Looking for parts to rebuild the 38mm Cereani forks on my 1976 400 Cross Country. Any out there?
Mike
35mm? I don't think they have 38's until the Marzocchi's. I have a 76 MC5 400 with 35mm Ceriani's. Check with Al Buehner on the suppliers page accessed from the Home page menu.
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R
The tubes measure 38mm, and it is a CS6 motor, bought it from the original owner. Less than 900 miles on the odometer. The only things that are not as-delete reed when he bought it are the air filter foam, fuel filter and fuel lines. I ride it around my neighborhood on the original Metzler knobbies.
Mike
Are the fork lowers a grayish green color or painted black with exposed silver large nut looking bottom. They are probably Marzocchi's. The GS6 had 35mm forks, both in 77 & 78. I have a 78 GS6 250, my brother has a 77 GS6 250. The first 38mm forks started in 78 on the MC5 and were orange painted Marzocchi's with bottom axle pinch bolts only on one side, unlike the previous grayish green 35mm's with pinch bolts on both lower legs on the axle. A lot of people overtighten them and crack the magnesium lowers. They should only be snug. The 74-77 250 engines are all the same, with the exception of a 38mm carb on 78 MC5's, but some had a longer bolt locking out 1st gear on some MC5's. 78-early 80 had slightly different porting, and some used internal rotor MotoPlats with no lighting coil.
Normally a 76 Cross Country would have straight leg 35mm bare Ceriani fork legs with a large flat web running down the front of the fork leg, but some, mostly 175's got the offset 35mm Marzocchi's.
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R
Some GS6 were also fitted with leading axle Cerianis but as Mike said they were also 35mm. No Penton was fitted stock with 38mm forks. That does not happen till 1978 when KTM was at the helm.
Larry P
They are center-axle, bare magnesium, and the tubes measure 1.49"inches with a Starret dial caliper. Bought from the original owner, have the original Mass. title in hand. He says the bike is bone stock as delivered from the dealer when he bought it in late 1976. VIN might shed some light, but I'm out of town right now and don't have it.
Mike
VIN will not help as I said NO Penton had 38mm forks. Also none that were Mag with straight axle.
Larry P
Maybe a dealer installed road race fork. Straight leg Ceriani's are shiny aluminum.
A couple pics might help. Text 618-553-1346
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R
Fascinating...definitely send a picture. I back-fitted Zoke 38's (forks and triples) to my 76 MC5 250 after shortening the fork tubes to make them historic legal.
The bike is in Texas. What a rocket. Anybody raced against it lately? : -)
Finally back in the country and trying to start accumulating parts for the winter project of getting this thing streetable again. Measured the forks myself and find that they are in fact 35, not 38 as I was told, and based on the info above and the manual sight the bike am sure they are the stock Cereani's as commented above. In checking all the numbers though, it leads to more questions. The frame number is 10 digits and starts with 546, suggesting a1975 build year, but the numbers do not seem to agree with the standard convention, or the title date of 1976. Then when I look at the motor numbers the s/n on the cases is R95, with 55..30.xxx.xxx part numbers, and cylinder casting number EZ81/1R, so 400 motor, but again, the numbers do not fully match convention. A bit confusing to me. Any thoughts on the matter? Thanks to all for the previous info.
Mike
54-6xxxxxxx would be correct for a 250 or 400 frame built in 76. The next two numbers would tell the month of 1976, for example 54-601xxxxx would be January of 1976. R95 could have been a factory special engine or un-stamped replacement put into the bike on the assembly line out of order. If there is no serial number, such as 55-xxxxxx located above the ignition cover on the right hand side of the engine just below the cylinder fins, it was unstamped with the engine serial number. There has been a number of those engines turn up and the actual usage of them are unclear other than they may have been repaired and then put into bikes on the assembly line or had been special use engines, possibly built with racing event intention.
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R
Next numbers are 04 so an April 76 build. The R95 is stamped in the correct location below the cylinder on the mag side, and also on the left side front near the front mount bolts.
Mike
Still working out the broken compression release. Looks like the body with the hex to R&I the assembly's shears off at the round body face down inside the bore between the cooling fins so there is nothing to grab with a tool to remove it. Guess I'll need to drill a pair of holes in the face, then grind a deep socket to create a pair of "pins" to fit me not them like a spanner to try to unscrew the broken body piece, then try to modify the replacement parts it to reduce its diameter to make it fit inside that bore and extend the operator to reach outside the bore so I can connect the cable. Good winter project, among other things on it. Thanks for the info!
Mike
Mike,
How about an easy out with and extension to get in there?
The actual valve stem is still there so no access into the center vent hole for an easy-out.
Mike
Can you post a few pictures of the compression release area ? If so maybe can suggest process on how to remove remainder of old release if you need help.
I don't think the system allows for posting photos.
Mike
Pulled the head and cylinder, turns out there is no vent hole in the cylinder wall corresponding to the external compression release so it appears that it never actually functioned. Still cannot get the broken body out of the cylinder, so still a project in works. Noted a couple of things. The engine serial number is stamped in the correct locations, but is only "R95", no full serial. Also there are obvious signs of someone doing a bit of die-grinder work inside the inlet area of the motor. Still need to clean up the exhaust side to see if anything was done on that side, as well. Cylinder bore looks pretty good, still mostly cross-hatched, light vertical scoring on the exhaust side of the piston. Bore measures 3.189" - 3.191" and the piston more like 3.183", so .008" total clearance. Have not measured ring gap yet. Planning to go to the meet at York, hoping to meet some of you with greater experience with the KTM's, decide how to move forward to get this thing together and streetable, and start accumulating the parts I will need. Any comments or thoughts are appreciated.
Mike