Smithy95 Posted January 19, 2014 Posted January 19, 2014 Hi everyone, I went for a little ride the the day and was stopping at a set of lights at a junction when suddenly the back tyre just locked up when I was shifting down. I didn't shift down too quickly as it was probably about 10mph coming from second to first and I barely touched my back brake. Anyway being a new rider I stalled it and upon trying to kick it back up it wouldn't start and sounded very strange. Eventually I got it going but the noise coming from the bike was horrific, but I needed to get it back home so I rode on it and about half way the noise stopped. Upon getting it home my dad and I checked it thoroughly and the noise hasn't come back and it hasn't locked up after about 10miles further riding. Does anyone know if this could be a possible problem that could cause more damage if left alone? It's an 01 plate dt125r with just under 25k onto the clock which has just had a top end rebuild recently. Sorry for the huge essay but has anyone got any ideas?
Moderator Cynic Posted January 20, 2014 Moderator Posted January 20, 2014 Sounds like a minor sieze, sometimes called nipping up. Check all your fluid levels, the noise is worrying. Does it still run ok. moved, say hi in the new members. Where you are etc.
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 Have done, okay I'll have a look at all the fluid levels but he mechanic did say he'd checked everything throroughly and topped anything up that needed it. Any other ideas? The only way I can describe the noise is like imagine a wet leaf stuck between your brakes and back wheel on a bicycle.
Moderator DirtyDT Posted January 20, 2014 Moderator Posted January 20, 2014 If it sounded strange at stationary then this points to a possible engine or gearbox issue. I am presuming there was 2 stroke oil in the bike? How mechanically minded are you ?
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 Me, very little, my dad however has rode bikes and sorted them all his life and has known the mechanic we bought it from for a long time. Of course when I got it back home though everything sounded normal so he's unsure and the noise is a weird one to describe. Yeah it stalled at a set of lights, I got it going but sounded very strange, so I turned it off then tried to kick it up again but it didn't work for about 5 minutes which it eventually started but still sounded bad. I decided to ride it home slowly and the noise did go. I assume the mechanic did fill it up with 2 stroke oil, it's been a family business for a long time so he's also been a mechanic all his life. The bike was cold but the way, the temperature gauge hadn't moved and I'd literally done about 1mile before it happened.
Moderator DirtyDT Posted January 20, 2014 Moderator Posted January 20, 2014 With the information I have I would have to agree with Cynic. You can't assume anything. YOU need to check things like oils, fuel and tyre pressures. A 2 stroke burns oil to run so it needs to be topped up. This is different to 4 stroke bikes.
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 Okay I bought he bike about 2weeks ago if any help. I've also got a little update, just tried to get it running, took absolutely ages, way too many kicks and once it was running the choke is all off. When the Choke is on, it's idling at 1.4 to1.5 but if you rev it lingers at about 3k before dropping back down to 1.4ish. When the choke is supposedly off according to the manual, the bike for some reason revs up to 5k, stays there for a while then slowly drops to idle before cutting out. Oil checked and is fine nowhere near low, checking fuel? There's enough and nothing's leaking overnight it's just been filled with standard unleaded less than 20 miles ago.
Moderator DirtyDT Posted January 20, 2014 Moderator Posted January 20, 2014 Then it sounds like a crank seal (probably left one) is shot. This will allow air into the system which will make the bike run lean (too much air to fuel ratio) and cause the bike to seize. This fits with what you said earlier. Take your spark plug out and post up a picture. it should be a dark brown/chocolate colour. if it is pale brown or whiteish then this also points to a lean mixture.
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 Here is a picture of the spark plug http://s1291.photobucket.com/user/Csmithyy95/library/ there's two of them I think that should work.
Moderator DirtyDT Posted January 20, 2014 Moderator Posted January 20, 2014 They look sooty enough. Ideally you need to do a running check which would be to put a new plug in, run the bike for a couple of miles, when safe to do so run the bike at about 3/4 throttle for about a quarter of a mile and, again when safe, use the kill switch to turn the bike off and coast to a stop. At this point you need to whip the plug out (it will be very hot) and then check the plug colour. this will determine if the bike is running lean. It won't help any high reving which is a common symptom of an air leak. Things to check That the bike does have 2 stroke oil in it. The plug swap as above. Run the bike and spray wd40 around the carb rubbers where the air filter pipe and the carb meets and where the carb and engine meets. Listen for a change in engine noise and speed. Oil pump settings. Carb settings - are standard.
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 Ok I'll give that a go in the near future, so if it's running lean it'll be a light browny colour rather than what it is at the moment?
Moderator DirtyDT Posted January 20, 2014 Moderator Posted January 20, 2014 Light brown or quite white if really bad. Always remember that a lean 2 stroke will seize and probably put a hole in the piston. This normally means a full engine strip to get the metal out meaning a possible rebore and new crank bearings.
Smithy95 Posted January 20, 2014 Author Posted January 20, 2014 My dad has come home and thoroughly checked over a lot of it, the only real problem now is that it won't idle without the choke on, it tries to then just dies..
Moderator Cynic Posted January 20, 2014 Moderator Posted January 20, 2014 Could be float height messing things now the leak is fixed. My dt is very sensitive to it.
Smithy95 Posted January 21, 2014 Author Posted January 21, 2014 Okay I'm not very comfortable opening all of that stuff yet and my dad thinks it would be unwise for me to try, even though I want to! So were sending it back to the mechanic later on this week and we'll see what he has to say, I'll let you all know.
Smithy95 Posted January 21, 2014 Author Posted January 21, 2014 Now the choke lever won't stay in the on position it just drops back down by itself.. Why could this be happening?
blackhat250 Posted January 21, 2014 Posted January 21, 2014 It will be worn smithy, i take it the oil feed pipe is still connected to carb, as this would pull air thru, and give you a lack of oil too. If it neeeds choke to idle, i would strip carb, and inspect,,this way all joints can be checked too.
Smithy95 Posted January 25, 2014 Author Posted January 25, 2014 You were right straight away by the way, it was a blown crank shaft seal when he rebuilt that part he must've nicked it cause he took the blame. He's replaced the seal but says it still sounds funny and wants to have another look at it after he's back from holiday, can a blown crankshaft seal cause engine problems?
Moderator DirtyDT Posted January 25, 2014 Moderator Posted January 25, 2014 You were right straight away by the way, it was a blown crank shaft seal when he rebuilt that part he must've nicked it cause he took the blame. He's replaced the seal but says it still sounds funny and wants to have another look at it after he's back from holiday, can a blown crankshaft seal cause engine problems? Yes. Left seal causes the bike to run lean and possibly seize. Right normally sucks in oil, and burns the gearbox oil.
Smithy95 Posted January 25, 2014 Author Posted January 25, 2014 After hes replaced the seal I seem to have lost quite a lot of acceleration in 4th and 5th and even 3rd. Could it have caused problems whilst it was broken?
Recommended Posts