel.             

Steve

Sure the MV is built like a Swiss watch, I agree with that!
From what I read the claim of the shaft to chain conversion saving 60 pounds is greatly exaggerated. Don�t know how much weight it saved but not that much.
Lastly, what put a downer on the MV was that in real life it is not much faster than a Guzzi 750 ambassador and the valve angles technology is hold hat.
Read the comparison here. Both 14 second quarter miles, with real top speed of 115!
http://www.yeoldecycleshoppe.com/roadtestlibrary/2016/11/26/1971-mv-750-four-road-test?rq=MV%20Agusta


Edit: a few years after the last MV America came out of the factory, the Kawasaki GPZ 550 came out and that engine was special in my book:

[Sheepdog]

Another great engine that I nearly forgot is the venerable Indian side-valve v-twin produced from 1922 to 1953. Displacement went from 61 to 74 and at the end to 80 cubic inches. Reliable and infinitely rebuildable, you can still find folks who ride these wonderful bikes. Though popular culture usually only talks about Steve McQueen on a Triumph, this was his street ride. I love the look and the super-low CoG of this engine and how it was an integral feature of these cool motorcycles...

[weevee]

..what put a downer on the MV was that in real life it is not much faster than a Guzzi 750 ambassador and the valve angles technology is hold hat.
Read the comparison here. Both 14 second quarter miles, with real top speed of 115!
http://www.yeoldecycleshoppe.com/roadtestlibrary/2016/11/26/1971-mv-750-four-road-test?rq=MV%20Agusta

That's the early MV Sport, and it was indeed dog-slow.  That model used an overbored GT600 engine fitted with the smaller (24mm) carbs, restrictive silencers and lower compression cyl-head (..note the two cooling fins on the bottom of the head casting).  The factory responded to criticism, and gave it a boost a couple of years later.  ..higher-compression pistons & head - known by its single cooling fin (check my pics) - bigger valves with more lift, and 27mm square-slide carbs.  The later Sport could just about stay with the Z1 Kawa up to 100mph (..as noted in the UK's 'Bike' Magazine, Sept 1975.  They called it: 'the most powerful 750cc motor made' at the time).

By today's standards they are dog slow - but mine (..fitted with 27mm round-bodied SSi Dell-Ortos, and almost open pipes!) would outdrag my old Le Mans no problem.

[Bucky]

Lots of great posts in this thread .

As a geezer, and pretty much a noob when it comes to doing any significant motorcycle wrenching,
my favorite motorcycle engine is my 1973 Eldorado 850.
Why? It's the first engine, motorcycle, I had any real confidence when working on it.
Totally rewired, new Gilardoni jugs/pistons and Scrambler Cycle alternator.
All of this possible due to the advice/support from sites like this, Kevin at Scrambler cycle, Greg Bender and Charles at Antietam Cycles. Thanks so much!

I saw my first Guzzi in 1970, an Ambassador, and was struck by the beauty of that engine.

[Brevaman]

Triumph 955i triple.  My '03 Sprint St has this motor.  It's nothing to look at because in fact, on my bike the lower fairing totally covers it.  118 hp, 74 ft. lbs.  It's a delicious ride for the other senses though.  You hear a turbine whine sound winding it up.  Then on decal, you hear a growly burble.  It's the nicest sounding stock exhaust note of any bike I've owned.  The motor on my bike is wrapped in an aluminum yoke frame that looks as though it could harness a jumbo jet.  It's rock solid, vibration free everywhere in the rev range.

 I'm more of an ADV bike guy and knew the ergo's of a sport tourer would be a challenge for my 68 year old body, but it's just so damn much fun to ride, I alternate tensing my core and letting my weight fall on my wrists.  It's got bar backs on it, so it's not too bad.

I had a K bike that also had a potent lump of a motor but it didn't sound anything like this Sprint.
 
I also love the sound of my Breva but for power delivery, it doesn't even come close. 

[gentlemanjim]

'Cause its just so pretty

[wymple]

'Cause its just so pretty

You got that right.