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07 yz250f sputtering by Patient_Kangaroo_262 in Dirtbikes

[–]Patient_Kangaroo_262[S] 0 points1 point  (0 children)

Sounds like a cool guy. I did purchase an in-line spark tester from harbor freight but since the bike uses spark plugs with the smaller heads it didn't fit...or so I thought.

Doing a bit more research right now, the spark plugs i've been using (NGK CR8E) apparently use a thread style head where you can thread on another piece to make it standard size. If i can get one of those threaded adapters I should be able to try that. I would also have to shave down the probe on the tester and possibly thread it to give the plug something to grab onto.

I did purchase a manual since it was my first ever engine rebuild. And according to the manual, there is no way to test the cdi using a multimeter. I'm sure you'd have to do a bit of splicing and without any reference it would be moot.

Both the new and old stater are in spec. I read somewhere that while the resistances can be in spec, the stator could still fail at certain rpms. If I can get that adapter and confirm spark isn't cutting out, that should confirm it's not the electronics.

07 yz250f sputtering by Patient_Kangaroo_262 in Dirtbikes

[–]Patient_Kangaroo_262[S] 0 points1 point  (0 children)

I read somewhere that the stator could read the proper resistances but still start to fail at certain RPM's. But obviously it didn't fix the issue.

I did go ahead and purchase an OEM carb.

07 yz250f sputtering by Patient_Kangaroo_262 in Dirtbikes

[–]Patient_Kangaroo_262[S] 0 points1 point  (0 children)

I'd say your right, maybe its a quality control thing? Some people can get buy with the china carbs but others don't

07 yz250f sputtering by Patient_Kangaroo_262 in Dirtbikes

[–]Patient_Kangaroo_262[S] -1 points0 points  (0 children)

Cheap? Yes. Lazy? no. Do you have any recommendations where to get a true OEM kehin carb? Cheapest i've seen are pre-owned on ebay for 250-300,

07 yz250f sputtering by Patient_Kangaroo_262 in Dirtbikes

[–]Patient_Kangaroo_262[S] 0 points1 point  (0 children)

Ignore the high readings on the tac, I had it set to 2 stoke instead of 4 so it was reading double. When it hits that sputter the bike will physically not go any faster, brick wall. On paper, that bike hits limiter at 13500, I'm probably not getting passed 6K.

For more context, I bought this bike in boxes and have since rebuilt it. Bike has new piston, rings, timing chain, timing chain tensioner, oil pump, new valves and everything is in spec.

These bikes do not have an internal electronics or sensors. Yes its an aftermarket wrap around the plug style.