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Discussion Starter #1
Hey so i'm new to riding and am really just learning about bikes, limited knowledge.
I'm just going to lay out all my issues in case one may be the cause of another.
Got the bike two months ago.
Was running great, always store the bike of the side stand and started noticing a slow leak each morning from my right carb overflow tube. After a couple weeks a noticed when using electric start (kick start is non functioning due to previous owners adding wide exhausts) she would start fine then the rpm's would drop and she would die unless I held the throttle open till she would keep running.
Next we got a heavy down pour and the bike wouldn't start. Had to boost her off a car which worked, but wouldn't start the next day until I gave the battery a full charge.
I also started to notice a slow oil leak which drips down onto the fins on the left side, it's been hard to trace but I think it may be from the gasket at the very top...
Had a poke around with a buddy, took the bottom of the leaky carb off and pushed (forgive my limited carb knowledge) a pin of some sort up a bit in hopes that we could decrease the amount of fuel. At the same time we had a look at my spark plugs. Had never changed one in my life before, that same right side the plug was totally black...Running to rich? When I rode home from his place the bike started misfiring on that right side. I stopped road side and pulled the plug cap off and the cap came right off the wire. This is how I discovered that the wire casing was dissolving and the end of the wires and the screw in the cap were gummed right up. cleaned it out and it got me home.
Changed the plugs last week and she ran great, no more issues when starting. That only lasted a couple days (and my ride to work is less than 15 minutes) and she started to gum up and misfire again. Here's picks. Could oil be leaking down my wires and causing this? Should I be replacing the wires? I don't think the whole ignition coil needs replaced just the wires, but i'm not really sure what the wires should look like at the end that attaches to the cap but it's probably not this.
Also could this black plug issue mean I need to adjust the carb on the right side/both?
Thanks a ton for any feedback!

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You can try trimming the spark plug lead back about 1/2 an inch and twisting the boot back on. The boots (connector to spark plug) have an internal resistor and should have a value of 5k ohms (5000 ohms). The resistance increases as they age so it might be better to buy a new pair (~$12).
The spark plug leads are molded into the coil and are not replaceable. They get awfully brittle with age.
Having been through all this, I ended up getting a replacement coil and boots from MikesXS.com. Here's the coil, it bolts right on with no mods needed, is the correct value, and works great:

https://www.mikesxs.net/parts/yamaha-xs650-dual-output-points-type-ignition-coil-oem-30400-306-672-4m4-82310-60-00
 

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There's an oil seal in the left side cam bushing that may be leaking. Unfortunately, it's behind the points plate so things get a bit more complicated. The seal itself is inexpensive, but you will have to learn about setting the ignition timing, something that will benefit you in the long run.
 

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Discussion Starter #5 (Edited)
Thanks all! I'll be replacing the coil this winter to deal with the wires. Now i'm dealing will carb issues, has some adjustments done but now she's running rich, plugs are sooty and black. I'm a bit nervous to touch anything other that the fuel/air mixture and idle screws, if I back the fuel/air screw out to lean it out would this be sufficient, or should I consider a float adjustment? Should probably post this in another thread.
 

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DON'T RUN THE ENGINE!!!
you have likely got gas thinned oil
Your cam and cam journals are probably melting
Check the oil level if it's over full and smell the oil if it smells of gas then your in for top end issues

The carbs shouldnt overflow over night because the peacock at the tank should be Off
gas gets in to the oil via the carbs while the engine is off ( if you don't turn the peacock off every time you stop the engine)
The thin oil doesn't lube as well and the engine overheats and parts wear out FAST causing the timing to become intermittent causing missing /hard starting and ultimately the engine to seize

Thin oil gets past seals and gaskets sand causes oil leaks

Thin oil gets past valve seals and rings and gums up plugs
 

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Discussion Starter #7
Simo, hmmm
I had been checking the oil levels every week since I got it and was finding it odd that the level seems to be getting slightly higher each time, just a a small amount. Based on your post I checked the oil today and it seems much thinner and dripped off the dip stick, seems thin and a slight smell of gas.
Damn, what am I looking at here? I've never left the petcock on, always shut it off. How do I fix this issue? My carbs are clean. Is it seals? Values?

I had a mechanic look at it the other day, My right side was running really lean so it hadn't been firing from a miss adjusted carb. He adjusted the float levels and both the air mixture screw and idle screw on both carbs, ran it home and seemed fine. Checked the plugs last night and they were black, sooty and dry. Took her out to start her up today and she would start and die after a few seconds (This I before I checked the oil for gas), I checked the plugs and they are soaked in gas, and I'm still getting a leak from the right carb overflow tube.
Woman at a lost of what to do here, thanks for the suggestions.
 

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Ok, if you're switching the peacock off it might not be as bad as I made out
But oiling issues is the main cause of top end failures on the 175's/200's
First off drain the oil, normally you'd do this hot but since you don't want to run the engine with thin oil just do a cold change
Oil should be changed every 500 miles regardless
2. Make sure the battery is charged!!!
Do you know if the mechanic set the floats to the correct height? Or just so they'd stop overflowing?
Pop the float bowl off the overflowing carb and check the overflow tube in the centre of the bowl for damage.
 
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