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Post by mellow on Jun 6, 2021 21:15:46 GMT 1
Evening men, I'm after some ideas if anyone has any. I competed In a long distance trial on my 35E dt125lc today, and shortly after beginning the trial the bike decided to stop wanting to tick over, which was quite awkward on the technical sections, and turning the tickover screw made no effect on the revs whatsoever, even when wound fully inπ I know it's not an RD but it's a mikuni vm26 carb so I'm hoping one of you knowledgeable guys can advise?π€ Any ideas what the issue could be?π€ Thanks.π
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Post by shaunthe2nd on Jun 6, 2021 21:36:24 GMT 1
Dirt in the pilot jet would be my guess. Strip and ultrasonically re-clean the carb. I assume previously ran well, if so just reset as before.
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Post by mellow on Jun 7, 2021 13:22:36 GMT 1
yep that is my guess, or blocked filter. yes bike starts fine and runs fine, just doesn't tick over have asked elsewhere and someone said main seals, but i'm sure that is one of those silly facebook posts that people put for every question Thanks for your reply.
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Post by rigga on Jun 7, 2021 15:59:48 GMT 1
Pilot circuit would be my first port of call too.
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Post by Chewie01 on Jun 7, 2021 16:10:02 GMT 1
For a dirt bike I would also make sure your air filter is freshly oiled to prevent dirt getting into the system.
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Post by mellow on Jun 7, 2021 16:26:16 GMT 1
yes i have started with the air filter. it was new few months back, it wasn't that bad to be fair but i cleaned it anyway, will oil when it has dried Next i will check the pilot circuit. not sure why but every other model of DT 125 LC runs a 25 pilot, but the model i have runs a 27.5, which is huge for a 125 i have heard so i may change it to a 25 pilot the same as the other models. I know the pilot essentially runs the tickover side of things, i just find it odd the revs dont rise when tick over screw wound right in, so i guess it must be quite blocked Thanks again for replies.
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Post by 4l04ever on Jun 7, 2021 16:46:59 GMT 1
The air corrector circuit usually gets air from one of the breather pipes on the side of the carb, so check they are all clean, and also look into feeding these pipes into a filtered or protected area so sh1t cannot get in.
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Post by tony2stroke on Jun 7, 2021 16:47:09 GMT 1
Another 1 for the pilot jet or circuit, I wouldn't change the size if it was running right on the 27.5, its most likely been done for a reason, although there may have been a partial block in the pilot circuit and someone got round it by using a larger jet.
I would clean out the jet and passages, then try it with the 27.5 before changing to the smaller 25 jet.
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Post by midlifecrisisrd on Jun 7, 2021 18:03:33 GMT 1
Not wanting to worry but I struggled to get mine to idle well
Ended up moving it on, running but not perfect. It would idle fine for 30 seconds but if you didn't blip it it would cut out
When I got it it ran like sh1t and stank. New stator sorted that
It was a 45e
Steve
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Post by mellow on Jun 7, 2021 18:13:04 GMT 1
The air corrector circuit usually gets air from one of the breather pipes on the side of the carb, so check they are all clean, and also look into feeding these pipes into a filtered or protected area so sh1t cannot get in. That's a good shout. I will check the pipes too thanks
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Post by mellow on Jun 7, 2021 18:15:55 GMT 1
Another 1 for the pilot jet or circuit, I wouldn't change the size if it was running right on the 27.5, its most likely been done for a reason, although there may have been a partial block in the pilot circuit and someone got round it by using a larger jet. I would clean out the jet and passages, then try it with the 27.5 before changing to the smaller 25 jet. The 27.5 is the standard size, but only for this code of DT All the others are a 25 so it has not been messed with. I do remember changing down on pilots to try as it never ticked over perfectly, as in the post above by midlife crisis
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Post by mellow on Jun 7, 2021 18:19:48 GMT 1
Not wanting to worry but I struggled to get mine to idle well Ended up moving it on, running but not perfect. It would idle fine for 30 seconds but if you didn't blip it it would cut out When I got it it ran like sh1t and stank. New stator sorted that It was a 45e Steve Yes i know the feeling well it used to be a pain, cleaned the carb out years ago and for a good few years it would tick over, but only if you "blipped" the throttle first when coming to a stop, which most 2 stroke riders do anyway, but it ticked over Mine is a swiss 35E Looks like i'll be delving into the carb again. Thanks for the reply
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Post by midlifecrisisrd on Jun 7, 2021 18:28:01 GMT 1
Mine was a Swiss 35e too π¬
Did you buy it from billbot?
We both bought stator from the same guy. Memory says from Italy but a long time ago
Steve
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Post by tony2stroke on Jun 7, 2021 18:47:38 GMT 1
Another 1 for the pilot jet or circuit, I wouldn't change the size if it was running right on the 27.5, its most likely been done for a reason, although there may have been a partial block in the pilot circuit and someone got round it by using a larger jet. I would clean out the jet and passages, then try it with the 27.5 before changing to the smaller 25 jet. The 27.5 is the standard size, but only for this code of DT All the others are a 25 so it has not been messed with. I do remember changing down on pilots to try as it never ticked over perfectly, as in the post above by midlife crisis Ah! the plot thickens, I hope its not your stator, I would still try cleaning 1st, then you will have to go through the process of elimination if that doesn't work, clogged exhaust baffle can cause trouble too, check the free cleaning fixes 1st I would say. I am not familiar with this model sorry.
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Post by mellow on Jun 7, 2021 19:20:43 GMT 1
Mine was a Swiss 35e too π¬ Did you buy it from billbot? We both bought stator from the same guy. Memory says from Italy but a long time ago Steve Yes mate I did. Its been used on green lanes for the last 6 years even through winterπ Yes the stator was from italyπ
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Post by mellow on Jun 7, 2021 19:34:30 GMT 1
The 27.5 is the standard size, but only for this code of DT All the others are a 25 so it has not been messed with. I do remember changing down on pilots to try as it never ticked over perfectly, as in the post above by midlife crisis Ah! the plot thickens, I hope its not your stator, I would still try cleaning 1st, then you will have to go through the process of elimination if that doesn't work, clogged exhaust baffle can cause trouble too, check the free cleaning fixes 1st I would say. I am not familiar with this model sorry. That's OK mate. The pilot is just wierd, every other dt 125 from the first to 1987 is a 25. Why this one has 27.5 is a mystery. All other jets etc are identical over all modelsπ It won't be the exhaust, had a straight through gianelli front pipe with DEP end can, again just a straight through pipe with wadding round itππ I'm going to attack the carbππ Thanks again all for your suggestions ππ
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Post by tony2stroke on Jun 7, 2021 20:23:42 GMT 1
Ah! the plot thickens, I hope its not your stator, I would still try cleaning 1st, then you will have to go through the process of elimination if that doesn't work, clogged exhaust baffle can cause trouble too, check the free cleaning fixes 1st I would say. I am not familiar with this model sorry. That's OK mate. The pilot is just wierd, every other dt 125 from the first to 1987 is a 25. Why this one has 27.5 is a mystery. All other jets etc are identical over all modelsπ It won't be the exhaust, had a straight through gianelli front pipe with DEP end can, again just a straight through pipe with wadding round itππ I'm going to attack the carbππ Thanks again all for your suggestions ππ I had a little Kawasaki AE80, awesome little bike did 82MPH, I kid you not, well speedo reading anyway, same straight through end can with wadding but cut open front pipe with all the washer plating removed from inside, every now and then it would loose some power and start playing up, I would change the wadding in the end can and good to go again, I wrapped the wadding too tight once, sucked all the power out of it, just to say, I did buy a fresco front exhaust thinking if its that good with my cut and shut then the fresco must be great, wrong, sucked all the power out, don't rule anything out unless you have checked it. I had a short ownership of a UK DT125LC powervalve without the powervalve, just turned to full open all the time, it was a little rocket, can't say I ever noticed a tick over problem, but I didn't spend much time on tick over.
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Post by mellow on Jun 14, 2021 17:06:11 GMT 1
well, just an update. i removed the carb, stripped and cleaned it all again, even removed the ball. all passages and jets clear. i checked float level. all ok. cleaned and oiled air filter which was quite new anyway, but just to eliminate. the tick over screw has no affect still on the tick over, even when wound right in. it lifts the slide. the slide bottoms out before adjusting the screw so i have no idea what the hell is going on. the plug was very black though. it almost sounds like its either not firing or its sucking air/bogging? i've even swapped the cdi. no difference. any ideas?
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Post by beardy on Jun 14, 2021 17:38:51 GMT 1
Just a shot in the dark. Your choke is turning off?
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Post by tony2stroke on Jun 14, 2021 17:47:20 GMT 1
Well if all clean and no blocking in exhaust, basic carb tuning says to change the pilot jet for a smaller one, I see the plug is oiled up, I would take the air filter out and try too. here is a link to the Mikuni carb manual to help in your quest. www.mikuni.com/c-manuals.htmlIt is def the correct carb code is it ?
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Post by tony2stroke on Jun 14, 2021 17:48:56 GMT 1
Just a shot in the dark. Your choke is turning off? Good call, we sometimes overlook the simple things.
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Post by mellow on Jun 14, 2021 17:52:23 GMT 1
Just a shot in the dark. Your choke is turning off? yes mate. if i pull it on it dies
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Post by mellow on Jun 14, 2021 17:56:48 GMT 1
Well if all clean and no blocking in exhaust, basic carb tuning says to change the pilot jet for a smaller one, I see the plug is oiled up, I would take the air filter out and try too. here is a link to the Mikuni carb manual to help in your quest. www.mikuni.com/c-manuals.htmlIt is def the correct carb code is it ? hi mate,i have actually gone down one size on the pilot jet as all other dt's rn a 25, whereas this one is 27.5 for some odd reason, but it's smaller now. yes i was going to remove the air filter to see if it improves, although it is clean, i don't recall seeing any animals in the airbox so don't think one has climbed in. It just bugs the hell out of me why lifting the slide with the screw does feck all
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Post by tony2stroke on Jun 14, 2021 19:55:01 GMT 1
I wonder if the throttle slide is worn (where the screw connects, the little cut out in the side) I have had this, they wear as people screw them in and out, they are soft metal, that would explain why it doesn't seam to do anything, or maybe the screw itself has been replaced with an incorrect item, not long enough maybe, who knows what's happened over the years with previous owners.
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Post by stusco on Jun 14, 2021 20:31:43 GMT 1
On my gamma the idle screws are all the way in and it does nowt to the tick ive never solved that problem either
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Post by midlifecrisisrd on Jun 14, 2021 20:34:00 GMT 1
When my 350 had the duff did on it would start and idle but give it throttle and nothing happened, still just idled π€
I know you have tried another cdi but worth checking rotor/stator/pick up as shows what timing can do
Steve
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Post by mellow on Jun 14, 2021 20:35:40 GMT 1
I wonder if the throttle slide is worn (where the screw connects, the little cut out in the side) I have had this, they wear as people screw them in and out, they are soft metal, that would explain why it doesn't seam to do anything, or maybe the screw itself has been replaced with an incorrect item, not long enough maybe, who knows what's happened over the years with previous owners. I have ordered a new idle screw, for that very reasonππ
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Post by mellow on Jun 14, 2021 20:36:27 GMT 1
On my gamma the idle screws are all the way in and it does nowt to the tick ive never solved that problem either I'm guessing it's adjusted on the carb top cable thenπ
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Post by stusco on Jun 14, 2021 20:36:28 GMT 1
I tried new screws still nowt
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Post by stusco on Jun 14, 2021 20:38:12 GMT 1
On my gamma the idle screws are all the way in and it does nowt to the tick ive never solved that problem either I'm guessing it's adjusted on the carb top cable thenπ Ive actually took the slack up at the throttle π¬
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