browndawg
XS650 Member
Hi Guys,
I bought an '81 XS650 Special back in November, and due to some titling issues, I haven't been able to do much riding other than up and down the street until just recently. I finally got the title issues resolved and got the bike out on the road.
Unfortunately, it didn't take long before the left cylinder quit firing, or firing intermittently. I pulled the sparkplug and found that it was badly fouled--a good bit of still-wet oil. I put in a new plug and the cylinder began firing again, puffing out lots of blue smoke at first, but seeming to run well. But, before long, it again wouldn't fire at idle, though it fires fine once you give it a little throttle. Also, I noticed a seemingly excessive amount of oil coming from the cylinder head breather. The crankcase is filled up to the top line of the dipstick, so this could be an issue with overfill? Also, the bike has spent a good bit of time idling over the last couple of months. I would crank it and let it idle every few days--I didn't realize that on these bikes just letting it sit idling isn't always the best.
In any case, next I checked the compression. Right was 120, left was 118. Pretty low, I know, but at least they're almost even, and I'd really like to get through the summer before doing a topend rebuild.
Can you guys give me some ideas on what my issue might be, and how to check? Perhaps excessive blow-by from bad rings? I don't have a compressor, so it's going to be tough to do a leakdown test--is there another way to check? Or could potential oil overfill account for the issue at all? Or even weak spark at idle in the left cylinder, so the blow-by oil isn't getting burned up?
I'm pretty new at this, learning as I go, and pretty much all of the ideas above--what I've checked so far and how--have come from forum searches. But at this point, I'm not sure what to do next. Currently I don't have the time or money for a topend rebuild, so I'm hoping to do whatever I can short of that to sort this issue for the next few months. Basically, I'm a fiction writer with a $900 car and a $1500 motorcycle (you know we don't make any money haha), and my first book comes out in May, and I'm trying to get both my vehicles in decent shape so I can get to all the promotional events/readings/etc through the summer months. I'd really love to have the bike in decent running order so I have a backup in case the car goes down.
Thanks so much in advance, guys!
I bought an '81 XS650 Special back in November, and due to some titling issues, I haven't been able to do much riding other than up and down the street until just recently. I finally got the title issues resolved and got the bike out on the road.
Unfortunately, it didn't take long before the left cylinder quit firing, or firing intermittently. I pulled the sparkplug and found that it was badly fouled--a good bit of still-wet oil. I put in a new plug and the cylinder began firing again, puffing out lots of blue smoke at first, but seeming to run well. But, before long, it again wouldn't fire at idle, though it fires fine once you give it a little throttle. Also, I noticed a seemingly excessive amount of oil coming from the cylinder head breather. The crankcase is filled up to the top line of the dipstick, so this could be an issue with overfill? Also, the bike has spent a good bit of time idling over the last couple of months. I would crank it and let it idle every few days--I didn't realize that on these bikes just letting it sit idling isn't always the best.
In any case, next I checked the compression. Right was 120, left was 118. Pretty low, I know, but at least they're almost even, and I'd really like to get through the summer before doing a topend rebuild.
Can you guys give me some ideas on what my issue might be, and how to check? Perhaps excessive blow-by from bad rings? I don't have a compressor, so it's going to be tough to do a leakdown test--is there another way to check? Or could potential oil overfill account for the issue at all? Or even weak spark at idle in the left cylinder, so the blow-by oil isn't getting burned up?
I'm pretty new at this, learning as I go, and pretty much all of the ideas above--what I've checked so far and how--have come from forum searches. But at this point, I'm not sure what to do next. Currently I don't have the time or money for a topend rebuild, so I'm hoping to do whatever I can short of that to sort this issue for the next few months. Basically, I'm a fiction writer with a $900 car and a $1500 motorcycle (you know we don't make any money haha), and my first book comes out in May, and I'm trying to get both my vehicles in decent shape so I can get to all the promotional events/readings/etc through the summer months. I'd really love to have the bike in decent running order so I have a backup in case the car goes down.
Thanks so much in advance, guys!