Nobody Can Fix This Boggy 2-Stroke Dirt Bike 

My 93 exhibited similar but not exact symptoms. Mine would "stutter" and overall have no power at high RPM. After checking the carb/cleaning a half dozen times, replaced the reeds, cleaned and inspected the PV, new gaskets and crank seal, new spark plug, cleaned the exhaust and repacked, checked for spark/timing all good I was about to throw in the towel. For giggles, I replaced the stator (even though it showed spark) and low and behold the beast was back from the grave and about bucked me off when I first rode it. Just throwing there out for others that instead of mechanical or fuel/air, check the electrical side of things. I was about to sell it as I was so aggravated. Hang in there Joe. I really enjoy our video's and unless you are Jett's mechanic, I think we are all learning along the way on our own bikes too. It's a constant learning process.

14:10 spark plug is twisting out with every high tech, haha…

So i'm not sure if anyone missed it or not, but at 38:00 and a bit after, that screw boss just above the crank primary gear is broken, and if you look close through the hole, it goes directly into the crank housing. This is another source of an air leak as it's sucking air from inside the clutch cover. I was originally going to say crank seal, but considering the few already found rebuild faults, this engine has been abused a few too many times. Joe I think this needs a full teardown. Someone did not know what they were doing before you picked it up. Edit: Also that crank seal is bad. When you were pushing the sleeve back in it was pushing oil out on the bottom. Either there is a tear somewhere or it's not round and not sealing the outside rim. If you look closely down by 6 o'clock it looks like someone punched a divot into the seal boss, probably from installing it with a flathead screwdriver.

Claw hammer for the win, just like Matt’s off-road recovery!

I had a 1990 CR250 with similar symptoms. I chased everything until I tried a new black box. Ran perfect with the new black box.

Don’t give up Joe! You’re hot on the trail, chasing this one down!!! If it was easy it would’ve been done by now! And probably by the last owner…. I’ll stay tuned for the exciting conclusion of this one!

Press on, Joe! Methinks the CDI box/ignition system may be malfunctioning if power valve o/haul didn't fix it. At least you found some other issues that you fixed.

If a cr250 from that era doesn’t scare you a little bit, it’s not running right……that’s your test! 🤣 I bought a brand new 99 and it was insane, lift the wheel whenever you wanted and also when you didn’t.

Admire your persistence with this one, you'll get it. I stand by my comment in the last vid - sounds like it's dropping spark at high RPM. You can hear it popping off, power valves/fuel would be a consistent bog. Start with a new coil, but honestly have a CDI and stator sourced if you need it. More electrical diagnostic work needed 👍

I always wait for you to say “looks perfect” after inspecting parts. LoL

Don't give up on it. Your success is the reason I'm subscribed. Read up on it and make the necessary corrections.

The trouble shooting section of my ‘00 CR250r manual says for poor performance at high speed check the ignition timing. Possibles causes: alternator, faulty ignition control module, faulty ignition pulse generator. Thinking years back when I got my CR250, the power valve was adjusted to be open all the time. The motor had no low end power but did not bog like that on the high end. These bikes are a blast and worth the effort.

You torqued those head nuts WAY past 20 before you even got to the torque wrench.

I had a '91 CR250 with a bad bog. I checked the power valve stator, pick-up, and coil. All checked out. I bought a Honda CDI, and that solved the problem.

This is one of the best CR factory plastics I love the mid and late 90s CRs

I just broke my foot..so I am going back on your older videos...thanks for the great content

Bongs coffee and dirt bikes. Already took my 66cc mountain bike to get coffee. Happy Sunday.

Make sure to tighten your spark plug it's loose !

Amazing how you remembered the missing washer and backward spacer. Didn't cost you a dime. All that teardown to find its 2-easy to make errors. Nice job! :)

That bike wanted to live. Without the bog you would have never found the clutch issue that could have grenaded the whole motor. Well done. I was very impressed you kept going to investigate!

Cannot wait to see what the bogging issue was ! Like always, awesome videos

for me when working on a case reed motor & you up jet & down jet & you get no change the issue lies with fundementals......the crv is fundemental, the first test ride proved that, so to imagine anything else is easy, ie...ignition, pipe, but when fuel is added or minused and no change the issue is always a fundemental issue. this guy is one awesome mechanic & it's enjoyable to watch the process. thanks Man

keep at it. thats a BADASS bike.

Don't give up just a little bit of patience and your knowledge you'll get it figured out

Spark plug was loosening up when adjusting power valve lol😂

Check that crack on the bottom of the case where the seller patched it it has to be 100% sealed on a two stroke

Love watching your videos mate, used to mess about with bikes when I was younger but never understood how simple 2t really were 😂. Inspiring me to get a non runner now

I herniated my l5s1 and i kept telling my Dr i feel like i broke my ankle. I went to Northwestern and told the Ortho Dr my story. This is weeks after seeing many Dr's. He said I'll x-ray your ankle. Would you know it, i broke my ankle. No F-in Shit! It is not against the law to have 2 problems at once, not yet! The PV isn't working correctly and probably has an Air leak. Everything healed on me, your bike will also. Keep at it!

Sometimes when my crew and I were called in to redo somebody else's work we learned to tell the homeowners that most likely this would turn out to be a complete rip out. Sometimes we were wrong but not often !

Would be interesting if you could somehow force the pv in the fully open position and then test ride to see if a difference. Love your channel!

Looking forward to the next video on this bike of motorcycle mysteries.

Yes the power valve looks questionable but I would also do a leak down test as it’s difficult to assess crank seals by appearance. Also I have had Stator check out within range and still be bad. I had a similar experience recently with my trx250r…checked everything and it still ran poorly from mid to top. Replaced the old ignition system from Stator to coil and it runs perfectly now.

Its perfect! Looks perfect! Never seeen so much perfection, yet it doesnt run right.

Long ago, a customer brought it a two stroke with a horrible bog. He never mentioned that he had replaced a shattered piston himself. Yes, there was a hunk of piston stuck inside the expansion chamber. A back story (pre purchase) can often produce positive results.

These old things can send you downs rabbit hole for sure. I work on a lot of old stuff and they can be real head scratchers. I’m wondering about the CDI box, no real way to bench test it. Maybe find a CDI that you know is good. You can’t quit until you solve the mystery.

Don't get frustrated Joe, you're better than that. I think the only real place left is the tension on the governor, what else could there really be, especially after rebuilding the power valves now, they're still not engaging all the time.. Sounds like a weak spring. Man that's a bummer but you'll get it, you always do. Plus you found a few little odds and ends that really needed taken care of - that a plus!

CDI box, I had one that did the exact same thing. Changed the black box and ran good as new.

Great channel I could watch you all day

Absolutely love the graphics and colours of the 1995 CR's this one is so close yet so far from being a kickass rocketship! I see the dreaded Husaberg 500 still lurking in the shop so you haven't given up on it will you give it another shot?? Keep up the great content.

Try removing the pv all together. If it runs great at mid to top end with all the power than you have found the only issue is the pv system. A pv system is designed to give added power to the low and mid range.

Guess sometimes it's good to go behind others work. Never know what was done wrong till you find it. Great job Joe

Sometimes the HT lead from the coil can go bad,they normally run rough at high revs,even though some of the leads are captive,it’s possible to grind the coil away where the HT lead enters…and do a big job after replacing the lead.This fixed my rough running on an old Kx250

Ol' Joe loves his dirk bikes. Finally a challenge to your powers. Gasket maker (form a gasket) was my friend

Oh no the dreaded CLAW HAMMER

Clutch basket has definitely seen better days 😂

That is unbelievably clean. That’s a good deal.

Love your video man🤘🏽❤️

Definitely can hear the power valve on a healthy 250. Very distinct sound

Another great video Joe sounds a lot better

Just commented on the first vid. Had almost identical problem, same bike. It was the needle and emulsion tube (part of the carb body) not like the little pwk's where you could change it. New needle and swapped to another carb body ran great! Couldnt believe it whacked that bike so bad! Impossible to dial jetting and always "broke up" or sounded like a plug fouling even though it didnt.

Great catch on the crank gear spacer! That gear definitely wasn't working properly.

I have complete faith in your skills to solve this issue...

Was thinking, did you check the reeds? but yeh maybe a spring or worn shaft on powervalve (maybe the valve it self worn?) also thought try a difrent pipe, 2 stroke's need the perfect pressure waves. Great video again. Big Up!

I honestly think that you have a vacuum leak. Either from the carb itself or from the JB weld or one of the seals. It would explain why changing the jets did nothing. The more you rev the more air gets sucked in rather than creating a stronger vacuum which helps make more power.

Power valves are a problem. The seal behind the stator did not look seated far enough. Also the gap between the pickup coil and the flywheel look excessive. Is that adjustable?

great vid as always

At 14.09 onwards you can see the spark plug turn on its own when the bike is being revved while checking if the power valve is working!

ive had the fly wheel it self go bad and tryed everything like you finally replace fly wheel never missed a lick after that

How frustrating, chasing problems down a rabbit hole, done too much of that !! hope you get it sorted

Had a similar problem with my 83 model changed a tried everything..then decided to chuck on a random carb from another 250 bike Fixed the problem

Plug is loose also check clock position on spring in upside down or wrong spring or week.You are a good man you will get it.

Used to race these from '93 to '96, great bikes especially the "93. Spotted the bad exhaust valve bearing as soon as you pulled the cover. The exhaust valves on those needed regular servicing because the valve itself was made of steel and unlike aluminium didnt shed heat very well so they tended to carbon up and stick. Also the slot in the valve used to get build up at both ends eventually not allowing the valve to fully open or close. If memory serves, there isn't supposed to be a stud holding the water pump cover on, thats a bodge job from a previous owner, also there should be two dowel pins to align the cover I think one was eliminated due to the stud. Also there is supposed to be a separator between the two water pump gaskets, I don't think i saw one. The center case is broken where a clutch cover bolt threads in near the transfer port channel, hard to tell if that hole goes all the way through, its supposed to be a blind hole, I think I saw some sealer in the channel where that hole would come through. I'll bet someone put a bolt in that hole that was too long, tightened it and broke through the case. Clutch basket looks hammered, if the clutch drags you know the cause. You really should get the right washer for the clutch, that one is too small on the O.D. and what about the thickness. Theres supposed to be a plastic keeper under the carb spring to retain the cable in its holder, didn't see it. I think you are correct and the power valve now isn't opening. Its been a long time but I think you are a tooth off on the shaft in the case. Lift the cylinder then pull the rod up and rotate it clockwise one tooth then drop it back in. Take the pin out of the top of the power valve shaft in the cylinder, loosen the allen bolt and let the shaft drop down just far enough so you can see it below the cylinder this way you will be able to see the fork drop onto the pin before the cylinder seats on the gasket. You need to sort where the metal flakes are coming from. It looks like aluminum and since there were no signs of wear under the clutch cover and it looks like the bottom end is new I'd guess theres a shim missing from the end of a shaft or a gear on backwards rubbing against the case. I know you said the reeds were perfect but I wish you would have shown them. Based on everything we've seen thus far its obvious whoever worked on this last shouldn't be allowed to own tools. Last thing that rear tire looks like its off a 125. Looking forward to the next vid on this bike when you get it all sorted.

Love your videos!

I've had a similar problem in the past and it was due to lack of back pressure in the exhaust. It actually sounded worse this time which would make sense being that the rest of the packing is gone. Its very possible that you fixed one problem (power valve) but with the packing removed caused a similar problem

She’s asking for more fuel on the top end but your in the right direction

Enjoyed it. Thank you.

I chased this same sounding problem for several months and went through my whole bike and then changed out a perfectly looking flywheel, and BAM! I had my bike back. Toss another flywheel on just to see.

I think when you found the problems with the gear spacer and the missing clutch washer, you should have disassembled the entire motor.❤

The chirping birds are a nice addition.

Very neat work

Brilliant video Joe watching from Edinburgh Scotland UK 🇬🇧 👍

Had 6 of these bikes the bogging is because the power valve was stuck open. The reason it's now not revving out is because the power valve is not opening. When putting the cylinder back on you have to make sure the pin at the bottom of the rod goes in-between the 2 fork prongs on the rod that comes up from the crankcase. Can be quite tricky to get it lined up correctly. I actually brought a 96 model that wasn't revving out just like yours is and it was because the pin wasn't lined up in-between the 2 fork prongs

I owned a 95 CR250 and it also bogged and fouled plugs all the time until I did 2 simple things. Upgraded to really good premix at 40 tp 1 and ran expensive plugs. After that, it ran clean after that reliably for the rest of the time I owned it. Good luck.

I’m new to this just tore down my first bike to pieces and put it back together. Successfully. I’ve learn from watching you whatever the problem is if you work long enough and hard enough, you’ll find it.

"Picked this up for $2000" FML, where I live, this bike would have been $4k not running.

Wow nice bike!! Love the content. Joe would love to see a Suzuki lt80 on the channel. I don’t think you ever had one on here

You have a great vid here , thanks.

Allright....let's go...we're all ready for part 3....what did you find wrong? Carb wore out, governor weak or what?

I've watched a few if your videos and love them..I see you fo alot of compression test but what about leak down to check for air leaks

Impressive mechanic skills

Love this. Name it the saga

Spark plug loose. When you take your head nuts loose do them a little at a time and in a pattern so you dont warp the head. That clutch basket is smoked, grooved out like crazy....probably should change crank seals while you are in there too. That wiseco crank /rod is garbage and will grenade in that motor. Good video!

I know the fellow goof with the plug but I think he's doing a good job at least he's willing to get in there and get his hands dirty and try,, most of the young people in my neck of the woods nowadays will hardly lay down the video games to get them a sandwich,, I love seeing young men who are willing to get out and do stuff like this, God bless stay safe out there, 😬🇺🇲

Need to change all the bearings and clean where all them metal shaving where clogged up bearings now working properly...well that's what I think buddy.....great video thanks for sharing 😊

I think the stock position for the needle's clip, would be the middle one and these bikes are shipped, set for sea level. The average elevation in Wisconsin is 988 ft. above sea level with the minimum of 564 ft. and the maximum of 1,909 ft. At those elevations, you might consider placing the clip back in the second place from the top. The clip position doesn't affect wide open throttle position, but does at mid throttle positions. At wide open, the needle is out of the jet. I'd check to see what main and pilot jet recommendations for your elevation are as well. The best place to begin. I'm surprised that no one could diagnose and fix the problem. The bike finally ended up in the right hands, Joe the engineer, busman and "can do" mechanic. You're ruling out what isn't wrong and working your way down the list, repairing what is wrong. Won't be long 'till the bike is in tip top condition. Following this one. Great job Joe :)

I commented on your last video. Good job on figuring out the powervalve. But it's your carburetor. The emulsion tube where the needle runs is wore out. Doesn't matter what jetting you put in it'll never be right. I had the same issue on the same year bike. You need a new carb.

As I said in your last video about this bike, you should try holding the throttle at a steady RPM spray some starting fluid where it's been JB welded, and see if it revs higher.... I am gonna stick to that theory..Also, your spark plug should be tightened to the correct torque specs... I'm guessing that you do a lot of that "off camera" but, your spark plug was loosening while free revving... just saying... Love your channel Joe, please keep us updated! Thanks...

Had the same exact problem with my yz250. Replaced reeds, intake boot, rejetting, tried a lectron, and replaced everything electrical. Still had the same problem. Turns out even though my timing marks were aligned, you still need to advance timing to spec. In my case a yz250 spec was .07 advanced. I also replaced dry side crank seal even though it was 2 months old and all my problems were fixed. So try to replace your seals and check your timing

I am so invested in this

Love your videos thank you

Cause and affect buddy. What makes the power valve work? What makes the thing do what it does to make the thing that makes the power valve work? Process of elimination. Your good at this. I have all the confidence in you. I know you will find the failure.

I had the same problem with my 94. Your power valve is not operating correctly. I was able to adjust it from the upper cylinder.Has to be that the "governor-ac tuator is sticking. Next time you have the clutch cover off please go over the kick start gear and why it would skip every 4 or 5 kicks. Great entertaining vids!!

Good diagnosing Joe. I'm with you....powervalves still not right. I'm wondering if the spring tension is setup backwards. Not sure if you can do that on CR's but I know you can on RM's. Just a thought.

yup i agree the govner spring or slide is hanging up u can see it fully

Dude that Wiseco basket looks grooved to hell.

Man I hate when Joe revs them to the moon with no load on them. I know it's not hurting the bike but it just has the same effect as nails on a chalkboard to me!!! 🤣🤣🤣

I wish you lived here in Ontario Canada! There are few good mechanics here! I bought a can am instead of a yamaha and ive regreted it ever since!

governor for sure my opinion you will get it you always do.

I've had the same on a similar age cr a couple of years a go, it was the carb, Keihin pj carbs were out causing needle to not work properly, Lund mx talked about this when building his 93 last year,

Is there any kind of ball thats in the governor, to make the centrifugal action work?