Anybody know what the rear travel is on that bike with the stock length shocks in the lowest frame position? Thats the one with the single lower mount back by the axle and the three frame mounts.
Also, are there any 100 liners out there? And, would it be possible to put a 100 liner in a 125 D cylinder? By eye, the alloy parts of the cylinders look the same, only the 100 uses a thicker liner but I could be wrong.
Brian
Brian
if you look in the featured bikes section you will see a 75 Six-Days,
there is only one lower shock mount on the swingarm and the shocks look to be 13.5"
as for the cyl i am to understand you "can not" put a 100 liner in a 125 cyl,
check with Forrest Stahl but that is what i am to believe,
maybe some one else can confirm this ???
hope this helps,
EDIT : i just measured a 125 "D" liner that is in a B cyl. that i have against a stock 100 cyl,
the "OD" on the 125 liner is 60mm and the 100 liner is 56mm,
"IMO" there is NO poss. way to install a 100 liner in a 125 cyl.
again i hope this info helps
regards,
Mike Gallagher, NJ.
[email protected]
I wonder if a 100cc liner could be made, We have a guy up here in the northwest who probably could do it.. Superior sleeve..888.700.5839
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
74'250 hare scrambler (project)
74' 1/2 440 maico
78' 440 maico
72' cr125 Husky (project)
74' TM125 suzuki
93' RMx 250 suzuki
Quotequote:Originally posted by brian kirby
Anybody know what the rear travel is on that bike with the stock length shocks in the lowest frame position? Thats the one with the single lower mount back by the axle and the three frame mounts.
Brian
Brian, I will get back to you on that tomorrow.
Of course, a 100cc D engine can be made. A liner with the correct I.D. of 48mm, and correct O.D. to be installed into the 125cc cylinder. It is likely that this special order or special built liner will need the ports to be cut out. I have seen liners like this in the past... just need to get out the grinder and cut the port openings to match the port specs. joe
Kustom Kraft has made custom liners in the past.
Bob Bean
1986 ISDE Italy
1987 ISDE Poland
1989 ISDE Germany
1973 Jackpiner 175
1974 Penton 250 Harescrambler
1976 Husky 250CR
1985 Husky 400WRX
1985 Husky 400WR
Am I missing something here? Why not bolt a 100 topend on the 125 bottomend? Sounds a whole lot easier.
Another question is what can you do with a longer travel 100? AHRMA does not offer it and AMA has dropped it. Some local VMX areas offer it and the Marty Tripes "Let's a bunch of us cheat" Series has it but there you might as well leave it a 125 and call it a 100.:D
Larry P
Quotequote:Originally posted by Larry Perkins
Another question is what can you do with a longer travel 100? AHRMA does not offer it and AMA has dropped it. Some local VMX areas offer it and the Marty Tripes "Let's a bunch of us cheat" Series has it but there you might as well leave it a 125 and call it a 100.:D
Larry P
I'm going to build one for the Marty Tripes races. I'll build it as a 100, if someone beats me it wont be because they have too big an engine, it will be because they outrode me.
Brian
Brian,
So if you are beat by a 125 2 stroke or a 200 four stroke it is only because they outrode you[?] Brian, Brian. We have found another point to differ on.[:o)]
Larry P
I agree with Brian. It sounds like he wants to build a legal bike for the race. He can't control what others do.....
Go for it Brian. I think you can be competetive with them. It isn't always about horsepower.
Quotequote:Originally posted by Larry Perkins
Brian,
So if you are beat by a 125 2 stroke or a 200 four stroke it is only because they outrode you[?] Brian, Brian. We have found another point to differ on.[:o)]
Larry P
I should rephrase that. I am going to build a legal bike, and if I get beat by someone because they have a little extra somewhere, I dont care. When I get beat, virtually 100% of the time, I can honestly say it was because the rider was faster than me, I cant remember the last time I got beat and thought it was because they had a better bike.
Plus, even if they have a little extra, from the photos I've seen, those Marty Tripes 100 guys will need some extra CCs to get their power to weight ratio to where mine is. :D
Brian
Brian, You can't use a 1975 frame for Sportsman Vintage. It is illegal. It is more than just a swingarm change. It is an entirely differnt frame design. So just getting the travel right is not legal. It will be still in the Post Vintage Historic Class. If you want to build a 100/6D that is not the problem. It is the frame is a long travel frame. I am surprise you weren't protested with your other bike with the modified swingarm. Rules state you must mount the shock in the middle hole on the CMF frame swingarm . Yours is moved way forward of that.
Just say'n,
Dwight
You can run any hole you want as long as your rear wheel travel is 4 inchs. What page did you see that rule? Never seen or heard of such. Have also seen a 1975 run in the classic class, under like design .
Quotequote:Originally posted by brian kirby
Anybody know what the rear travel is on that bike with the stock length shocks in the lowest frame position? Thats the one with the single lower mount back by the axle and the three frame mounts.
- OEM '74 1/2 & '75 Ceriani/Corte & Cosso
13 3/8" long
Shaft travel , 3 5/16"
Rear wheel travel = 5"
- 2003 Works Performance
13 1/2" long
Shaft travel , 2 3/4"
Rear wheel travel = 4"
- 1975 Gas Girlings (these came on '75 Six-Day I bought)
13 3/8" long
Shaft travel , 4 3/16"
Rear wheel travel = 6 1/4"
Bob
Quotequote:Originally posted by gooddirt
You can run any hole you want as long as your rear wheel travel is 4 inchs. What page did you see that rule? Never seen or heard of such. Have also seen a 1975 run in the classic class, under like design .
I can no longer find that rule with regards to the Penton swingarm about mounting in middle hole. There used to be one. As for the 1975 frame is it different. It is not of like design. Only the engine is similar. If you want to use that excuse then why not run a Husky 175GP in the Sportsman class. The engine is of like design although the the frame is quite different.
11.1 CLASSES AND ELIGIBILITY
These classes are intended for model year 1974 and like machines that are essentially unchanged.
Other 1975-model motorcycles are not eligible.
NOTE: Like-design Sportsman machines:
a) 1975 Maicos are not legal for AHRMA vintage competition, although the 1975
frame may be used as a replacement for the 19741/2 GP models. The '741/2 fork
assembly, swingarm, hubs and engine must be retained. Any and all 1975 models
must meet the 7-inch-front/4-inch-rear wheel suspension travel requirement measured
at the axle.
b) 1975 Bultaco model 134-136, 143 and 144 frames may be used as replacement
frames in Sportsman. Swingarm must be pre-1974, 4-inch travel.
The Sportsman eligibility list is now complete with regard to non-like-design post-
1974 machines. However, proposals for inclusion of like-design machines are always
welcome.
m) No major components may be later than 1974 (i.e., frame, forks, engine, gearbox,
wheels, etc.) (This should also include ribbed Ceriani forks as they were not available till late 1975)
12.1.2 Historic 125: Certain 88-125cc machines built up to and including the 1977 model year
that made up the first generation long-travel, small bore motorcycles. Eligible machines
include:
1975-77 Bultaco Pursang 125
1975-77 Can-Am TNT, Qualifier and MX 125, up to MX3 (MX4 and later see Gran
Prix classes)
1975-78 CZ 125
1975-78 Honda CR, MR, MT 125
1975-77 Husqvarna CR, WR 125
1975-77 Kawasaki KX, KE, KD 125
1975-77 Maico 125 GP
1975-77 Montesa Cappra 125 VA & Enduro 125. VB, 1977 & 1978 models only; no
later-model components, including swingarm.
1975-77 Penton/KTM 125 with Sachs or KTM engine. (1978 Penton/KTM is
================================================
not a like-design model. See GP classes.)
1975-77 Suzuki RM, TM, 125
1975-77 Yamaha MX, YZ, DT, 125
1978 Kawasaki KX125 A4
Quotequote:Originally posted by Dwight Rudder
Brian, You can't use a 1975 frame for Sportsman Vintage. It is illegal. It is more than just a swingarm change. It is an entirely differnt frame design. So just getting the travel right is not legal. It will be still in the Post Vintage Historic Class. If you want to build a 100/6D that is not the problem. It is the frame is a long travel frame. I am surprise you weren't protested with your other bike with the modified swingarm. Rules state you must mount the shock in the middle hole on the CMF frame swingarm . Yours is moved way forward of that.
Just say'n,
Dwight
Dwight.
First, I am aware the '75 is not legal for AHRMA vintage, where did I ever say I was going to race it in an AHRMA event? This bike will be for the Marty Tripes 100 vintage class which allows any kind of rear shock configuration limited to 7" of travel.
Second, the RULES never said anything about what place to mount the shocks, it was in the "cheat sheet" Dave Boydston put together with the shaft travel lengths for different bikes. If you go to the "member resources" page on the AHRMA website it is at the bottom of the page. On the Penton the visible shock travel had a note that said "middle hole, always check". It was NEVER in the rules.
On my other bike, it has 4" travel (a little less actually). I pointed out the modified shock mount at tech the first time I took it to James Smith so he would specifically measure it differently than a stock CMF frame. My bike is no different than putting a Mag swingarm on an older Husky or older Maicos with frames hacked up to do the "Wheelsmith" mod like the 74.5s. It is completely legal and if someone wants to protest the bike, fine by me, they will lose their protest deposit.
Brian
Dwight "Half Cocked" Rudder. Just teasing Dwight. Brian is right on this one but it brings up the point once again of AHRMA's analness on some things like a 1/4 inch too much travel and looking the other way on engine mods and pipes that could never have existed in "The Day". AHRMA is the NASCAR of Vintage motorcycling as far as rules go.
Larry P
Brian " Second, the RULES never said anything about what place to mount the shocks, it was in the "cheat sheet" Dave Boydston put together with the shaft travel lengths for different bikes. If you go to the "member resources" page on the AHRMA website it is at the bottom of the page. On the Penton the visible shock travel had a note that said "middle hole, always check". It was NEVER in the rules."
I knew I had read it somewhere as it has been brought up before. Thanks. If you plan on racing it only in the Marty Tripes 100 series that would be no problem. Only would be if raced in AHRMA Vintage 100 or any other Vintage class. You should have said so to begin with. As for your other bike, I might have to see that measurement myself. LOL. Remember on a setup like that 3/4 of the bumper is counted as travel. Not just the 1/2 bumper as on the stock bike. Besides. I don't think I have ever seen a swingarm like that used back in the day. The other swingarms you mentioned were stock but on another frame. So, What was your point on modifying it ? What were you trying to accomplish ? I have seen others go to longer travel shocks for more control but move the mounting to the rearward hole so the travel at rear wheel would be legal. But you would have to shorten the shock travel to be legal ? Just wondering. Maybe something I need to do myself.
Quotequote:Originally posted by Larry Perkins
Dwight "Half Cocked" Rudder. Just teasing Dwight. Brian is right on this one but it brings up the point once again of AHRMA's analness on some things like a 1/4 inch too much travel and looking the other way on engine mods and pipes that could never have existed in "The Day". AHRMA is the NASCAR of Vintage motorcycling as far as rules go.
Larry P
But that is the point. AHRMA is right in trying to preserve the vintage racing and not turning it into a competition of modifying all the old bikes into more modern bikes. I just don't understand what some mods are trying to accomplish. Others we can obviously see and they are bending the rules to the limit and then some.
Dwight
I think AHRMA should have a rule of only one brand of bike allowed. This way even playing field for all involved. This would be the right thing to do, in this political correct world we live in today. Then it would come down to the rider. My vote PENTON would to be the brand. :D later Gary
Quotequote:Besides. I don't think I have ever seen a swingarm like that used back in the day. The other swingarms you mentioned were stock but on another frame. So, What was your point on modifying it ? What were you trying to accomplish ?
I didnt modify it, the swingarm was modified by the original owner "back in the day" in SoCal. Paul Johnstone bought the bike from the original owner, then sold it to me. I have not changed a single thing on the bike, it is exactly as the original owner raced it in SoCal in '72. I have no idea what the original owner's intent was modifying the lower mount, but I am not going to change it since its the textbook definition of a "period correct" mod.
James has a computer at tech with a program he enters the measurements from swingarm pivot, top and bottom shock mounts and rear axle, it then tells him how much visible shaft travel is allowed on custom mount setups. The shocks I'm running measure out at about 3.9" of travel when mounted on my bike, James did it himself. Just for my own curiosity, since I've never actually done it, I am going to take the spring off a shock and do the "actual travel" measurement to see what it has.
Brian
Brian, interested about the program. Is it available somewhere or is it a program he wrote? I haven't raced an AHRMA race for several years, but I remember they had some kind of conversion chart for many of the standard bikes and modifications. But if you had some sort of custom modification, the chart did not work. I remember riding for Mid-Valley CZ in 1973-4, we cut the frame, move both the upper and lower mounts, etc. These mods were done in 1973-4 time frame. No way could the charts AHRMA had be able to accurately give me a shock travel distance to equate for wheel travel because of these mods. They made me remove the springs and did an actual measurement at Tulare. Again, this was several years ago, maybe 10 or more.
I haven't checked the rule book lately, but I think it is still WHEEL or AXLE travel, not shock travel.
Good luck with the 100.
Lloyd
Lloyd,
I'm not sure where the program came from, but it is a simple triangulation program, all you do is plug in the distances from the various points and it calculates the theoretical travel at the rear axle. James' sister is a programmer, so she might have written it. The have it specifically for custom configurations that dont fit the chart so they dont have to make people take their springs off like they used to. James is a smart guy, you are not going to slip anything by him at tech. You are right though, if there is any further doubt, actual travel as measured at the rear axle is the final say.
Brian
AS a side note, I would guess my setup would be close to a Falta CZ, Mag Husky, or 74.5 Maico. In the chart from AHRMA the Falta CZ and Mag are listed as 2 3/4" and Maico is 2 1/2", mine shocks measure 2 3/8".
Brian
If I'am not mistaken bill cappel ran his 1975 and won the national ahrma series 125 classic class, or at least he ran it a year or two.
Baby Brian,
Here's what you missed at Diamond Dons. Fun Fun Fun!
http://www.youtube.com/watch?v=FwCdTF5ych8&feature=youtu.be
See ya next trip! Pablo
[/quote] I didnt modify it, the swingarm was modified by the original owner "back in the day" in SoCal. Paul Johnstone bought the bike from the original owner, then sold it to me. I have not changed a single thing on the bike, it is exactly as the original owner raced it in SoCal in '72. Brian
[/quote]
I can promise that he didn't race the bike that way back in 1972. Maybe in 1975-76. Nobody changed lower mounts till 1975
Dwight,
Nobody is a lot of people. I had a older Berkshire in early 1974 that we forwarded mounted the shocks on but bent the swingarm from no gussets and went back stock. We did it in about April after getting in one of the 74.5 model Pentons which had forward mount and laydown stock from the factory.
Larry P
I am glad to know someone else bent a swingarm back then[:p].
Ron Carbaugh
Ron,
My Mother didn't call me "The Flying Monkey" for nothing.:D
Larry P
Here's a note. In 1969 or even in 68, The Kawasaki F21M had a different than normal rear shock setup. The shocks themselves were 3 7/8" of travel, but where they were mounted gave the swing arm 4 5/8" of travel.
So some of the guys I knew, were moving their shocks too. One of my friends who rode a Baja 100 Harley moved his and that was back in early 1970.
Donny Smith
Paragould, AR
Quotequote:Originally posted by Dwight Rudder
I can promise that he didn't race the bike that way back in 1972. Maybe in 1975-76. Nobody changed lower mounts till 1975
Regardless of when it was done (I didnt do it so I have no idea) the bike IS legal, and has been verified multiple times that it is legal. Moving shocks forward is not against the rules as long as it meets the travel limits. Personally, I would never do that mod to a bike now because I prefer to leave them stock, but this bike is a time capsule of the SoCal racing scene when Pentons still dominated before the YZ and the Elsinore. This bike will never be changed from its current configuration because I want to preserve it as it is.
Brian
If it was me, I would save that swingarm and buy another stock swingarm to use when racing. That way you can save the originally modified swingarm to use or display at a later date.
IMO,
Dwight
Just in case some folks who are not familiar with my bike will know what we are talking about, I will put a couple of pictures. The only difference from these pictures is I had Works Performance build a set of legal shocks for it since the Konis in this picture didnt last long after I started riding it. Also, I forgot, James had to put spacers in these Konis because they were over 4" after he calculated it, I think I needed two of them.
(http://i1177.photobucket.com/albums/x348/kartwheel68/DSC_0023.jpg)
(http://i1177.photobucket.com/albums/x348/kartwheel68/DSC_0033.jpg)
I never bothered to measure it, but I would guess its around 2" forward of the stock mount.
Brian
WOW, I was expecting some over the top, wild works machine,the way this little Penton beats 250cc and 400cc bike in the woods?
Does not look that dangerous to me! Maybe it's the rider that's dangerous! IMHO....
Pablo(socal)
I dont know how much credit goes to me, or the fact that Mr Penton and KTM designed one of the most perfectly balanced, best handling motorcycles I've ever ridden in my life, any size, any brand, any year. IMO the only thing that keeps a '72 Sachs powered CMF Penton from being the best dirt bike ever made is the shifting.
One last thing on early 70s bike mods and I'm done. I know for a fact that people did move shocks forward before '75 because I've seen pictures of the Super Rat Ernie raced. It had leading axle 35mm Betor forks (like on a Sherpa), the frame was sectioned and the engine lowered in the frame, hand made aluminum tank, reed valve, and a box section steel swing arm with shocks mounted as far or farther forward than on my bike. The bike was so modified you couldnt even tell what kind of bike it started out as. This was in '72 out of a tiny little Mom & Pop dealership in Pensacola Florida, 2000 miles away from the Mecca of motorcycling in SoCal. The bike was so trick it even got nicknamed by Dixie Cycle News as the "$2000 Super Rat". Lots of experimentation was going on back then, and its hard to say when something could or could not have been done. If Ernie had a bike that had forward mounted shocks in Pensacola in '72, I have no reason to doubt it could happen in SoCal too.
Brian
Compared to a stock Rat, the $2000 J& R Super Hodaka was far superior ... Maico-like handling in a sub-200 pound package. The swingarm mods were directed at keeping the bike from looping out in the deep woops of the sandy Gulf Coast race tracks. It worked quite well. More suspension travel was a byproduct of lengthening the swingarm. We didn't fully appreciate it at the time. 100cc racing back then was all about porting, reed valves and how many holes you could put in the piston intake skirt. A CMF Penton may have been as good or even a better bike, but they didn't show up at the MX track in our area.
Ernie P.
Chattanooga, TN