Big red 250es engine noise vid posted

**matt22895** · 09-12-2011, 03:34 PM

i have a 1985 bigred250es and it has a knock coming from the bottom end on the right side cover i did the screwdriver test and heard it loudest right in the middle of the case under the honda logo but it could be heard throught the motor just quieter id dosent go away when riding im not sure what is making the noise

http://www.youtube.com/watch?v=Tu_IBQ2qRio

**Headsup** · 09-12-2011, 03:37 PM

Check the oil level. try to readjust your Cam Chain. Maybe thats it

**matt22895** · 09-12-2011, 03:49 PM

oil was just changed and chain was tightend i think its a bearing but dont know

**RodKnockRacing** · 09-12-2011, 04:29 PM

could be rod bearing or crank bearings

**dougspcs** · 09-12-2011, 04:56 PM

Cam chain is auto adjustable..remove the hydralic adjuster on the front of the engine and check it as per the manual you can find on the site.

Start with the simple..but it doesn't sound simple. Sounds f*&^ed..how did this happen?

I got an brand new (NOS) engine in case it doesn't work out for you..PM me if interested.

**matt22895** · 09-12-2011, 06:06 PM

yah im pretty sure the crank bearings are toast it just kinda developed over time but now its bad

**tri again** · 09-12-2011, 10:06 PM

Originally Posted by matt22895

yah im pretty sure the crank bearings are toast it just kinda developed over time but now its bad

I had a 250es knock that I would have bet 100$ was a rod knock.
Made me sick from 40 yards.
Took a breath and counted exhaust pulses.
They coincided perfectly with the knock timing.
Figured it was in time with valve noise.
Adjusted the valves and it was gone.
Hope yours is a super easy fix.

This computer doesn't want to play audio for some reason
but sure sounds like a good idea to post 'funny' noises.

**atc007** · 09-13-2011, 07:04 AM

When I read this,I simply assumed rod. But I can't discern Anything from that video. Set your valves,and then if it is still there. It will be your timing chain is worn out ,or a rod kit.

**Jon Boy** · 09-13-2011, 09:45 AM

i don't have a Big Red, but that's almost how my 125 is sounding. basicly from the same spot your discribing too. i'll be finding out what it is on mine before too long, when i get the case repaired. i've heard it could be anything from a wrist pin to a spun crank bearing. guy who gave me the quote on fixing my case wouldn't give me a quote for it (it had been stolen and damage occured), because there was no way for him to know exactly what might be wrong with out taking it apart and he wasn't about to work on it till he knows he is getting paid for his work.

here's mine for referance if your wondering.

http://youtu.be/Zk2o24XRqfs

**dougspcs** · 09-13-2011, 10:49 AM

The other side of this is..doesn't really matter what the individual part is that failed!!

But why? You aren't just going to open it and replace one part..you are gonna rebuild it completely. The 'why' part will tell you how much other collateral damage there is..

If it was run oil of oil or the oil was water contaminated..it total over haul. If it's just an incidental bearing spin(unlikely) then you might get away with just lower end repair.

Pull it out, tear it down, rebuild it right and you get another 25 years from it..

Don't try and diagnose from the outside noise!!

**matt22895** · 09-13-2011, 01:30 PM

yeah im gonna adjust the valves and timing chain then if its still there im going to pull the side cover off and see if there is any play or damage in the bearings if not i have a parts motor i could use it needs a top end and all the stuff on the right side but i think i could make one good motor out of two

**Jon Boy** · 09-13-2011, 03:07 PM

yeah, check it out and get it fixed when you can. at the very least, you could possibly get one good motor out of the two. i've been waiting to get mine worked on to find out exactly what the deal is and the time is getting close.

**matt22895** · 09-13-2011, 05:43 PM

yeah i might just get a parts bike with a good motor there dime a dozen here and i read your thread sucks they stole your bike and damaged it but its good you got it back

**HondaClaw** · 09-13-2011, 09:14 PM

I would cry if my machines made that noise, because I have no clue how or what to do once I open that engine

**dougspcs** · 09-13-2011, 09:34 PM

Still sitting on the fence as to whether I should sell my NOS 250 engine just for this very reason..

Both my 250s couldn't be stronger at the moment, but in a few years who knows what will happen and I might need a good motor really bad.

It's sitting in a box under my workbench at the moment..if someone offer me the money I want I just might, but to be honest I'm happy when everyone I offer it too turns it down!!

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Big red 250es engine noise vid posted