Jump to content
Sign in to follow this  

Help! Horrific screeching noise

Recommended Posts

I was riding across the street from my house... all of a sudden there was this horrible screeching noise. I hit the killswitch, and stopped. Started it again, and it made the noise in neutral. put it back in gear and rode back, but there was no loss of power. the noise changed in pitch with the RPMs. It is an RM250 2t, and it has a power valve. I drained the trannny fluid and it was fine.

Since it made the noise when there was no load on the tranny, I assumed it was the motor. I could move the piston by turning the flywheel by hand, easily, so it shouldn't be the crank right? No loss of power, couldn't be the top end. My other thought was that it could be the power valve. Any ideas? I was gonna take this bike to the dunes on thanksgiving, I need help quick!

thanks

Share this post


Link to post
Share on other sites

My guess would be your clutch,start it up and hold your clutch in and out and see if it stops!

Share this post


Link to post
Share on other sites

Hey, I've got the exact same screeching noise at the moment on an 07 KX 250. I was in the middle of nowhere on a trail when it started so I had to ride for quite a while to get back to the car. The bike still rode fine, I had no loss of power or anything either, but the noise was getting louder and louder.

Another thing I found was as soon as I clicked into 4th gear the noise went away completely, but was there in 1st, 2nd, 3rd. Makes me think it's a gearbox issue possibly? But then it also does it in neutral so I dunno.

Share this post


Link to post
Share on other sites

sounds like a gasket leak it could the one at the head but probably the one at the crank. also, check to make sure your oil is still brown, and not white. i had a case where the water pump seal went and leaked water and coolant into my bottom end, which caused the crank bearing to oxidize and make a horrible noise like that.

Share this post


Link to post
Share on other sites

Could be any number of things.... piston against cyl. wall, wrist pin bearing, crank bearing, con rod bearing... maybe something in the clutch... hell, maybe your power bands are just slipping. :busted:

If it were me, I'd pull the motor out and take a look. Fix what's wrong before the problem gets any worse than it already is. The good news is two-strokes are easy to R&R.

I'd much rather catch a problem when it looks like this:

DSC08456.jpg

than when the piece breaks off and turns your crank/conrod into something that looks like this:

IMG_0010.jpg

Share this post


Link to post
Share on other sites

Well some experienced friends of mine believe it is the crank bearings/main bearings. I've already split the cases to replace a water pump bearing and seal, as it is an internal water pump model, so I have some experience. I was planning on selling it and buying a 450 with some money I have saved up, but not anymore.

What kind of bike could I get that has plenty of power that is around 1500 bucks? Just a temporary ride, til I can fix this and sell both of them. I saw some yz426s on craigslist the other day, are they any good? I ride a little sand dunes, jumps, desert, and rocky trails, and wanna try some motocross.

Share this post


Link to post
Share on other sites

I'm going to fix it myself... but It will take me a while. probably two months. Missing two months of riding season in AZ is no fun, especially when you have to suffer through four months of 100+ temperatures.

Share this post


Link to post
Share on other sites
I'm going to fix it myself... but It will take me a while. probably two months. Missing two months of riding season in AZ is no fun, especially when you have to suffer through four months of 100+ temperatures.

Suffering is -20 and below here in utah,aaahh weather is 100+ temps escepially in your lake havasu:thumbsup:

Share this post


Link to post
Share on other sites

I do ride in the heat of the day which is around 90 to 100dgs,i can stand the heat alot better than i can stand the cold.After doing a year in Adak Alaska my tolerance for being cold is really low!

Share this post


Link to post
Share on other sites
I'm going to fix it myself... but It will take me a while. probably two months. Missing two months of riding season in AZ is no fun, especially when you have to suffer through four months of 100+ temperatures.

Let me get this right...you're gonna take $1500 and roll the dice on a used bike...that may blow up the day ya get it....

OR you could order a new crank/piston kit with gaskets for about $500 thru Thumpertalk Store...put it together one of these nights this week...ride it this weekend.

Share this post


Link to post
Share on other sites

$1500 would do even a new head/cylinder/piston/crank/clutch/all fluids/gaskets/seals/bearings....pretty much your entire rotating assembly. Do not buy a used bike. I was in your situation too...blew up a 125 and found out $500 would fix it but then had the cash and bought another 125 of the same year that needed some fixing up but ran for $575. Bought it and blew it up after only 3 or 4 rides...so then I had to part that bike out and piece together one and sell the other parts to fix the one and lost about 3 months of our 6 months of riding here in Ohio

Share this post


Link to post
Share on other sites

an engine builder will pretty much rebuild your entire engine for something like $800 that would leave you $700...... and you would have a entirely new engine.

you could do the same for yourself for $550... and have $950 left over. there are enough videos online and threads here that you would have all the info you need to do the job. even if you had to spend $200 on special tools to do the job, you would come out ahead and have all the tools for next time. Rocky Mountain would have every part and tool you needed to you in 3 days..... TT in probably a week..... either way you could be riding before Thanksgiving no problem...

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×