bb3924 Posted July 21, 2014 Posted July 21, 2014 Dec 1975 (build) DT 175 Enduro Trials and tribulations later, the bike is running, not perfectly, but running well. The "perfectly" part will be a function of the carburator. Anyway, here's the "first" in my life and not sure if anyone else has ever heard of this oddity... So, my son rides this bike. Arrived home from work and decided to try it out. So, upon starting it, the tachometer was not functional, cable was connected on both end, and then I engaged the first gear with clutch in... slowly release and I swear the bike's motor/gear pushed drove backward. Was this an anomoly or is sum-ting-wong? Bear in mind, I recently had the bike torn down and camshaft seals and bearsing on both sides replaced to eliminate air sucking issues diagnosed with help of this forum. Bike runs well, but this oddity of "reverse" on the bike is either a figment of my and my son's imagination (flat ground) or a loose "cog" in the machine that should be addressed before bigger problems develop. HELP! Thanks Beautiful in Michigan in July!
Moderator DirtyDT Posted July 22, 2014 Moderator Posted July 22, 2014 Probably the woodruff key has not been put back in after the rebuild or it has sheared. It is a small piece of metal that fits into a slot in the crankshaft.
Moderator Cynic Posted July 22, 2014 Moderator Posted July 22, 2014 A dt175 will happily run backwards all it needs is a backfire to give the piston enough energy and off she goes. Generally though it will be badly set ig timing.
Moderator Airhead Posted July 22, 2014 Moderator Posted July 22, 2014 Yep, bump start it backwards, than ask your mate if he wants a race
jimmy Posted July 23, 2014 Posted July 23, 2014 Yea, it's a 2 stroke thing. BSA Bantams were particularly keen on it
dt502001 Posted July 23, 2014 Posted July 23, 2014 I want to know how you had the camshaft seals replaced? LOL sure it was a typo on your part but if you can find a camshaft in a 2t your a magican. Bear in mind, I recently had the bike torn down and camshaft seals and bearsing on both sides replaced to eliminate air sucking issues diagnosed with help of this forum. . Who ever fixed it DON"T let them BS you they F'd up and the timming is wrong.
bb3924 Posted July 25, 2014 Author Posted July 25, 2014 I did have both the bearings and the seals changed, which required a teardown of the engine. So, this "reverse" condition only happens occasionally with the "tell" being the failure of the tachometer. Then, turning off the engine and restarting it usually puts it back into forward. I agree, the timing is probably off too as it runs well at high rpm, but not well at lower rpm. Thanks for the info and confirmation of my thoughts. I didn't tackle the seal/bearing replacement job. He charged me $400 for both labor and parts. I suspect the parts were next to nothing. But, that job is beyond my skillset. I sure hope it isn't another $400 of labor to get to this woodruff key...
Sacha Posted July 26, 2014 Posted July 26, 2014 The woodruff key is pretty straight forward... but you'll need a flywheel puller.
dt502001 Posted July 26, 2014 Posted July 26, 2014 Shouldn't cost you anything they didn't tighten the flywheel properly thats the only reason why it would do the key in! Take it back and tell them to fix it right this time. It a 20 min job to replace the key and set the timming. PS 2t dont make alot of power down low got to get them into the power band.
Recommended Posts