{"title":"Parts That Fit Stihl MS311 and MS391","description":null,"products":[{"product_id":"lil-red-barn-stihl-ms311-replacement-piston-47mm-replaces-part-1140-030-2002-2-day-standard-shipping-to-all-50-states","title":"Compatible with Stihl Ms311 Replacement Piston 47mm, Replaces Part # 1140 030 2002","description":"\u003cp\u003eSuitable, high quality replacement Compatible with STIHL MS311 REPLACEMENT PISTON 47MM, REPLACES PART # 1140 030 2002 HOW THESE CYLINDERS AND PISTONS ARE MADE - Cylinders are cast in AC4B aluminum alloy by a slow gravity-fed die-casting process, which leaves more material in the cylinder wall. Before plating, each cylinder goes through thirteen preparation stages so the coating penetrates evenly, and the chrome layer is held between 0.04 and 0.06 mm. Machining is done on CNC equipment. Casting tooling is checked monthly and retired at 50,000 pieces, so the last cylinder off a tool measures close to the first. WHAT IS CHECKED BEFORE PACKING - The inlet and exhaust ports on every cylinder are inspected and the burrs chamfered. Every twentieth cylinder off the line is measured in full against tolerance. The factories behind these parts have more than thirty years in cylinder and piston manufacture and also build to specification for original-equipment customers. ON ASSEMBLY - Use a piston ring compressor when you rebuild a two-cycle engine. Rings forced in by hand are how a piston land gets broken before the engine has run.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eCompatible with STIHL MS311 REPLACEMENT PISTON 47MM\u003c\/li\u003e\n\u003cli\u003eREPLACES PART # 1140 030 2002\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"1","offer_id":34486242738333,"sku":"RA-XBSX-E9XF","price":32.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/61oXpXZmFcL.jpg?v=1793400539"},{"product_id":"lil-red-barn-stihl-ms391-replacement-piston-49mm-replaces-part-1140-030-2003-2-day-standard-shipping-to-all-50-states","title":"Compatible with Stihl Ms391 Replacement Piston 49mm, Replaces Part # 1140 030 2003","description":"\u003cp\u003eSuitable, high quality replacement Compatible with STIHL MS391 REPLACEMENT PISTON 49MM, REPLACES PART # 1140 030 2003 HOW THESE CYLINDERS AND PISTONS ARE MADE - Cylinders are cast in AC4B aluminum alloy by a slow gravity-fed die-casting process, which leaves more material in the cylinder wall. Before plating, each cylinder goes through thirteen preparation stages so the coating penetrates evenly, and the chrome layer is held between 0.04 and 0.06 mm. Machining is done on CNC equipment. Casting tooling is checked monthly and retired at 50,000 pieces, so the last cylinder off a tool measures close to the first. WHAT IS CHECKED BEFORE PACKING - The inlet and exhaust ports on every cylinder are inspected and the burrs chamfered. Every twentieth cylinder off the line is measured in full against tolerance. The factories behind these parts have more than thirty years in cylinder and piston manufacture and also build to specification for original-equipment customers. ON ASSEMBLY - Use a piston ring compressor when you rebuild a two-cycle engine. Rings forced in by hand are how a piston land gets broken before the engine has run.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eCompatible with STIHL MS391 REPLACEMENT PISTON 49MM\u003c\/li\u003e\n\u003cli\u003eREPLACES PART # 1140 030 2003\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"1","offer_id":34486640738461,"sku":"EV-BTFO-RHWY","price":30.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/61oXpXZmFcL_110c5752-623e-4460-ae9e-f5a0fcc7db2d.jpg?v=1793400629"},{"product_id":"47mm-pop-up-piston-kit-fits-stihl-ms311-ms362-1140-030-2002-1v-w6ue-ckkx","title":"47mm Pop Up Piston Kit Fits Stihl MS311 MS362 1140-030-2002","description":"\u003cp\u003ePop-up piston kit, 47mm, for the Stihl MS311 and MS362. Replaces 1140-030-2002, since superseded to 1140-030-2009. Contents: piston with a raised crown, ring, wrist pin and circlips. The domed crown sits closer to the cylinder head at top dead center, which tightens the squish band and raises compression; it is an aftermarket part, and 1140-030-2002 is the standard factory number it replaces. The MS311 and MS362 share a piston: both are 59.0cc, 47mm bore, 34mm stroke. The MS391 is 64.1cc on a 49mm bore and takes 1140-030-2003; some catalogs list it against 1140-030-2002 and they are wrong. Aftermarket 49mm big bore cylinders are sold to convert an MS311, but a stock MS311 is 47mm. Measure squish on assembly with a solder test through the plug hole and pick base gasket thickness from what you read. Raising compression raises combustion temperature, so set the high-speed mixture a little rich and take the first tank gently. Piston kit only: cylinder, needle bearing, gaskets and crankshaft seals are not included.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003ePOP UP PISTON KIT, 47MM - Piston with a raised crown, ring, wrist pin and circlips. The dome tightens squish clearance and raises compression. An aftermarket part; 1140-030-2002 is the standard factory piston it replaces.\u003c\/li\u003e\n\u003cli\u003eMS311 AND MS362 ARE BOTH 47MM - Both are 59.0cc on a 47mm bore with a 34mm stroke, so they share this piston. Replaces 1140-030-2002, since superseded to 1140-030-2009, so either number gets you here.\u003c\/li\u003e\n\u003cli\u003eTHE MS391 IS NOT THIS PART - The MS391 is 64.1cc on a 49mm bore and takes 1140-030-2003. Same series, same stroke, 2mm more bore. Some catalogs list the MS391 against this number and they are wrong.\u003c\/li\u003e\n\u003cli\u003eBEWARE THE BIG BORE KITS - 49mm cylinder kits are sold to convert an MS311, which is why MS311 and 49mm turn up together. A stock MS311 is 47mm. If you have not fitted a big bore cylinder, 47mm is your size.\u003c\/li\u003e\n\u003cli\u003eMEASURE YOUR SQUISH ON ASSEMBLY - Check it with a solder test through the plug hole and choose base gasket thickness from what you measure. Too tight and the dome contacts the head. Richen the high-speed setting slightly and take the first tank gently. Cylinder, needle bearing, gaskets and crank seals are not included.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009606774938,"sku":"1V-W6UE-CKKX","price":34.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/61IQ6zdjZGS.jpg?v=1793382543"},{"product_id":"49mm-nikasil-cylinder-piston-kit-for-stihl-ms391-3-bolt-vr-59o3-n37c","title":"49mm Nikasil Cylinder \u0026 Piston Kit for Stihl MS391 - 3-Bolt","description":"\u003cp\u003eA 49mm Nikasil cylinder and piston kit for the Stihl MS391, a straight replacement at the saw's 49mm bore. The kit contains the Nikasil-plated cylinder, piston, piston rings, wrist pin and circlips. This is the 3-bolt intake version: these cylinders were built with 3-bolt and 4-bolt intake manifolds, so count the bolts holding the intake to your old cylinder before ordering. It replaces cylinder assembly 1140-020-1204. While the saw is apart, check the crankshaft bearings for play and the crank seals for hardness, and pressure and vacuum test the crankcase, because a worn bearing or an air leak will score a new piston as quickly as the old one. Use a ring compressor on assembly, tighten the cylinder screws evenly, and check the carburetor setting once the saw is run in.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e49MM CYLINDER AND PISTON FOR THE STIHL MS391 - A Nikasil-plated cylinder with piston, piston rings, wrist pin and circlips: a straight replacement at the MS391's 49mm bore.\u003c\/li\u003e\n\u003cli\u003eCOUNT THE INTAKE BOLTS FIRST - This is the 3-bolt intake version. These cylinders were made with 3-bolt and 4-bolt intake manifolds; count the bolts holding the intake to your old cylinder before ordering. It does not fit a 4-bolt saw.\u003c\/li\u003e\n\u003cli\u003eREPLACES CYLINDER ASSEMBLY 1140-020-1204 - The 3-bolt intake version. If your parts list shows this number, match the bolt count and this kit covers it.\u003c\/li\u003e\n\u003cli\u003eCHECK THE BOTTOM END WHILE IT IS APART - Rock the crankshaft for bearing play and look at the crank seals. A worn bearing or a hardened seal will take out a new top end, so deal with either before the cylinder goes on.\u003c\/li\u003e\n\u003cli\u003eBEFORE THE NEW TOP END GOES ON - Pressure and vacuum test the crankcase and replace a cracked intake boot or split impulse line. Use a ring compressor, tighten the cylinder screws evenly, and check the carburetor setting once the saw is run in.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009621717146,"sku":"VR-59O3-N37C","price":159.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/71szRN-5QDL.jpg?v=1793382984"},{"product_id":"compatible-with-stihl-ms391-piston-kit-49mm-bore-replaces-part-1140-03-ou-h55k-5s2q","title":"Compatible with Stihl MS391 Piston Kit, 49mm Bore, Replaces Part # 1140-030-2008","description":"\u003cp\u003eCompatible with Stihl Piston kit, 49mm, includes everything in the picture, Replaces Stihl part # 1140-030-2008, this kit will fit the Stihl MS391 saw, Be sure to mic your piston assembly to ensure correct mm size before ordering. New aftermarket\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eCompatible with Stihl MS391 Piston Kit, 49mm Bore\u003c\/li\u003e\n\u003cli\u003eReplaces Part # 1140-030-2008\u003c\/li\u003e\n\u003cli\u003eNOT MADE IN CHINA OR TAIWAN\u003c\/li\u003e\n\u003cli\u003e**Family run business with 25 years of repair experience and parts sales\u003c\/li\u003e\n\u003cli\u003e**We strive to provide high quality parts and excellent customer service!\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009648750746,"sku":"OU-H55K-5S2Q","price":32.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/51rLYgiY3gL.jpg?v=1793383202"},{"product_id":"49mm-big-bore-nikasil-cylinder-piston-kit-for-stihl-ms311-ps-aq33-vaff","title":"49mm Big Bore Nikasil Cylinder Piston Kit for Stihl MS311","description":"\u003cp\u003eA 49mm Nikasil cylinder and piston kit for the Stihl MS311, taking the saw from its stock 47mm bore to 49mm. The kit contains the Nikasil-plated cylinder, a 49mm piston, piston rings, wrist pin and circlips. This is the 3-bolt intake version: these cylinders were built with both 3-bolt and 4-bolt intake manifolds, so count the bolts holding the intake to your old cylinder before ordering. It replaces cylinder assembly 1140-020-1204. If you want a straight repair at the original 47mm size, look for a 47mm MS311 piston instead. Before fitting, pressure and vacuum test the crankcase and replace hardened seals, a cracked intake boot or a split impulse line, since an air leak scores a new piston as fast as the old one. Use a ring compressor on assembly, and check the carburetor setting once the saw is run in, because the larger bore draws more fuel.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e49MM BIG-BORE CYLINDER AND PISTON FOR THE STIHL MS311 - Takes the MS311 from its stock 47mm bore to 49mm. The kit holds a Nikasil-plated cylinder, a 49mm piston, rings, wrist pin and circlips.\u003c\/li\u003e\n\u003cli\u003eCOUNT THE INTAKE BOLTS FIRST - This is the 3-bolt intake version. These cylinders were made with 3-bolt and 4-bolt intake manifolds; count the bolts on your old cylinder before ordering. It does not fit a 4-bolt saw.\u003c\/li\u003e\n\u003cli\u003eWANT THE STOCK 47MM SIZE INSTEAD? - This kit changes the bore. For a straight repair at the original size, a 47mm MS311 piston is the part to look for.\u003c\/li\u003e\n\u003cli\u003eREPLACES CYLINDER ASSEMBLY 1140-020-1204 - The 49mm cylinder and piston assembly. If your parts list shows this number, match the intake bolt count before ordering.\u003c\/li\u003e\n\u003cli\u003eBEFORE THE NEW TOP END GOES ON - Pressure and vacuum test the crankcase and replace hardened crankshaft seals, a cracked intake boot or a split impulse line. A larger bore draws more fuel, so check the carburetor setting once the saw is run in.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009656287386,"sku":"PS-AQ33-VAFF","price":159.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/71szRN-5QDL_f4ef1123-994d-481a-91c4-ddf1c3223eb9.jpg?v=1793383375"},{"product_id":"pop-up-piston-kit-stihl-ms391-49mm-1140-030-2003-64-1cc-g1-vaa7-jege","title":"Pop Up Piston Kit Stihl MS391 49mm 1140-030-2003 64.1cc","description":"\u003cp\u003ePop-up piston kit for the Stihl MS391. Bore 49mm. Replaces Stihl 1140-030-2003, superseded to 1140-030-2008. Supplied with rings, wrist pin and circlips. SPECIFICATION Bore - 49mm Stroke - 34mm Displacement - 64.1cc WHAT A POP-UP PISTON IS. The crown is raised, so it projects further into the combustion chamber at top dead centre. That reduces chamber volume and raises compression. Stihl does not catalogue a pop-up piston for this saw - the factory part is a flat top. This is a performance variant and it is sold as one. MEASURE YOUR SQUISH CLEARANCE. A raised dome consumes squish clearance. If the base gasket has also been deleted, the two changes stack and the crown can contact the head. Check the clearance with a length of solder through the plug hole before final assembly. Deleting the base gasket and fitting a pop-up piston are alternatives, not a combination. THE NEAR MISS THAT CATCHES PEOPLE. The Stihl 039 and MS390 are also 49mm, also 34mm stroke and also 64.1cc - identical on paper to the MS391. They take piston 1127-030-2005, a different part family entirely. Measuring your bore will not tell the two apart. Go by the model on the saw. THE 1140 FAMILY BY BORE MS311 and MS362 - 47mm - 1140-030-2002 MS391 - 49mm - 1140-030-2003, now 1140-030-2008 - this kit MS400 - 50mm - 1140-030-2014 Check the cylinder through the exhaust port before fitting a piston alone. A raised compression piston in a tired cylinder is a waste of the part.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFITS THE STIHL MS391 - 49mm bore, 34mm stroke, 64.1cc. Replaces Stihl 1140-030-2003, which Stihl has since superseded to 1140-030-2008. Either number on your parts diagram means this piston. Supplied with rings, wrist pin and circlips.\u003c\/li\u003e\n\u003cli\u003eTHIS IS A POP-UP PISTON, NOT THE STOCK FLAT TOP - The crown is domed so it projects further into the combustion chamber at top dead centre, which reduces chamber volume and raises compression. Stihl does not make a pop-up piston; the factory part is flat topped. If you want the engine exactly as Stihl built it, this is not that piston.\u003c\/li\u003e\n\u003cli\u003eMEASURE YOUR SQUISH BEFORE YOU RUN IT - This is the warning nobody selling pop-up pistons gives, and it matters. A raised dome eats squish clearance directly. If you also delete the base gasket you are stacking two compression increases and the crown can touch the head. Do one or the other, measure the clearance with solder before final assembly, and do not assume.\u003c\/li\u003e\n\u003cli\u003eNOT THE MS390 OR THE 039 - and this is the trap. The 039 and MS390 are ALSO 49mm, ALSO 34mm stroke and ALSO 64.1cc, and they take a completely different piston, 1127-030-2005. Identical dimensions, different part family. Bore measurement alone will not save you here - go by the model on the saw and the number on your diagram.\u003c\/li\u003e\n\u003cli\u003eTHE REST OF THE 1140 FAMILY - MS311 and MS362 are 47mm and take 1140-030-2002. MS400 is 50mm and takes 1140-030-2014. MS391 is the 49mm one. All four share the 34mm stroke, so they look alike in the box and only the bore separates them.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009660448922,"sku":"G1-VAA7-JEGE","price":34.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/61sMlaCv8SL.jpg?v=1793383501"}],"url":"https:\/\/performancesawsupply.com\/collections\/parts-that-fit-stihl-ms311-and-ms391.oembed","provider":"Performance Saw Supply","version":"1.0","type":"link"}