ranger Posted April 18, 2009 Share Posted April 18, 2009 a good friend's elderly father gave me his old '71 yamaha ct1 175 enduro a few months ago, as it had been collecting dust since 1976! i cleaned the carb and put a put in a keyster kit, sealed the tank, replaced all the corroded gaskets, added new bel-ray oil in the injector, and she fired up today! when the smoke cleared, she seemed to be running darned good...though only with the idle/air screw screwed all the way in. i warmed her up, drove around the block a few times, and was having a quite a blast...then suddenly...SMOKE...tons of it...billowing gray out of the tail of the pipe and the pipe/engine connection. she died, and though i was able to restart her, she smoked like crazy and runs like crap. the plug was pretty fouled...but a new plug didn't make a difference. ps: i hadn't changed the transmission gear oil yet..i was waiting til i got her warmed up. ps2: i didn't test the oil injector first. ps3: my girlfriend claims to have heard a "squeal" come from the bike before it started smokin'. what happened? now what? Link to comment Share on other sites More sharing options...
Moderator mervin Posted April 19, 2009 Moderator Share Posted April 19, 2009 Crank seals i reckon, that smoke was the engine sucking in the gear oil methinks, the seals will be well past their sell by date now Merv Link to comment Share on other sites More sharing options...
XSwheels Posted April 19, 2009 Share Posted April 19, 2009 I agree, crank seals. Link to comment Share on other sites More sharing options...
ranger Posted April 19, 2009 Author Share Posted April 19, 2009 crankshaft seals, eh? are those the "oil seals" (parts number 14 and 17 on this shematic) : http://www.bikebandit.com/assets/schematic...a/YA4256_02.gif ? can they be repaired without removing the motor from the bike? anybody know if there's a test i should do first, and/or if there's a "how to" thread anywhere on the forum? (i've searched, but didn't have much luck). Link to comment Share on other sites More sharing options...
Moderator Cynic Posted April 19, 2009 Moderator Share Posted April 19, 2009 crankshaft seals, eh? are those the "oil seals" (parts number 14 and 17 on this shematic) : http://www.bikebandit.com/assets/schematic...a/YA4256_02.gif ? can they be repaired without removing the motor from the bike? anybody know if there's a test i should do first, and/or if there's a "how to" thread anywhere on the forum? (i've searched, but didn't have much luck). Yep thats the ones. You have to make an honest decision about this, you have to fully strip the motor down. Split the cases then build it back up. You can do the seals on their own (just if you are carefull and patient) without spliting the cases but in the long run you will get a better job if you do, and tbh its not a lot more work once you have stripped the motor that far down. The thing to remember is all the other seals in the motor will be in a similar condition and you can check the main bearings properly too. The other thing to remember with the wonderful design of these motors is the output shaft bearing needs a complete engine strip to change it. None of the work is all that hard if you have a little common sense and a reasonable amount of spanner skills, removing siezed screws etc. Cost of the bits and pieces for mine at least was about £80 and thats everything to do bearings,seals and gaskets. So she will be good as new once i'm done. Its not exactly a how to but if you look at my post DT175 engine rebuild in the offroad/dualsport section that is pretty much what your looking at, the engines really aren't that much different. Bar the gearchange mechanism and the way the clutch is actuated. Link to comment Share on other sites More sharing options...
Recommended Posts