Miss / backfire in 98 XR650L
 

Hi I'm looking to pickup a XR650L, 1998, with 8000 KM (5000 Mi) on it. Good price, but I am hesitataing because it has a miss at idel that turns into a backfire off idel. Carb needs to be done, but the miss concerns me more. Potentially a tight valve? is there an automatic decompressor that may be firing that may be triggering a valve to open?
An known issue withthe year?
Any advice would be great.
Thanks in advance

My '98 has done 14000km so far, with no problems. When I was playing around with the carb it was backfiring downhills if I had it running rich, but I've never had it miss at idle. Check the spark, more likely to be electrical than mechanical. I've had bikes play up like that with faulty CDI's.

As far as I understand there is no major changes in the XR650L motor from '93 through to 2005, except for the addition of some smog gear which everyone removes anyway.

I agree with Matt that its unlikely to be mechanical cos its a very steady engine, but I'd suspect its carburation. check the plug, first, but then check carb settings (ie idle screw position) and cleanliness of pilot jet etc. also check for airleaks around the carb and birds nesting in the airbox

Thanks for the input guys, I'm going to go for the deal, they are taking my 92 ZX11 straight across for it. I picked up a 85 DR200 about 18 months ago, and just got back into the dirt more than I was enjoying the street. The DR is a great little bike, but a bit under powered for me, I'm Alberta, Canada and regularly get up and around 7000 feet in the foot hills / Rockies, and it really suffered up there.
Thanks again.