1. Its doing everything a four stroke does, just does it using two strokes or cycles. Backfire, Blowing Crankcases Or Spitting: If you notice that your engine suddenly started backfiring or one carb started spitting more than standard, that is the earliest possible indication of bad reed valves. No problems there, Both of them held just under 2 pounds of pressure with zero loss in 24 hours. Some bikes you can replace it from the outside, some you have to replace from the inside which sucks cause you have to split the cases to do it. incorrect. What came out was rather dark & dirty looking. A. Nov 16, 2010. Model of your vehicle. If the fuel pump diaphram goes it usually causes fuel to fill the crank through the impulse line. #1. midlifecrisisrd. No Engine Start. Most of the time the story ends with a blown engine. Apr 26, 2021 at 2:40am via mobile. Remove the cylinder head cover, the spark plugs, pushrods, and rocker arms. Moderator. So, it was definitely looking like crank seals were the culprit. is it running OK? Beyond checking compression, carburetion and ignition, Brad says the single most important test to run on a 2-stroke is a leak-down test. Location: Kansas City, Missouri. The Pressure Test The step by step is : Last active. Coolant with an opaque, brownish appearance. 4 Symptoms Of A Bad Reed Valve: The symptoms of bad reed valves are usually similar to the below-explained indications: 1. Symptoms include: over reving, overheating, stalling on acceleration, failure to idle, and worst of all, an engine seizure if the problem is neglected. The fuel air mixture screws on the side of the carburettor are marked H for High for the engines high speed adjustments and the L means Low for the engines low speed adjustments. The only way to tell is to look for other signs or to go through the problems one by one, I'm in the same boat as you right now and it sucks. Bad crank seals will not affect compression, they do not leak fuel. 1 of 2 Go to page. Do not pressurize the bottom end more than about 10psi or is will turn the seals inside out. Fouled plug says you are getting too much fuel. Step 1. A leaky crank seal could be allowing air or gearbox oil into places it doesn't belong and causing all kinds of issues. The first thing to check before anything else is the mixture screws. Sep 19, 2010. The SRIS and CCI injection system both have valves and theoretically won't leak, but you can . No oil puking. If the seals are the same type that's in an Lc or pv, they have an outer rib going around them which means a crankcase split, but I'm not familiar with your bike - a microfiche pic will help you determine that. . It is a 12mm hose ( almost 1/2 inch inside diameter ), not the smaller hoses. Only show this user. On the other side we got a couple of oil seals. 00:00 00:00. The process of replacing valve seals involves disassembling, The entire engine until you can reach the valve spring. The seals between the cylinder and exhaust pipe are the most common place that exhaust leaks can occur. Set it up on a fixture and use dial gauges to check the dimensions and all that jazz. this one's deeper inside the motor and seals around the crankshaft. Ignition timing not set properly. If you find this problem, suspect the main bearing seals. One example is a failing PTO bearing causing the seal to elongate and allow air to enter the crankcase leaning the fuel air mixture on that side eventually detonating the piston. Small leaks can cause oil to accumulate on the undersides of the engine, while larger ones may produce a drip of oil from the front of the engine. Gearbox oil has a very distinctive smell when it burns so it is easy to tell it apart from the two-stroke smell. Re: What are the symptoms of a bad rotary. Overheating of the engine. Troubleshooting Air Leaks. Triple Cranks. If the crankshaft seal dries out, cracks, or breaks, it can cause an oil leak. Does it pop and fart out the carb like a burnt intake valve on a 4 stroke? Once you've found a leak, fix it and retest. That will tell you if the pump is good or not. Symptoms of bad crank seals GT380? 3:51 PM - Jan 31. The SRIS and CCI injection system both have valves and theoretically won't leak, but you can . The fuel air mixture screws on the side of the carburettor are marked H for High for the engines high speed adjustments and the L means Low for the engines low speed adjustments. To check them on the ignition side is easy, just pop off the flywheel and ignition stuff and see if there is dust or dirt accumulating on the crank and the case near the seal. Cracked and leaking lines will give the same symptoms as a bad crank seal. Which way do crank seals go? Remove the pipe from the cylinder to look at the condition of the rings or seal. Dirty oil gradually drips down through the foam cowling liner and onto the swivel tube/tilt bracket area. If you had bad crank seals, the motor would puff LOTS of white smoke when it runs. Dirty oil gradually drips down through the foam cowling liner and onto the swivel tube/tilt bracket area. If it passes a pressure test, apply a vacuum. S. Mixture Screws. So, clutch side crank seal must have gone. 1. Crank Seal Replacement on Stihl motor. A small "air leak" at a crank seal or an intake gasket will cause the usually perfect fuel/air mixture in the crankcase to become slightly lean.sometimes very lean. Quote. Possible flooded engine: Try starting with throttle wide open. Originally Posted by bitzz Lousy idle, screams at top end, plugs show lean after screaming at top end. The BEST sign that your seals are gone is failure of a leakdown test. M. MajorMotion New Member. 3000 miles on the bike still starts easy and runs . If the seal on this side goes bad, you'll get air leaks. make better power, but basically if i time the ignition to 1.4 mm before. Overheating: Ignition problem: Spark plug fouled, broken, or misgapped. Hi. If its out if true, balance, runout is out of spec, bearings in the crank are bad, it has tons of hours and is assumed bad, etc. Engine oil with a milky appearance. Apr 7, 2020 #1 My question is will there still be good compression (140) with bad crank seals? 1 CLEAN AWAY Start by cleaning off any dirt or foreign matter from around the clutch cover. Bad Piston rings shown some signs of which we are going to explain:-. What I did was hook up a vacuum pump to the RV oil return line to the tank. White smoke through the tailpipe. Ignition timing . A leak down test works by pressurizing the crankcase cavity and cylinder. When we see smoke coming out from the exhaust is not a good sign in your dirt bike . 67. (856) 785 9455. Triple Cranks. Brought to you by Barnacle Bill's Marine Supply. InfiniteMiles. #6. Here are 10 reasons and fixes to help prevent lack of fuel to a 2-stroke engine. Thread starter MajorMotion; Start date Apr 7, 2020; 1; 2; Next. A small air pump is used to pressurize the cavity to 5psi and the pressure is monitored in the cavity for around five minutes. You need to look at it and feel for a gritty feel in the bearings. live with the start-up smoke, until you need to rebuild the engine. Most technicians will suspect a problem with the reed valves only after they have exhausted all other potential problems. Could have been wrong tho. Only show this user. The valve can only go in one way unless you modify it or damage (not likely) it. The two stroke actually has four things going on also 1. compressing the cylinder mixture while 2. drawing mixture into crankcase 3. blows (ign) the piston down while 4.transferring/savaging the mixture. Oil leaks are the most common symptom of a problem with the crankshaft seal. Piston skirt seizure in the cylinder. There's an o-ring around the outside. sledcrusher said: dodgetruck2 said: i would think a bad crank seal would cause to low of idle, because the lack of presure and fuel that should stay inside the engine but is bein leak through the seal. A plug is inserted into the intake manifold and another plug or block off plate is used on the exhaust to create an airtight cavity. I've checked closely and excluded other possibilities like the oil lines/fittings and . The sled would be revving and very lean. RD LC CRAZY GOD. . Symptoms: When piston damage involves the skirt, here are the signs that follow: Piston noise or piston slap (caused by the piston hitting the cylinder wall as a result of excessive rocking) Poor engine performance. I decided to flush out the RV case. * VISUALLY EXPLAINED * Efficient Understanding!Uniquely explained like never before, this video will give you a firm understanding of how this system works. Head gasket failure. More air means higher idle. If you find that your 2-stroke engine is leaking, it is likely due to the seals or O-rings. Joined. Symptoms of bad crank seals GT380? The first thing to look for is brass shavings in the lowest oil hose under the carbureator. Labyrinth seal failure symptoms. It could be timing, it could be an oil seal, the pistons rings, it could be carb or intake related, or it could be your oil pump if you have one. Quote; Post by tz375 Wed Feb 17, 2016 9:17 pm. I decided to flush out the RV case. Spark plug. Dry running damage. If it is a BN carb the plastic cap for the fuel inlet will leak. Not all were plastic but the plastic ones are easy to crack especially at this age. If the crank seal goes it will cause a lean condition on that side. This leaking of smoke is not good for your engine. but as Robert mentioned, they are suppose to remover liquid gas/oil from the crankcase to keep it from building up. Low octane fuel. Quote; Post by tz375 Wed Feb 17, 2016 9:17 pm. On 2 stroke dirt bikes, there is a rubber seal on either side of the crankshaft. In 4-stroke engines, the lubricating oil is in the crankcase. If this symptom shows up in conjunction with one of the other symptoms, a compression check is definitely in order. Posts: 19,285. advanced. The Theory of Air-leaks. gaz. I was going to refresh the piston anyway at some stage so good chance to check it. Crankshaft bearing worn or damaged. Brought to you by Barnacle Bill's Marine Supply. Sometimes it wont run at all, other times it will race away. . In the end it was engine out and stripped .The owner had a fresh crank fitted a couple of weeks before and it turned out the new labrinth seal was under size .Once sorted all was well. Bingo, did the leak down test with motor on the bench (could have done it in the bike but was sure its the seal leaking) with the clutch basket removed and the crank sprocket removed (clutch holder tool worth every cent) so you can see the seal. 00:00. 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