Seller Said This Dirt Bike Has a Horrible Bog 

This channel is like meditation for men!

spray starting fluid where the JB weld is while holding the throttle at a steady RPM and see if it revs higher due to a leak and sucking air...

Before you tear anything down, check the power valve. That's what it sounds like to me.

check pipe , to make sure there is no obstruction ! I had this issue with a 2001 cr250

I'm amazed at how many times you miss 2nd 😊

Since re-jetting didn’t have much effect, I wouldn’t rule out electrical just yet. Just because the spark plug checker shows a plug is ok, that doesn’t mean the other components aren’t breaking down.

Mid range bog=power valve sticking or misadjusted. Set the power valves up right and try a 170-175 jet. You should solve it that way.

A walk around with our Vinny is just not right 😂

Do a crankcase leak down test, check power valves and check for exhaust restriction.

My buddy's yz 250 sounded like that, and to find out it was a partially clogged silencer.

Take your pick of which to tackle first: 1. Crank seal 2. Power valve 3. JB weld

Just fought a similar battle on a 2000 KTM with a Keihin carb. Hours of swapping jets. Long story short, it was the carb. Found an OEM (not Chinese replica) and it instantly solved the problem.

IMO it's pulling air from the crank seals. I would inspect the case for cracks because of J.B weld deal. Joe sweet bike overall 🎬🔥👍🫡

This was one of my all time favourite bikes I've owned.

Since the bog is at the mid to upper RPM's only, It would likely be an obstruction in air flow. Check Power valves to make sure they are fully opening at the higher RPM. Also, make sure your pipe and muffler are clear.

You beat me to another bike, had this one saved on Market Place myself and was pondering about purchasing. Awesome find and enjoy the videos.

I remember when I could read jet #s without using glasses a flash light and magnifying tool. 😂😂😂😂😂

Joe you finally bought a bike that stumped. You will never accept defeat. All your viewers know that. So I'm looking forward to your next video. I'm curious on what the bike needs to be done to correct the issue.

Check you harness grounds , ohm out your coil ..even cleaning your fly wheel an make sure it set right , I think its electrical

Check the power valve see if the last owner played with the settings in the power valve. You can adjust it to open sooner or later on the cylinder there is a stamp that says H and L check to see the position.

Did you check that ground where the frame was painted

Ol' Joe loves his dirt bikes. Nice looking cycle, a very popular/big seller, now let's tear it apart. Lots of teaching/learning moments

I REALLY like that bike... I can see why the previous owner was frustrated with it. Like you, I would have started with the carb, but after seeing the air screw only turned out 1/4 turn and inspecting the carb, I would have checked the power valve. I would certainly check it before resorting to completely tearing down the engine because it has decent compression and visually everything looks good.

Do a leak down test first and while doing so spray soapy water around the jb weld case repair. Check power valve for excessive carbon build up or possibly worn or broken power valve. Silencer may need cleaned and re packed. Clean up all ground contact points on the frame. Had a bike years ago with a bad port job done by a goon that acted just like this. Rule out the above mentioned before tearing it down. Good Luck! It’s a good looking bike!

Those spark checker can be a simple check but they have no combustion chamber pressure on them so don't rely on it completely or it can bite you

If this year still has the exhaust power ports, they might be carboned up and sticking. Definitely worth cleaning those and putting stock jets back in. Check the muffler packing too. I have a 1989 that I bought new. Still runs like a champ. Original everything if you can believe it. I love it!

Man i'm stoked you're making this video. I have a 97 that has a similar problem. I replaced the right side crank seal with no improvement.

Never cared for the "95" purple. I had a new 94, which was gorgeous. Either way, this was a nice score on your behalf.👍🏼 With some patience, this bike will return a hefty sum at some point. Detail the hell out of it and keep it in the showroom condition that it is.

See what s up the JB weld.

If I had one a small hole would be much better than a crack, which will need drill at the ends to make sure it doesn't travel laterally.

Just wanted to say that I love the videos Joe. I am 15 and have always had a passion for working on these machines. I have 2018 Suzuki drz 125l and I enjoy upgrading it. Ive been consistent watching for a few years and have picked up on quite a few things🤙

My 2002 did the same thing it was Servo for my ev power valve.

I would go for the crank seals, after checking the power valves

Check the powervalve. The fact that 155 ran the best might indicate that that the jetblock gasket might be broken.

Look at the baffle material in the silencer

Lol! I once worked on a bike a whole afternoon before I realized it had a sidestand switch preventing it from starting. I had the carbs off, plugs out, battery charging and all.

Pro circuit pipes work amazing on these bikes, I raced cr250’s from 1990 to 2008 the I switched to Yamaha 450’s

Vinny just called me and said...David please tell my owner...I am 1000% sure it is the ignition...CDI...coil...I don't want to be near the backfires..😊

Yeah, Id think your chasing your tail with the jetting, I suspect air ingression thru the crank seals or that crack in the crankcase... somewhere its getting in. These faults are real buggers to solve but great when you nail it. At least you can shut the garage door on it and dont have to ride it home. Have fun!!

52 pilot on these hondas is what we ran.

JB Weld on cranckcase is letting in air. The higher the revs, the more it sucks in, the more lean the mix :)

Wow a CR! Nice 👍

Nothing sounds better than a two stroke dirt bike in my opinion, actually anything two stroke!

I've had this same exact problem with my 1990 Yamaha YZ 125. Turns out the mechanic put the power valve in backward. Once he fixed the issue, it revved out perfectly again.

Check the power valves

I had a 93 same exact bike alot of good times on that machine!!

$2000 for a bike that year, that good of shape is a DEAL

Check the spark plug cap. Honda uses a resistor cap 5 ohms max. If ohms is 10 or higher with cause a retarder ignition. Also could be stator one coil runs the high revs after 5k rpms . In my opinion it's a timing issue. Cap is a issue I have come across many times. I am 58 years old. Been riding and wrenching for 50 years...

Brilliant video Joe watching from Edinburgh Scotland UK 🇬🇧

I reckon power valve sticking as its bogged hard at the beginning. I've had that happen to two yz 125's. If not could be the JB weld, or crank seals.

When the jetting wasn't having much effect I was back to thinking ignition. Maybe check the gaps in the magneto pickups, the magnets in the flywheel, coil resistance, ignition module, etc. I could see one of those having an RPM dependent failure, such that it works fine below a certain RPM but then breaks up at higher.

Power valve stuck shut

Happy Days Joe Has Posted 🔥🔥🔥

I had a 96 kx250 that ran identical to that. It ended up being the power valves not functioning properly

My 89 CR250 had a very similar issue and it was the power valves not working correctly. The power valves are a different setup on this but it's worth looking into.

That is a VERY COOL spark plug tester!!! Never knew such a thing existed!

My favorite Cr250 eva had a huge picture on my wall when i was a lad best look Cr in my opinion lovly nice score mate

First thought when you pulled it off was the crank seals, they get hard and brittle after 20 years on a 2T. All that junk around the flywheel made me think it was blowing premix out on that side. I didn’t see any oil coming out the muffler so I don’t think it is the rhs seal. I guess it could be the power valve not opening.

2 stroke dirtbike go-to checklist for me when it comes to performance issues. *Jetting/Spark Plug *Reeds *Powervalve issue/dirty *Crank Seals -stator side will cause air to be. sucked in, causing lean condition. -clutch side will suck trans fluid into crank cavity making bike run very rich Usually one of these is always the cause, of a consistent performance issue. If it's intermittent, especially once warmed up, usually electrical. I see you touched these basis and took all the right steps.

My first thought was power valves. Sweet looking bike! ‘93-‘95 are the best looking bikes Honda ever put out!

Air filter is filthy

Love your show man beautiful Honda keeping ripping

Just had a bike with same symptoms. Chased the carb forever. Showed it to a pro mechanic friend, he told me to check the coil. That was it, I was shocked.

BIG FAN of the spark plug tester !!

Kinda clanky kicking it over..

Yo, dude. What is up with your granddaddy’s GoldWing! Don’t leave me hanging. Please ASK ME ABOUT THE DIAMOND PLATES!

Check the power valves for sure, they need regular cleaning anyways. But my money is on a bad coil, it's breaking down at high rpm. If it had an air leak from that JB weld or flywheel side crank seal you'd think smaller main jet would make it worse. Looking forward to seeing the fix! Retired auto mechanic here but recently got into small engine stuff and enjoying the change!

Love that year of CR. Great find.

my money is on crank seals (due to smoke on first start) or CDI/spark related. It is like the issue i get with water on spark boot/coil grounding out the spark an or if the old cr has power valves being stuck closed.

I just bought a 03 cr250 with bad bog! It ended up being the power valves were adjusted wrong. the servo motor wasnt opening the ports for mine at the right time. If this ytear has that motor, definitely worth checking! It still has the slightest bog at low rpm so i will be doing a carb tuning like this in the near future. great video, hope you find the cause on this bike, these things EAT!

I have Lernt sooo much from watching you over the past few years Joe! you have solved Almost Every problem there is. Thankyou :) - Could your problem have somthing todo with the Pipe?/Chamber clogged?

Not for this occasion, but for hard starting,and especially big bores, tilt the bike on it's side until you see gas overflow, put the bike in gear and rock it back and forth. Fuel is sucked into the engine and really helps promote firing. 2 strokes only, unless you want cam chain and valve timing problems. As a long term CR500 Honda owner and rider in all weather conditions, this really saves your right leg and all of it's components.

I had this same issue with a 91 cr125r and i couldnt ever figure it out to the point i just sold it.

Oh heck yeah I loved that bike same age as me

I once had a Yamaha 200 2 stroke 2 cylinder, as a boy of 14/15 year old, and at one point you had a mechanism on the ignition system with, when the engine made more rpm, the spark was made earlier by adjusting the moment that the points were opening. The ignition time was changing with more or less RPM. Now did I buy a complete little set and I just put it on, and the engine did run but did not have the higher rpm anymore. Same as with your bike. I also changed the carburetor, the exhaust pipes, and so on. He had more rpm when I made it leaner, but no power on the top.... I sold the thing before I found that. Then I got a Yamaha YZ250 from I think from around 1985, and there I got the same problem when I got trouble with the engine. The top of that Ignition changer was put on exactly the wrong way, so the ignition time didn't change but stayed the same all time. Again bought it in original parts of Yamaha and I think the did the same thing again: assembled it exactly wrong. I took the top of and turned it 180, so the time changed by more RPM and the problem was gone. It is a bit silly explained, but I am dutch and not very well know with the technical terms in English. I think it is about timing...

I learn so much every time I watch a video. Thank you for these.

Its obvious man first you need to do a leak down test. You plug the exauhst and pump in air through the intake and see if it holds air. If not its crank seals or the base gasket. Next you check to see if the power valve is coaked up with carbon. Do this and you will find the problem.

Power valve 100 percent😊

It's acting like an old 1964 jeep I had, when coil started to fail. While cold, it ran fine until it warmed up. As soon as the coil heated up, the spark just scattered. Replace the coil, she ran like a dream.

I agree with some other posters, check exhaust for an obstruction before a teardown. Never hurts to check it.

Beautiful bike, you really find nice ones...

Man I buddy had one just like that and that thing was a handful but very fast

Bogging. Hmm. I remember bogging on another bike, but I don't remember what was wrong. It is always interesting to go through the process of finding out what is wrong with the bike and fixing it. 🙂👍

Wide open throttle, 5 kicks....THAT is your compression. Which was slightly low. Check if the midbody gasket is leaking too if it has one.

Can't wait to see part 2.

Holy crap..Great deal on this bike..even if it has problems..vintage Hondas are hot commodities now .

What a beautiful bike.. watch all your videos,well most of them. You have fixed so many bikes. I have learned a lot from u. You have probably been asked this a lot but do you keep most of them after you fix them and also have you came across a 85 Honda 250r ATC. Or one of my other favorites 200x. Keep doing your thing bro . Your videos are what I end my day with. Thank you

This looks like a keeper. Sweet bike.

You got a great deal on that one!!!

If there were an obstruction in your pipe it would not idle or rev out either. It’s most likely the power valves sticking. Good luck.

I had Honda of Troy build me a Brian Swink replica 1995 CR250 team bike. Thing was a beautiful. Was identical except that I had Pro Circuit suspension instead of the factor kits. The growl at full throttle in 3rd gear was amazing. The first day I had it i stepped off it on the left side in my garage with shorts on and the footpeg filleted my calf. Super sharp. Learned a lesson there. Took 20 stitches to close it completely up.

I would like to say the powervalve might be gummed up or not opening right. Great Vid!!!

a clean machine!...Thanks for the carb class...how about change the crank seal next...

Lot of well thought out comments . Nice job everyone! 😊

cdi? sounds like the spark might not be advancing

You should also check the jet block gasket. If someone was chasing a carb issue and dipped the carb, sometimes the dip eats the jet block gasket.

96 cr250 was my favorite bike of all time! Best engine no frame that year!

Powervalves?

Carb tuning is what i need to do and i learned a lot from your videos Thanks for posting

Maybe try FMF pipe & silencer.