Messages

1

Competition / Re: 2020 Classic Nats

« on: December 27, 2019, 09:25:18 pm »

Agreed BigK, a practical rule improvement that makes it a bit easier to roll out the old bike.

This year's pre 78 turn out at Viper has been impressive, and being able to ride EVO and be reasonably up with the pack makes for a few more fun rides.

2

Competition / Re: 2020 Classic Nats

« on: December 27, 2019, 12:36:21 am »

This is the statement put to the decision makers about the pre 78 rule change (from MA website), seems sensible and congrats the the MA MX people for making the decision:

"With many pre 1978 model motorcycles delivered from new in 1977 with
both front & rear wheel travel exceeding the current 229mm (9 inches), it
seems silly to be asked to de-engineer a motorcycle from standard OEM
specifications, as delivered in 1977, to meet the 229mm (9inch) travel
restrictions for the pre 1978 competition class. Relaxing the travel
restrictions to OEM specifications will not only reflect the true era of
motorcycles from the period but also encourage more potential
competitors to the class. It is currently a deterrent for new competitors to
enter the class having to de-engineer their machines from OEM
specifications."

Now, someone with a better knowledge of pre 75 bikes than me please put the same logic to MA for the pre 75 class.

3

Competition / Re: 2020 Classic Nats

« on: December 26, 2019, 12:04:53 am »

KTM/Penton 74.5 250 & 400

4

Competition / Re: 2020 Classic Nats

« on: December 24, 2019, 06:11:04 pm »

Great news about pre 78 suspension rule change to allow a standard pre 78 bike to compete without spacers to reduce the suspension travel.

Would be good if the pre 75 rules were the same so pre 75 bikes could be run as they were factory made without having to fit spacers

5

Wanted / Re: Need '78 KTM 400 exhaust

« on: October 20, 2019, 11:58:11 pm »

Thanks Hoony, lookin' for an original because I want it to look right and if I cannot find an original then a lend of one to get it copied

6

Wanted / Need '78 KTM 400 exhaust

« on: October 19, 2019, 03:15:36 pm »

Need a pipe for my '78 KTM 400 Mx bike, anyone have one to sell?

Or, if you have one you cannot part with then some photos/dimensions (or a lend) to help me get one made would be ok.

Thanks

Michael

(perhaps the '79 pipe is the same?)

7

Husqvarna / Re: '75 WR400 bits

« on: May 19, 2019, 04:27:37 pm »

Sidestand - got one - send me the postal address - you owe me a beer.

8

Tech Talk / Re: electrexworld stk-185

« on: April 22, 2019, 03:20:03 pm »

yes, on my CR450 Husky, was easy to set up and gave a strong spark even when the kickstart was "pushed" by hand, and the retard by electronic setup was a great help in kick starting the 450, price was cheaper than the others and delivery from the UK was reasonable, very happy customer

9

General Discussion / Re: Plastic Guard suppliers

« on: January 21, 2019, 01:05:23 am »

Rosco - if you do buy from DC ask then NOT to drill the holes in the side plates - they must have a crappy jig because on my 2 Pentons the holes were way off - or the KTM factory welded tabs at random places but I don't think so......
Do the holes yourself to get a good fit.

10

Tech Talk / Re: Alluminium disc rotors, your thoughts?

« on: July 15, 2018, 05:05:34 pm »

Thanks Micks,  that is part of MA I did not know about - a good resource

Some Googling:

Strength (and hardness) is inversely proportional to ductility; this means the greater the tensile strength (and hardness) the less ductile and more brittle is your material. Since it is already established that Ti alloys (like, Ti-Al-V) have high values of strength, it follows that they would be hard but brittle, which means while it would require greater stresses to fracture a Ti alloy than say Aluminum, once that stress is reached, a Ti alloy will instantaneously fracture and fail, unlike an Al alloy that will plastically deform significantly before failing.

What is peculiar about titanium and its alloys is that even very limited amounts of other elements, in quantities that in steel would be acceptable as impurities or would be beneficial, particularly oxygen and nitrogen are detrimental for toughness. Titanium is a sensible fella. He embrittles very rapidly if you allow him to oxidise or pick up other elements (he tends to pick them all up and by the way that’s why he's so difficult to machine, he has a tendency to allow other elements to diffuse into itself very easily).

11

Tech Talk / Re: Alluminium disc rotors, your thoughts?

« on: July 14, 2018, 05:48:50 am »

GMC - you are correct about Titanium - I should have checked the rule says:

12.13.0.1 The use of titanium in the construction
of the frame, the front forks, the
handlebars, the swinging arm, the
swinging arm spindles and the wheel
spindles, is forbidden unless OEM. The
use of light alloys for wheel spindles is
also forbidden unless OEM. The use of
titanium alloy nuts and bolts is allowed.

So brake parts look ok

12

General Discussion / Re: Forumn disappeared

« on: July 12, 2018, 05:32:52 pm »

same here

13

Tech Talk / Re: Alluminium disc rotors, your thoughts?

« on: July 09, 2018, 06:41:02 pm »

Check the rulebook b4 using titanium
(happy to be corrected but as I recall it's ok to make components out of any old aluminum but titanium of which even the crappiest grade is stronger than ally is a not on - go figure)

14

Tech Talk / Re: Best value twin shock?

« on: June 15, 2018, 06:12:19 pm »

have got shocks from YSS - he asked me questions to make sure the bike was correct for the year, about my riding ability, my weight and even the ride height but first telling me what standard was. for $1200 the shocks were very close to correct when delivered and have done a lot of races without fault and no leaks at all.

15

KTM / Re: 1973 MC5

« on: February 16, 2018, 08:25:18 pm »

Slakewell, that's the best thing about this board, you learn something every day, on my 77 MC5 I made shims to go in between the frame and the swing arm, and it was an absolute pain to set up and get it right, now that you mention the correct way to do it it's like turning on the light....