JayLeatherland Posted October 13, 2012 Share Posted October 13, 2012 Hi guys, I am currently working on my new XT125 X 2006, it's my winter project bike, trouble is I can't get the dam thing turning over. I definitely have spark, I definitely have fuel ( if I pour some done the spark plug chamber) yet it won't fire up? What could potentially be wrong with this? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 13, 2012 Moderator Share Posted October 13, 2012 Moved to the workshop. Spark, fuel and compression are all you need. The timing has to be right also so check the compression and the timing. What exactly happend if you pour fuel into the plug hole and try and start it? Cylinders can get flushed of oil so leave the plug out for a while and try a little clean engine oil down the bore and turn it over with the plug out. Then take the air filter out and squirt some wd40 into the carb and push the starter. Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 14, 2012 Author Share Posted October 14, 2012 Hi, I have been doing a little more investigating today and I have removed the piston to find that it was installed the wrong way round, the arrow was pointing towards the rear of the bike, not the exhaust side. Could this be my problem? Also, at TDC what position should the valves be? Currently the inlet is fully sealed but the outlet is slightly open? Link to comment Share on other sites More sharing options...
dt502001 Posted October 14, 2012 Share Posted October 14, 2012 Tdc valves fully closed, with the head removed the valves shoudl fully close ,sounds like you have a bent ex valve .Does the piston have any marks from the ex valve hitting it? The pistion has relife cutouts for the valve and the in is smaller than the ex.. Did you do a compression test prior to removing the head? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 14, 2012 Moderator Share Posted October 14, 2012 Hi, I have been doing a little more investigating today and I have removed the piston to find that it was installed the wrong way round, the arrow was pointing towards the rear of the bike, not the exhaust side. Could this be my problem? Also, at TDC what position should the valves be? Currently the inlet is fully sealed but the outlet is slightly open? It won't help!!!! I think (but you need to check) Inlet Valve Clearance (Cold Operation)0.08~0.12 mm Exhaust Valve Clearance (ColdOperation)0.10~0.14 mm Link to comment Share on other sites More sharing options...
blackhat250 Posted October 14, 2012 Share Posted October 14, 2012 Sounds like someones had this apart, and thrown it back together, , and with you tryin to start it, have bent the valve, Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 14, 2012 Author Share Posted October 14, 2012 No I never did the compression test, I only did the thumb over the spark plug thing, it didn't budge my thumb! I thin I need to invest in a compression tester. Yeah I think the piston has some marks on it, it sounds more and more like the valve is bent. Is this a big, expensive job to repair? I have found all sorts of problems with it so i agree that the owner before has chucked it back together not very well I think. Link to comment Share on other sites More sharing options...
blackhat250 Posted October 15, 2012 Share Posted October 15, 2012 valves are cheapish, £20-30, but you"d have to grind them in, [ be as well do inlet,] then shim them for clearance, Link to comment Share on other sites More sharing options...
dt502001 Posted October 15, 2012 Share Posted October 15, 2012 The xt 125 has screw type of valve adjustment,so no shims to buy ....and a used valve will work if you can find one from you local wrecker.They migh have a wrecked head from a different bike with the same size valve, dosen't nessarly have to come from a xt but you have to know the size of yours. To get the valve out without a spring compressor so you can measure it,put a piece of wood under the head and a rag to keep the valve in place.Put a deep socket over the top of the valve and hit it hard with a hammer the 2 keepers will pop out if only 1 comes out hit it again. Or buy a new valve and a laping tool and laping compound Try Utube how to lap in a valve ther has to be a vid on it.It's not hard. You will need a valve spring compressor to get the valve in ,,, any local garage should be able to help with that.might even loan you a laping tool for 20 min to lap in the new valve turn the piston around if it didn't hit hard it should be reusable. Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 15, 2012 Author Share Posted October 15, 2012 Thanks guys, I've ordered the new valve today, £18 for a new one, it wasn't in stock so I've got to wait 5-7 working days. I'll let you know how I get on when I have done it. How do I know if the piston is damaged or not? It has some scuffs on the top but no major sign of damage. I'm thinking just do the valve for now and see if we can get the bike running. While I am waiting for the valve I will have a good search to see what else is wrong with this project of mine :-) Thanks again for al you help and support, it is appreciated. Link to comment Share on other sites More sharing options...
dt502001 Posted October 15, 2012 Share Posted October 15, 2012 Go for it reuse the old piston it didn't hit at 700rmp idle or 5000 rpm....... just as someone tryied to start it and it would have bent the valve immideatly so the piston was cold . You can sand out the marks in the piston so they don't creat hot spots Just make sure nothing get's under the rings. Put some gas in the intake side and see how much gas sepes out with it closed ,,Might as well lap it in and get a fresh seal,,speaking of seals might want to change the valve seal while you in there only a few $$ more. Ops get a new piston c cir clip you have to wait for the valve so get it as well you realy don't want to reuse the clip that holds the wrist pin in. Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 17, 2012 Author Share Posted October 17, 2012 Latest update, removed both valves, both bent! When we were inspecting we thought that they were in the wrong holes, so I cancelled the one that I ordered because if they were in the wrong hole it meant I would have ordered the wrong one. Anyway, now I need both valves and really dont want to wait, does anyone know where I can get these valves from sharpish? I've tried local breakers but no-one has any? Any ideas where to try? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 17, 2012 Moderator Share Posted October 17, 2012 It's not the kind of part normally kept in stock. Local yami dealers. Have you looked on eBay to see it there is a Complete head for sale? Link to comment Share on other sites More sharing options...
dt502001 Posted October 17, 2012 Share Posted October 17, 2012 Yep your at the mercy of the dealer,I don't know about your dealer but mine charges 10% more for 2 day shipping Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 24, 2012 Author Share Posted October 24, 2012 New Valves are here and lapped in nicely, just got to put it all back together and give it a try, fingers crossed. I'll let you know later how I get on, wish me luck! Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 24, 2012 Author Share Posted October 24, 2012 Yesssssssss! It finally turns over, first time aswell. Need to set all the carb up now though get it running nice. When it was running it was smoking quiet a lot, any ideas why this could be? Could this be because the carb isn't set up right? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 24, 2012 Moderator Share Posted October 24, 2012 I needs a bit of a ride before you can state that smoking is an issue, you've only just built it after all! I assume that you checked and re-fitted any seals on the valves when you fitted them Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 24, 2012 Author Share Posted October 24, 2012 Yeah the seals were done really good, I will give it a good ride and see what happens. Link to comment Share on other sites More sharing options...
JayLeatherland Posted October 26, 2012 Author Share Posted October 26, 2012 Help me please set the carb up!!! I can't get it to run without the choke on, it's frustrating me. Anybody got any carb advice? Link to comment Share on other sites More sharing options...
dt502001 Posted October 26, 2012 Share Posted October 26, 2012 Sounds like you need to clean the carb,make sure every jet hole is totaly clean. as the last owner couldn't get the piston in right don't count on the fact that they didn't mess with the carb. Turn the a/f mix screw in fully counting how many turns before you pull it out to clean,most are around 3 turns you may need to turn it out or in to get the bike to run without choke.But the carb has to be clean first. make note of the float height. the main needelclip should be in the middel ie 3rd notch from the bottom.Hope that helps Link to comment Share on other sites More sharing options...
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