KTM Intake Manifolds
By Alan Buehner
When KTM developed their engines, they designed their alloy cylinders with bolt-on intake manifolds onto which the carburetors could be installed. The first generation of manifolds (from 1972 thru 1977) were “straight” with an upward angle. The next generation were “cocked” to the side with an upward angle. The following photos will help you to identify and know about the differences about the various manifolds used on the KTM cylinders from 1972 thru 1980.
This is important to know because these different styles of manifolds were used with different styles of air boots which will be featured in the next “Tech Tips” article.
The intake manifold “A” (part no. 52-30-037-000) was used on the first batch of 175 cylinders in late 1971. It was for attaching an Amal carburetor which bolted to the manifold.
The intake manifold “B” (part no. 52-30-050-000) was used on the 175 7 fin cylinders from 1972 thru 1976. It was used for attaching Bing 30 & 32mm carburetors.
In 1977 the 175 cylinders were shortened to 6 fins and the manifold (part no. 52-30-050-500) were shortened and a groove added to accommodate a rubber adapter (part no. 54-30-060-000) for the new Lectron carburetors. The new KTM 125 cylinders came with a similar manifold (part no. 51-30-050-600).
Photo “C” is an intake manifold gasket (part no. 52-30-038-000) used on the KTM 125 and 175s.
Photo “D” is an intake manifold gasket (part no. 54-30-038-000) used on the KTM 250 and 400s.
Looking at the 2 photos, you can see that the opening of gasket “D” is larger than “C” and gives you an idea on size of the intake manifolds.
Item “E” shows the “straight” intake manifold (part no. 54-30-050-300 used on the first KTM 250s in 1973 thru 1976. It was for attaching a 36mm Bing carburetor. With the introduction of the MC5 frame in 1976, a modified intake manifold (part no. 54-30-150-300) was introduced for the modifications of an alloy air box.
A similar looking manifold (part no. 55-30-050-300) was used on the KTM 400s from 1974 thru 1976. It was for attaching a 38mm Bing carburetor. With the introduction of the MC5 frame in 1976, a modified intake manifold (part no. 55-30-150-300) was introduced for the modifications of an alloy air box.
Item “F” shows a “cocked” intake manifold (part no. 55-30-050-400) used on a 1978 KTM 400 GS. It was used to accept the old style “slip on” 38mm Bing carburetor.
1978 KTMs came with a new generation of “cocked” intake manifolds. They came in different lengths to fit either the MC or GS models. They are grooved to accept the rubber boot (item “K”).
Item “G” is a 250 MC manifold (part no. 54-30-150-500).
Item “H” is a 250 GS manifold (part no. 54-30-050-600).
Item “I” is a 400 MC manifold (part no. 55-30-150-608).
Item “J” is a special adapter (part no. 55-30-051-500) for converting a “slip on” 38mm Bing carburetor for use with a rubber boot (K).
Item “K” is a 250 rubber boot (part no. 54-30-060-000) for the 36mm Bing. Not shown is a 400 rubber boot (part no. 55-30-060-000) for the 38mm Bing.
