CR250 Pinging at WOT

[nsxxtreme]

I have a 2000 CR250 that was ported by Bill's Pipes. It also has a Bill's Pipe and muffler on it. Currently I am running 87 octane unleaded in it. If I stick it in to high of a gear and the open the throttle up it pings horribley.

The bike seems to have power but the top end is flat.

Suggestions? I am going to try 92 octane. I am thinking the top end may need to be rebuilt. Anyone know what the compression should be?

 

[2-strokes-4-life]

I have a 2000 CR250 that was ported by Bill's Pipes. It also has a Bill's Pipe and muffler on it. Currently I am running 87 octane unleaded in it. If I stick it in to high of a gear and the open the throttle up it pings horribley.

The bike seems to have power but the top end is flat.

Suggestions? I am going to try 92 octane. I am thinking the top end may need to be rebuilt. Anyone know what the compression should be?

the cheap gas is whats causing it to ping.they are designed to run on premium pump fuel or better.also the pinging you are hearing which is also called detonation can destroy your top end in no time.

 

[buffsabs11]

i hear a very slight pinging every once and a while. is this ruining my top end? how do i prevent it?

 

[2-strokes-4-life]

i hear a very slight pinging every once and a while. is this ruining my top end? how do i prevent it?

it is possible to cause damage if you continue to run the low octane fuel in it,at the very least its not gonna run very well with it.try dumping the entire tank and starting with a fresh batch of premium and see if the pinging goes away,if it does then i wouldnt worry about it.just make sure you use better quality fuel from now on

 

[nsxxtreme]

the cheap gas is whats causing it to ping.they are designed to run on premium pump fuel or better.also the pinging you are hearing which is also called detonation can destroy your top end in no time.

I am hoping this is the case. I run a little CR80 on the same gas and it has no problems. I am hoping the pinging hasn't caused damage already.

Have others with CR250's experienced the same thing?

 

[John Cena]

I think the manual recomends a minimum 91 octane, maybe even 93 min.

 

[sakirider]

check yur main jetting...main jet controls mixture from 3/4 to full throttle. If you added pipe and other work you need to test before riding the thing hard...only way to do that is to do it yurself...i see alot of so called tuners try and jet peoples bikes while in a shop with no testing...how do they know what altitude yut at....what the temperture is. Fuel may have something to do with it but remember the higher the octane the slower the burn...id say right now you got detonation going on which will in a short while melt that sucker down. A better fuel will help but you need to work the jetting out first.

 

[James]

I am hoping this is the case. I run a little CR80 on the same gas and it has no problems. I am hoping the pinging hasn't caused damage already.

Have others with CR250's experienced the same thing?

My 02 will ping if the jetting is on the lean side with 93 octane. I usually put a bigger main in and the problem is solved.

I have never had pinging in the 00 or the 01.

 

[nsxxtreme]

I am running a 48 pilot jet and a 175 main jet. Needle is on the second clip.

My problem is I just got back into riding and I dont know how a CR250 with a power valve should run. All the work on the bike was done by the previous owner. It was ported by Bill's pipe. They look like a reputable company but I dont know anything about them.

This bike seemed to have power but flattened out up top. I am going to try premium the detonation is just awful to hear.

 

[James]

The 00 will taper off on top..but not run flat by any means. Mine pulls hard at max rpms and is going FAST. Also, I have run the piston/rings until the bike was nearly impossible to start cold and it still had a respectable top end pull.

I have the stock porting so maybe yours was redone for better low end or maybe 175 is too lean for your setup. I think I generally run a 178 at 600-1500 ft. I sometimes go to a 175 in the middle of summer if it is really hot/humid and will use 180 if I am riding in moderate weather on the farm where I will be wide open most of the time. I still managed to seize my 01 out there with that setup though. I also run the needle 2nd clip (from top). Come to think of it, when I bought the 2000, the previous owner had a 175 main in it and I rode it like that the first winter (before I figured out jetting) and it never pinged. Definitely felt/ran tight though.

Did you check to make sure your power valve is operating properly? If it isn't opening fully, it will cause it to run flat on top and it may overheat it which could contribute to the pinging.

My amatuer 2 cents.

 

[trevor9a]

If it's pinging or knocking don't ride it until you fix it. Detonation will cause damage to your cylinder walls and head. I thought I had my jetting down and climbed a long hill wide open. It started pinging really bad and then smelled burnt. Took it apart and found a chunk of plating missing from my cylinder wall and the cylinder slightly scorched.

 

[nsxxtreme]

My amatuer 2 cents.

You amatuer 2 cents is appreciated.

I'll check into the power valve. Currently I have about an 1/8 of the throttle up top that I can turn and the bike goes no faster. It doesn't have much of a kick as power bands go. Low and midrange power seem to be good but I have nothing to compare it to.

Bought a service manual today. :cool:

Wont be until the weekend that I get to try it out.
Everytime I heard the pinging I closed the throttle. I have seen what detonation can do.

 

[James]

Currently I have about an 1/8 of the throttle up top that I can turn and the bike goes no faster. It doesn't have much of a kick as power bands go. Low and midrange power seem to be good but I have nothing to compare it to.

Let us know what you find out.

When it is running right, it should stand up easily..almost too easily...in 1st-3rd gear. If you are moving along in 4th or 5th and twist it, it should accelerate hard and may bring the wheel up on power alone. As long as you are in the right gear (as I think most bikes will sputter and possibly ping in an obviously too high gear) there should be no hesitation and it should accelerate until it reaches full rpm. If you are cruising at 7/8s throttle and turn it to full, it should go faster. I wouldn't say it "kicks" like a lot of two strokes I have ridden, but it comes on with authority.

 

[nsxxtreme]

Changing the gas to Premium fixed my problem.

I can lift the wheel in 1st and 2nd not so much in 3rd.

Thanks for the help.