HL500

[Graeme M]

Firko, I don't think we are at odds here. I was observing that there seems to be a view that for the advances that Japanese engineering offered, the TT500 was not really any more powerful, or faster, than the ubiquitous brit 500. But I wonder at the fairness of that observation.

Now, I have nothing against the Brit singles so I am not driven by some ideological agenda. Rather, it's just that to my mind, if we make the comparison fairer, what then is the outcome. The truth is that the TT500 of 1976 was not a greatly different jigger from the street legal XT. The XT was burdened with more weight, but both shared (as far as I know) the same exhaust system (with the exception of the secondary muffler that everyone removed anyway), the same carby, same valve sizes, presumably the same piston, and the same heavily baffled airbox. Later model TTs did have a slightly less restrictive muffler, and there were a couple of years where valve sizes differed, but none of those differences conferred major performance advantages.

Without knowing the state of tune of many older singles, I would hazard a guess that most would not have been restricted to the same extent. Especially if they were racers. What was the comparative form of the B50MX? Valve sizes? Compression ratio? Carb size? How much muffling and airbox baffling? I have no idea and I might be completely barking up the wrong tree, but I always felt it was drawing a long bow to compare any well tuned racing Brit single to a stock TT500, as the magazines were.

What I'd rather know, is how does a TT with a nice pipe, a less restrictive air box, bigger carb and a hi-comp piston compare. My 79 TT500F was relatively stock. I whacked on a reverse cone mega and that thing fairly flew with no other mods. It was demonstrably quicker than any of my mates' 500s, which showed that it could certainly be made quicker. Watching any well modded TT500 at vintage DT shows them to be no slouch. But I'll bet that a bone stock TT500 would not be as fast.

You suggest that a B50T equates to an XT500. Perhaps so - do you believe that on the whole their state of tune is laregly similar? if so, what are their respective wet weights and claimed power? Not to prove anything, I am genuinely curious.

My main point is that the 500 Yammie was a rugged, strong and reliable engine that with a few of the accepted mods of the day would  likely be as strong as or stronger than any of the similarly tuned Brit singles. Yamaha had not particularly improved on the concept in technology terms - after all, there is probably only so far you can go with a 500cc, 2-valve 4 stroke. That said, perhaps the weakness of the head on the stock engine may have been the real barrier to outperforming the older singles?

[Marc.com]

I cop it about my Jag too until I give 'em a drive....then their attitude invariably changes. It's the same with old BSA's.

Same with Harleys Firko, people usually bag them when they are non owners, knockers, and it is generally based of myth and legend, after you have owned one you become a legend.

So back to the TT500 motor versus the B44/50, B50MX motor may have been released not too much before the TT500 but its DNA was pretty Jurrasic, you could trace it back to the B40 where the TT500 was more the start of an era of Japanese 4 strokes rather than the last gasp of an era of British ones.

I think the B50MX required far more major bits to get it to work as a serious race tool,  but it is a compact, short and light motor for a 4 stroke.  If we look at what the CCM and Cheney race bikes had done to them to go fast relaibly back in the day and in the UK now, it seems like you need 3 speed box with stiffed splined shafts, updated clutch, alpha big end, ported head, B50MX cam shaft, electronic ignition, carillo rod.

The TT500 engine on the other hand has much shorter shopping list, it had pretty/very strong bottom end and much more modern head design than the B50, high comp 10:1 540 piston, cam, SR500 inlet valve and you are pretty much there. you can stroke them to 600cc and fit Carillo rod but I don't feel it was mandatory like the B50 engine mods. 

[JAP 454]

 high comp 10:1 540 piston, cam, SR500 inlet valve and you are pretty much there.
Got it in one, Marc, just add 38mm Mikuni and methanol and go the rat on Dirt track, I've built 4 motors just as you describe, oh yeah, I forgot,  one of the motors is STD bore,
Foss

[firko]

Good points made by everyone. I suspect Graeme thinks I was favouring the Beeza over the TT500 but I wasn't and in reality think they're both good bits of gear. I'm loath to go into a 'this engine's better than that engine' discussion as I think they're both great engines capable of performing well in stock trim or equally capable of producing serious horsepower.

So back to the TT500 motor versus the B44/50, B50MX motor may have been released not too much before the TT500 but its DNA was pretty Jurrasic,

The B50's DNA actually dates back to the C15 of the late fifties Marc. TO me the TT500 engine is the natural successor to the BSA . The Honda XR 4v being the next step in the progression chain.

I've got a mate building a serious horsepower TT500 engine for his HL and I've ridden AJ's 540cc B50 and 580cc CCM and I'd hate to pick a potential drag race winner.

[JAP 454]

I've no experience with the unit BSA motors, but I'd have a CCM in a flash , however , in '94 when I was looking for a motor for my Sandracer that wasn't gunna cost an arm and a leg, I fitted a  TT 500 motor, raced it at various places and had a ball, other young blokes also rode it at Surfair , Sapphire and Canberra ,the XT / TT motors are relatively cheap, bloody reliable and hot up bits are readily available, weight is a slight issue, my Sandracer weighs a touch under 105 kilos wet, goes like s##t off a chrome shovel and is FUN to ride. It's cost me two exh valves , two sets of valve springs, a cam chain and a set of rings since '94, the 3 other motors have been just as reliable

With the chookie framed ones, gettin drive is the problem !!, mind you, only at certain tracks, the # 59 Gally pulls like a steam train at Sapphire and Canberra but spins up at Nepean.

Anyway, I guess what I'm trying to say is that the XT TT 500s are a great motor, easily tune-able and as some-one else said, the standard setter of their day.
Foss

[Graeme M]

I agree with most of what's been said. I have been a long time fan of the 500 Yammies. I was never a racer, in fact I was, and still am, the quintessential play rider. And from the day I first saw a TT500 I was hooked. I've owned a heap of them, probably one of each model plus a few of some years (at least 6 C models I think). The best was my 79 F model, but the HL I owned for a few years was the realisation of a long held dream. I still kinda regret selling it. It always blows me away seeing how well these things go in vintage racing these days, especially dirt track. That engine is just brilliant as everyone has said.

If I had the money I'd build me a short suspensioned HL based on a GMC frame with a lightly worked engine to go play rode round a few dirt tracks. I do like the extravagant HLs, but with about 8" front and rear they look just right.

[Colin Jay]

There used to be an advert for the TT500 that featured a cutaway of the engine etc and had a lot of sales pitch copy - I can't recall but I don't think it suggested that you'd end up winning any MX races on it.

I have a collection of genuine sales brochures and old magazine ads for quite a few of the TT/XT/SR500's, so here are a few quotes from some that to me show where Yamaha was aiming its marketing for the TT/XT 500;

From the sales brochure for  the1979 TT500F; “… It’s great for riders who want an off-road playbike, a desert racer or a TT racer. Nearly any form of off-road riding is performed magnificently by the TT500”.  However, it also says “The engine is mounted in a lightweight, modern motocross frame.”

From a period ad for the 1979 TT500F; “…and you’ve got an off-road playbike second to none.”

From the sales brochure for the 1976 XT500C; “Mount that power plant in a modern, lightweight motocross frame. … The result is a motorcycle with the same easy handling and positive feel as Yamaha’s world championship motocrossers. The fantastic XT500. It’s the perfect machine for short range touring, commuting and an off-road adventure.”

The reference to the frames being light weight, modern MX frames needs to be put into a bit of context, in comparison to many of the Japanese MX frames of the mid 1970's they weren’t that bad, comparing them  to a European bike of the period is a different matter altogether.

The debate of TT500 V's BSA is a bit like comparing fresh home grown apples with apples bought from a supermarket that have been in cold storage for a long time. Yes they are both the same, but they are separated by a time period that will show one as better than the other.

The thing with comparing the BSA’s with the 500 Yamaha’s is that you are comparing one product from the end of an era, with another product from the start of a new era. BSA were an ailing manufacturer, short of funding who were in effect trying to make the best of an aging design using antiquated equipment, where the Yamaha was a fresh (clean sheet) design made using state of the art equipment by a manufacturer who was riding on the crest of the wave that was the 1970’s boom in worldwide motorcycle sales and particularly the boom in off-road (recreational)  motorcycle sales in the USA . The Japanese were truly making “hay” from the newly affluent middle class that were “discovering “ the freedom of motorcycling in general and off road riding in particular.

I will admit that the only unit construction BSA single that I have ridden was a very rough C15T many years ago. However, I do own a collection of SR/TT/XT500’s (13 in total) and also a 1949 G80 Matchless. I don’t try to compare my G80 with my stock SR500. Although they are both 500cc 4 stroke singles, there are so different that they  might as well come from different planets, as they are two distinctly different bike to ride and I just enjoy each for what they are.

Viva la difference.

CJ

[TM BILL]

I cop it about my Jag too until I give 'em a drive....then their attitude invariably changes. It's the same with old BSA's.

Same with Harleys Firko, people usually bag them when they are non owners, knockers, and it is generally based of myth and legend, after you have owned one you become a legend.
 

Marc please dont ever compare those 2 wheeled Yank steam engines  with legendary British Motorcycles and automobiles  yes i have ridden (under the cover of darkness) a Yank traction engine ( a couple actually as i thought the first one must have been forked  but no apparantly thats what their like  ) I dont think Jag owners generally ailienate themselves from other motorist or drive like they have carrot stuck up their arses 

Its generally not the bike , its the wanker attitude 95 % of the owners seem to have that other motorcyclist dont like  Having ridden a couple i now understand its not so much an attitude as a combination of confusion , embarrassment and frustration  Having spent all that money on the thing and an equally rude amount on the branded Village people outfits for him and her only to find that they would get to their destination quicker and in more style if they had used their Senior citizen bus passes 

I like both BSA singles and the big Yam singles , they are both very capable Classics  As has been said the old Beeza was fully developed where as with the Yam who knows how much more they could have drawn out of it if they continued with the 3 valve head 

[Davey Crocket]

Couldnt agree with you more Bill, most disapointing motorcycles I have ever riden, I rode them in the daylight though so it appears to not matter when you ride one. You could compare it to having Eva Longoria standing in front of you.......naked....ready to deep throat and you realise you dont have a penis anymore (sorry Ali).

[TM BILL]

Joan i rode them at night so as not to be recognized  You could drawn a comparison to dating a fat chick , their a lot of fun but you wouldn't want your mates to catch you on one  except the the harley wasn't even fun and the fat chick was faster

[TM BILL]

 to saddle the competition TT version with anything other than the HL frame was criminal.

To my knowledge, the TT500 was never intended to be a competition bike. I have always belived that the TT500 was designed to be a "Play Bike"

Not sure Yamaha sat down an decided to build a 'play bike', but that is certainly how it ended up. That Yamaha supported the HL500 development to some degree means they had visions of doing something more with the TT500. Also the HL had won a GP so the potential was there,

Dont think the HL ever won a GP  Aberg won the first race at the 77 luxembourg GP and fiised 3rd on the day (a great achievment) but Mikkola won the overall GP and the title 

[cloggy]

Back in the day when I was a bike salesman a mechanic mate had a B44. He could take it out of the frame, rebuild it and put it back in inside 3 hours. This was born of long practice.
The 500 could trace it's lineage back to the Triumph Terrier. It was cheap and could be built with knackered preworld war 2 machinery. No mechanical adept would consider going round the world on one. Getting to Canvey Island and back was an achievement
 Jap singles were decades ahead in terms of design and build quality. Thousands went through Africa on all manner of jap singles.
When after 18 years I finally sold my AJS and bought a SP400 I couldn't quite believe the flogging it would take. I also couldn't see why it was necessary for wheel and swing arm bearings to last months. I'd never even adjusted any of those in the previous 20. Kawasaki copied the A10.
Yamaha spent nearly all their budget on making the engine last. The frame was an afterthought.
 The KLX was the first jap 4stroke single to address handling
Jeff Smith, talking about his time with Rotax, tried to get them to see that an overhead cam aircooled motor was going to be heavy and carry it's weight high. He said for motocross back then you didn't want revs, and that pushrods were the way to go as they made adequate torque, were light and didn't have  cooling problems. The B50 had been developed on the back of scrambling . The yam was designed as a road motor.

[Marc.com]

Its generally not the bike , its the wanker attitude 95 % of the owners seem to have that other motorcyclist dont like  Having ridden a couple i now understand its not so much an attitude as a combination of confusion , embarrassment and frustration 

As has been said the old Beeza was fully developed where as with the Yam who knows how much more they could have drawn out of it if they continued with the 3 valve head 

Hey i resemble those remarks, still we will leave the Harley discussion until Bill has straddled my hog. Gunna be rude mate;D


Anywayz back to the TT500 Bill, I think Yamaha did the 3 valve thing on the TT500 motor and then suddenly realized its potential and the idea got whipped back to Japan to pop up later in the FZ road bikes.

I think for a lot of 4 strokes compression is the way forward, Wiseco's awesome bang for the buck 540cc piston kit gives quite a bit more compression and that's where most of the zap comes from. Popular build in Japan is the SR400 bottom end so bike is still legal with big piston.... gives short stroke 500, I am heading in that direction with my Daytona high port head engine. It is heading to be the motor in my HL with 10.5:1 and ports like a top  fuel dragster.





have cute B44 motor in the works for my Cheney

[TM BILL]

Marc i did say 95% of owners  i will be happy to make myself available for a test ride 

[Oppet]

Hi all!

My frame project is little bit closer to finish now, got also one australian guy make me swingarm  . im starting slowly to do engine rebuild.
Here must be lot of knoledge of these engines and how to make them go.

Im planning on using my dellorto 38mm and gettin,g head ported for that. Othervise i dont have an idea what would be good cam? Do i need tighter valve springs, i have sr head so i think using original valve size. I dont want anything extreme, just good reliable power for mx, maybe +40hp and good torque. Anybody with good basic ideas?



Little disapointed now that i didnt do it all by myself, as i used hva frame i had to make tubes that go to shock mounts bend too much, doesnt look so nice, also im using hva geometry. We will see how it comes, maybe i have to order frame also from australia