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2001- 2008 KTM Pro Senior 50cc Motocross Bike or KTM 50 SR SX is designed for kids in the AMA 7-8 pee wee class. 50cc liquid cooled engine with 3 shoe adjustable centrifugal clutch assembly. 19mm carbuetor and hydralic disc brakes from and rear.

Pro Sr. Spare Parts Notes - This model had very minor changes made from years 2001 - 2008. Most all parts are interchangable between these years '01-'08. Plastics and engines are also interchange with Pro Junior models from 2002-2008. 

Have any questions about parts? Or need help choosing the right ones? our sales reps are some of the most knowledgeable. E-mail us, or call (239)566-9666 9:00AM to 7:00PM eastern time Mon-Sun.

2002 - 2008 KTM50 Pro Jr Motocross Bike or KTM 50 JR SX is designed for kid in the AMA 4-6 pee wee class.

50cc liquid cooled engine with 3 shoe adjustable centrifugal clutch assembly. 14mm carbuetor and hydralic disc brake in front and drum brake in rear.

Pro Jr. Spare Parts Notes - This model had very minor changes made from years 2002 - 2008. Most all parts are interchangable between the years '02-'08. Plastics and engines are also interchange with Pro senior models from 2001-2008. 

2002-2008 KTM 50 Senior Adventure model designed for generall off road riding for kids up to nine years old.

Spare Parts Notes -This model had very minor changes made from years 2002 - 2008. Most all parts are interchageable from '02-08 models.

2002-2008 KTM 50 Junior Adventure model designed for general off road riding for kids up to 4-6 years old. These models have an AIR cooled engine.

Spare Parts Notes - This model had very minor changes made from years 2002 - 2008. Most all parts are interchageable from '02-08 models.

High Performance Parts - KTM50s produce a lot of power considering the tiny size and light weight of this 49cc engine. The best gain in performance for your dollar is simply is a freash rebuilt engine. Replacing old worn out parts with a new piston & ring kit, crankshaft or reed block will help your bike produce the power it once had.
 
 
The engine power needs to get to the ground by way of the clutch assembly. The clutch is an another important area with great gains in KTM50 performance with clutch replacement and fine tuning.  A old worn out clutch will slip and not allow the engines full power to get to the rear wheel. If your KTM50 has a unknown amount of hours or you bought the bike 2nd hand its probadly a good idea to replace the complete clutch assembly & basket with a new one to make sure everything is in proper specs. you can always keep the old clutch as a spare if you think it still has some life in it.

 

Have a model made between 1994 and 2001? These older bikes use the Morini Franco engine as shown below.

1997 – 2000 KTM Pro Senior
Above is a 1997 - 2000 KTM 50 Pro senior model. These year models all use a Morini Franco S5-GS engine. The “GS” is the code for the 4-pedal reed block cylinder. This easy to see it from a distance because the cylinder is BLACK in color and uses a intake manifold with four bolts. The piston has a ovel hole in the intake side. The ring are the same top and bottom. Check the head gasket some models had a rubber “o”ring and other bikes had a copper ring/paper head gasket. The other only difference for the different years is the clutch assembly. The early year bikes had a 2-shoe clutch design and the last couple of models had a disc style clutch. Its best to remove the clutch cover and see what model clutch style you have.
KTM50 Pro JR 1998-2001
To the right is a 1998 - 2002 KTM 50 Pro Junior model. These year models all use a Morini Franco S5-GS engine. The “GS” is the code for the 4-pedal reed block cylinder. This easy to see it from a distance because the cylinder is BLACK in color and uses a intake manifold with four bolts. The piston has a ovel hole in the intake side. The ring are the same top and bottom. Check the head gasket some models had a rubber “o”ring and other bikes had a copper ring/paper head gasket.
1997 KTM50 Pro Junior

To the left is a 1997 KTM 50 Pro Junior model. This year KTM50 Pro Jr. model uses a Morini Franco S5-T engine. The “T” is the code for the 2-pedal reed block cylinder. The 1997 Junior model was the only year & model that used the “T” cylinder. This easy to see it from a distance because the cylinder is silver in color and uses a intake manifold with only two bolts. The piston has a round hole in the intake side. The ring are not the same top and bottom. The top ring is a “L” shape the bottom ring is just flat.

KTM 50 SX & KTM50SXR model 1995-1997

KTM 50cc bike from 1995- 2001 used MORINI FRANCO MOTORI engines, some people say FRANCO MORINI MOTORI. These bikes are built solid and will be around for a long time, passed down from one kid to the next when they out grow them. Chassis parts are difficult to find but the Morini Franco engines are very popular and we have a great supply available.

Above is a 1995-1997 KTM 50SX or KTM50 SXR model. This year KTM 50 model uses a Morini Franco S5-E or S5N engine. The “E” code is for non-reed block STEEL cylinder. The “N” is code for non-reed ALUMINUM cylinder. This easy to see it from a distance because if the cylinder is “SILVER” in color is the aluminum cylinder. If its BLACK in color it's the STEEL cylinder. Both cylinders have a intake manifold with only two bolts.

The pistons are different for these two models. The STEEL cylinder piston rings are not the same top and bottom. The top ring is a “L” shape the bottom ring is just flat. The aluminum cylinder piston uses two flat rings.

Have any questions about parts? Or need help choosing the right ones? our sales reps are some of the most knowledgeable. E-mail us, or call (239)566-9666 9:00AM to 7:00PM eastern time Mon-Sun.

 

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