ESE's works engine tuner

[Frits Overmars]

.... I was going to post some stuff on the 70's Husky 4 speed auto set up but can't find all the info....

Maybe because the Husky I rode was a 3-speed auto....

[richban]

Maybe because the Husky I rode was a 3-speed auto....

How was that to ride?

[F5 Dave]

Tri-Matic Bro!



sorry, a bit of island humour for our offshore chaps

[Frits Overmars]

How was that to ride?

For me it was great; I almost started liking motocross. I did not have to worry about shifting down when I got into deep sand or up steep slopes.
But a pro MX rider who knew what he was doing, might not have benefited as much as yours truly.

[F5 Dave]

I'd read about some 'Mercan winter bog enduro race (about '80) & some top rider scooped it using an auto & said it was almost like cheating, along with the heated hand grips.

Never seemed to come to any more though.

[jasonu]

Forget that shit - get a 30Hp aircooled on track that runs like a clock all day!!

Where are you going to find one of those???

[TZ350]

Posted because someone asked me how to mount a GP engine into a RS chassis.



The rear engine mounts make use of the original RS mounting points without any modification to the frame there.



We used a piece cut from the original GP frame for the front mount.



We found that where the front mount attached to the RS frame it would break away and we had to glue and screw some hefty bracing there.

And now we also have the bolt where the front mount attaches to the frame bracket running through a red nolathane bush to absorbe some of the vibration.



We had to cut one head fin off and trim the back of the cylinder fins to clear the frame because the motor had to be shifted about 15mm to the right to get good chain alignment.

[F5 Dave]

Stop it! You'll only encourage her

[husaberg]

Maybe because the Husky I rode was a 3-speed auto....

For me it was great; I almost started liking motocross. I did not have to worry about shifting down when I got into deep sand or up steep slopes.
But a pro MX rider who knew what he was doing, might not have benefited as much as yours truly.

I'd read about some 'Mercan winter bog enduro race (about '80) & some top rider scooped it using an auto & said it was almost like cheating, along with the heated hand grips.
Never seemed to come to any more though.

I found it although it seems Frits and me are both right. (Nothing new for frits but a rare husa moment)
I did a google search the production ones were both 3 and 4 speed and the Swedish army were a big buyer of them.They made them for 12 years all up. (Likely longer for the military)
The test rider here attached (1976)below (a non pro)says basically exactly what Frits assessment was, also what Dave said about them. I was more interested how it worked.The interesting thing was how it could help the non pro plus the consistency
I know very little about auto trans. but the drag racers love them (no corners to contend with either though)

http://www.motorcycle-usa.com/290/10...Automatic.aspx
http://www.bikeexif.com/husqvarna-automatics

The Husky Auto was a serious race bike but it came about as a spin-off from a Swedish Army contract. In essence, the contract specified that raw recruits, who had never ridden a bike before, had to achieve complete motorcycle competency in a week. However, the Swedish Army didn't want recruits merely to cruise up and down the highway wearing mirror shades, looking cool and waving to the girls. No, they had in mind full blown enduro riding skills - and on snow and packed ice too.
Husky's answer was a 250cc, fully automatic motorcycle complete with the option of permanent skis for winter terrain. The squaddie merely sat on the Army bike, opened the throttle and away he went - and over killer difficult terrain too.
Husqvarna was a small factory but was packed full of clever engineers and, unlike the Japanese, very used to working on micro budgets. The Auto racebike reflected this low budget approach to engineering.
Most of the bike was a direct lift from existing Huskys. This included the reed-valved, single-cylinder two-stroke engine and all the chassis. Only the gearbox was unique to the Auto and this fitted inside a regular Husky engine case.
A 384cc two-stroke Single, the Husqvarna 390 Automatic featured a gearbox with a centrifugal clutch and a series of dog clutches.
The heart of the gearbox was the clutch mechanism. Initially, drive was taken up by a centrifugal clutch - like a Honda 50 Cub - and then a series of a dog clutches engaged sequentially locating higher gears. It was brilliantly simple and even more brilliantly effective with bomb-proof reliability and faultless changes even under full power.
When the throttle was closed, the engine free-wheeled and the clutches disengaged so that the correct gear was available when the rider need to accelerate again. If the bike had a problem, it was the freewheeling element.

Hill descents became a real, hardcore thrill. Not only was there no engine braking available - a very, very scary experience for the first time auto rider - but the rear wheel stability which even mild two-stroke braking provided was absent. Although the Auto had state-of-the-art handling for its day, it skated and skittered downhill in a very disconcerting manner.

The lack of engine braking was exacerbated by the brakes - or lack of them. It's worth remembering that, at this time, dirt bikes had drum brakes - not the discs of today. The Husky's brakes were as good as anything around at the time but once the linings were wet, they didn't work for some time afterwards. Get the wrong combination of a river crossing followed by a steep hill and Auto riders could crack walnuts between the cheeks of their bottoms on the way down

Automatics have a strong following in the four-wheeled offroad world, so it’s not surprising that they’ve been tried in dirtbikes. And Husqvarna got it mostly right from the start: according to VMX’s writer Rob Shoemark, “The first commercial release of the Automatic was in 1976 and the last was 1988. Throughout that whole time the transmission was basically the same with only minor design enhancements.”
Since 1980, Husqvarna has been supplying the Swedish Army with auto all-terrain bikes that can be ridden proficiently by new recruits after just one week of training. And how does it work? “It is mechanically simple,” VMX reports. “Based around a centrifugal clutch, drive is firstly taken up by that clutch, then a series of a dog clutches engaged sequentially, locating higher gears. It was not only simple but very effective and reliable. What about changing back down? Once the throttle is closed, the engine goes into free-wheel mode. Once you apply the throttle again the gearbox was ‘told’ what gear it should be in by the speed of the back wheel.”

Initial reports from the motorcycle media varied. But the good outweighed the bad, and sales were strong enough to merit twelve years of non-military production. “The 1988 430 water-cooled automatic was the last automatic model released,” says Shoemark, “and it was the automatic at its best. Finally without any doubt, and with proper maintenance, the Automatic was a truly great competitor in any enduro field—and was campaigned accordingly by the factory. It was a gem. Interestingly, that last model was also a three-speeder—all the auto versions up to that point, from 1976 onward, had utilized four speed gearboxes.”

Oh great to have you back Frits too. Is there any update in regards to the FOS cylinder and the Trombone pipe you posted from a associate?

[Frits Overmars]

... How does it work? “It is mechanically simple,” VMX reports. “Based around a centrifugal clutch, drive is firstly taken up by that clutch, then a series of a dog clutches engaged sequentially, locating higher gears".

False. A better descrition is given in the second page that Husa posted above. In case you missed that: each gear has its own centrifugal clutch, and all gears except the highest gear have unidirectional freewheels (called dog-bone clutches because of the shape of the locking elements in them) so they can be overriden by a higher gear.

No news about the FOS cylinder, except that everything takes way more time than it should.
The trombone pipe works a treat and the sealing is bullet-proof now, but with a six-speed gear box you hardly benefit as far as lap times go. On our kart tracks fewer gears might actually yield better lap times; Richard Maas is investigating that now.

[FastFred]

The trombone pipe works a treat and the sealing is bullet-proof now.

How is the sealing done?

[Frits Overmars]

How is the sealing done?

That's not for me to divulge. Maybe Richard will tell.

[wobbly]

I have recently lost a couple of customer engines due to plug failures.
Initially it was blamed on deto causing the issues, but now I find out there is a recall from NGK due to faulty manufacture.
The local importer is desperate to keep this quiet, im not.

[2T Institute]

For me it was great; I almost started liking motocross. I did not have to worry about shifting down when I got into deep sand or up steep slopes.
But a pro MX rider who knew what he was doing, might not have benefited as much as yours truly.

There is only deep and very deep sand on Dutch mx tracks

Been using Denso plugs for a fair few years after I had a few new-out-of-box NGK failures.

[twotempi]

Have a box of new-in-the-packet B9EGV's NGK plugs coded 1Hx5 which are on the list.

Who do i see to get these replaced ??

And who is the NZ stockist of Nippon Denso plugs ??

Most people gave up on the Champion brand for the same reason. Seems that NGK have the same issue.