My 2017 ktm 300 xcw started Knocking Real bad After my last race. So I tore it down to diagnose and Fix the Noise. Diagnosis: Piston Slap @ 54hrs. Fix: Top end Rebuild.
Gladius Jon should I take my cylinder off and measure the bore before ordering a piston? Did you measure your bore with one of those T things or did you just check the ring gap and go by that?
I don't know about KTM, but the Yami manuals didn't warn me to place a rag to prevent the cam cap position clips from falling into the motor. I didn't even know the clip was there until I lifted off the cam cap and heard it rattle into the motor. My son did the same thing. Very well made video.
Just a plain, straightforward top-end job. An advantage to a steel sleeve is I can hit it with a hone to deglaze it during a piston or ring replacement.
The reason for multiple base gaskets of different thicknesses is to combine them to produce the optimal piston height in the cylinder (ref. X dimension). Power valve height should also be checked (ref. Z dimension). Refer to videos by Andrew Cooksey on setting X and Y dimensions.
I have exactly the same issue right now - was great to find this. Looked at plastics, kick start on pipe and all-sorts with nothing. Started all of a sudden out on a ride and I babied it back. It does feel slower. First think is a comp test I think - then I'll pull the cyl this weekend. Will get a Wiseco piston kit for $150 and try that - hoping beyond hope it's not a main seal or crank issue because I don't want to split the case to be honest.
First I heard this with my volume down and thought it was kind of the typical mild engine noise you hear from 2 strokes, then I turned it up...... my gosh I bet that was loud as heck in person. Glad it was a simple fix. I always check my ring gap but admittedly never check power valve clearance
I recommend with that wiseco piston you should let the bike fully warm up every time it's ridden, they can expand faster than a stock piston and seize. If my cylinder is bad I send my piston and cylinder out to be machined and coated for eachother. But if the cylinder is still good like yours I just give her an extra 5 min to warm up and haven't had any problems. Love your content and looking forward to seeing more harescramble vids. You have made me sign up for my first race this year.
@@Bryan-Hensley I avoided vertex pistons because I was nervous that they were the cheaper brand, but I pulled apart my yz250f to do some head work and inspected the piston. I found out It had a vertex piston in it, and I've done at least ,300hrs on it myself so id say they're pretty good quality.
@@B.hughes they used to be $300 per piston back in the early 2000s. I almost thought I was looking at the wrong brand when their prices dropped. I think KTM went with another brand for a few years which probably caused the price to fall. The vertex might not be a good motor cross piston though. I have good luck out of wisco too. I'm running one in a cr 250 now. It's probably closing in on 100 hours. It's still got pretty good compression. It's due rings and since I don't trust wisco as good I'll probably put in a new piston just to be safe
vertex is the OEM piston manufacturer for KTM, take a look at the inside of the skirt on the intake side and you will see the vertex logo. I buy vertex pistons to save a couple bucks and still have the OEM piston!
A MYSTERY !!! New motorcycle runs GREAT on 87 octane and Castrol 10W-40 synthetic oil. 600 mile service, still runs GREAT on 87 octane and Castrol 10W-40 synthetic oil. 1806 miles, 87 octane and Castrol 10W-40 synthetic oil. ENGINE KNOCKS. This time a Full tank of 93 octane and Castrol 10W-40 synthetic oil. STILL KNOCKS. This is on a Triumph bonneville 1200 engine. Seems to be a common occurrence on these all over the world. So it can’t be the gas or oil obviously. England had very high octane fuel but they still knock. We were thinking the cam-chain tensioner but the oil is always the same. High octane fuel doesn’t eliminate the knocking. Tried that myself just yesterday. The only thing I can come up with is a software problem with the ECU during the service at the dealership. Considering this is the common denominator because the bikes are serviced at different dealers in different countries BUT connected to the same mainframe in London to Triumph headquarters that effect the bikes that get ECU updates. From the information given in this video if the timing is off, or the mixture and the timing is off, the result is a misfire. What else could it be ????? Triumph tells us it’s normal but my these bikes run GREAT other than this knocking. People have tried valve adjustments, with no difference. Keep in mind these are NEW motorcycles. Help please ……..
For general information I would advise against using crows foot type wrenches to torque anything, they have a tendency to strip a nut. The link here in Amazon is for torque extender box end wrenches, can be used for hard to get at nuts and bolts and don't strip the head.(T&E Tools 93222 3/8” Drive Metric Torque Adaptor Set - 12 Piece Torque Wrench Adaptor Set). Glad to see she was only a top end failure.
I was going to say piston slap .... But i wouldn't have guessed the wrist pin bearing .... Usually its worn rings only glad you got it fixed ! And before any serious damage ...... My 125 is due for a new piston but im waiting for summer here in ohio .
Definitely ! My buddy had the same kind of issue going with his KTM the Piston broke around the bottom of the skirt he now replaces his piston every 50 hours religiously
Yikes.. any engine failure at 55 hours is ridiculous, man. I can't believe that. I can't believe the wear that people are seeing with low hours on their machines. I really hope I don't have to deal with this crap for a long time. I have never had engine issues on any of my bikes besides a race back in 2003 when we forgot to mix the oil in with the gas (whoops). I ran the same piston in my KTM 125 during 2 race seasons, and 5 additional years of hard riding. I sold it with it still running nice and tight.
Ktm will never have the same quality as Japanese bikes, as long as they keep trying to make them lighter by using shitter metals and making things thinner
Hopefully you can answer this…. My motorcycle only has 2000 miles on it, but I had a tiny oil leak. It goes into the shop running great, but it comes out with the oil leak fixed but now it’s knocking. Not bad but enough to notice it. What could they have possibly done to cause this knocking ? They also did the second service that included an oil change. They claim they did not make any valve’s adjustments. I hate that it’s making this kind of noise when it’s just broken in.
That's an unusual failure. Do you just thing you had a bad small end bearing from the factory or do you think it was due to something else? What kind of oil and ratio are you using? Do you usually warm the bike up before hammering it or do you run it hard cold?
What do you mean by you "could move the piston back and forth in the jug?" Do you mean you could slightly spin the piston back and forth in a circular motion or in a linear back and forth motion? I'm trying to diagnose a my issue and I see the the piston has some wiggle to it in both of the above directions, but not up and down.
All my 4K videos have that 360p bug. Go into the video editor (in youtube's studio) and make a simple change and save it. It should then show up in the higher resolutions. It amazes me that RU-vid with a staff of developers ignore that bug,
I have old Jawa 50 from Czechoslovakia its common bike for us and its 2 stroke... These bike are undestroyeble it runs on diesel and even on alcohol with no problem.. Friend tryed it... I give love to my bike and I did renovation and be carefull on it but today it didnt run ok and I have weird noise from motor.. Its not transmission i know that so I think its carbon built up (most likely bc i give it more oil then should) or engine knock... Parts are cheap but u know these bikes u ride one day and next 3 days u repairing it... But I love it xD
I have the exact same problem with my x trainer 300, dry air filter, a whole lot of piston slap, worn wrist pin, wrist pin bearing went kerplooey in my hand, minor scratches in the piston from dirt inhalation, I still have to clean the carb. I thought the whole bottom end was loose due to the fact that The piston had “axial play” but it was just a wrist pin worn down so much, coincidence or not, I noticed it in a hare scramble too, but it was 100% my fault because I let the “dirt accumulation” on the air filter get a little out of hand👍
@@floridagliderpilot4101 I took heed from your videos and been doing little works. I think I have a big end knock too so will give a go before end of the year.
thanks for video. can you post a link the break-in video? Im replacing my 300 jug today with new nikacil and wiseco. for 2003 model only wiseco was avail dec 2021. had millenium tech do the replate and ring filing.
Doing a 2001 300 exc rebuild and it’s been such a pain trying to figure out the process with millennium tech. My 300 jug is scratched pretty badly and they don’t make replacements to my knowledge.
I have a pretty good idea why. But I dont want to give it away yet, next weeks video 😉. Yes, I did retrieve all the missing needles. I must have recounted them 10 times hahahaha!
hi, i was looking to get 300 to make a supermoto for city rides and for small island vacation rides . the only thing that makes me think about it is maintenance . how often piston needs change ? how many km or hours is it worth it or look soem something else ?
It’s really not good for the engine, it can take a few miles of street but not much more. I changed my top end every 50 hrs. Which would be 500-1000 miles on street. Honestly, get a 4 stroke for street. Ktm 350 and beta 350 are great. Ton of power, and only a few more lbs heavier then 300 exc.
And gas mileage is terrible on two stokes overall. Get a 4 stroke. I made a street legal 250 2 stroke and hated it. Sold it with only 30 miles. Bought a fe501 and I've already put 100 miles on it in the first day. Way better power, mpg, reliability, and gearing.
dont listen to that stuff, im riding a 2-stroke literally 15+K km already, with the STOCK top end... if u dont engine-brake it, it will last alot longer than these 50hours lmao
The cir-clips.....you didn't show us how you did them. I always struggle with em, shit job. Make sure to always stuff lots of rags into the engine openings when putting the clips in. If you lose a clip into the engine you'll be splitting the case the get it back.
my bike made the same nose about 2 mouths and put new top end on glad i did as bottom piston ring was seized and barrel was scored the fuck out of exhaust side
I hope you can help me out with this issue, I just rebuild the top end of my 2005 honda crf 250r. after trying to find out what was the hard ticking and knocking, I did all shorts of things like checking the shims, changing the timing chain and the rocker arm. the sound still present, I disassemble the engine to check if something was up with the piston, to my surprise the piston looks tilted to the left one side is higher then the other and it was hitting the side of the valve head. do you think it the problem is in the crankshaft? Note: The cylinder and the piston are new. Any ideas? Please help!
@@GladiusJon I bought the bike without a piston, so I bought a new Piston and cylinder head. looks like the piston is a bit crooked. when I have it on top dead center, one side of the piston is not flush to the top of the cylinder head.
I do on my 2021 ktm 300 xc tpi with only 10 hours, did you figure it out? Does it only clank like that when you’re holding the throttle at 50 to 75 percent because that’s when mine does it. Doesn’t do it at idle or while wide open
@@connercrow8629 And Yeah it's the same . It never happens at idle. And it starts when the rev is at 5k . I don't think it happens when the throttle is wide open
Check jetting. Mine did the same until I went abit richer. This was after pulling the engine apart and checking everything. Knock (pre-ignition) caused by a lean condition sounds very similar. Ktms are apparently notoriously lean when being ran with carburetor set to Ktms spec.
Good job on proving down hill engine breaking bud u really called that one i change my 250 xcw at 80 hrs and never have i seen wear like that also vertex is what ktm puts in so thats what i put in and if you take the time to look there is always 2 jug gaskets on from factory thats y you get a few in the kit anywho good luck to ya and just pull the clutch in racing and engine breaking when its faster and easier being only 15 or less seconds no bigge going down mountain bad idea
Engine braking was not the cause of my bearing failure. Yes there are 2 gaskets stock. But I wanted to increase my compression. And I also wanted a forged piston. There is more then one way to skin a cat so to speak... good luck believing the engine braking myth..
Engine braking is really not an issue as long as your slightly rich on the pilot. To provide further protection I personally run 40:1 in all my KTMs and 32:1 in my sons 105 KTM. Some folks swear by using less oil in the mix but myself I would rather have the extra oil
I think you the one having what I would call premature wear would need luck on the engine braking myth not me I run 60:1 and never had a problem my bike has 150 hours on it yes i have done top end twice just cause the hrs were racking up but yeah different strokes for different folks
well the wrist pin bearing failed so thats why in this case. also top end should be done between 15 and 40 hours on 2 strokes depending on displacement. 450 4 stroke pistons have a service life of like 10 hours because the skirt is so short.
