Because the engine has run a few heat cycles, the gaskets may have compressed. It had 12,600 miles on it before i rebuilt it which is why i bought another one to fix. After the cylinder is clean, apply oil to it, the piston and the rings before assembly. Be sure to clean the piston also. If the bike is a 2 stroke don’t forget to chamfer the ports. When I tighten them in the ring compressor I cant even get the compressor to touch the piston because the oil rails are pushing out so hard. Resolved by rebuilding the head with the valve seats reground and new guides. This reduced clearance may result the piston to come in contact of the head causing permanent damage. It is VERY IMPORTANT to be sure engine is totally cooled down, and then check the torque of the cylinder head nuts. Why is there oil getting on to my piston after top end rebuild it only run for 6 miles the cut out got it home and oil is getting on the piston. Before you start cleaning make sure the gasket areas are clean with no residue of gasket or sealers. For cast iron rings, after carefully washing cylinder in warm, soapy water, wipe dry then clean with WD40, use paper towels to wipe all excess oil from cylinder. Results for cold and dry are listed below. We'll start with a quick review on the motorcycle top end rebuild. Clicking this will make more experts see the question and we will remind you when it gets answered. Top-end rebuilds are a necessary maintenance task associated with high performance off-road two-stroke motorcycle ownership. After honing is complete, be sure to clean the cylinder thoroughly until there is no residual material. Get it into top gear and go WOT a bit. (801) 569-1068. My 02 rancher 350 is still running strong with a namaur piston and top end kit. Posted by Anonymous on Jan 29, 2017. Was the honing of the cylinder properly done? Valve seals are worn and oil is seeping past them. Now wait a few minutes until the engine is slightly warm to the touch, repeat #2, letting the engine get slightly hotter. Place the ring squarely into the piston groove, taking care to keep it flat. Maybe it's also time to have the block refreshed by rehoning the cylinders and installing new ring sets, and the usual rebuild with new gaskets, rod and crank bearings and the usual assortment of goodies. This power on and power off RPM breaks in the piston and rings evenly on the intake and exhaust sides. It should go in most of the way and stop. He slipped the piston through the cylinder a few times and said, "It's okay." Everything was clean as well as checking ring gaps for proper tolerance. Change the oil, and filter, at 1/2 the normal time, then use as normal. Finally, with the piston installed on the rod, coat the piston and rings with the same premix oil the motorcycle will be running, then coat the inside of the cylinder with the same oil. Piston rings transfer heat to the cylinder wall. This is not enough, and you will need to clean with dish soap and water. Sign up for a new account in our community. High-grade synthetic oils will also degrade eventually. I have owned my 1978 sport SC for 27 years. It is now time to do another check of the cylinder head nuts for proper torque. The common belief is that performing a top-end rebuild is a simple task that anyone can do, which is true, however, the devil is in the details. It never hurts to do another spark plug reading and double-check the head nuts after your first long ride. These low RPM’s actually puts much more stress on the engine parts. 1; 2; First 2 of 2 Go to page. With the piston removed, you … Here, we'll go over a checklist to make your build will last, as well as a step-by-step break-in process. Not only is it important for piston lubrication, but also for the crank bearings and seals. Not only is it important for piston lubrication, but also for the crank bearings and seals. Place the rings in the proper position on the piston and install the pistons in the bore with a piston ring squeezer. Just completed a engine rebuild. Refer to their procedures while doing this. Cleaned & regapped the plugs. I mean it is a possibility though. In English this would be oil that can by wiped off to expose the piston top below. Worse yet, a gasket thinner than the original will result in less deck height (piston to head clearance). Do I need to bore my cylinder? Now you know, follow what the engine manufacturer recommends! Install the camshaft into the block and line up the marks on the camshaft with the crankshaft. In any case I would prefer not to have to pull the block and get it rebuilt. Next, put some after run oil on the sides of the piston, and push it as far as you can into the sleeve, without using too much pressure. zdude1967, August 14, 2009 in Engine & Drivetrain. Different honing tools are better used for different applications, with common tools being brush hones and flex hones. set timing Go out for a drive. But that's more than what should be there. The metal comes from the parts wearing in and some metal comes off and ends up in the filter. Checking the crank. After first start up I noticed some blue smoke when blipping the throttle. That means if you use oil or a thread locking compound the studs will be over-stressed due to the over-tightening of the head nuts. We have placed cookies on your device to help make this website better. First, use a cleaning solvent with a brush and then again with a rag. Tech. Cause - Piston to cylinder clearance too large or engine over-revved. If it has a bridge in the exhaust port, most pistons require this area to be relieved. Hense the wet look piston tops. Oil drips down the valves after the engine has been shut off, and the cam leaves the valves open for the oil to slide on to the pistons. Jump to Latest Follow 21 - 35 of 35 Posts. Be sure that the crosshatch is at 45 degrees. The vertical clearance remaining in the piston ring groove after the ring is installed. He was asked to check again, which he refused, and said that it was correct, and that he was too busy. For cast iron rings, after carefully washing cylinder in warm, soapy water, wipe dry then clean with WD40, use paper towels to wipe all excess oil from cylinder. And with an increase in volume, it can compensate for the bleed-off of the bearings. This bearing is cheap enough to buy, so it's worth changing it whenever you do a top end rebuild. 2. THis is the second honda rancher 350 ive rebuild. READ the piston specs, and if you don’t understand, be sure to reach out to Wiseco for specifications. Brewdude is a tech writer for many publications with over 150 tech articles published. Dirty oil is a very preventable cause of oil consumption. Put only a drop or two of non-detergent oil on each piston skirt. Did you spec your valves? P.S. When I was finished with the rebuild, the engine began to use oil, so I tore it apart to see what was wrong with it. Unbolt the handle assembly and remove it, then pull out the pumping piston attached to the handle. Oil is normal as well from the assembly oil and the rings seating. Better there than anywhere else. A word about the rings before we go any further. Many rings have a topside for proper sealing. Be sure these critical steps and precautions have been taken. Read on to see the most common mistakes that you should avoid. Put only a drop or two of non-detergent oil on each piston skirt. Most times the cycling head nuts will need some re-tightening. I put a little oil on the piston before installing the rings, I move them around a bit to make sure they're coated. After placing the gaskets, be sure while assembling the piston in the cylinder that the ring gaps are in proper placement. Jump to Latest Follow ... and i said i would fix it for him. At first start up, keep the engine just above idle and give it a few revs up and down. Blowing oil smelling smoke after rebuild. Oil drips down the valves after the engine has been shut off, and the cam leaves the valves open for the oil to slide on to the pistons. Wiseco photo. Most companies give the head nut torque rating with the washers, nuts and studs being clean and dry. Recently, a cylinder was bored with requested .0035” clearance. #1 before rebuild – 117psi #2 before rebuild – 97psi #3 before rebuild – 140psi #4 before rebuild – 140psi The two thin rings along with the wavy ring are your oil rings. The metal is completely normal and so is the smoke after a rebuild. The down side to improper break-in are seized pistons. I always recomend the oil filter be changed after the first days run, That gets the dirt out that will collect when doing the rebuild, and not to idle it. Assume tappet cover seals are leaking a bit as top of cover is clean. Don’t just take someone’s word that clearance is correct, always double check it! Changed oil & filter. But it's not like a big puddle, maybe 1/16th deep in the middle of the piston. Put the borescope into C3 and found oil filling the gap between the piston and cylinder and a pool of oil on the top of the piston - probably covering 1/8 of the piston surface (apparently piston top is not quite level). Hense the wet look piston tops. Honing is required to be done after boring, and if the cylinder was not bored, it still is needed to deglaze the cylinder for proper ring break-in. Check all fluid levels to be sure there is no loss of engine lubricant, or, if water-cooled, engine coolant. Top-end rebuilds are a necessary maintenance task associated with high performance off-road two-stroke motorcycle ownership. Typically, it would be a combonation of possible bad rings and definately bad valve guides/seals. Putting in the time and money to rebuild your motorcycle engine is both a critical job and a prideful accomplishment. Bike is a 09 KX450F. My 02 rancher 350 is still running strong with a namaur piston and top end kit. My photos do not seem to indicate this...however the car has been sitting in a hot Arizona garage not running for 6 months. Proper engine break-in is equally as important as a proper rebuild. I have followed the initial torqueing down procedure for the head studs. Being that the edges of the pistons are not clean do you think that suggests the rings are OK. This is the first oil change since the rebuild. Don’t be afraid to run it normally. After assembly, kick engine over ten or twenty times before starting. Removed spark plug from C3 and found it in good shape except for being wet and past due for a change. After the running in process the oil must be replaced with fully synthetic oil and a new oil filter fitted (Included in the price) The base price includes all new parts required for the job and the labour to carry out the process. I absolutely love honda ) and it was a whole top end rebuild allong with a split the cases to fish out the extra pieces of pison. Sometimes no additional tightening is needed, but don’t be alarmed if you need to, because this is normal. Valve seals are worn and oil is seeping past them. Be sure NOT to keep the RPM too low and don’t lug the engine. Increasing engine oil is the last step of the process of cleaning piston for reuse. This can be done by hand once the oil is removed, although you may have to put the jack in a vice. March 29, 2018 / by The old oil was thick and black, but otherwise free of debris or metal shavings. Enjoy your rides, and be safe! With 185k miles on original parts I assume the rings are worn somewhat but there shouldn't be this much oil on the top of the piston from worn rings, I think. According to my Ford manual, the ring gaps should have been .015-inch to .023-inch for the top rings and .010-inch to .020-inch for the secondary rings. Don’t assume it is correct, check it. Many motorcycle manufacturers have a desired head nut tightening sequence. Depending on the application, the side clearance is typically .001-.003-inch. I may have assembled using a little to much oil on the cylinder was my first thought. A larger chamfered oil hole at the top of the small end on some rod designs provides a “funnel” for improved oil reservoir for floating pin When reassembling your top end, always be sure to double check your piston-to-wall clearance. Again, read the instructions that came with the piston. The saw didn’t do any better after the carburetor rebuild so onto further work. So many mistakes can happen while breaking in the piston and rings, resulting in rings never properly sealing or/and piston galling. This will increase both oil … This creates a case where oxidized oil has collected on the cylinder walls and created a somewhat shiny surface coating that has completely filled in the peaks and valleys of the honing process. They will all need to fit into Be sure to keep the engine RPMs above normal idle and keep the RPMs going up and down slowly. Check the fluids as you did before after the engine has completely cooled down, and do another spark plug reading. The common belief is that performing a top-end rebuild is a simple task that anyone can do, which is true, however, the devil is in the details. The earlier cases, as well as the magnesium cases will require the greatest amount of modifications. ... Fitted pins-poor oil lubrication and wear Top of piston scratches, erosion or burning- … We want to help as many people as we can avoid that feeling. As was mentioned in Fred's answer, always use non-synthetic oil for the break-in. Want Answer 1. Classic Zcar Club Camshaft and Lifters . This will be your last break-in run. This time, start and run longer until the engine gets near operating temperature. P.S. Copyright © Wiseco Piston Company Inc. All Rights Reserved. Be certain that the ring gap is within specification. Thanks for the info. Call Us Today! First, you want to wiggle out the pickup tube followed by taking out the bolts on the top. It's easy! When I have it tightened down, I turn the engine over by hand 5-7 times before I ever fire it up. If your engine is a 2 stroke, mix to the proper fuel/oil ratio. My concerns are do the pistons tell a story that rings are worn because the oil is not burnt onto the pistons to the degree that it cannot be wiped clean with a dry rag. They are stock pistons by the way. However, if you are draining more than 5 mil of oil from the top of the piston either it was overfilled or oil has migrated from the lower. Typically, it would be a combonation of possible bad rings and definately bad valve guides/seals. Double check this and be sure the proper ring is on the proper landing on the piston. By Forged-steel connecting rods were used in all applications through 1962 and in select 421 applications through 1966. The piston will now lift off, and you will see a needle roller bearing (the small end bearing) that you can remove from the con rod. After the new piston is installed and the cylinder is torqued down, you're left with the next major task of a four-stroke top end rebuild: the head rebuild. If water-cooled, once the engine coolant starts rising in temperature, shut the engine off. For just about any 2-stroke, whether vintage or a newer, a 32:1 fuel/oil mixture is very common, but check your manual for the recommended ratio. Non-detergent oil in engine oil tank as well. 1. oil gets past the rings of the piston. The underside of this piston features an “L” suffix, indicating that this piston is intended for the left bank of a V engine. Now is the time to let the engine totally cool down again. Everything You Need to Know About Ring Gap! Back in the Brew Bikes shop, it was double-checked, and clearance was .0015”. Then, install the head. When complete, it looked like it was tighter. Wiseco is Going Racing with Honda HRC again in 2021, The Best 2-Stroke Engine Rebuild Video You'll Ever Watch, Mixin' Gas, Makin' Memories: 2020 Wiseco 2-Stroke MX World Championships, Polaris RZR: Rebuilding the Legends with Wiseco, 2020 Wiseco 2-Stroke MX World Championships Are Back On.