85-86 250r knocking sound

[hrc85250r]

hey, i have a 85' 250r that i restored, and i have had it about a year and a half now, it has always had this wierd knocking sound coming from it....it has almost all of the tranny gears replaced, the main bearing, rod, crank and top end have less than 10 hrs on them....i replaced the counterbalancer assembly witha brand new honda one, including a new hinson adj holder....i figured that would have got rid of the noise, but nope....still knocks....i was wondering if this is normal....i have heard all lq 250r's have a knock or tick...idk, help me out 250r guys!!!! i dont want to throw something out of my tranny..

[85 250sx]

Well i asked about that same question not to long ago and never realy got a straight forward awnser. But my water pumper aslo does it. and it comes frome the trans area
This is my first 2 stroke so i wasnt sure if it was normal in them or not. But after riding with a friend with a blaster i noticed his did the same and he told me it was normal, just hope its normal on the 250r's as well. When you rev the engine is it harder to ear over the exhuast? or does the knocking also get louder? Because i and on my freinds you can only realy notice it at idle. hope this help you any

[hrc85250r]

yeah, mine is the same, it is like a deep knocking sound that you can hear at idle...kind of as the piston moves up and down.....you cant hear it at all when it is cranking or has a load on it......

[Fox250R]

Mine does the same!! Mostly notice it when it idles..I was told most of all Rs do it. Some more then others........

[Derrick Adams]

Seems like most 2 strokes do this. Both mine do.

[hrc85250r]

hey fox....cant you put video on here? if you could get a clip of yur wheeler idling, that would save me from splitting my cases.....thanks man...

[Tri-ZNate]

I remember several threads where if the person wasnt running a high enough octane it would cause the engine to knock.

[hrc85250r]

i run half cam2 half ultra pump gs, and i have 210 compression....

[Hornetpowerspor]

210 is pretty high. A good (safe rule af thumb) is 160 lbs on pump gas. Sure, some run higher but that is safe. Now a power valve motor is different. As the rpms increase the power valve opens thus raising your port timing, thus lowering your compression. So 180-200 lbs isnt uncommon for a powervalve motor on pump gas. I would try running some higher octane and see if the noise goes away.

[hrc200x]

I had a '87 trx 250r that would make a knock sound, people told me it was piston slap. I could only heard it in neutral and it would be right after I reved it and the RPM was comming back down. I guess its the piston hitting the side of the cyclinder from excess wear. Wouldn't really make sence to hear it on a freshly rebuilt motor unless they used a wrong sized piston or bored/hoaned it too much. Or maybe its just the nature of the beast.

[hrc85250r]

im out of gas, so when i get more gas i will get straight cam2, which is 112 octane and see if that helps....let me tell you what though, when i put the race gas/ultra mix in it definately made a difference in power, but mayybe i havent got all of the power cause its still detonating, we'll see maybe tomorrow night....the station with pump race gas is a half hour away on a reservation....

[Fox250R]

ill try to get a vid of it tomorrow...

[Ordo]

You won't get rid of the noise, well not that easily. It's the counter balance. They all make the noise you are discribing. Some louder than others ecspecially when you start boring them out or changing from a factory piston to aftermarket. You would have to start adding wait to the counter balance if the new piston&rings were heavier than the stock set. And vise virsa for a liter setup. I might do a write up in full detail for you guys later. Hope this helped.

[hrc85250r]

wow, thanks ordo....that makes sense....i bored mine .080 over now, and it is louder than it was on the .020 piston, and its obviously a wiseco....the weight is off, so the counterbalance is going to be off a little too.... and thanks fox, if you can get that vid it would help me out....

[slothminx]

its definitly isnt the engine knocking at idle, engines only knock like that when under load on the wrong octane but if it is that the engine is knocking you can change the ignition timing to compensate but i cant remember if you retard it or advance it

will

[Blown 331]

its definitly isnt the engine knocking at idle, engines only knock like that when under load on the wrong octane but if it is that the engine is knocking you can change the ignition timing to compensate but i cant remember if you retard it or advance it

will

Retarding the timing will reduce spark knock but you will also lose power.

[hrc85250r]

yeah, i tried that, i have best results +2 degrees..... but i talked to psi today, and they said that most likely its piston slap, i think im gonna pull my top end and check the piston-cyl wall clearance, the wiseco box said that the clearance was 3 thousandths (.003), so hopefully thats what it is and i will make sure the place i had it done at buys me a new piston and does the next bore job for free....bastards

[tp250ratc]

my 86 r has a clunk, clunk, clunk sound while at idle or low rev. it definately makes you think something is wierdo. this same bike also runs out great and hauls arse while riding it. i'd say your knock sound is normal in your bike. for comparison sake, i have a suzi quadracer 250r that has a much different sound at idle than the honda r. it is more like a small engine rev- like a chainsaw, weed eater, etc. no knock, just whiney- so to speak.

[hrc85250r]

thats exactly what mine is doing... it sounds like there is a serious problem with a main bearing or something...i will be splitting the cases tomorrow night to find out whats up...hopefully nothing, but its best to make sure cause god knows engine parts are big$$$$ compared to a gasket set and a couple hours.....thanks man

[bigyellow4x4]

i have been told it the ports in the head are round and big gives pist slap and new ones have a running in the middle so it not there? so how do * balance the motor if you habe to light of pistion in it with counterbalance. i have car knowlage on balancing so do hipo bike shop spin balance these motors?

[Fox250R]

thats exactly what mine is doing... it sounds like there is a serious problem with a main bearing or something...i will be splitting the cases tomorrow night to find out whats up...hopefully nothing, but its best to make sure cause god knows engine parts are big$$$$ compared to a gasket set and a couple hours.....thanks man
Dude your looking to much into this..5 or more people have said their Rs do the same thing at low rpm...So why go though all the trouble lol..Like they always say if its not broke dont fix it.. Maybe your ping is alot worse than what im thinking...You need to film it :)..

[hrc85250r]

i am going through all the trouble cause i dont have a lot of money to fix it if it throws something through the cases or something grenades inside the tranny.....and i wont know if its broke unless i split the cases, and it isnt a ping, its a knock.....and i would tape it but i dont know anyone with a digital camcorder....

[Ryan DeBerry]

All 2 strokes do it at idle. I have a nice NICE 86 250r and you can hear it. It's normal. If you don't like the knocking then get a 4 stroke!

[Fox250R]

All 2 strokes do it at idle. I have a nice NICE 86 250r and you can hear it. It's normal. If you don't like the knocking then get a 4 stroke!
My buddy has a 03 CRF450 and it knocks too LMFAO!

[YTZ250#1]

every 250r has a knock to it.I was told by the best honda tech that I know that it is a slight piston slap,and it won't ever go away.you can replace every part in the motor and it will still be there.you won't have a problem with it,just run it.