Penton Owners Group

Hi,
Can someone please tell me how much fork oil use in the ribbed lower leg 200mm travel Ceriani forks on my 75 Mint 400 ?? Thanks !!
Dave McCullough

I'd like to know that also. I have the frame painted and the engine at Garys for a check up, and I will be rebuilding the forks soon myself. There was a post some time ago that referred to filling the forks with oil by collapsing the forks and adding oil to a measurement below the top of the tubes for optimum results. You might try a search on fork oil level or capacity.
I found this posting by Merlin regarding a 74 250:
springs out,forks compressed,6" to 6 1/2" from top,6 1/2 softer,6 stiffer. Hope that helps. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S

Here is a chart with for oil capacities.

FORK OIL CAPACITIES                  
Model   Type Fork   Diameter   Travel   Total Disassembly   Viscosity  All 10wt.                                            Refill                              
1979 MC80 250/400/420   Marzocchi   38mm   275mm   390cc   365cc   10wt
1979 MC80 125/175   Marzocchi   35mm   250mm   300cc   280cc   10wt
1979 MX6 250/400   Marzocchi   38mm   270mm   390cc   365cc   10wt
1979 MX6125/175   Marzocchi   35mm   250mm   300cc   280cc   10wt
                  10wt
1978 GS6    Ceriani Leading Axle   35mm   240mm   230cc   215cc   10wt
1978 MC5   Ceriani Leading Axle   35mm   265mm   270cc   250cc   10wt
1978MC5 250/400   Marzocchi    38mm   270mm   380cc   360cc   10wt
1978 MC 5 125/175 & All GS6   Marzocchi    35mm   250mm   280cc   265cc   10wt
1977 GS6 & MC5   Marzocchi    35mm   220mm   240cc   220cc   10wt
Late 1977 MC5   Marzocchi    35mm   240mm   265cc   250cc   10wt
1976 Cross Country or MC5   Ceriani Leading Axle   35mm   220mm   230cc   215cc   10wt
   Marzocchi    35mm   220mm   240cc   220cc   10wt
1975 All Models   Ceriani Straigh Leg   35mm   190mm   235cc   220cc   10wt


Send me an email and I can forward and excel file that has this all listed in order.  When I copy and pasted, chart got jumbled up somewhat.
Rocket

Thanks Rocket !! You have mail.
Dave McC

The chart is vary valuble but it has a draw back. you can fill each leg with the correct amount of oil but if you measure you will find that the oil level may vary from one leg to the other, the reason for this is because of small differences from one leg to the other, It ususally works out to be only a few cc's of oil. this is just my opinion but oil level is more important than oil amount. The reason for this is because as the fork compresses, the amount of air in each leg is being compressed as well and it acts like an air shock, having the same oil level in each fork leg will help to level out the amount of compression resistence in each fork leg..
alot of guys make a major mistake when they use a heavier fork oil because the forks are too soft, It is better to add a few CC's of fork oil to keep them from bottoming out. doing it this way you will not lose the suppleness of a lighter fork oil, you will gain a stiffer set of forks were you need them most... at the top half of the stroke instead of all the way through it.....
by the way, adding air pressure to your forks is not good either, It is hard on seals and in order to get too much help from them, you need to add alot of pressure.It is better to go up to the next stiffer set of fork springs... and keep your forks supple in the first part of the stroke and stiff enough on the second part as to not bottom out off that next jump.... just my 2 cents worth....

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
75' GS400 (finished project bike)
72'sixday (project bike)

Rocket - you wrote:

1977 GS6 & MC5 Marzocchi 35mm 220mm 240cc 220cc 10wt
Late 1977 MC5 Marzocchi 35mm 240mm 265cc 250cc 10wt

Any idea what's different or how you tell an early '77 MC5/GS6 fork from the Late '77 MC5 Marzocchi? Looks like oil capacity is quite different. I always thought the '77 35mm Marzocchis were all the same until they went to 38mm in '78.

Thanks,


Jon McLean
Lake Grove, OR

Quotequote:Originally posted by Big Mac

Rocket - you wrote:

1977 GS6 & MC5 Marzocchi 35mm 220mm 240cc 220cc 10wt
Late 1977 MC5 Marzocchi 35mm 240mm 265cc 250cc 10wt

Any idea what's different or how you tell an early '77 MC5/GS6 fork from the Late '77 MC5 Marzocchi? Looks like oil capacity is quite different. I always thought the '77 35mm Marzocchis were all the same until they went to 38mm in '78.

Thanks,


Jon McLean
Lake Grove, OR

Jon
I don't know what the difference is between the early and late 35mm Marzokes.  It looks like the early 35's had 220mm of travel and later had 240mm.  I imagine you could measure your travel and then know what oil amount to put in.  I got this chart somewhere quite a while ago, can't guarantee that it is 100% accurate.
Rocket