[Good Vibes]

29hp sounds low, but is it low when compared to the Brit bikes of the 50's that is the era of bike that the Chennai RE plant began producing from its beginnings up to 2013 when the CGT was born.  But is it that bad?

From the 1992 edition of ENCYCLOPEDIA OF MOTORCYCLES edited by Erwin Tragatsch and revised by Brian Woolley, I  list the Brake Horse Power for the following motorcycles produced in the Post WWII era (up to 1959):

1. AJS Model 18 498cc            21.1 hp
2. Aerial VH Red Hunter 497cc 24.6 hp
3. BSA B33 499cc                    23.0 hp
4. BSA A10 GF 646cc twin        35.5 hp
5. Matchless G9 498cc twin      30.0 hp
6. Norton Manx 30 499cc         33.0 hp
7. Royal Enfield Bullet 498cc    25.4 hp
8. Ryl Enfd Meteor 692cc twin  36.5 hp
9. Triumph T 100 twin 498cc    34.0 hp
10. Velocette MSS 499cc          39.0 hp
11. Vincent HRD Comet 499cc   28.4 hp

So, given the light weight and superb handling of the CGT (and while it ain't a Gold Star), we should to be pretty happy with the on tap horsepower we have in our gorgeous little 535cc single banger so faithfully styled on the Café Racer's of the 50's and that it so  well represents - don't we?
The 60's era saw significantly more horse power from the 500 singles, but only in pure race machines and then multi cylinder bikes took over.

 

 

[longstrokeclassic]

Very informative post.  Makes you realise just how dark the rose tint really is 

[ROVERMAN]

I have the original version of the Encyclopedia of Motorcycles and is is my go to for any bike related questions, great book.
Roverman.

[Richard230]

I have a 22-volume motorcycle encyclopedia, called The World of Motorcycles, which was published in 1977 by Orbis Publishing Ltd., London and edited by Ian Ward.  A very impressive and interesting source of motorcycle history.  But it is getting a little outdated by now. 

One comment about those horsepower listings: I assume those are claimed by the factories and not tested on a rear-wheel dyno.  To me that would make them a little suspect and perhaps not completely comparable between models.  But still that is fun information and the power ratings sound about right when comparing their on-road performances. While I never owned one of those bikes, I always love to hear about them - and more so when someone else does the research. 

BTW, if anyone has a particular interest in British motorcycles I have copies of road tests from the 1930's through the 1960's that were published by a couple of British magazines referred to as the Blue'on and the Green'on.     I am always willing to look up a road test or two and comment on them here. (As an example, they were able to push a 1960 Bullet 350 up to 88 mph on their test track.) Those two magazines were very compete in their testing, much more so than any U.S. motorcycle magazine until the arrival of Cycle World in 1962.

[REpozer]

It's my assumption ( never assume)that the early British singles were long stroke engines.
Long stroke engines are generally designed for "work" or producing torque.
Part of the thrill of riding a RE motorcycle is riding within the" torque curve".

[la_r3_cgt_rider]

Very  .  How much HP does the pcv add to all those bikes? 

[1 Thump]

It's my assumption ( never assume)that the early British singles were long stroke engines.
Long stroke engines are generally designed for "work" or producing torque.
Part of the thrill of riding a RE motorcycle is riding within the" torque curve".

Generally yes, but I know that at least one of the listed bikes had a square motor, probably more.

[Otto_Ing]

Very  .  How much HP does the pcv add to all those bikes? 

PC-V is the equivalent of a carb tuning. Without other changes to the engine, intake and exhaust system it won't do much to performance.

With PC-V, free flow silencer and our airbox kit the GT lands up somewhere around 26hp at the wheel, which is around 33-34hp at the crank.

My bikes dyno chart.

[Rattlebattle]

I feel it's only fair to point out that the bhp quoted were real British horses and were actually delivered. Without tuning the actual bhp produced by the CGT is nowhere near 27bhp, more like 17bhp according to my supplying dealer's dyno.

As has been said, English classic "cooking" singles of the 50s were long-stroke with heavy flywheels (heavier in fact than the Indian Enfield Bullet) and some of them (particularly sidecar tugs like the Aeriel VB, Norton Big4 etc) were still side-valve. These fifties bikes were used for everything as few could afford a car. Fuel consumption mattered and often owners tried to eke out fuel as best they could. Only in the sixties when people began to have more disposable income and started buying Minis did more sporting singles emerge, often shorter stroke unit construction. The exceptions were of course Goldies and Velocettes, the latter being considered a bit anachronistic by the end of the sixties, the proper Goldies having ceased production in 1963.

I used to own a DB32 350cc Goldie; having ridden a CGT I can tell you that even at 535cc it is nowhere near as fast or powerful as a DB32 ( top speed 105mph) let alone a DBD 34 500.

[ace.cafe]

I think that the list has some inaccuracies.  The Bullet hp is crank hp, unless it was a Big Head model or Fury.
The Manx hp listed is at least 5hp too low.
But it does reveal the basic idea that the OP intended.

One of the important factors is that the old bikes were not strangled by bureaucratic regulations like the new ones are.  The new ones need to be freed of the restrictive cats and mufflers and intakes, in order to be compared to the old ones in an "apples to apples" comparison.

In that kind of match-up, the CGT 535 shows 25-26 rear wheel hp, as evidenced by the dyno tests of MeVoCGT and Otto in their "before" dyno graphs, equipped with free flow intake and exhaust and Power Commander to properly tune the mixture to suit.
In the "after" dyno test with the Ace head, and equipped with the same intake/exhaust system, it showed 32.5 hp at the rear wheel on an otherwise stock engine.
I feel that these are more representative of a comparison of similarly equipped machines.
IMO.

[Richard230]

Motorcycle Consumer News tested the GT when it was first introduced into the U.S. market. It produced around 20 hp on their Dynojet dyno and that was with a very loud "sports" muffler installed.  However, it was not broken-in as I recall and would likely have run better and made more power if it wasn't so new. It was tested against the Yamaha SR400, which didn't do any better powerwise and handled worse.

[Otto_Ing]

I can confidently state that my bike will beat the crap out of a stock bike at any given time. I think also the 25hp figure on MeVoCGT's bike does not give enogh credit to the intake mods we did to the airbox. Not wanting to start a bean counter discussion about 0.5 or 1 hp and dyno accuracies, so leaving it there. 

Nevertheless the toll to BS in form of restrictions and questionable technology is pretty impressive.

[Arizoni]

It's worth pointing out that any horsepower readings from a Dynojet are rear wheel horsepower.

It takes a special rig to tap the crankshaft directly to find out what the engine horsepower, without the losses in the transmission and drive chains actually is.

These drive losses at the rear wheel can be over 8 horsepower so it should not be surprising when a 27 horsepower engine can only get 17-19 horsepower readings on a Dynojet or other dynomometer.

All of the manufactures that make motorcycles test the engine  to determine the horsepower it can make.  They do not list rear wheel horsepower in the data they release to the general public.  It would serve no purpose except to make their products look under-powered when compared with the other motorcycles on the market.

The engine on the bike ace is talking about in his post above, with the ace head installed,  is actually putting out over 40 engine horsepower at the crankshaft.

[Otto_Ing]

It's worth pointing out that any horsepower readings from a Dynojet are rear wheel horsepower.

It takes a special rig to tap the crankshaft directly to find out what the engine horsepower, without the losses in the transmission and drive chains actually is.

These drive losses at the rear wheel can be over 8 horsepower so it should not be surprising when a 27 horsepower engine can only get 17-19 horsepower readings on a Dynojet or other dynomometer.

All of the manufactures that make motorcycles test the engine  to determine the horsepower it can make.  They do not list rear wheel horsepower in the data they release to the general public.  It would serve no purpose except to make their products look under-powered when compared with the other motorcycles on the market.

The engine on the bike ace is talking about in his post above, with the ace head installed,  is actually putting out over 40 engine horsepower at the crankshaft.

It's possible to measure transmission losses up to the clutch on the DynoJet rig. Which is what some "reputable" motorcycle magazines do and I plan to do next time I take the bike to the dyno. In the case of the Enfield we are missing the primary chain, nevertheless close enough. My dyno guy who usually measures Ducatis says they typically lose 10hp in the transmission.

[mevocgt]

I can confidently state that my bike will beat the crap out of a stock bike at any given time. I think also the 25hp figure on MeVoCGT's bike does not give enogh credit to the intake mods we did to the airbox. Not wanting to start a bean counter discussion about 0.5 or 1 hp and dyno accuracies, so leaving it there. 

Nevertheless the toll to BS in form of restrictions and questionable technology is pretty impressive.

That was with a stock replacement K&N.  I put the Ace/Dettro on with the head. 

[mevocgt]

The engine on the bike ace is talking about in his post above, with the ace head installed,  is actually putting out over 40 engine horsepower at the crankshaft.

Ace or Otto once said it was about a 1.3% loss if I remember correctly.  So that would mean that we are running 42.3 at the crank.  Roughly......So yes, and it pulls like a train...?

[ace.cafe]

There might be some quibbling about exactly how much crank hp is available since we have no crank hp test data, but I think the estimates are in the ballpark.

However, what really impresses me is getting that kind of peak hp at barely over 5000 rpm. This indicates the kind of train pulling torque curve that MeVoCGT mentions.
Very broad torque curve with over 36 ft-lbs peak gives excellent power available at any riding speed, with impressive ability to roll on the acceleration power in any gear for passing traffic or just plain fun, and all on tap at rpms below the stock rev limiter speed.
I consider that aspect to be one of the most successful attributes of the head. I was very happy about that.
 

[Farmer_John]

So you don't need to unlock the PCV rev limiter?

[mevocgt]

We didn't change redline on the bike.  It's still at 5500...

[Aus.GT]

So you don't need to unlock the PCV rev limiter?

Not until Cams are added, He He

[ace.cafe]

Correct.
All the power gains are within the limits of the stock rev limiter under 5500 rpm.

Note that in the attached dyno chart, ALL parts of the Ace billet GT head curves, both torque and hp, are higher everywhere . There is no power sacrificed anywhere in the rpm range with this head. And it all happens below the rev limiter cut off rpm.

However,  as Aus.GT points out, there is room to go higher in power and rpm with the use of cams and other mods.At that point, the rev limit on the Power Commander would be increased to 6000 or 6500 rpm, depending on application.

[Good Vibes]

I was thinking of my favourite British single being my 1956 Norton ES2 when I wrote this comparison.  My Norton was bought in 1968 and had a capacity of 490cc with a bore and stroke of 79mm x 100mm compared to the CGT's 87 x 90 and much lighter flywheels. I got clocked at 78mph by a Traffic Cop who said my mate (on a similar aged Norton Dominator 500 twin) left me standing. He was correct about my speed because I looked at the speedo on hearing his siren. Interestingly, he let us both off as he said we were riding well.  Imagine that happening today?

Anyway, whatever power my Norton had, it would do 90mph with me lying on the tank and with enough road length.  I was never able to get much above 90mph.  My CGT accelerates way quicker to 120kph but runs out of steam at 130kph (80mph).  It will go faster but as with the Norton ES2, it needs a lot of road or a race track with a long straight. So really, not much different.

The final Norton Manx's (early 1960's) had a square configuration with overhead cams and were tuned to 50bhp.  Their top speed was over 100mph.  They wouldn't idle as way too cammy for that but non-the-less were fast beautiful bikes and not dissimilar in look to our little CGT's. Handling of both is probably comparable.

[ace.cafe]

My CGT will do 5000 rpm in top, which is 90mph according to rpm and gearing. I don't rely on the speedo, although in this case the speedo agrees.

It's current configuration is Sports silencer, PCV, and Ace/Derottone airbox with stack.

[Rattlebattle]

I was thinking of my favourite British single being my 1956 Norton ES2 when I wrote this comparison.  My Norton was bought in 1968 and had a capacity of 490cc with a bore and stroke of 79mm x 100mm compared to the CGT's 87 x 90 and much lighter flywheels. I got clocked at 78mph by a Traffic Cop who said my mate (on a similar aged Norton Dominator 500 twin) left me standing. He was correct about my speed because I looked at the speedo on hearing his siren. Interestingly, he let us both off as he said we were riding well.  Imagine that happening today?

Anyway, whatever power my Norton had, it would do 90mph with me lying on the tank and with enough road length.  I was never able to get much above 90mph.  My CGT accelerates way quicker to 120kph but runs out of steam at 130kph (80mph).  It will go faster but as with the Norton ES2, it needs a lot of road or a race track with a long straight. So really, not much different.

The final Norton Manx's (early 1960's) had a square configuration with overhead cams and were tuned to 50bhp.  Their top speed was over 100mph.  They wouldn't idle as way too cammy for that but non-the-less were fast beautiful bikes and not dissimilar in look to our little CGT's. Handling of both is probably comparable.

I had a Norton 19S a few years ago. It had the longest stroke of any English single (though it might have shared that honour with the Panther). Being a 600cc it had loads of torque - they were mainly used as sidecar tugs in their day. A lovely bike that wasn't much quicker than an ES2. Both of course can be tuned to produce considerably more power. Pushrod Performance is the main man for this in the UK.

A Manx will do a lot more than the ton; even 350 Goldies did 105mph. Are you sure the Norton had a lighter flywheel than the CGT - I doubt it. My brother weighed the flywheels in his iron barrel Enfield - it weighed less than that in his B33 BSA - a rough equivalent to the ES2. To me the current RE bikes don't slog like they used to...

[Otto_Ing]

Ton on the 350 Goldie sounds a bit optimistic to me though.

[SSdriver]

My CGT will do 5000 rpm in top, which is 90mph according to rpm and gearing. I don't rely on the speedo, although in this case the speedo agrees.

It's current configuration is Sports silencer, PCV, and Ace/Derottone airbox with stack.

Same here...Motad silencer, Pcv, k&N... 90 mph with gps... and not lying on tank.
I'm happy with the GT performance...think it's underrated for a big single.
Cheers...Jimmy

[Good Vibes]

Hi Rattlebattle

My composition was wanting, as I was referring to the CGT having the lighter flywheels.  The Manx's, that were purpose built for the Isle of Mann that is a 264 mile race so reliability was also an attribute built into the engine design.  They had double overhead cams and could do 140mph, pretty good for a 498cc single.  Some post production tuners got 60hp from them and slightly more top speed.

I too am very happy with my CGT that has the standard Keihin ECU although mine was re-mapped by the Chennai factory to prevent the stalling I had, and it came fitted with the sports muffler that is very loud.   I did stuff some chicken wire into the tail end to create a little back pressure that stopped the popping on deceleration, and it ran smoother and a little quieter.  I removed it a couple of weeks ago and it is noticeably noisier so will probably re-stuff it again.  It doesn't take much to make a difference and the mesh can be inserted about 50mm into the visible internal tail pipe with the rest twisted up and curled around the cavity behind the end of the tail pipe and the muffler back end to hold it in place.

What is the CGT's 0 to 100kph (60mph) time?  anyone know?

[Rattlebattle]

Ton on the 350 Goldie sounds a bit optimistic to me though.

I think not. The 350cc Goldie was at least as successful as the 500cc version. It was the 350 DB32 that used to win all the races, to the extent that races became a procession of 350 Goldies, rather like Yamahas a few years later. They were competitive in most branches of M/c sport too; the owners handbook had loads of data on cam timing, cams and carb settings. In road racing form with a GP carb fitted BSA claimed 105 mph top speed. I'm sure that this is realistic. It was almost a racer for the road - the reason why rockets wanted one, preferably a 500cc admittedly, though the 350cc was more civilised. Few rockers lusted after a Bullet; by the time the big head one arrived the world had moved on...

[Otto_Ing]

I think not. The 350cc Goldie was at least as successful as the 500cc version. It was the 350 DB32 that used to win all the races, to the extent that races became a procession of 350 Goldies, rather like Yamahas a few years later. They were competitive in most branches of M/c sport too; the owners handbook had loads of data on cam timing, cams and carb settings. In road racing form with a GP carb fitted BSA claimed 105 mph top speed. I'm sure that this is realistic. It was almost a racer for the road - the reason why rockets wanted one, preferably a 500cc admittedly, though the 350cc was more civilised. Few rockers lusted after a Bullet; by the time the big head one arrived the world had moved on...

Ok it was a racing Goldie 350.

[Rattlebattle]

Well, not really. You could specify what you wanted from the factory. Young men being what they are most specified clubman's trim i.e. clipons, GP carb, rearsets and RRT2 close ratio gearbox. They were fast in that format without tuning for racing.

[ace.cafe]

The Bullet is not too lowly, though.
A good street modification of the Iron Barrel Bullet can beat a Gold Star DBD34, and we have done so on numerous occasions on the local roads with the Fireball.
Bullet Whisperer's F.A.B. 500 race bike has beaten racing Manxes and G50s in the BHR , and no Gold Stars even close.
Linsdell's Bullet beats all 500 singles of any kind.

So while the stock Bullets may be rather pedestrian,  they can wake up quite well in the right hands.
The Big Head Fury was fast until the bottom end gave up, and a Carrillo rod with better bearings mostly solved that.

No disparagement of the Goldie intended, but just pointing out that the Bullet is not always a slug.
 

[Rattlebattle]

Don't get me wrong; I know that Bullets can be made to really fly (as can most bikes given the right development). I didn't intend to disparage the Bullet, rather to say that as bought they didn't compare well with the Goldie. Manx Nortons are a different thing altogether; they were never road legal - pure racers like the AJS 7R, Matchless G50 etc.

[Otto_Ing]

Thanks for the excursion in time RB. I've read somewhere that back than each bike would come with an idividual "dyno chart" as well. That must have been a lot of effort.

[ace.cafe]

Thanks for the excursion in time RB. I've read somewhere that back than each bike would come with an idividual "dyno chart" as well. That must have been a lot of effort.

I think it was stated that each DBD34 engine must do 40hp on an engine dyno(not rear wheel) before they would put it in a bike. I don't know if they actually supplied a dyno chart with it, or not.

No doubt that the Goldie is a legendary iconic bike. Very collectible too.

[Rattlebattle]

Yes, it was the one to which many rockers aspired. Though not quick off the mark on account of the close ratio box they were reckoned to have the legs of an average Bonnie once rolling. These days there are specialists that can supply all sorts of upgrades that really leave only the outline of the engine unchanged; it's the same with Manx Nortons and their ilk. One has to compare apples with apples when considering the relative merits of old bikes. Back in the day nobody imagined that a Bullet could be made to go so quickly as Steve Linsdell achieved. Me, I'd love a pre-war Ariel single.

[Ariel Red Hunter]

It's possible to measure transmission losses up to the clutch on the DynoJet rig. Which is what some "reputable" motorcycle magazines do and I plan to do next time I take the bike to the dyno. In the case of the Enfield we are missing the primary chain, nevertheless close enough. My dyno guy who usually measures Ducatis says they typically lose 10hp in the transmission.

Yes, very high losses with gear driven primaries, and all indirect transmissions, as illustrated by the quote on Ducati's.  The horsepower claim for the Ariel VH (Red Hunter) is in error.  That is for a VB engine.  The VH was factory tuned and ported, and gave 27 hp, or mine did.  Top speed tells the story.  My VH would just break 90 mph, stock.

[Ariel Red Hunter]

The Bullet is not too lowly, though.
A good street modification of the Iron Barrel Bullet can beat a Gold Star DBD34, and we have done so on numerous occasions on the local roads with the Fireball.
Bullet Whisperer's F.A.B. 500 race bike has beaten racing Manxes and G50s in the BHR , and no Gold Stars even close.
Linsdell's Bullet beats all 500 singles of any kind.

So while the stock Bullets may be rather pedestrian,  they can wake up quite well in the right hands.
The Big Head Fury was fast until the bottom end gave up, and a Carrillo rod with better bearings mostly solved that.

No disparagement of the Goldie intended, but just pointing out that the Bullet is not always a slug.
 

In my day (60 years ago) I owned and tuned a Goldstar.  There was another rider there at Ascot racing a 500 lunger RE, Shell Thuett.  Shell's engine was as fast as our Goldie, but he couldn't keep the lower end in it.  Crank flex and crankcase panting, or so his #1 wrench told me.  Nortons, G-50 Matchless's, Velocette's and Goldstars had very rigid crank cases.  All of us could race every Friday night for six months of the year on the same bottom end.  That's a lot of racing.  K model Harleys were beatable on half mile tracks, but very tough to beat on mile tracks.  Bart Markel was their top rider.  Bad Bart (actually a nice guy) was known as a win, or blow, or put through the fence type rider.

[Ariel Red Hunter]

Ok it was a racing Goldie 350.

No, 350 Goldies could break 100 as stock roadsters, if they were set-up right at the dealers.  We sold a few out of the shop I worked at, and they were very carefully set up.  Little giant killers, we called 'em.  They had the legs of all the 500's of the day.  They were a good 10 mph faster than my Ariel NH Red Hunter, and mine was geared and carbureted to a gnat's eyebrow, just like the Goldies were.  The Velocette Clubman 350 split the difference, at 95, or 96 mph.  My Ariel would not only hit 90, it would hold it hour after hour, riding from LA to Las Vegas.

[Otto_Ing]

Acc. to the adds I see here in Europe, particularly Germany the EURO4 complient models have 3 horses less than the EURO 3 models. 

[Richard230]

Acc. to the adds I see here in Europe, particularly Germany the EURO4 complient models have 3 horses less than the EURO 3 models. 

Ouch!  That doesn't leave much.   

[Otto_Ing]

Ouch!  That doesn't leave much.   

Let's see, these figures come from independent dealers. I've not seen anything official yet.

[malky]

  Me, I'd love a pre-war Ariel single.

I raced one in the 1970's. A late 1930's Red Hunter. I rode it 50 miles to the track, raced, and (sometimes) rode it home. I replaced it with a Triumph 500 Grand Prix, big mistake, foulest handling thing on two wheels I've ever ridden.

[ace.cafe]

While peak hp is an enticing figure, the "area under the hp curve " is at least as important,  and probably more so. On a street bike, top rpm is not commonly seen, but midrange is king.
A broad torque curve is a requirement for it.

A peaky curve at top rpms may be faster, but it needs much more shifting to stay on the juice, and requires keeping the rpms up there much of the time.

[malky]

 
https://www.youtube.com/watch?v=gT0TXrUKNIY

[SSdriver]

Malky...this pretty much explains why we bought Enfields when we could have bought nice reliable Jap machines. Jay picked up this Velocette back in 1971 when he could have had any number of "modern machines", with multiple cylinders, electric start etc. Here we are 46 years later and the big single Velocette is much cooler than any of those cookie cutter bikes. Like Jay said "you have to ride it to understand the feeling".

I love my GT and trying to coax a little extra horses out of her is all part of the fun. 46 years from now I'll realize how cool a decision it was to buy this GT. Well maybe I'll leave that to the Grandson.

Cheers...Jimmy

[dginfw]

Acc. to the adds I see here in Europe, particularly Germany the EURO4 complient models have 3 horses less than the EURO 3 models. 

3hp on a new UCE bike is like,.. what, ..,10% ? 

[ace.cafe]

I anticipate that the GT with the billet head will be ev everything that people wanted it to be, and maybe more.
The basic bike is lovely, and classic. It just needs some hp.