Here's a Q for you tech guy's like Mike Winter, Mike Lenz or Larry perkins, as well as the rest of you aficionado's.
Are there any differences in the Gray leg (slider) Zoke's and the Gold leg Zoke's (i.e. travel & piston rod flow holes, general performance) or is it just the color?
Reworking '77 250 MC 5 to have a set of sweptback triple clamps, I have a set of 35's & 38's trips' leg's & all. Looking for '78 Torque pipe (fatter pipe) and someone to rebuild my 13.5" Marzocchi gas shocks.
All this came about after I saw the '77 400 Moiseev on the 495KTM site about a couple years ago. Anyone notice that it appears to be sporting some hefty travel with those newer forks, ('78'9'80's?) and the fatter pipe? Can anybody tell if the rear shocks are any longer?
My Main concern is how will this effect the geometry of the bike in general with handleing characteristic's.
I would like to set-up my machine the same as this, or as close as possible considering my 6'6", 250 lb. frame. Any clue on rear shock set-up especially, would be greatly appriciated.
Thanx, Mark
'77 250 MC5
'82 250 MC(//)
Mark,
The gray legs started out greenish-gold but it fades/wears off. It was not paint, but some kind of coating for the magnesium legs, someone here probably knows what the coating was. '77 Can-Am MX-3s had the same forks and most of them have the greenish-gold gone too.
Brian
'72 Berkshire
I can rebuild your Marzocchi shocks, I have new seals, o-rings etc.
Rocket
I have been toying with swapping out my zokes which are 35 mm for a set of the later models which are 38, they are longer but I think ther are a couple of ways you can deal with it... you could leave them stock and then use longer shocks that keep the fork angle the same. or you could push the fork tubes up into the triple clamps to return them to stock. what I do not know is if there will be a problem matching the them to the steering head.. some bikes use tapered bearing and the 76/77 uses ball bearings...
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)
To the best of my knowledge, ball bearings were used throughout the 1981 models with Marzocchi forks. 1982 models used tapered roller bearings.
Tony
I believe the forks on the 77 400 are 78 model 38mm, or maybe even 80 models. The longest you can go in the rear is 14 inches due to engine clearance. Even at `14 you may need to do a little more grinding on the engine. It is ground there at the factory some already on the mc-5's. Make sure you have 14 and 1/8 inches bolt hole to bolt hole after grinding so arm will never hit engine from loose shock bushings. Be careful this is already a weak point from the factory grinding and can crack if engine run with loose mounts at all. You dont want to take out much more, but 14 inchers can be made to work alright. Just make sure your getting more shaft travel with your 14 inch shocks over the 13,5 inch, or your gaining nothing. The pipe on that bike looks to also be a 78/79 OEM with an aftermarket rear end. 79-82 front wheel and he made the rear brake a full floater. You need to avoid raising up the front of the bike much more than the rear. You can do this by sliding up the forks and if not enough put a spacer above the top out spring on the damp rod to limit travel. 78 and 79 forks didnt work real well. To fix this use "fluted" 80/81 damp rods. Terrycable and Hi Point also made kits for the 78-79 forks. That 77 is basically how I have my 77 set up, only I stayed with 13 and 3/4 inch shocks and limited the forks to 9 inches travel. I am building one for my son this winter where we will be going with 14 inch shocks and as much travel up front as we can under the guidelines I mentioned above.
A couple of '77 MC5 setup notes from a 6'3" 250# guy-
> Stiffer springs front and back are a must, and neither 35mm fork or stock Marzoke shock springs are easy to find. I've got 2" pre-load spacers in front, oil at 5.5" from top and 10 lbs air, 3 bull ring spacers + stiffest preload setting on purple shock springs and 30 lbs air in canisters...front not bad, rear just tolerable. Stickers say 2kg per sq cm, which = 28 lbs/in. Not sure if more pressure could be handled or would help. I may try Ohlins heavier main springs if they'll adapt, probably will need heavier damping too.
> Steering works if you run the forks up though the clamps 1"-1.5" or so, which requires the swept back bar mount...which then cramps long-armed rider position. Tall bars help, as do pegs in lower mounts for long legs. But then the kicker hits the top mount nub which hammers it off the shaft. I filed a notch in the upper mount to act as a flat kicker stop.
> Longer shocks would improve steering, prevent need for forks abve top clamp, eliminate need for swept back bar mount, etc.
> 38mm forks are an improvement, but then puts you out of Historic class for AHMRA or similar class restriction, if applicable in your local club. If you're to go to 38mm, might as well go to better braking of double-leading shoe front brake of '82 KTM 250, to be able to go as deep as the Evo Yamahas in the corner....worthwhile mod as they work fantastic, but takes some fabricating.
Hope this helps.
After all of that, it might be easier just to get a 82 KTM and call it good. Besides, I saw you race the 77 400 last Saturday and you did really good.
Britt Boyette
1976 125 MC5
Just a note, 38mm forks are legal in AHRMA Historic but not dual leading shoe brakes. You can use the later conical KTM hubs on a Vintage or earlier PV bike, but not the dual leading shoe brake.
Brian
'72 Berkshire
my plan is to go with the 38mm forks and then put spacers below the top out springs. I am actually thinking of not using the swept back upper handlebar mounts because it causes you to be too far back over the seat which is not so good for tight corners.. If I have to I may use longer spacers up front to get it to turn better... I have a couple othere ideas for the motor too.. As for the braking, We have a local guy that rebuilds the front shoes and Arc's them so that the really stop well....
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)
You might get Bob Wardlow to sell you a set of his trick Billet Custom Machined Handlebar Risers to allow you to slide the forks up in the clamps farther, while maintaining the original forward bar position. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
Here is Big Mac on the mighty 400 MC5 at the Salem Fairgrounds indoor racing. Forks look okay to me.
(http://i93.photobucket.com/albums/l50/MotoBrittB/Penton/DSC_06771.jpg)
Britt Boyette
1976 125 MC5
They don't call me Big for nuthin'.
Looks like an XR75 under there.
LOL! To give a little perspective from the other side of the size scale, here are two of me (5'7" 140lbs) also on an MC5 400. :D
(http://the-gunfighters.org/Aonia4002.jpg)
(http://the-gunfighters.org/Aonia4001.jpg)
Brian
'72 Berkshire
Didn't know that something like that was even available....but that sounds like a good idea....
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)
WOW, a lot of responses here since my original question! Thanx to everyone for the advice! Just got back to this after busy week with work, life, wife & kids. I have just about everything I need to do my conversion. Rocket, I will let you know when I am ready to rebuild Marz shocks, does that include new rubber shaft dampers & some paint work?
As for the Gray & Gold legs, I have them right here in front of me & it looks like two completly different color's. I'll measure & compare after I get them apart & replace seals. I'm going to go with the 38mm's after I rebuild those as well then adjust hieghth from there & try the 14" shock idea providing I have the swingarm clearence.
Any direction on 14" Long Shaft shocks? Ohlins? Works Performance? Bilstiens? Anything?
I am looking at '78 & '79 pipe's. What do you guys say they are worth? good to nice shape, $150, $200?
Thanx, Mark
'77 250 MC5
'82 250 MC II TYP 542
The forks on the '77 400 in my picture are dark gray, all the gold coating is gone but if you lift up the boot its still gold where it was protected from exposure. If the forks are a dull matte gray they used to be gold (later ones painted orange) and are made of magnesium, if they are lighter shinier silver they are aluminum. Most of the KTM lowers were mag and either gold or orange, while most other bikes that used Marzocchi forks like Can-Am used aluminum lowers.
Brian
'72 Berkshire
Brian,
You are absolutly right!! They are Gold under the boots. I'll be dammed, shouldhave looked for that before.
Thanx, Mark
'77 KTM 250 MC5
'82 250 MC
I didnt know there was gold under there either until I replaced the fork seals the first time and took the boots off. I dont know what that gold coating is, but it did not last very well.
Brian
'72 Berkshire
Progressive has shock springs that will work on the Marz or most anything else for mc-5's. 03-1364B 140/190 lb progressive for us heavyweights and 03-1365B 120/170 lb for you regulars.
Also:
03-1368B 105/150lb
03-1367B 95/140
03-1370B 90/130
or get this
03-1371B 270/310!!!
Also
03-1386B 65 lb
03-1387B 75
03-1389B 90
03-1391B 110
03-1392 120
They also have some narrower springs for those non race restorations
02-1351 thru 02-1354
The B means black. They also have chrome and some blue.
You have to find a progressive dealer.
I would advise the progressive rate springs.
Dont buy em all, I still need some more!
Race Tech is making vintage fork springs now. Anyone looked into them?
Renthal Mini High Bars do not set you back in the seat at all, even with the swept back mounts. They have a modern straight bend, work real nice with the swept back mounts. Feels like your sitting on a modern bike.
Whoops forgot. Hi-Performance Engineering makes bar riser mounts. 1 or 1.6 inch rise. They are in Three River Falls MN. A ssnowmobile/ATV accessories outfit.
Woops 2. You MUST notch a flat area on the upper peg as was mentioned above if using the 77 duel peg frame in the lower mount. If not you will bend your kicker or the foot peg mounting brackets on the frame. I would also highly advise to fill in the area where the peg stops hit the frame bracket (when down) with weld. Just fill in the entire area at the bottom of the frame bracket, between the frame tube and the bracket. The more filled in the better. I had one bend there. All in all, with the suspention set up right, the right bars and stiff seat, I love my 77. More than a 78, 79, 80 or 81.
Mike, my MC 5 is on the work stand now... by the way, A friend of mine asked me about a front wheel off of a KTM, as it turns out, it is a front wheel off a 79/80 conical style....He had picked it up when he bought another bike, He has no KTM's so the wheel is going to me... It will go on the bike when it shows up.
because the bike has not been ridden much the last few years I need to do a bit more work to it, nothing major but more than just dump fuel in the tank and go ride.
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)74'
250 hare scrambler (project bike)
HMMMMMMMMMMMM! The pipe's I was looking at on ebay went away? Guess I had better jump on them the next time I see one.
Thanx MG
Gentlemen - these have been at vintagemx.us for a while. Would these be from a 78 or 79 KTM based on his description? I'm just curious...my winter project(s) were NOT going to include a 38mm retrofit but ya never know....;)
http://www.vintagemx.us/cgi-bin/largephoto.cgi?C=gUaFp44ntw3MARTm&w=4
If those decals are original, they may be off of a late 78/early 79 short production run KTM MX-6 model, like 2 of which I own. If so, they may have the 4 hole damper rods, which are a lot smoother than the 78 production forks. I have read an article that recommends drilling 2 additional holes on the damper rods on stock 78 38MM forks to smooth out the inital damping on the overly stiff dampened newly introduced KTM 78MC5 38MM Marzocchi forks. The difference between KTM forks and the Can Am versions are the diameter of the axle holes. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
Are the holes too big or too small for the Can Am?
Britt Boyette
1976 125 MC5
Britt,
The Canned Ham axles are larger in diameter.
Brian
'72 Berkshire
Mike, Thanks for clearing something up for me. I have a set of forks with the 4 holes and never had seen that before.