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scott s
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« on: November 06, 2007, 04:42:23 pm » |
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You guys seem to know a little bit about everything, so.....
Last week, I found a 1980 Yamaha XS650 on Craigslist for a hundred bucks...even came with a spare motor! Since I already have an '83 XS, I figured I could use it for parts if I couldn't get it running. I'd REALLY like to get it going and make a cool cafe' racer out of it. I can't seem to get it running, but it will turn over with the starter. I posted this on a couple of Yamaha sites I belong to, but wanted to get as much info as I could. (BTW, the '80-'83 XS's have a TCI electronic ignition, so I can rule out points/condenser and, theoretically, a timing issue....I think....)
Here's what I've done so far:
* Changed the plugs and caps, cut off about 1/4" of the wires to get to fresh copper.
* Charged the battery to full on the trickle charger (wasn't really that low).
*Tested for spark by laying the plugs on the head and cranking it over. I have spark to both plugs.
* Pulled the gas tank and petcock. Gas tank looks great. No trash or debris. The diaphragm in the petcock looked fine so I cleaned out all the passages and reassembled it.
* Pulled the carbs and gave them a thorough cleaning. I drained the float bowls and cleaned them. Pulled the emaulsion tubes and all the jets and cleaned them. Cleaned the slides and needles. Cleaned all passages I could find with carb cleaner. Gave the carb bodies a good cleaning inside and out. Checked the diaphragms; they have a couple of "wrinkly" spots on them...very small...but no holes or tears and seem to function when I push the sliders up and down. I can feel "compression" on them, so to speak.
*Sprayed carb cleaner in the intake tract while the carbs were off and tried to start it. I didn't even get a backfire or anything this time.
* Gave the bike a bath and a good general degreasing.
The first time I tried to crank it (after changing plugs, before pulling the carbs) I was able to get it to "catch" or "chug" a couple of times, like it was trying to start. I was able to get a backfire out of the left carb/exhaust with starter fluid. Now, as I said above, I can't really get it to do anything.
What next?
1)Can I assume that since I have spark at the plugs that the TCI is OK?
2)Could the TCI give me spark but not at the righ moment to make it run? Sort of a timing issue, so to speak?
3)Why wouldn't I at least get a backfire when I sprayed carb cleaner in the intake with the carbs off?
4) Could there be anything valvetrain related that's keeping it from running? If the cam chain/tensioner broke, I wouldn't even be able to get it to turn over w/o hearing a horrible noise, right? Should I pull the valve covers and look for anything?
5) Anything else I can try before I put the carbs back on and try running some fresh fuel through it?
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