SeanRides
New Member
- Local time
- 2:04 AM
- Joined
- Nov 5, 2016
- Messages
- 3
Hey guys, so I bought myself a 1979 Yamaha Dr 125 at the beginning of last summer, in a non running condition. It being my first 2 stoke (and admittedly, my first bike) I decided to tear the engine apart so I could get it running as good as possible. I have experience working on cars, engine work and all. So I split the cases, took everything out, cleaned it up, and replaced everything that seemed damaged. In the engine I replaced the:
Piston
Piston rings
Crank bearings
All of the gaskets and seals
And the Ball bearing in the clutch.
I cleaned up both case halves, all of the transmission parts, clutch friction plates, oil pump, absolutely everything pretty much. So I pit the engine back in the bike, and spark was being really wonky. Sometimes there was a spark, other times there wasn't. So then I got into the ignition system. At which point I replaced:
Points
Condenser
Ignition coil
Spark plug
And so now I have a nice blue spark. Awesome. But my bike still wouldn't run so with EVEN MORE sleuthing around, found that there was no fuel getting into the combustion chamber. At this point I figured it must have been the reeds, so I went ahead and replaced those next. (Note that the caurborator was cleaned and is functioning properly, the reeds were wet, so it must be, right?) However I'm confused by the fact that it still doesn't seem like there is much fuel getting to the spark plug.
As you might imagine, still doesn't run. The compression is good (I don't have a compression tester, but if I put my thumb over the spark plug hole, it pushes it off with ease) and it has a really good spark. It doesn't seem like much fuel is getting to the plug, because it's not very wet at all, but it DOES smell like fuel.
So here is my thought: bad timing. I don't know what else it can be.
List of all of the repairs I have done:
Battery
Headlight
Headlight wiring harness
Throttle tube
Rewired all of the factory wiring (checked and double checked, I used a wiring diagram)
Cleaned caurborator
Reeds
Piston
Piston rings
Crank shaft bearings
Cleaned engine internals
Replaced all gaskets
Spark plug
Ignition coil
Points
Condenser
Flasher relay
Cleaned oil pump
Cleaned and lubricated chain
Cleaned sprockets
Fuse
Cleaned flywheel
Replaced magneto woodruff key
Even with all of that replaced, the engine won't sputter, even with starting fluid. One important note is that the end of the crankshaft, where the nut that's holds the flywheel on threads onto goes, is slightly bent. The crankshaft is straight apart from this, but I'm wondering if this could throw the timing off? The flywheel seems to be sitting and rotating the way it should, but I know that the smallest screw up matters.
My question to anyone who has made it this far though reading my motorcycle life autobiography is this: what do YOU think might be wrong with it, and what do you recommend I try? Any help at all would be appreciated so much, even if you recommend something most people check first off. Maybe I missed it. Over this winter, I'm going to RE-RE-build the engine, and see if I missed anything internally, but that's beside the point.
ANY HELP ALL WOULD MEAN THE WORLD TO ME!!
-Sean F.
Piston
Piston rings
Crank bearings
All of the gaskets and seals
And the Ball bearing in the clutch.
I cleaned up both case halves, all of the transmission parts, clutch friction plates, oil pump, absolutely everything pretty much. So I pit the engine back in the bike, and spark was being really wonky. Sometimes there was a spark, other times there wasn't. So then I got into the ignition system. At which point I replaced:
Points
Condenser
Ignition coil
Spark plug
And so now I have a nice blue spark. Awesome. But my bike still wouldn't run so with EVEN MORE sleuthing around, found that there was no fuel getting into the combustion chamber. At this point I figured it must have been the reeds, so I went ahead and replaced those next. (Note that the caurborator was cleaned and is functioning properly, the reeds were wet, so it must be, right?) However I'm confused by the fact that it still doesn't seem like there is much fuel getting to the spark plug.
As you might imagine, still doesn't run. The compression is good (I don't have a compression tester, but if I put my thumb over the spark plug hole, it pushes it off with ease) and it has a really good spark. It doesn't seem like much fuel is getting to the plug, because it's not very wet at all, but it DOES smell like fuel.
So here is my thought: bad timing. I don't know what else it can be.
List of all of the repairs I have done:
Battery
Headlight
Headlight wiring harness
Throttle tube
Rewired all of the factory wiring (checked and double checked, I used a wiring diagram)
Cleaned caurborator
Reeds
Piston
Piston rings
Crank shaft bearings
Cleaned engine internals
Replaced all gaskets
Spark plug
Ignition coil
Points
Condenser
Flasher relay
Cleaned oil pump
Cleaned and lubricated chain
Cleaned sprockets
Fuse
Cleaned flywheel
Replaced magneto woodruff key
Even with all of that replaced, the engine won't sputter, even with starting fluid. One important note is that the end of the crankshaft, where the nut that's holds the flywheel on threads onto goes, is slightly bent. The crankshaft is straight apart from this, but I'm wondering if this could throw the timing off? The flywheel seems to be sitting and rotating the way it should, but I know that the smallest screw up matters.
My question to anyone who has made it this far though reading my motorcycle life autobiography is this: what do YOU think might be wrong with it, and what do you recommend I try? Any help at all would be appreciated so much, even if you recommend something most people check first off. Maybe I missed it. Over this winter, I'm going to RE-RE-build the engine, and see if I missed anything internally, but that's beside the point.
ANY HELP ALL WOULD MEAN THE WORLD TO ME!!
-Sean F.