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Discussion Starter #1
I recently bought a 2001 VN800 Classic with about 12K miles on it. IT runs great except for the fact that sometimes it backfires or hesitates during take-off or at low RPM. I changed the spark-plugs on it, and it seems to help a little (CRE7E).
I did notice that the "california-emission" components had been removed by the previous owner, leaving two vacuum lines unattached in the compartment that housed the components.
Would switching to a hotter plug help in any way (CRE6E).

Thanks,
Vulcan Ric
 

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Vulcan Ric said:
I recently bought a 2001 VN800 Classic with about 12K miles on it. IT runs great except for the fact that sometimes it backfires or hesitates during take-off or at low RPM. I changed the spark-plugs on it, and it seems to help a little (CRE7E).
I did notice that the "california-emission" components had been removed by the previous owner, leaving two vacuum lines unattached in the compartment that housed the components.
Would switching to a hotter plug help in any way (CRE6E).

Thanks,
Vulcan Ric

The 800's are cold natured beast. If the pilot screw has not been adjusted, then I would say that is your problem. Does it run better after fully warming up, which takes about 10 miles.

bluestringer
 

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Discussion Starter #3
No, I haven't changed any adjustments on the carbs. It does run better when it's warmed up, but the back-fire still occurs at low-RPM. I also forgot to mention that it takes 3 or 4 tries, with the choke fully on, to start it. That's in 40 deg.+ outside temp.

During the summer months, it would start right up on the first try.
 

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i would look to the carb first for proper adjustment

no need to change heat ranges-just make sure the right plug is in the bike :wink:
 

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When I did my mods removing all the emissions stuff, there were no vacuum hoses left unplugged. The vacuum switch was removed and the line plumbed directly into the stop****. Then the lines from the heads were removed and bridged, marbled in the middle. The only line that is still open is the tank vent that runs from the front of right side of the tank to underneath the seat. Could it be that a lack of vacuum in the line is affecting the fuel delivery which is compensated when the motor is running faster but not enough when it is idling?

Also, it wouldn't hurt to switch to the 6E spark plugs. I did and haven't had any problems, but don't know if the plugs had anything to do with it because of the other changes made at the same time. For $12, it seems worth a try.
 

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Discussion Starter #7
Thank for the info.
I will start by checking the routing of my vacuum lines, having those two lines just dead-ended didn't seem right.
I did replace my plugs with 6E today and noticed that the rear plug had a trace of black fouling on it, and the front seemed ok. Is this normal?
Also, while removing the rear plug-wire from the spark-plug, the wire separated from the boot and I noticed a green substance on the end of the wire and inside the boot.
Didn't have a chance to try it today, but will go for a ride tomorrow and see if swapping the plugs made any difference.
Thanks again for you help.
 

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#2 cylinder fouling plugs is common on the 800's :wink:
 

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Discussion Starter #9
I went on a ride yesterday and notice an improvement on my bike. Changing to a hotter plug also improved the starting from a cold state, (on the first try). Still am experiencing some back-fire, once in a while, but not nearly as much as before.
Will have a closer look for a possible vacuum leak somewhere, or possibly carb. misadjustment.

Thanks again
 

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get it checked out-changing heat ranges is a band-aid for another problem
these 800's don't need a hotter plug :wink:
 
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