I Need HELP!!!

[matt22895]

i recently purchased a big red 250es and there is a wierd knocking sound coming from the bottom end on the right side also it doesnt go away while driving anybody have any thoughts?

[stevensj13]

Possibly the valves?

[Dirtcrasher]

You said bottom end, the SX and ES are bulletproof engine wise unless they run low on oil. Something could have backed off, or the mains bearings could be bad but thats rare in an oil bathed 4 stroke. You may have to get a gasket, yank the right cover and do some inspecting. Search around, we have free service manuals everywhere.................

The only common issue is the one wy clutch but it makes a winding down noise, then a clunk at shut down. Not all the time..........

[atc007]

Rod bearing,or somethings loose in that side,,Either way,,you already know what you have to do...

[tri again]

I've been working on engines since forever and I would have bet 100$ that
my 87 br had a rod knock.
Sounded horrible from 40 yards.

After I calmed down and counted the exhaust pulses compared to the knock,
I determined it was the same frequency as the valve timing.
Someone forgot to tighten a valve adjuster locknut.

or they adjusted them with it NOT at tdc.

If you pull the valve covers off, you can hold down on the rockers with a rag and see if they quiet down.
Or just go thru the motions and adjust them the right way.

Easy and darn near free.
Search key and look for 'knock'.

With machines this old, it's hard to tell who did what over the years.
I've heard of flywheels coming loose or never tightened, that kinda thing.

[matt22895]

Thanks for the replies guys i have a manual and seen that there were bearings on that side of the case so thats what i assumed. and dirtcrasher i had one of those four wheeled contraptions it was a 86 250 fourtrax it had the one way clutch winding noise its defiantly not like that but if it helps this is a quiet knocking you can only hear from close definatly not what you describe drjoe171 but i apreciate the reply.