Hey all!
I've posted this in other places before but just have not gotten anywhere with this. Seems to come up as a 2-stroke problem every time I google lol.
My bike (2000 KLR650) has 50,400km, FMF Q4 Full system, and MCP Carb Kit. Worked perfectly last year.
The issue:
This year since pulling it out in March or so, I've noticed a low RPM bog. When cold it happens around 1,500rpm when slowly applying throttle. It will bog down a few hundred rpm, and then shoot up and be fine. Sometimes stalls like this when cold (happened to me mid way through a left turn and almost got hit... very scary...). Idle is a bit shaky at around 1,000-1,100rpm when cold, Idles fine at around 1,300-1,500rpm when hot.
Once warmed up the bog happens around 2,500rpm, and stalling is no longer an issue. Just a noticeable hiccup in the power delivery.
The worrying thing is when its cold (I warm it up for about 60 seconds, and that's not even enough anymore... never had this problem when it was cold last year) it will sometimes make a "knock" or "stutter". Only once. It feels like the engine stops combusting (a misfire?), and it just forces its way inertially through a cycle before firing up again. Sometimes it will stall out pretty aggressively, sometime it will just lightly hiccup and make a weird noise. This ONLY happens when the bike is cold - 1-5 minutes from starting. Again, used to take 30-60 seconds with choke on before I could ride it totally fine... This is a new issue and its kind of freaky...
What I have done:
1) Seafoam, didn't work
2) Spark Plug, no change
3) Total carb tear-down... 3 times. Once with an ultrasonic cleaner, and all of the rebuild attempts used up about a half can of carb cleaner through all of the ports... I have a very very hard time believing something is plugged in the carb. Needle, pilot jet, and float bowl gasket are all new as of late last summer. I hear that the needle jet in the front of the carb wears out? Though this shouldn't cause a low rpm bog... I know my enricher circuit U-ring is quite grimy, but that should only affect deceleration (pops etc, whatever). Float height looks fine, I never messed with it.
4) Confirmed exhaust manifold torque - It's good.
5) checked for air leaks in the carb boots. It seems fine when spraying combustibles all over it, though I still ordered replacement ducting to make removing this stupid carb easier.
6) Fresh Rotella T4 and oil filter, no change.
What I need to do, but not sure if it can be responsible for this issue:
1) Valve Clearance (way overdue... need to wait until I have space to do it as shop rates are way too insane...). No hot start issues, so not even sure if this needs to be urgently addressed...
2) Open left side - I'm sure doo has been done at some point with this high mileage, but it stresses me out not having seen it in person.
3) Open right side? Could plugged oil screen cause engine hiccups? I imagine if this was the case the bike would've died by now. Again, runs great in mid-upper rpm ranges, and I've been daily driving since March basically with no changes. Hesitant to open right side because I don't want to rebuild the water pump, and I hear the shaft shears easily and requires a full engine tear-down to fix. F*** that...
Would LOVE anyone's input on this... It's driving me absolutely mad, and is kind of ruining my joy of riding at this point... Taking it to a shop is not really financially an option right now, and I don't really have a consistent work space so I can only very sporadically tackle these issues one at a time.
I've posted this in other places before but just have not gotten anywhere with this. Seems to come up as a 2-stroke problem every time I google lol.
My bike (2000 KLR650) has 50,400km, FMF Q4 Full system, and MCP Carb Kit. Worked perfectly last year.
The issue:
This year since pulling it out in March or so, I've noticed a low RPM bog. When cold it happens around 1,500rpm when slowly applying throttle. It will bog down a few hundred rpm, and then shoot up and be fine. Sometimes stalls like this when cold (happened to me mid way through a left turn and almost got hit... very scary...). Idle is a bit shaky at around 1,000-1,100rpm when cold, Idles fine at around 1,300-1,500rpm when hot.
Once warmed up the bog happens around 2,500rpm, and stalling is no longer an issue. Just a noticeable hiccup in the power delivery.
The worrying thing is when its cold (I warm it up for about 60 seconds, and that's not even enough anymore... never had this problem when it was cold last year) it will sometimes make a "knock" or "stutter". Only once. It feels like the engine stops combusting (a misfire?), and it just forces its way inertially through a cycle before firing up again. Sometimes it will stall out pretty aggressively, sometime it will just lightly hiccup and make a weird noise. This ONLY happens when the bike is cold - 1-5 minutes from starting. Again, used to take 30-60 seconds with choke on before I could ride it totally fine... This is a new issue and its kind of freaky...
What I have done:
1) Seafoam, didn't work
2) Spark Plug, no change
3) Total carb tear-down... 3 times. Once with an ultrasonic cleaner, and all of the rebuild attempts used up about a half can of carb cleaner through all of the ports... I have a very very hard time believing something is plugged in the carb. Needle, pilot jet, and float bowl gasket are all new as of late last summer. I hear that the needle jet in the front of the carb wears out? Though this shouldn't cause a low rpm bog... I know my enricher circuit U-ring is quite grimy, but that should only affect deceleration (pops etc, whatever). Float height looks fine, I never messed with it.
4) Confirmed exhaust manifold torque - It's good.
5) checked for air leaks in the carb boots. It seems fine when spraying combustibles all over it, though I still ordered replacement ducting to make removing this stupid carb easier.
6) Fresh Rotella T4 and oil filter, no change.
What I need to do, but not sure if it can be responsible for this issue:
1) Valve Clearance (way overdue... need to wait until I have space to do it as shop rates are way too insane...). No hot start issues, so not even sure if this needs to be urgently addressed...
2) Open left side - I'm sure doo has been done at some point with this high mileage, but it stresses me out not having seen it in person.
3) Open right side? Could plugged oil screen cause engine hiccups? I imagine if this was the case the bike would've died by now. Again, runs great in mid-upper rpm ranges, and I've been daily driving since March basically with no changes. Hesitant to open right side because I don't want to rebuild the water pump, and I hear the shaft shears easily and requires a full engine tear-down to fix. F*** that...
Would LOVE anyone's input on this... It's driving me absolutely mad, and is kind of ruining my joy of riding at this point... Taking it to a shop is not really financially an option right now, and I don't really have a consistent work space so I can only very sporadically tackle these issues one at a time.
