KTM Clutch Case Covers
What's the Difference
by Alan Buehner
There were 3 generations of KTM clutch case covers that were used on the KTM engines from 1972 thru 1980.
FULL CLUTCH CASES – as shown in Photo “A” – were used on the 1972-73 KTM 175 engines and also on the 1973 KTM 250 engines.
CONTOURED CLUTCH CASES – as shown in Photo ”B” – were used on all the 1974 KTM engines. The smaller size reduced the amount of oil required in the cases and most likely allowed the clutch baskets to spin quicker. Note the gusset on the bottom left. This is part of an internal channel to help direct oil flow away from the clutch basket as it spins.
MODIFIED COUNTOUR CLUTCH CASES – as shown in photo “C” - were used on all KTM engines from 1980. The lower right corners were cut-away (as shown by arrow in photo) to allow the engine cases to fit around the left foot peg on the redesigned frames. Note the gussets on the top right and bottom left. These are part of two internal channels to help direct oil flow away from the clutch basket as it spins.
The extra top gusset was added in 1975.
There were 2 versions of each generation of the clutch case covers.
The first version has a 14mm opening for the14mm kick starter shafts used on the 125 and 175 engines (as shown in photo “D”). These were also used on the early 1973 black 250 engines.
The KTM part number for these cases are:
51-30-001-010 – full case
51-30-001-110 – contour case with lower gusset
51-30-001-510 – contour case with dual gussets
510-30-001-610 – contour case with cut-a-way corner
The second version has a 17mm opening for the 17mm kick starter shafts used on the 250 and 400 engines (as shown in photo “E”).
The KTM part number for these cases are:
54-30-001-110 – contour case with lower gusset
54-30-001-510 – contour case with dual gussets
540-30-001-610 – contour case with cut-a-way corner
Something to be aware of is that the engine cases and the clutch case covers share a steel alignment sleeve with a measurement of 17mm o.d. X 15mm i.d.
On the 1972 thru 1977 engines, this sleeve is positioned on the kick starter hole for the KTM 125 and 175 engines (as shown in photo “F”). For the KTM 250 and 400 engines the sleeve is positioned on the shifter hole (as shown in photo “G”). The location of this sleeve could cause problems if you are looking for a replacement cover.
On all the 1978-80 engines this sleeve is positioned on the shifter hole.