But the shape of the intake snorkel has got a lot of design attention and is understood and works well where the old ones were simply designed to get air from the filter to the carb.
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Hi everyone,
As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.
When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.
Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.
Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.
Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.
Thanks for your patience and support!
Horsepower, Our Vintage 250s and the new KTM 250 @ 50 HP
- Thread starter 1982 XC 430
- Start date
But the shape of the intake snorkel has got a lot of design attention and is understood and works well where the old ones were simply designed to get air from the filter to the carb.
Yes my 2 RZ500's came on the pipes at 6K, would lift the front wheel, but it was NOT a fast as the Suzuki
Gamma 500 or as hard to ride.
In the end, there is still no replacement for displacement. That is why powervalves were so needed in 125 & 250 2 strokes. Not enough torque developed.
Rowan
Husqvarna
AA Class
But has anybody actually stuck one of the modern bikes on a dyno and checked these ´supposed´ output figures? I remember back in the early ´90s I owned a 1989 ktm250 (last of the left side kicks) and, with half a tank of juice, it weighed MORE than my ´87 430 auto with a FULL tank. So much for factory claims!!
Horsepower is just a theoretical calculation related to torque and revs - it can not be read on a dyno. And of course the factory will quote figures from prototype blueprinted machines - throw in production line manufacturing variations and there is all probability that their claims of 50hp are closer to 40.
Of course it is all about rideability and personal preference.
Horsepower is just a theoretical calculation related to torque and revs - it can not be read on a dyno. And of course the factory will quote figures from prototype blueprinted machines - throw in production line manufacturing variations and there is all probability that their claims of 50hp are closer to 40.
Of course it is all about rideability and personal preference.
Picklito
Husqvarna
Pro Class
Cool thread. All good points. Rowan I like your comments, too. Claims are just that. On the other hand, I'd have to say the production tolerance today is very small compared to what Husky put out in the 70's and 80's.
Pretty much any KTM 250 is gonna hit that power output, but having had a chance to ride many bone stock Husky 430's, I'll just say that... they varied. Production tolerance was horrible. Actual squish distance and compression ratio were all over the map. There were slow bikes and fast bikes. Suzuki had some problems like this with their RM's, as did Honda with the early Elsinores. Some were fast, some were, uh, so-so. A "good" stock Husky 430 made HP in the low/mid 40's. Not impressive numbers (even for the 80's), but the torque curve was and IS awesome!! But overall, ya, current power outputs are impressive.
Pretty much any KTM 250 is gonna hit that power output, but having had a chance to ride many bone stock Husky 430's, I'll just say that... they varied. Production tolerance was horrible. Actual squish distance and compression ratio were all over the map. There were slow bikes and fast bikes. Suzuki had some problems like this with their RM's, as did Honda with the early Elsinores. Some were fast, some were, uh, so-so. A "good" stock Husky 430 made HP in the low/mid 40's. Not impressive numbers (even for the 80's), but the torque curve was and IS awesome!! But overall, ya, current power outputs are impressive.
2premo
Husqvarna
Pro Class
interseting read
there was another thread that went off on porting, specifically about knife edge
I looked at the ports on my 430 and they were very rough, I mean to the point of sloppy, one of my 430's was ported and man was that fast, gave up no rideability just had more power
so back to the point I looked at my newer 360 ports and they are very clean, no (globs) of material just mainly smooth passages
as was stated earlier moder technology, but in this case not so much as the execution of quality castings, sound engineering on the flow, well designed intake and exhaust, but the porting as cast is better by far, now go back to the days of privateers porting their own equipment and you saw a huge disparity, we were teched every race for tear down,
in conclusion moder casting, fit and finish as well as computer aided design is everything or at least a big difference
there was another thread that went off on porting, specifically about knife edge
I looked at the ports on my 430 and they were very rough, I mean to the point of sloppy, one of my 430's was ported and man was that fast, gave up no rideability just had more power
so back to the point I looked at my newer 360 ports and they are very clean, no (globs) of material just mainly smooth passages
as was stated earlier moder technology, but in this case not so much as the execution of quality castings, sound engineering on the flow, well designed intake and exhaust, but the porting as cast is better by far, now go back to the days of privateers porting their own equipment and you saw a huge disparity, we were teched every race for tear down,
in conclusion moder casting, fit and finish as well as computer aided design is everything or at least a big difference
2premo
Husqvarna
Pro Class
that was what I was talking about mismatched liners, globs, gaskets in the flow, poorly shaped ports etc.
fran...k.
Husqvarna
AA Class
I would expect you are totally correct. The modern carbs are significantly shorter so more of the horn is in the carb on the pre mono shock ones.
I don't think the weight of the piston has been yet added to the list.
I also wonder what one of these air cooled bikes would sound like if one fabricated somelthing like a power valve and bolted or otherwise attached it to the inside of the exhaust passage. Diverging from the max hp intent of this thread lowering the roof of the exhaust port lowers the pressure when blow down starts and increases the percent of time the chain is in tension.
Fran
husqyhamm
Husqvarna
AA Class
Manufacturer paper and brochure claims are one thing. Back to back dyno testing and tuning with road tyres for rwhp, different story.
500 AC ,blueprinted, otherwise stock, tested right up there with the best 450 SM1 machines within their class regulations. That is way ahead of any current stock 2t 300s.
All dynos and their operators and factors are different. One will measure 46rwhp, another 50 on the same bike, same tune, different days. They are relative and help evaluate power delivery graphs and according tuning to improve.
For max accelleration and speed you want as long a level line at max hp across the rpm range as possible (sustain). I.e. when you shift up you want to be within the band range, obviously geared accordingly. Peaky snappy power...not much haul in it.
500 LC, flowed, blueprinted, decked, squished, piped correctly. Still the rocket sled of them all.
500 AC ,blueprinted, otherwise stock, tested right up there with the best 450 SM1 machines within their class regulations. That is way ahead of any current stock 2t 300s.
All dynos and their operators and factors are different. One will measure 46rwhp, another 50 on the same bike, same tune, different days. They are relative and help evaluate power delivery graphs and according tuning to improve.
For max accelleration and speed you want as long a level line at max hp across the rpm range as possible (sustain). I.e. when you shift up you want to be within the band range, obviously geared accordingly. Peaky snappy power...not much haul in it.
500 LC, flowed, blueprinted, decked, squished, piped correctly. Still the rocket sled of them all.
2premo
Husqvarna
Pro Class
500 LC, flowed, blueprinted, decked, squished, piped correctly. Still the rocket sled of them all.[/quote]
my brother had one, an 85 CR500 that was ported pipe was Up-Tite, head milled and reshaped
a little hard to kick but an absolute missile
I was going to ride it and his advice was "when you roll on the throttle you better have a plan cause it is going to happen fast"
my brother had one, an 85 CR500 that was ported pipe was Up-Tite, head milled and reshaped
a little hard to kick but an absolute missile
I was going to ride it and his advice was "when you roll on the throttle you better have a plan cause it is going to happen fast"
86 400 XC
Husqvarna
Pro Class
Last year a friend with a KTM 450 SX and I had a couple rounds of drag racing on a new strip of pavement.
We both race cars and just got into bikes so it was time to see how my 75 360 CR would hang with a 4 stroke.
3 for 3 he won, but only by a bike length. The 82 500 will squash the S.O.B. this summer. evil grin
We both race cars and just got into bikes so it was time to see how my 75 360 CR would hang with a 4 stroke.
3 for 3 he won, but only by a bike length. The 82 500 will squash the S.O.B. this summer. evil grin
husqyhamm
Husqvarna
AA Class
my brother had one, an 85 CR500 that was ported pipe was Up-Tite, head milled and reshaped
a little hard to kick but an absolute missile
I was going to ride it and his advice was "when you roll on the throttle you better have a plan cause it is going to happen fast"[/quote]
Would love to get those 500LC specs
Would love to get those 500LC specs[/quote]
I had a 610 (my first husky) That i found out Up-tite had ported the head, hi-comp piston, Up-tite exhaust, etc. That bike felt like about 70HP and I rode it in tight woods. WTF was i thinking?
Or for a little more you could have this fun beast on craigslist, just posted yesterday.
