ktm 495 question

[Mike Hufnagel]

Finally picked up a 1982 495 (in pieces) for a good price. Came with 2 motors (one runs)and a host of goodies.  Anyway, does anyone know what the purpose of the twin plug head is? If there were any benefits why did some later model years  have only one plug?

[tofriedel]

Mike,

I can't answer your question, but the 1st 495's (1981 models) were single plug heads.  Even some of those were modified to a dual plug head.

If you do not get an answer on this site, go to -
http://www.ktm495.mxbikes.com/.

Tony

[SouthRider]

Don't know the specific reason it was on this bike - but in that era it was common.

Two reasons that they were often used:

A place to install a compression release for large displacement or high compression motors to make it easier to start them.

The spare spark plug occasionally came in handy if the primary one fouled - just switch over the ignition lead (although it was usually fouled too...).

I believe that a few manufacturers also used them to have dual coils & hotter spark, but I don't think that was ever the case for this engine.


Doug? Dane? anything to add?

[Larry Perkins]

I raced a 495 in a Casey Folks desertc race in the 80's that was a test bike for Dirt Bike magazine and then refurbished by KTM and sent to Letko Cycles that had a dual plug Motoplat.  It fired both plugs.  I am not sure of the year anymore but I remember that and that it was Scary Fast!

Larry P

[Mike Hufnagel]

I have the dual lead coil on this one.

I remember the dual plug holes on an old Suzuki TS i had growing up.

Another guy I talked to thought it might have been an EPA type of thing considering the year it was. I kinda diregarded that though, being an off road bike.

I think what I might do to this bike is put it on the street. I have a 82 250 already plated, (haven't taken any measurements or tried it yet) but I think the motor will fit it even though the 250 is a twin shock ( it has the swing arm bolt running through the cases ). Vintage supermoto?

[thrownchain]

The Yamaha enduro I grew up on had the 2 plug holes in the head, only used the one, but some people put in a compression release to act as a brake. On the bigger bore 2 strokes they used the release as a help just to start the bike. Yami 360. But I agree, if you ran 2 plugs and fouled one out, good chance the other wasn't in any better shape.

[Big Mac]

My '81 495 has dual Motoplat coils wired in sequence to fire twin plugs. Not sure the real need for it, but supposed to make for better combustion across the head. Early 70's CZs had twin coils and double plugs both firing too.

[Mike Hufnagel]

I also thought that it would be for a more complete combustion. Look at what the fuel drag cars are using for ignitions considering how much fuel they use in those.

[garrettccovington]

A Street Legal Super-Motard KTM 495! Whoaa!

72 six-day
79 KTM MC80 250