Anyone else racing on original factory rings?

[Big Mac]

Anyone who follows this forum is familiar with Thom Green and his "'76 250 MC5 (Original Owner)" signature. But check out this tidbit of info...he bought this '76 KTM/Penton new from the dealer back in the day, put a pipe on it and some aluminum side covers, and raced it a couple seasons. He dug it back out of storage a few years ago for some trail riding, and now has about a season and a half of pretty hardcore monthly racing as well as the recent ISDTRR.

So Thom now says he's thinking maybe it's about time to check the rings again, just in case they're starting to show a bit more wear. Seems Thom's only had the top end off ONCE in the bike's entire life, and the rings measured well within spec at the time....so here 28 years later, the original factory stock rings are due for another look-see, just in case! The pic here of Thom, who's no featherweight, roosting and lofting the front end during the final +50 class moto in Tulsa speaks of the strength of this particular motor--I guess it's just now broken in sufficiently...

http://www.tvrc.org/Photos/Photos%202004/Isdt04/TULSA_ISDT_RR_2004_252.jpg

(Photo courtesy of Chkitout and Texas Vintage Racing site--thanks!)

I doubt there are more than a handful of old race bikes out there sporting original rings and still running strong. I'd guess KTM motors make up a sizeable % of those that can be found. I know I was pretty amazed when Thom told me about his "nearly fresh" top end. We chatted with Mr. John Penton hisself at the RR, and I mentioned the still-on-original-rings bike. He seemed pleased and satisfied, but not bowled over by it...should have figured.   Mac

[Rocket]

Big Mac
The 76 175 that I rode at Tulsa, #219 was all original, never been apart as far as I can tell.  When I bought the bike this summer it still had the original Metzler tires that looked like new, but had cracking in the side walls so I pulled them off.  Started first kick every morning and never missed a beat.  
Rocket

[tomale]

Very cool Rocket, Jon my face is turning red. I have to say that the 250 ran like the champ it is. We sure had a great time at the reunion ride. I would have liked to meet a few more of the guys that were there that I missed. Rocket, I saw you but did not get the chance to say Hi. to my disappointment. Maybe next time.

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
78' 400 MC5

[farmer58za]

Lovely pic Thom
It was good meeting you at the RR.
My '75 400 has never been opened. I was given a head gasket when I bought it. The owner said he planned to use it when he did a top end check. The bike was never raced but has seen hard use as the clutch  slips. Motor is a bit rattly but then what isn't after 30 years .
Regards
David

Regards

David
'75 KTM GS175
'75 KTM GS250
'75 KTM GS400

[Rocket]

Thom
I wish I would have had more time to meet everybody too, weekend went way too fast.  Hopefully next year.  I've also got a 75 400 that still has the original piston and rings.  They last a looong time!
Rocket

[Big Mac]

Okay, so maybe there's at least 4-5 KTMs out there on original rings still, after lots of hours racing. My point of reference until meeting up with vintage Penton/KTMs a couple of years ago was that of wrung-out rat bikes I guess. Seems like here in the wild west where there is (or at least has been) plenty of close-in places to ride, anything that ran, got run and run hard--which means very few left from the era that were properly cared for or put away in any kind of semi-fresh condition.

I've come into and cracked open about a half dozen '70s KTM top ends, and from all of those, only 2 had been over-bored. One standard bore '73 250 showed only .001" wear and another was only at .003" out. Something to do with the diamond-hard steel those Euros used (gratefully). Still, after many changed hands, no way to know how many rings any of the ones I've owned have been through. Have never found a bike from that far eastern island country that showed that little wear. So, I'm STILL impressed!!

[Mike Lenz]

In 96 I bought a 74 250 from CA. Owner said he raced it two years or so and then rode it spareingly, desert racing mainly. Never tore it down. I checked the compression and it was 195 lbs! All the other bearings were tight so I decieded to just go over it and race it in 97. Since 98 my son has raced it off and on. Today it still has 195 lbs compression!! I really dont understand ZERO wear, but I like it. By the way Ive been racing my 400 off and on since 98 and it to still has 190 lbs as it did in 98! I have torn down my 400 because I broke the countershaft off(must be running pretty good to do that) and I am starting to get some play in the rod as all these 400's do. Maybe the new rod kits are better. This was a NOS rod. But the top end was still good to go. I also have gone thru a clutch I believe in both bikes in that time. Oh yea and a new spark plug for each once a year. I actually wear out the electrode on the plugs I can run them so long (Im still running the old Bosch silver tip plugs that came in them back then, until I run out someday). I am running Maxima Super M at 32 to 1 and have not had to decarbon them either, however I also am careful to not rum them overly rich on the jetting which is the biggest cause of carbon buildup. I also make SURE the airboxes  are TIGHT and carb boots are properly fitted and sealed, and I grease the inside of the airbox (im talking 74 style bikes here) and keep my filters clean and well oiled. Most the engine problems Ive seen on KTM's were do to air leaks between the filter and carb or the front carb mount. Loose or not properly fitted and sealed boots (or carbs) or leaks in the airbox.
Am I spoiled with all this reliability... you bet!!!

I just re read this and I cant fault any who dont believe it, but its true. I cant hardly believe it.