Can this make my 250R knock??

[trikezilla]

Hey all,

Ok, heres the deal. I am running my 83R at 32:1 with Bel-Ray H1R synthetic race oil. At idle I notice a definate knocking / louder clicking. It isnt a sporadic knock...its very consistent. Never louder and never softer. This is a definate knock and not a "PING". I am not sure how loud it is at higher RPMs as I cant hear it over the exhaust itself (so that means I cant tell if it gets faster at higher RPMS either.)

-Am I running too lean? The plug color is always right.
-Can a lower octane fuel make the engine knock? I am running Regular unleaded....if this is the problem what grade should I use? (see sig for engine mods)
-If I go to 20:1 would the ticking go away you think. Im gonna try it next fill up, but I am curious:lol:
-What part(s) failure typically makes a knoinkg noise? Its coming from the tope end (but the engine still makes tons of power). Could this be the piston, connecting rod/bearings, wrist pin worn out and/or its bearings?

Lol, and yes I have read my Clymer about these problems, but I just want more knowledge from people that have actually experienced;)
Any help is much appreciated :beer

Charlie

[timex69]

sounds to me like your crank rod bearings are starting to go but thats just me...i know my cr80 ddi that before my rod bearings totally went.

[dufrain]

Could be piston slap also.Check your compression psi with a guage,You can rent one free at autozone.

[trikezilla]

As in "crank rod bearing" you mean the bearings that are in the cases right?

The way I understand it: The bearings that actually hold the crank horizontal in the motor went, and then the bearing between the counter balancer went right?

[trikezilla]

I will maybe look at the compression, but Im positive its good due to the stong power from off the line to wide open. I will run one though before I do take the head, jug, ect. off.

[ChrisD]

I don't know what to tell you here....my 85R has sounded like a timebomb for the past 4 years. It does have a rattle to it, especially noticable at idle. It would usually go away when you put a load on it.

If your jetting wasn't right, you would hear a very distinctive ping / death rattle under heavy load in the upper revs so it's not that.

You probably have piston slap from your cylinder getting worn or a piston cage bearing that's worn. It might be getting close to time for a rebuild, but I doubt that the rattle you hear will leave you stuck miles back in the woods. The 250R motor has a notoriously loud chatter to it to begin with.

[kloby]

low octane rating could cause this yes ..... - nodz - i would never run regular unleaded in any powersport playtoy

[BLAZERONE22]

I've had that rattle in my air R for 3 years now, I thought it was piston slap until I did a topend job on it and it did'nt go away. I was thinking maybe counter balencer bearings.

[3Razors]

You might try 91 octane and see how it acts.

[trikezilla]

Ok, next fill up I will go up to 91 octane :)

Dave: So you redid the topend and it didnt go away? Did you relace everything then? I take it you didnt look at the counter balancer bearings then right?

I dont notice anything odd when its under a load...just at idle like I mentioned. I wish I could hear over the dumb BRAAAAP BRAAAAPP!

Well, I am going to run 91 Octane, mix it at 32:1 ( I made a mistake in the previous post of stating it mixed at 32:1)

Could 40:1 be to lean???

Hopefully I can get it to sound a bit better by changing variables like gas to oil ratios etc. If not Im gonna look at the top end.

Why does a low octane fuel cause a knocking noise??

[mikey's250sx]

low octane ignites at a lower temperature so it actually ignites while the piston is moving up in the stroke still causing a pinging noise.

i do not believe the oil mix ratio will create or alleviate the knocking noise.

[BLAZERONE22]

Ok, next fill up I will go up to 91 octane :)

Dave: So you redid the topend and it didnt go away? Did you relace everything then? I take it you didnt look at the counter balancer bearings then right?

I dont notice anything odd when its under a load...just at idle like I mentioned. I wish I could hear over the dumb BRAAAAP BRAAAAPP!

Well, I am going to run 91 Octane, mix it at 32:1 ( I made a mistake in the previous post of stating it mixed at 32:1)

Could 40:1 be to lean???

Hopefully I can get it to sound a bit better by changing variables like gas to oil ratios etc. If not Im gonna look at the top end.

Why does a low octane fuel cause a knocking noise??

Yeah, fresh bore, piston, wrist pin, rod beaing was in spec. It more noticable at idle, I had a bunch of guys at the trike rampage take a listen and they thought piston slap. like I said, I think its the balancer bearings but its just a guess until I crack her open.

[freaksfix]

I have owned about a dozen 250r's,, from 83-87 trike and quad and ive had probly half of them apart... everyone of them had the same noise,,, to this day i still dont know what it is..... im at the point if my R didnt sound like that when i started it thats when i would worry...

[BLAZERONE22]

Yeah after 3 years I'm not to worried about mine. I have a spare if it does ever let loose...

[250rCRazed]

Ok, next fill up I will go up to 91 octane :)

Dave: So you redid the topend and it didnt go away? Did you relace everything then? I take it you didnt look at the counter balancer bearings then right?

I dont notice anything odd when its under a load...just at idle like I mentioned. I wish I could hear over the dumb BRAAAAP BRAAAAPP!

Well, I am going to run 91 Octane, mix it at 32:1 ( I made a mistake in the previous post of stating it mixed at 32:1)

Could 40:1 be to lean???

Hopefully I can get it to sound a bit better by changing variables like gas to oil ratios etc. If not Im gonna look at the top end.

Why does a low octane fuel cause a knocking noise??

Not saying that the problem has anything to do with pre-mix ratios, which I doubt it does, but just letting you know that 40:1 as opposed to 32:1 would give a RICHER A/F reading. The reason is, for every unit of liquid going into your motor, with 40:1 you'd have less oil and therefore more fuel in that given amount of liquid, creating a RICHER A/F mixture. Many tuners will play with the mix to fine tune jetting, but it is only meant for fine tuning, particularly because trying to lean out the mixture too much 20:1 and further will foul plugs, and you could obviously sieze up your motor if you try to make the mixture too rich with not enough oil. As far as your noises go, I agree that the 250R's are noisy to begin with, my Air R does seem to be noisier than my 86R though. Good luck figuring it out.
-Aaron

[kloby]

40:1 is LEANER than 32:1

[RideRed250R]

no 250Rcrazy is talkin AFR.... think about it... the AIR to fuel ratio... with 32:1 the A to Fuel ratio is leaner but theres more oil in the mixture... LESS FUEL??? Leaner... when you add more gas and less oil 40:1 you have a richer mixture... the richer the mixture it starts to ignite better but less oil causes early ring failures and stuff like that... hes got that end down


as for the noise... i have a splitting head ache and iam trying to explaint his... The 250R has a unique port lay out.... all cylinders of the 250R have this... where the crank case is pressured then forced up through to the piston detinating... causing it to make the deep CLICK noice.... from the force of the air... if your familiar with Cheetah cub banshee cylinders thats what iam tlaking about...the port layout makes the click... also blazerone22 and the rest are right the counterbalancer will WHINE... which in turn sounds like a slap cause its really clanky... its cause the bearings and teeth will evently wear and make a noises... but most the time its just cause the gears are straight cut from factory, it causes less horses to be lost through the balancer..
MAN I NEED A ADVIL
Adam

[kloby]

whoops must of missed the AFR - lol - my bad

[RideRed250R]

np its just a cool thing if you think about it
you can richin and lean your AFR with your oil mixture
adam

[trikezilla]

Wow...I learned a lot from this post! I never thought you could make the thing rich and lean by simply changing the AFR!!
Thats interesting how the port layout is and how that can make a deep click.

Anyhow, thanks for all the information its greatly appreciated, and I can rest easy cuz Im not so worried about seizieng it or blowing her up lol

[rally4x4racer]

nice post -

Can this "deep click" be felt? I just noticed my 84 R is clicking in nuetral - this is such a deep click I can almost feel it in my foot - it seems like it is in the bottom end - (and I just noticed it. )
heres the kicker - I just changed the oil and put motul synthese 2 stroke gearbox oil 10w40 in it. I never noticed this before - is it because the oil I am running?
It does not do this after I pull the clutch in and kick it down to 1st gear.

anyone?
thanks - r4r

[gravelord]

the tick sound, never louder, never quieter, you can only hear it at lower rpms is the piston slap, its not bad, my 85 250r engine had it, and my newer one with a 89 bottom end in my atc has it as well, alittle louder because the heads milled. my friend on here, "deathman" who i go riding with also said its the same thing, but its quiet you have to listen for the sound, if yours is loud enough where you can hear it almost as loud as your exhaust - id say you have a issue. if you can barely hear it warming it up, then you put your head closer to the engine (lean forward well sitting on the bike) then you can hear it, (thats about how loud mine is), then its piston slap that they all have. i spoke to someone, they said the aftermarket cooled heads clear up the problem alittle, BUT yours is a air cooled one, id be more worried about other issues. i dont know if they have the same problems as the liquid. wish you lots of luck.

[JackFlack]

I can hear and feel mine at idle. Mine has allways been there since I bought it.

Sounds like someone hitting the top end with a rubber malet.

[4cylinders]

hey, not really sure if you are hearing piston slap. all the reed valve engines I've heard make that sound, kind of a click/buzz. might be the reeds, or piston/rings passing over the ports. some people can't hear it, loud exhaust or hearing problems.

[rally4x4racer]

this may be my famous last words, but.... "how about I just ride the hell out of it and see what happens?"

[rustyhondas]

that is what a 250r sounds like at idle.

[hrc85250r]

here's the deal. your motor has time on it. once one of these motors are ridden, beat and pounded for many many years, the gears all get some slop in them, from tooth to tooth, as well as he bearings. if you rebuild the bottom end, you will mellow the noise, but it will still be there. i have rebuilt the motor in my rider twice now, with all new bearing, rebuilt cranks, new crank bearings and top end, and the knock has always been there at idle. it could be the crank/crank bearingsm but im guessing its just time on the motor.

[rally4x4racer]

since this post I have been to the shop a couple of times.

The first time I fired up the bike with a friend - we took turns ripping accross the yard. NO NOISE ........
Today I kicked the bike over and got it running.... NO NOISE. I ripped around the yard for a bit and then pulled to a stop. NOISE!! Now that I got the noise back I paid close attention to it as I do not think it is normal if it is intermittent - do you?
it has an organic (destructive) kind of 'crack' to it. When I hear it I just keep thinking fiber disks - because it is not as solid as a metal knock - or metal on metal.
I noticed that when I shifted into 1st with the clutch in - the bike lurched forward. I tightend the clutch cable and it helped that some.

this can not be normal!! ideas?

[stefan34]

I have the same problem only I noticid when I did a smaller main jet in the carb (because it smoked too much and didn't pull right). and now it runs great only that sound I didn't like to much but if you guys say its normal I believe you.

[rally4x4racer]

:w00t: I will let you know when it blows up :w00t:

[Liquid-Darkness]

My 85 here has a little knock to it at idle. It does quiet when its in gear. The main jet when I got it was about 6 sizes too small. But it seems to be a low hour machine. Also I noticed my connecting rod has very little play and seems to be in great shape. No play up/down. I heard the same knock in this one and my old one.