85 Honda 250sx clunking noise

[Dustin96]

Hi everyone hope someone can help me with my issue. I just bought a 1985 Honda 250sx it ran and drove great for about 15mins but now I'm hearing a clunking sound in every gear besides neutral and reverse? If you got any ideas it would be greatly appreciated.

[Name Brand]

Mine made some popping noises before my differential broke. The 1985 SX is not sealed as well as other years and water will get in and do damage.
Open up the cap on the rear differential with a 17mm and check the fluid. Look for water intrusion, metallic particles mixed into the fluid and of course chunks of gear or bearing. It's probably best to drain that fluid and change it even if everything looks ok. Use a little magnet on a stick tool and see what you can pick up. If there's any chunks, then it's time for a rebuild. I believe their were a few members here do rebuilds if you can't locate a replacement differential. Once it's back together raise all those vent lines as high as possible on the machine.

[Dustin96]

Well I checked the fluid all seems good in there no water.Then I removed the swing arm and took the back cover/gear part off the "side gear" as I've seen people call it and all those gears look good to. But can hear the noise spinning the gear that's on the shaft that runs threw the motor so bad bearing in the side gear then??? Not sure if there's something else it could be since all gears work good just makes the bad clunking noise.

[Dustin96]

Anyone??? Sorry just trying to get this thing fixed.

[atc007]

Trace the power back from the engine. Do NOT pull the 90 degree output shaft out of the engine. Your universal joint may be bad , but good money is still on the pinion bearing being bad. Google search is your friend. There is tons of information about theses problems.

[Dustin96]

I have the swingarm removed and still hearing the sound it's for sure coming from something in the motor.

[Dustin96]

I'll post a video in just a little bit so you can hear the sound.

[Dustin96]

Here's a video of the noise. Sorry I didn't upload it directly here but Photobucket wasn't working so I had to use YouTube. https://youtu.be/pWmXru8QrXQ

[atc007]

Were you spinning the output shaft by hand there? Either way, you have some tearing to do . My guess,,,would be someone pulled that shaft out and you have washers at least missing,maybe more. The one sound was really bad,but I couldn't make sense of what you were doing there.

[Dustin96]

Sorry had to hold my phone close to the output so you could hear it but yes I was spinning the output by hand.

[Dustin96]

Sucks it makes that nasty noise, got it on a great deal for my area ($150) and all the plastics are in great shape and everything works besides that nasty sound.

[Dustin96]

I did order a guaranteed usable condition complete output gear box, I seen some people say you can change that without splitting the cases if you push it out from the other side with a rod/pipe or similar diameter?

[atc007]

NO!! If you are going to pull it, you lay the bike on it's right side,kickstarter down. And pull straight up out, there WILL be washers left freefloating and they may fall. I have pulled the change off twice,one TRX and one SX. I have never seen an output fail,or make noise. Good luck !

[fabiodriven]

Ordering parts when you don't know what is wrong is not going to fix your bike. You can post and post and beg for the answers, but there is only so much we can do on this end. You have to dig into this and figure it out. I'm not saying the gearbox you ordered isn't going to fix it, but you're just guessing.

[Dustin96]

I'm not begging for the answers I was just posting to see if someone had a similar sound. Since when I googled other people's issues didn't sound the same as mine. Thank you atc007 for the help I really appreciate it.