Piston kit, 48mm, for the Stihl 63.3cc backpack blower engine. Replaces Stihl part number 4244-030-2006. Contents: piston, ring, wrist pin and circlips. Fits BR350, BR430, BR450 and BR450C blowers, and the SR430, SR430-Z, SR440, SR450 and SR450-Z mist blowers and sprayers. Those machines share a powerhead - the same carburetor and the same ignition coil run across the group - so the piston is common to all of them. The near miss is the bigger backpack blower range. BR500, BR550, BR600 and BR700 are 64.8cc on a 50mm bore and take piston 4282-030-2003. Sixty three point three against sixty four point eight looks like a rounding difference on a spec sheet, and it is not - the bores are 48mm and 50mm. Those machines are also 4-MIX engines with a valve train, while this one is a conventional two-stroke. Which matters for the rebuild: there is no valve train in this engine and no valve clearance to set. The 0.10mm lash figure you will find in Stihl's 4-MIX literature does not apply here. One oddity worth explaining. The ring for this piston is 1125-034-3001, and the 1125 prefix belongs to the 034, 036 and MS360 chainsaws. It looks wrong and it is not. Stihl uses the same 48mm by 1.2mm ring in both places. Piston kit only. Cylinder, needle bearing, gaskets and crankshaft seals are not included. Check the cylinder bore for scoring before you fit a new piston, and find out why the old one failed - on a blower that usually means an air leak, a lean setting, or a neglected air filter letting dust through.
- 48MM PISTON KIT - Piston, ring, wrist pin and circlips. Replaces Stihl part number 4244-030-2006. For the 63.3cc two-stroke backpack blower engine. The ring is 1125-034-3001, 48mm by 1.2mm.
- FITS THE BLOWERS AND THE SPRAYERS - BR350, BR430, BR450 and BR450C, and the SR430, SR430-Z, SR440, SR450 and SR450-Z mist blowers and sprayers. They share the same powerhead, the same carburetor and the same ignition coil, so the piston carries across.
- THE BR500, BR550, BR600 AND BR700 ARE NOT THIS PART - Those are 64.8cc on a 50mm bore and take 4282-030-2003. The displacements are close enough to look like a rounding difference and they are not - 48mm against 50mm. They are also 4-MIX engines with valve trains, where these are conventional two-strokes.
- CONVENTIONAL TWO-STROKE - NO VALVES TO SET - There is no valve train in this engine and no valve clearance to check. If you have been reading 4-MIX service information for a 0.10mm lash figure, it does not apply here.
- DO NOT BE PUT OFF BY THE RING NUMBER - The ring for this piston is 1125-034-3001, and the 1125 prefix belongs to the 034, 036 and MS360 chainsaw family. It is the correct ring for this blower. Cylinder, needle bearing, gaskets and crankshaft seals are not included.