Posted May 31, 201212 yr Hi all, First post on here and hoping for some help. I purchased a DT125R 2001 Reg off a friend a few months ago and have finally got it insured and on the road. Love the bike however, it seems to be a tad slow, tops out at about 50-55 in the red line of 5th gear. I have 2 questions.... Surely it should go faster than this? And should it not have 6 gears instead of 5? The bikes power valve is set up standard with the keyhole lining up correctly. It has a DEP end can, but standard expansion pipe. It has no reed switch in the speedo but i think this has just been unplugged, not sure if this is the issue as the bike seems to rev well passed 12k and the reed switch is supposed to limit the revs to around 7k? Any help is much appreciated!!!
May 31, 201212 yr It should have 6 gears yes. Sounds like you're not getting use of 6th gear. 55-60 would be the time to change from 5th to 6th.
May 31, 201212 yr Author Thanks for the replies. It only seems to have 5 gears. Would there be an obvious fault for if it can't change up to 6th?
May 31, 201212 yr If you look on the side of the engine near the front sprocket it will say 1N23456 which is your gears. I think even the early LC's had 6. Do you know how many teeth the front and rear sprockets have. As Ryan was suggesting it could be that it's been set up for loads of acceleration which would kill off the top end speed.
May 31, 201212 yr Author Yeah it does have 6 gears. Took it out for a run just now and counted. Just me being a rookie and thinking it was only 5 gears. But that makes it slightly worse as it does 55mph at 12000rpm in 6th. Surely thats a bit slow? The gearing is 16 front and 57 rear. Any ideas as to why its this slow? Appreciate everyones help!
May 31, 201212 yr Moderator 57/16 is right, perhaps you are experiencing clutch slip? can you see the revs change when you give it a handfull of throttle in high gears with no apparent change in speed?
June 1, 201212 yr Author It does seem to do that slightly but it still accelerates just really slowly then tops out. I adjusted the clutch cable to see if it was the clutch and it's made no difference?
June 1, 201212 yr Moderator it may have worn or glazed friction plates, continual riding in this condition will 'cook' them nicely if it's slipping
June 1, 201212 yr If you can hit 12000 rpm in either 5th or 6th then there is definatly something wrong,,,,,, the bike should be flying at that stage. It does sound like slipping clutch.
June 2, 201212 yr Author I'll try taking a look at the clutch to see if they are worn. Hopefully my Haynes manual will be able to assist. Thanks for everyones help!
June 2, 201212 yr Before ya go pulling the clutch out,,,,,,,, look in your haynes manual,,,,,,,it explaines how to reset the clutch lifting arm manually. There is a raised notch on the casing and when arm is adjusted propperly there is a mark on it which will line up with the notch on the case. Then do-up the clutch cable again and see if it's any better. This will reset clutch again BUT this will only work if the clutch plates have NOT become glazed. I would try this first. Get your bike into 3rd or 4th at a standstill. Front brake on,,,bit of throttle without stalling,,,,then easily let clutch out. If ya can let clutch leaver almost all the way out then you have a slipping clutch,,,,,,,,,lets hope there not at the glazed stage eh !!!
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