Hey guys since I finally paid to have my bike setup to run right, $100 to jet it the bike has been pinging now mostly when I'm on the pipe. Had the best guy around the area jet it, and its now running a 160 main, 45 Pilot and a N8RH needle in the middle clip position. I run Hess 93 octane with yamalube 2R @ 32:1, and I took a good listen to it today. It really sounds like some bb's rattling around inside the cyl head every once and awhile when I'm really on the pipe. I'm on the throttle alot, and ride mostly sugar sand. My mods are performance engineering ported head, wiseco piston, Vforce reeds, FMF fatty & silencer (new packing),and twin air filter. Today I tried turning the airscrew in a bit, it just made it noticably more sluggish and still was pinging. I am going to try raising the clip a notch to drop the needle and see how it works out, right now the bike runs very clean with little to no spooge or smoke when warmed up. I'd hate to run race fuel in it, as it's very hard to get in this area and is at least a 1/2 hr drive. Also I've spent hours online doing jetting research, and I heard the late model RM's are really hard to jet & have alot of compression. What do you guys think? I'd hate to blow up my brand new top end, oh and I also checked the crank bearings etc while it was apart for play & it was fine. :bang:
Pinging issue
- Thread starter 1998RM250
- Start date
ws6transam
Member
- Nov 17, 2005
- 309
- 0
I fumbled for all of last season with trying to get to the bottom of my jetting troubles; sometimes it would lean out so far that it'd stall out under wide-open conditions and other times it would run great.
Then this winter, I found a piece of white plastic that was floating around the float bowl, presumably from the tank. So I cleaned it out really well, then INSTALLED A FUEL FILTER and haven't had a problem since.
...just a suggestion.
Then this winter, I found a piece of white plastic that was floating around the float bowl, presumably from the tank. So I cleaned it out really well, then INSTALLED A FUEL FILTER and haven't had a problem since.
...just a suggestion.
I think you're going to need it. I don't know if you saw my post in one of your other threads but if the guy you bought the bike from raced it as a pro I'd bet he had the compression boosted and ran race gas. It's worth at least giving it a try.1998RM250 said:
If it runs better with race gas and you don't want to spend the money on it you can always have the head modified to run pump gas again but send it to a reputable tuner to get the work done--don't skimp cuz you're going to want it to be done right.
Aye carumba! You are slowly melting your top end running it lean/in drastically lean conditions. I really am leaning (no pun) towards jetting lean and not detonation. Marine fuel, jetting experts and all the bolt on mods from China aside, you need to learn to read your plugs and make changes for jetting. Unless you learn to PROPERLY jet your bike, you will need to carry the jetting expert with you every ride. All your mods are a moot point/does not really matter, to jet. You need to start at the pilot and work your way up to the main. Make 1 adjustment at a time, ONE! Your mods matter as much as the altitude, temperature, humidity, barometric pressure and riding conditions. They all matter the same. And the condition of your bike, overall, not just the engine. Once you get it right, you know where to go in the future to keep it correct. Used and abused are part of the same word for a VERY good reason. Getting through all the bs to get it correct is not easy, you may even need to rethink what you have been doing, somewhere down the line? 1, Do you have a shop manual and hand tools?
The jetting can be spot on but if the fuel isn't a high enough octane to match the compression your still going to have a problem.
- Thread starter
- #6
I can not thank you guys enough, I have learned so much from this site. I'm begining to question this "expert tuner" as well as he keeps telling me it's bottom end noise, no way I've heard those noises before and its definately not! Funny this guy works on everyones race bikes here and swears by him, but hes not a two stroke guy anymore at all, nobody is infact they all dis on my bike everytime I bring it out. Alot of people are running my jetting on pump fuel and it seems okay, but then again their head isnt ported. The previous owner did run race fuel in the bike btw, I didnt have a pinging issue on pump though but the right crank seal was blown out so it was all messed up anyways. I'm going to call the guy who did the headwork, he just happens to work in a local shop now and I randomly ran into him when he was inspecting my head! I do however have a suzuki repair manual, but it's not as good as a clymers. When It comes to jetting I have a pretty good basic idea how to do it right, but I paid this guy good money and he's telling me if anything my bike is still running rich BS!
I don't want to argue with him, but what happens when my new wiseco piston melts? He wrote guarantee on all work done, so if it melts and not shatters I would think he's at fault.
Edit: I called a local fuel supplier and they sell 90 octane unleaded without ethonal (sp) and he said it burns at a lower temp, but nobody in the area sells race fuel!
I don't want to argue with him, but what happens when my new wiseco piston melts? He wrote guarantee on all work done, so if it melts and not shatters I would think he's at fault.
Edit: I called a local fuel supplier and they sell 90 octane unleaded without ethonal (sp) and he said it burns at a lower temp, but nobody in the area sells race fuel!
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It could melt due to detonation too.1998RM250 said:
- Thread starter
- #8
What is the difference between the two? stock jetting on my bike is 162 main, 48 pilot, and a n3wk needle so I'm not too much leaner then stock.
Edit: I talked to the guy, he's trying to tell me I had an N8rh needle in there when I know for a fact it was a N3WK because I just broke it a few months ago and had to order a new one. He put the N8RH needle in there and was going by stock jetting as a baseline on the 02-03 RM250 which is the K2 model and wayyyy different. I don't want to argue with him, but I know I'm right about my stuff because hes the only "pro mechanic" around and everyone will dislike me if i question his work. He's got his jetting numbers all mixed around, good thing I wrote down along time ago (over a year) what was in there and the numbers were all stock jets. Pretty sure N3WK needle, 162 main, and 48 pilot is stock on the 01'. Man I'm going to be an expert at this by the time I'm done. :coocoo:
Edit: I talked to the guy, he's trying to tell me I had an N8rh needle in there when I know for a fact it was a N3WK because I just broke it a few months ago and had to order a new one. He put the N8RH needle in there and was going by stock jetting as a baseline on the 02-03 RM250 which is the K2 model and wayyyy different. I don't want to argue with him, but I know I'm right about my stuff because hes the only "pro mechanic" around and everyone will dislike me if i question his work. He's got his jetting numbers all mixed around, good thing I wrote down along time ago (over a year) what was in there and the numbers were all stock jets. Pretty sure N3WK needle, 162 main, and 48 pilot is stock on the 01'. Man I'm going to be an expert at this by the time I'm done. :coocoo:
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2strokerfun
Member
- May 19, 2006
- 1,500
- 1
What is sugar sand?? A lot of people richen up their jetting a bit to run in sand. It can really put a load on the engine.
- Thread starter
- #10
Well the guy wrote me back and said he's not going to argue with me about it, he wrote down what was in there but hes totally wrong. I KNOW what was in there, i checked myself numerous times and if he was a real enthusiast like he claims to be he wouldn't be getting mad talking about this stuff. Sugar sand is almost like baby powder, its very deep and I'm sure puts alot more stress on the motors. I really want my stock jetting back and my money at this point, the power feels flat and I don't want to melt my new piston.
Detonation is caused by insufficient fuel grade. Compression is the main determining factor here. Higher compression requires higher octane fuel. This can be heard while under load and on the throttle.
A lean engine will usually surge and the plugs will be really light colored.
It sounds like you need to forget the 100 bucks you wasted with that guy and get yourself a bag of jets and some tools. Get a pilot jet 1 size up and 1 size down from stock and a couple mains either way. Plan on spending an afternoon tinkering. Find a place to ride on firm ground, not that sugar sand, and follow the guide in this link...... http://www.dirtrider.net/forums3/showthread.php?p=1340315#post1340315
Also make sure the float closes the needle valve when the arm is parallel with the carb, you'll need to pop the bowl off for this. And don't get too caught up on the different needles, just pick one and play with the clip position. Once you get the rest of the carb sorted out you can fine tune the midrange with different needles.
I had an 02 and everyone said it was the worst bike ever to jet. It liked airscrew adjustments but ran fairly constantly on the needle and main through most temps.
And you might want to make sure the petcock filter and tank vent are clear befor you start too. It might sound like alot of work but it'll go quickly and you'll have a much better understanding of how the bike works. Not to mention that good feeling you get when your buddy comes riding that fancy thumper with you and his pro tuned carb won't get the bike running or it pops and spits all the time..... :)
A lean engine will usually surge and the plugs will be really light colored.
It sounds like you need to forget the 100 bucks you wasted with that guy and get yourself a bag of jets and some tools. Get a pilot jet 1 size up and 1 size down from stock and a couple mains either way. Plan on spending an afternoon tinkering. Find a place to ride on firm ground, not that sugar sand, and follow the guide in this link...... http://www.dirtrider.net/forums3/showthread.php?p=1340315#post1340315
Also make sure the float closes the needle valve when the arm is parallel with the carb, you'll need to pop the bowl off for this. And don't get too caught up on the different needles, just pick one and play with the clip position. Once you get the rest of the carb sorted out you can fine tune the midrange with different needles.
I had an 02 and everyone said it was the worst bike ever to jet. It liked airscrew adjustments but ran fairly constantly on the needle and main through most temps.
And you might want to make sure the petcock filter and tank vent are clear befor you start too. It might sound like alot of work but it'll go quickly and you'll have a much better understanding of how the bike works. Not to mention that good feeling you get when your buddy comes riding that fancy thumper with you and his pro tuned carb won't get the bike running or it pops and spits all the time..... :)
- Thread starter
- #13
The guy wants me to bring it back to him, I'm thinking I should just tell him get rid of the N8RH Needle and go back to my stock N3WK then go from there, what are the differences anyways? I'm ready to jet this thing on my own, I mainly brought it to him to findout what was wrong with it because I was stumped. Thanks, you guys are lifesavers and your help is worth way more then this guy could ever ask $$$ wise!
1998RM250 said:
Dare to dream. :rotfl:
There is a guy to talk to about needles, JD. He has been hard at it for quite some time. An expert if you will. http://www.jdjetting.com/
2strokerfun
Member
- May 19, 2006
- 1,500
- 1
Like Fox said. Rely on the (real) experts all you can. You can spend days and days and big big money trying to find a perfect needle, especially if you don't have a baseline needle to start with. I like Sudco for carb parts unless my local dealer happens to have it or is willing to order it for me.
Used and abused, are part of the same word for a good reason. The carb has parts that wear and fail also. Did we get a look at the pinging plug yet?
I have the JD kit in my bike and it runs great. The needle he has is the trick and you can't get it anywhere else. It has a completely different taper to it. If I remember there wasn't a kit for my '01 but he said the '02 kit would work...it did.whenfoxforks-ruled said:
- Thread starter
- #20
whenfoxforks-ruled said:
I took a look at the plug, and it is dry but carbonized. Looks to me as if the guy who jetted it never even changed the plug. It was wet when I gave it to him, now everything just looks dried up and crusted onto it. :think:
Would I be better off runnin 90 octane non ethanol or additive gas then the 93 with all the crap in it? I really want to at least try a 50/50 mix of race fuel and pump seeing the previous owner ran straight race fuel on the stock jetting and now its running 93 crap with a leaner tune, no wonder its pinging! I keep telling the guy the situation and how it was setup before to run, he's telling me "if anything the bike is still running kind of rich in my opinion". He's getting a little nasty with me since I'm "questioning" his jetting experience, but I think he's gooning it and even I know more obviously. :bang:
1998RM250 said:
Obviously. :whoa:
That's why you had to pay someone $100 to jet the bike for you. :coocoo:
Start with a needle from JD Jetting and invest the time to learn to jet the rest of it yourself. You'll find that the time spent will pay you back for years to come.
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- Thread starter
- #22
Rich Rohrich said:
No I just couldnt figure out what was wrong with it, thought there were other issues besides the carb. It had the stock jetting so I figured while it was in his shop I'd have a "pro" jet the bike because I figured he would do things the right way and know what they are doing. I'd say I know more when I have to tell him how to jet it, and he was blaming the pinging noise on my bottom end bearings. Not even close to the same noise lol, I'm no expert but I have a basic idea of jetting and I just thought this guy would get my bike 100% right. Go ahead flame away, we all make mistakes. :bang:
Edit: If it's pinging while I'm on the throttle 100% it would be the main jet I have to increase in size correct?
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Pinging is detonation and you need a higher octane gas. Jetting will not fix it.
Too bad you got the $100 lesson in jetting...or maybe how not to jet but you have come a long way and are at least willing to listen. Keep moving forward Chris, you'll get there.
Too bad you got the $100 lesson in jetting...or maybe how not to jet but you have come a long way and are at least willing to listen. Keep moving forward Chris, you'll get there.
- Thread starter
- #24
RM_guy said:
Thanks Dave, I still appreciate very much how you helped me out and gave me the stator, without it my bike still wouldn't be running most likely. So running it richer will not help with the detonation at all, or running non ethanol fuel? Those were my hopes as I cannot find race fuel anywhere. I'm hoping the past 3 rides I didn't damage the new forged piston, it doesn't ping very often but it is there. :whoa:
RM_guy said:
That's not entirely true. Additional fuel can lower the combustion chamber temps and raise the knock threshold. It's a crude approach but running overly rich can squash knock pretty effectively, but there are obvious tradeoffs.
A couple of other things to consider:
- it will be harder to jet for good throttle response with alcohol based fuel because ethanol has a fixed boiling point around 173 degrees f and a very high latent heat of vaporization, along with requiring a different A/F ratio then the rest of the fuel. In short it acts very different then pure gasoline and screws up the fuels distillation curve which can cause jetting issues.
- the octane distribution of ethanol based fuels will be very different than pure gasoline. As a result the knock sensitivity can be very erratic from load to load of fuel. It's best to tune on the safe side till you get used to running with ethanol. Two-stroke riders who switch to ethanol based fuels without other changes very often run into knock and detonation issues they never had before.
As was suggested earlier, modifying the porting and the cylinder head to match the available fuel is the best long term approach.
