DanMach
XS400 Addict
82 XS400J. Had it for about 3 or 4k miles now(its at 29k). Its been running great the whole time I've owned it. No popping on decel, stuttering, irratic idle, anything like that. Just runs great. Last time I rode it I shut it down and started it back up about 6 times within 10 minutes(Drive thru late at night, hard to hear me over the exhaust).
Went to go start it today so I could warm it up and change the oil(per manual) and it wouldn't start. Well, it did start for about 3 seconds then I stupidly touched the throttle and it died. So I tried to start it a few more times and it ended with a very loud exhaust bang. I figured it might of been too cold out(Its had issues starting in the cold before). So I tried it again around 4:30 today(75 out) and same deal. Just a loud bang.
It was semi low on gas so I filled it up with fresh gas from the station and same deal.
Any suggestions?? It was running fine 5 days ago and this is somewhat random. I'm thinking right now the best course of action would be this:
1. Check the fuel line from petcock to ensure proper gas flow.
2. Check air filter.
3. Pull plugs and check them. (Should I try to start this some before hand? To see if they're wet?)
4. Check spark.
5. Check valve gap. (Tight exhaust could cause backfire I believe.)
6. Check the carbs and make sure they're getting gas.
I'm trying to hold off on the carbs because an exhaust backfire should be caused by being too rich, right? I feel like its going to be the valves because its gotten harder to start as its gotten colder. At first I assumed it was the weather, but maybe the valves were just slowly going out of tune and causing it. It ran fine once it started though.
Anyways, I would really appreciate any suggestions or ideas. I'll be sure to post a follow up tomorrow night after I check everything out.
Thanks guys(and gals)!
Went to go start it today so I could warm it up and change the oil(per manual) and it wouldn't start. Well, it did start for about 3 seconds then I stupidly touched the throttle and it died. So I tried to start it a few more times and it ended with a very loud exhaust bang. I figured it might of been too cold out(Its had issues starting in the cold before). So I tried it again around 4:30 today(75 out) and same deal. Just a loud bang.
It was semi low on gas so I filled it up with fresh gas from the station and same deal.
Any suggestions?? It was running fine 5 days ago and this is somewhat random. I'm thinking right now the best course of action would be this:
1. Check the fuel line from petcock to ensure proper gas flow.
2. Check air filter.
3. Pull plugs and check them. (Should I try to start this some before hand? To see if they're wet?)
4. Check spark.
5. Check valve gap. (Tight exhaust could cause backfire I believe.)
6. Check the carbs and make sure they're getting gas.
I'm trying to hold off on the carbs because an exhaust backfire should be caused by being too rich, right? I feel like its going to be the valves because its gotten harder to start as its gotten colder. At first I assumed it was the weather, but maybe the valves were just slowly going out of tune and causing it. It ran fine once it started though.
Anyways, I would really appreciate any suggestions or ideas. I'll be sure to post a follow up tomorrow night after I check everything out.
Thanks guys(and gals)!