1975 KTM 250 MX - 1st Project Bike/Newbie

[KTMTOM]

Great info John, thank you! It's settled for me. Res. down as the Euros would have it! Anyone have some pix they could share on how the clutch & throttle cables were originally routed on this bike with the number plate installed? Decided afterall to go with the stock Magura throttle with the front pull/trap door.

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[SouthRider]

Keep in mind that shock install was done by the dealer - not the factory. They were shipped with shocks (and fork springs) in a box to collapse the bike & keep the container size small. That said - there were pictures of bikes on brochures from the factory, and they probably changed over time. Each dealer installed them as they saw fit.

Originally all shocks were installed heavy side down, and then as Dane reminds us they were flipped by racers to reduce the unsprung weight. Over time dealers began installing them in the "up" position.

If you want the period correct look of a "racer" then the shocks should be mounted with the reservoirs "up".

And yes - a few ounces added all the way to the end of a swingarm does increase the "leverage" of adding that weight. Imagine adding 10 pounds weight to the swingarm at the rear axle nut & trying to lift the wheel - then move the 10 pounds to the other end of the swingarm by the countershaft & try lifting from the wheel again.

Every time the wheel raises or lowers the shock has to carry that little bit of extra leveraged weight when they are in the down position.

Unsprung weight is a huge issue - it refers to the weight that is not carried by the suspension or the "dead weight". It is always preferable to minimize unsprung weight as much as possible. Factory race bikes go to elaborate lengths to reduce fractions of grams of unsprung weight. It is also the reason that modern bikes have upside down forks today......

Oh - and the reason to put the nuts on the inside is to minimize damage caused by "impacts" (trees, rocks, bikes) to the nuts. The bolt heads are less vulnerable to damage than the nuts are.


Clark




1979 SERA Louisiana State Champ

[KTMTOM]

GREAT information! That's great stuff, thank you! Hope not to offend anyone here, but I located a gentelman on KTMTALK in the vintage classifieds who reproduces stickers and agreed to reproduce the OEM stickers that go on the bottom of the reservoirs. So... If nothing else, I'm leaving them on the bottom just to show the stickers off! He's also reproducing the "WELTMEISTER" sticker I was questioning in another post. Seems like he can do just about anything so look him up for all your sticker needs!! Screen name "Hwy"... I'll post some pix when I get them put on this week.

Current progress. Far as I care to go without the air-box in place which I hear got "color" today!


1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[400gs6]

Great thread.  The bike is looking fantastic.  I've bought a few decals from Hwy, he does very nice work for short money.  FWIW, I've never been able to remove or install a CMF Penton pipe with the air box in place.  I'll be surprised if you can get the pipe in place (and without scratching it up) with the airbox mounted.

Here's a pic of my old '75 Penton.  All original, 700 street miles. Never in the mud.

[KTMTOM]

Wow, that's beautiful! I put 700 miles on my 2009 in the last 3 months, can't imagine holding onto a bike for 30 some years and only having that many miles on it! Good tip on the pipe/air box install. I THOUGHT I took the pipe out before removing the airbox, but just don't recall so that's good info. Goes in real easy with a few twists & turns without it in place. I was just can't recall how the box went in. Does it slide in from the side, or from the top down? Guess I'll figure it out, but for sure, trying not to scratch everything up is the key! Thanks again!

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[400gs6]

Mine went in from the side.

[KTMTOM]

It's the little things, but I got the stickers for the Zokes today. LOVE the detail! It's a little thing as I say, but sure ads a lot to the overall look of the project. Now it's onto finding Bing carb replacement parts. Called and talked to Bing today and learned they don't make the slides in mass quantity for my 54 anymore so the small custom run of them that they do have puts the price up close to $150. Ouch. Sure, for a few more dollars I could put something else on, but I'm really goin for more the OEM feel. Has anyone ever heard of turning down a slide just enough to take out any scuffs/scratches and chrome plating it? Not sure what thicnkness coating a slide would ad, but it seems by adding a bit extra and turning it back down to match the bore of the carb body would do the trick? Maybe??? Wishful thinking?!  




1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[400gs6]

Great thread.  The bike is looking fantastic.  I've bought a few decals from Hwy, he does very nice work for short money.  FWIW, I've never been able to remove or install a CMF Penton pipe with the air box in place.  I'll be surprised if you can get the pipe in place (and without scratching it up) with the airbox mounted.

Here's a pic of my old '75 Penton.  All original, 700 street miles. Never in the mud.

[KTMTOM]

Wow, that's beautiful! I put 700 miles on my 2009 in the last 3 months, can't imagine holding onto a bike for 30 some years and only having that many miles on it! Good tip on the pipe/air box install. I THOUGHT I took the pipe out before removing the airbox, but just don't recall so that's good info. Goes in real easy with a few twists & turns without it in place. I was just can't recall how the box went in. Does it slide in from the side, or from the top down? Guess I'll figure it out, but for sure, trying not to scratch everything up is the key! Thanks again!

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[400gs6]

Mine went in from the side.

[KTMTOM]

It's the little things, but I got the stickers for the Zokes today. LOVE the detail! It's a little thing as I say, but sure ads a lot to the overall look of the project. Now it's onto finding Bing carb replacement parts. Called and talked to Bing today and learned they don't make the slides in mass quantity for my 54 anymore so the small custom run of them that they do have puts the price up close to $150. Ouch. Sure, for a few more dollars I could put something else on, but I'm really goin for more the OEM feel. Has anyone ever heard of turning down a slide just enough to take out any scuffs/scratches and chrome plating it? Not sure what thicnkness coating a slide would ad, but it seems by adding a bit extra and turning it back down to match the bore of the carb body would do the trick? Maybe??? Wishful thinking?!  




1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[KTMTOM]

AHHHHHHHHHHHH!!!!!!!!!! So my tank and side panels have been "delayed".... Sent them back to my buddy in Indiana to get repainted and expected them this week. They were just in his buddies paint booth letting the clear dry for a few days before putting the stickers on and shipping them off. Friday night, according to a nosey neighbor, 3 guys in a panel van broke into the shop and stole EVERYTHING in the shop, including my tank & side panels!! WHY DIDN'T THE NEIGBOR CALL THE COPS?!!!! They took off with well over $150k in tools and car parts being worked on. Long story short... Just got the call from my buddy who was telling me this story, just now for the first time, that he was with the state police in a barn not far from there and they had located some of his parts, and my tank/side panels, all be it they had be spray painted black to hide the new paint job!! Feel bad for the guy. He was SICK about it to say the least. No kidding!! So I'm thinking to myself... How flipping lucky and I, but man... Both my buddy and his buddy are getting totally hosed on the deal. If it wasn't bolted down and they don't have receipts, insurance is pretty much giving them the finger.... Terrible situation,  but the good news out if it all is, I still get my tank and side panels back! Can't imagine what it would have cost to try to find a replacement tank in as good a shape as the one I have... Oh my.... The project lives on!

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[Speedy]

quote:Originally posted by KTMTOM

AHHHHHHHHHHHH!!!!!!!!!! So my tank and side panels have been "delayed".... Sent them back to my buddy in Indiana to get repainted and expected them this week. They were just in his buddies paint booth letting the clear dry for a few days before putting the stickers on and shipping them off. Friday night, according to a nosey neighbor, 3 guys in a panel van broke into the shop and stole EVERYTHING in the shop, including my tank & side panels!! WHY DIDN'T THE NEIGBOR CALL THE COPS?!!!! They took off with well over $150k in tools and car parts being worked on. Long story short... Just got the call from my buddy who was telling me this story, just now for the first time, that he was with the state police in a barn not far from there and they had located some of his parts, and my tank/side panels, all be it they had be spray painted black to hide the new paint job!! Feel bad for the guy. He was SICK about it to say the least. No kidding!! So I'm thinking to myself... How flipping lucky and I, but man... Both my buddy and his buddy are getting totally hosed on the deal. If it wasn't bolted down and they don't have receipts, insurance is pretty much giving them the finger.... Terrible situation,  but the good news out if it all is, I still get my tank and side panels back! Can't imagine what it would have cost to try to find a replacement tank in as good a shape as the one I have... Oh my.... The project lives on!

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

Hello Tom.
For a SHOW bike,the mounting does no matter.For competition you would absolutely mount the shocks with the reservoirs UP.
About carb for your PENTON KTM.
Penton offered the bikes with a stock BING,or the far better LECTRON carb.
Has anybody ever told you where the name BING came from?

[KTMTOM]

Good stuff, thanks. NO Idea where the name Bing came from, but I hear rumor it may be from the sound it makes when it hit's the trash can!

1975 KTM 250 MX
2009 KTM 250 XC-W (e)

[Rain Man]

Oh Speedy you are so correct in that statement about the Bing and the Lectron carbs!! Just ask 400GS6, he just put one on his 400 that ran lousier than lousy.
 Nice 250 KTM TOM. I got a Canadian built KTM frame with a  fork lock on it.
 The pictures are actually helping me in my direction building a 74 Penton 250. an almost mirror image... So your getting advice on this site as well as us seasoned POG vets.
 Now whats the answer Speedy??  why do they call it a Bing. Something to do with aircraft I bet?

Raymond
 Down East Pentons