500ex needs help real bad

[44oEX]

I just got my 500ex kit from fst and I put everything together two days ago. The problem is that it runs like if it was on the choke but I don't even have a choke. It runs way to rich and just spuders. I had a 42 pilot jet and drope it down to a 38 again and put in a hotter plug ( DPR9Z ) and it help but only in neutral as soon as I drove it around it did the same thing. I was told that my filter was probably to dirty so I took it off with no air box lid. That help alot but it is still to rich. The plug is realy black.

Do I have to go to a smaller pilot jet cause I figured bigger motor=bigger jet. Could it be that because I have a longer stroke I need smaller jet or something?

I am going to check the timing again but I thing it's good and the valves are set properly right now. It start on the first turn every time.

It anybody has a 500ex what jetting do you run?
Does anybody have any clue to what could be wrong?
I E-mail fst yesterday but no anwser.

PLEASE HELP I have like 2k in the motor and can't use it

[Doibugu2]

Why don't you call FST?

Also, sounds like your having a problem with your main jet not the pilot jet. What main jet do you have in it?

Mikey Dunlap is a member here, you could even PM him. But I think it would be best if you call him.

There is a guy on here I believe his screen name is chad502ex. He has a very long signature, he may have his settings in there. Do a search for a post by him, it may help.

[44oEX]

I have a 185 main right now but I just put it that big cause I don't want it to be to lean. I will set the main jet once I have the motor droken in cause you need to have it full trottle to set the main and full trottle is not good on a new motor. But it is not the main jet cause I don't go past haft trottle. It is to hard to call fst cause you can only call at certain time and it's always busy.

[Doibugu2]

Check this article out, it may help.

http://www.exriders.com/techarticles/jetting.html

Where is your needle at? I would still drop down your main jet a little bit.

Also, if your plug is black, I would replace that. Will the bike idle?

How old is the gas?

Is it spuddering because it's rich or starved for gas? Does your exhaust have any color?

[44oEX]

I know it has something to do with the slow jet. I know it would have to be smaller it just does'nt make any sence that I would have to go smaller on a bigger motor. I just thing something else is wrong and don't know what.

[44oEX]

I just put in a new plug, the disks in the pipe are black and the gas is new with some octane boost. The needle is at the same place as it was with my 440. I think it's the third one down.
I spuders cause it has to much gas the bike idles when it's cold but when it warms up it does'nt, it's like if you put the choke on a hot bike.

It you don't undersand my problem just warm up you bikes and put the choke then drive around

[Doibugu2]

I know what your saying, but I'm 1000 miles away, so I really can't help much. All I can do is give you ideas to try.

What happens when you start it and give it some throttle?


Also, are you saying it will idle forever, or just till it's warm?

I would pull your carb apart and double check everything. I know guy had a problem when you got a new pipe and tried just about everything. He ended up having dirt in his carb. Tear it apart and double check everything.

Send FST an email and see if he will respond. Attach this thread as help. Like I said Mickey comes here a lot and he is by far the best person to ask.http://www.exriders.com/techarticles/jetting.html

[44oEX]

To tell you the truth really I don't know if it will idle or not cause I got an new cam and It says I have to have at least 2000RPM but when the motor gets hot and I let go the trottle it shuts off I am pretty shore that the carb is clean I cleaned it just before I put it on. but thanks any help is welcome.

[MIKE400EX]

Might want to check the float level in the carb, also maybe there is some crud on the needle or seat that is keeping the float from shutting the fuel supply off.
BTW, a DPR9Z is a colder plug than an 8Z.

[cals400ex]

i would make sure the intake boot is not ripped. also make sure there is a good connection on both sides of the carb. if there is an air leak, it won't run right.

[skemp]

Originally posted by cals400ex
i would make sure the intake boot is not ripped. also make sure there is a good connection on both sides of the carb. if there is an air leak, it won't run right.

What he said. Something isn't right. A pilot won't have this big of an effect on the entire rev range if it is slightly off. After checking for air leaks (make sure the boot isn't folded over or anything), consider the needle. Many times on a modded two stroke you will have to jet down in certain areas of the rev range if the powerband has been drastically shifted to the left or right (through porting for example), although I don't think this is your problem. There is a problem somewhere between the carb and the motor, whether it be a piece of sand in your needle/seat or a bad seal at the carb to boot junction. Good luck. :)

Originally posted by 44oEX
I just put in a new plug, the disks in the pipe are black and the gas is new with some octane boost. The needle is at the same place as it was with my 440. I think it's the third one down.
I spuders cause it has to much gas the bike idles when it's cold but when it warms up it does'nt, it's like if you put the choke on a hot bike.

It you don't undersand my problem just warm up you bikes and put the choke then drive around

Ok I know you say in a later post that your breaking in the cam etc but lets look at he above.

I had the same problem (only idle cold w/no choke and stall when warmed up) and rather than miss something I just tore apart the carb "again" and blew out all the jets and mainly around the seat of the float level needle (also check for wear or damage etc) and then started looking for the air boot leak. Well the leak is harder to find than you might think but I finally found it but even with the carb gone over the extra time it idled much better.

If you want to try and spray carb cleaner or some other liquid around the area of the boot while its still cold (fast idle) and if the rpm changes you deff have yourself a leak.

Now for the rich jetting. I think you first have to go back to step one in your mind and treat the 500 just like any other engine etc. If the mid range throttle opening is bogging and fouling the plugs then either the needle position needs adjusting or the problem with the float level is flooding the needle jet (wow just like mine was :) ) and till that is cleared up you will not be able to jet it right.

Your pilot is fine and if anything maybe on the low side. I had tried from a 50 down to a 45 and though the larger was not right it didnt do what your talking about.

So go ovver the carb again and look into the air leak and see what happens.

BTW my ideas are based on the stk carb which I assumed by your posts, if its an FCR or ? then some of this could be different.

Have fun as jetting is a blast :rolleyes:

[RIjon]

Originally posted by 44oEX
I was told that my filter was probably to dirty so I took it off with no air box lid. That help alot but it is still to rich. The plug is realy black.




Are you using the stock 400ex carb?

From what you are explaining the engine doesn't sound like it's getting enuff air

I would think even tho it seems like there is too much fuel ..might the bore size of the carb be a restriction?

Just a thought

[44oEX]

Yes I am using the stock carb with the stoke bore.

Thanks for al the help. I check the timming yesterday and that was not it so I will clean my carb again tonight and let you know what happened. If I can get it brokin in I will tell you if it is worth the money or not. It probably is.

[MIKE400EX]

Is there anything stuck in the air boot to the carb (filter>>carb)?

[44oEX]

No I cleaned everything right before I put it together.
But thanks anyway.

[nakomis0]

I just kinda skimmed through the post. But does it sound like it the needle just needs to be lowered? If its simply a rich jetting problem.

I would just drop the needle a position or 2, maybe put in a smaller pilot jet.

All this stuff is probably going to have to be adjusted again when you change your main jet.

..and calling FST is a very good idea.

I'd think a stock carb on a 500ex it would run like chit no matter what jet ya got in there...:confused2

[Dunlap]

I already e-mailed him and told him we run stock carb with stock jetting and a 165 main in Chads 500ex.If that does not fix it then there is something wrong. Just so you know a bigger motor most of the time will run smaller jetting than say a 400 or 416.

[Doibugu2]

Originally posted by Mickey Dunlap
I already e-mailed him and told him we run stock carb with stock jetting and a 165 main in Chads 500ex.If that does not fix it then there is something wrong. Just so you know a bigger motor most of the time will run smaller jetting than say a 400 or 416.

Can you give a short explination as to why you would run smaller jetting on a larger engine?

clearly that confuses some of us exriders.

[Dunlap]

It all has to do with volumetric efficiency. The higher velocity in the intake port sends a stronger signal (or sucks harder) to the carberator richening itself up automatically. The bigger the motor goes, as long as the ports stay the same size and the head flows the same amount, the smaller jet you will run. We don't have to change the pilot jets because its pulling the fuel through the jet harder and automatically richening itself up. The only reason we have to go up on the main jet is because the head flows better and the bigger cams on the 500EX motor. If you just put a bore and stroke kit with stock head and stock cam, etc., you would be smaller jetting than you would be with a 400 stock engine. I hope I have explained it clear enough.

Originally posted by Mickey Dunlap
I hope I have explained it clear enough.

You sure did...thanks for the input Mickey..:)

[Doibugu2]

Originally posted by Rico
You sure did...thanks for the input Mickey..:)

Two thumbs up. I would have never thought of that.

[chad502ex]

Originally posted by 44oEX
I just got my 500ex kit from fst and I put everything together two days ago. The problem is that it runs like if it was on the choke but I don't even have a choke. It runs way to rich and just spuders. I had a 42 pilot jet and drope it down to a 38 again and put in a hotter plug ( DPR9Z ) and it help but only in neutral as soon as I drove it around it did the same thing. I was told that my filter was probably to dirty so I took it off with no air box lid. That help alot but it is still to rich. The plug is realy black.

Do I have to go to a smaller pilot jet cause I figured bigger motor=bigger jet. Could it be that because I have a longer stroke I need smaller jet or something?

I am going to check the timing again but I thing it's good and the valves are set properly right now. It start on the first turn every time.

It anybody has a 500ex what jetting do you run?
Does anybody have any clue to what could be wrong?
I E-mail fst yesterday but no anwser.

PLEASE HELP I have like 2k in the motor and can't use it

440ex, just to help ya out a bit on your new 500, my site has alot of info or tips to assist ya in your new 500EX build. Interesting enough is that I'm not surprised your not getting the support you need for your new kit, this is the main reason why I've learned as much as I have about my 502 over the last few years. What's funny is that my 502 and a friends 508 smokes his 500's he builds in Bedford PA drag strip by many quad lengths. The guys who owns those 500's were really upset to get beat so bad. Anyway, I hope the info helps you, and feel free to contact me for more,...

Chad502ex.com

[oste]

:confused:

First I'd call the guy who did the motor work and see what he'd recommend.

If he won't help I'd clean the carb.

I'm guessing you still have the stock carb on the beast?

Put a smaller main jet in, try going to a 165.

Check for spark, maybe you got electric problems?

[Nospowered400]

Where do you get the 500 kit from? LInks?

[chad502ex]

Originally posted by Nospowered400
Where do you get the 500 kit from? LInks?

Hey NOS, didn't you read the first post of this thread, 440EX indicated where he purchased the kit. I'm not trying to be agressive or anything, but I'll never say for obvious reasons

:devil:

Chad502EX.com

[Dunlap]

Originally posted by chad502ex
Hey NOS, didn't you read the first post of this thread, 440EX indicated where he purchased the kit. I'm not trying to be agressive or anything, but I'll never say for obvious reasons

:devil:

Chad502EX.com :devil:Read the Bible,I love the ending!:devil: :devil: :devil: :devil: :devil: :devil: :devil: :devil:

[chad502ex]

Originally posted by Mickey Dunlap
:devil:Read the Bible,I love the ending!:devil: :devil: :devil: :devil: :devil: :devil: :devil: :devil:


Revelation?

[Nospowered400]

I am new to this site so there fore I have no clue what FST is. Didnt know I was gonna get flamed.:mad:

[chad502ex]

Originally posted by Nospowered400
I am new to this site so there fore I have no clue what FST is. Didnt know I was gonna get flamed.:mad:

OH, NOS. I apoligize. I wasn't "Flam'n" you. Didn't mean for you to think that.

FST= Four Stroke Tech. no website.

Chad502EX.com

[Nospowered400]

Originally posted by chad502ex
OH, NOS. I apoligize. I wasn't "Flam'n" you. Didn't mean for you to think that.

FST= Four Stroke Tech. no website.

Chad502EX.com

Well thanx for not flam'n me, I get enough of that at work:( I am looking for the biggest possible kit for the 400 but the only thing I have found is the 465 from Trinity. I had no clue you could go to a 500.:eek2:

[chad502ex]

Originally posted by Nospowered400
Well thanx for not flam'n me, I get enough of that at work:( I am looking for the biggest possible kit for the 400 but the only thing I have found is the 465 from Trinity. I had no clue you could go to a 500.:eek2:

NOS, yes its possible,... Actually, it's possible to hit 508 and 512cc. 490 and 501 kit is great

Chad502EX.com

[Pappy]

this thread reminds me of that ancient pappy saying:

"man who win pissing contest is bigger dick":bandit:

[chad502ex]

:rolleyes:

whatever,...

:scary: tho!

Chad502EX.com

[Nospowered400]

I hate to ask but where can u get them? 490 from FST too? How do you get in touch with them or see there products.

[Dunlap]

You can call from 3 to 6 est. mon.- fri.814-842-6159. 500 kits are in stock and ready to go. We need your crank for a core and it cost $800. For more info you will need to call.

[440C12]

You said that it starts up on first turn everytime, that means that your timing is ok. The only thing that I can think of is that your carb float maybe stuck after you cleaned it. Since you cleaned it several time already I would'nt tell you to clean it again. If the carb is on the bike now and it still doesn't run right try knocking the carb float bowl a couple of times with a screw driver handle and see if that may work. If the timing is correct and you checked the air leaks, clean the carb etc and is still not working, I would definately put the settings on the carb exactly like it was before you installed the 500 kit. Try that and see if it idle and revs ok. Make sure you don't ride it. If the old settings allow the bike to idle and rev normal then you can bet your money that it's the jetting that is causing your problem. By installing the 500 kit you've already made some major changes to the motor, rejetting the carb before you even started the bike adds more scenarios to what may be wrong. Hope this helps.

[44oEX]

I just want to thank every for the help.

I did what mickey said and it work. Now it runs good still not perfect but that it just a little fine tunnig with is no problem. It semse pretty pepy but I will let you now once I have it broken in. Probably by monday or thusday I will ride all weekend.

500EX RULES (when it works)

[Doibugu2]

So what exactly did you change to get it to run right?

[44oEX]

I put the stock needle back in instead of the one that came in the jet kit. I took the main jet down from a 185 to a 165 and I cleaned the filter. I whent for a drive yesterday for like a hour and it runs fine. I could do 4 gear wheelies sitting down at under haft trottle ( still breaking it in ) and I had a passenger so I can even give it a shot to get up and it would still get up on two wheels no problem.

The only thing I don't like is that it gets really hot. I have a home made secondary oil cooler that I am going to put in when it's time for my oil change I will take of the side cover and tap it, the head has already bin taped. I just hot it help. I will probebly build a home made over size oil tank when I get a chance.

[Greg Z]

165 sounds a little lean :-\ i would say go some where around 170's some where

[44oEX]

that is what mickey FST sad I chod run but when I got the beaster brokin in I will see what it does at full trottle.

[chad502ex]

440ex, I'd bet ya almost anything (not really) that you'll be rich for sure. 165 main jet, that's a laugh!! If your running slip on pipe with filter and stock carb you'll be 155 main- tops 158. Good luck, hope this helps. Keep us informed what ya find on the top end. My "Carb Chart in Tech Talk on my website should assist you in dialing in your new 500. Good luck.

Chad502EX.com

[440C12]

Hey Chad502, I didn't know that you can run a woodruff advance key on a high compression motor? I have a 440 with JE 12:01 and Sparks Racing told me that it was a bad idea. I rode my buddy's 400EX with the advance key, FCR39 any X6 Exhaust and it responds really nice. You think it's safe to advance the timing without detonation?

[44oEX]

No problem chad I will let you know as sone as I geta chance to burn another tank of gas and put my oil cooler

[chad502ex]

Originally posted by 440C12
Hey Chad502, I didn't know that you can run a woodruff advance key on a high compression motor? I have a 440 with JE 12:01 and Sparks Racing told me that it was a bad idea. I rode my buddy's 400EX with the advance key, FCR39 any X6 Exhaust and it responds really nice. You think it's safe to advance the timing without detonation?

440C12, yes u can run an advance key on just about any motor. the key does nothing but advances your timing in the bottom end of the hp curve. I personally prefer a "Building" look on my dyno curve (straight up, flat on top, then straight down for entire powerband) . This give my motor more use of the powerband. Peaky power sucks for thumpers. Peaky power is for two strokes. What kind of thumper uses power in one tiny little area of the powerband in the upper rpm's of the motor? Thumpers are built to use the entire powerband, especially down low. So, advance keys are excellent for bumping the low end power curve up a notch. As far as using them on high compression motors, just be sure that your not running to lean and the motor is dialed in as close as posibble. Running lower octance fuel causes early detonation and with high compression motors and lean condition could cause the "Ping" to slam the top of your piston and down to the crank. Basically, they are worth the money ($6) if your not looking to run your motor wide open cause keys are better for low end only and don't change top end at all. Negative- motor runs a little hotter if no race fuel to cool. Positive- huge low end snap which stretches your arm length 4"/yr. LOL

Hope this helps.
:)
Chad502EX.com

[chad502ex]

Originally posted by 44oEX
No problem chad I will let you know as sone as I geta chance to burn another tank of gas and put my oil cooler

OK, kewl

Chad502EX.com

[44oEX]

Hey chad I just check out your web site ( pretty good ). I look at your dyno chart. and I was a thinking it was a little low. With all the stuff you have in the bike I was tinking it would be closer to 50-55. could it be because you have it set up for wood racing ( cam ) and that would lower your peak hp.

[chad502ex]

Originally posted by 44oEX
Hey chad I just check out your web site ( pretty good ). I look at your dyno chart. and I was a thinking it was a little low. With all the stuff you have in the bike I was tinking it would be closer to 50-55. could it be because you have it set up for wood racing ( cam ) and that would lower your peak hp.

440EX, your right, my dyno on my 502 does looks a bit lower that what you might think it would be, but trust me, this dyno is really what you would expect to see when you bore and stroke to the max. In other words, I've built my motor for bottom end torque not for peaky hp. Two strokes motors are suppose to be hitting max power in the upper rpm of the hp curve, but four strokes have power that is suppose to be for the entire powerband not just in the tiny top rpm range. I've tried to build my motor for the most power from idle to max, that is why my dyno looks steep from idle then flat all the way to max rpm then back down.. Whats really impressive is the torque on this motor. Take the derivative of hp function, you get torque. the 502 has 78ft/lbs of torque (3x stock). Torque wins races not hp.

Chad502EX.com

[44oEX]

Ok so if I get this correcly since you have a better carb and bigger vavles then I do even if I have a wilder cam I will only have about 45Hp or even less:confused:

[chad502ex]

Originally posted by 44oEX
Ok so if I get this correcly since you have a better carb and bigger vavles then I do even if I have a wilder cam I will only have about 45Hp or even less:confused:

440EX, I'd bet on it! But keep in mind that Torque is where its at with thumpers not HP. Let's compare: Even with the new Honda 450R that has 64.8mm stroke (or whatever it is) will no way have as much torque as our stroker 500's will- even if you stroke the 450R! As a matter of fact, if you stroke the new 450R almost 7mm, you'll still only have only 2mm bottom end over a stock 400EX. See the point?

Lets say:
450R stroked 7 mm on top of 64.8 only gives you 71.8mm stroke compared to 7mm stroke on 400ex crank bumps up stroke to 77mm. 77mm to 71.8mm. Big difference in Torque #'s, isn't it?

Bottom line is between the 416 dyno and a 502 dyno is only from 42 to 46 hp respectively. But the torque between 416 and 502 is basically stock torque to 3x the torque (78ft/lbs) respectively.

Torque wins races!

Hope this helps. :)

Chad502EX.com

[44oEX]

on the dyno run in 5 gear 85 +MPH what was your gearing with the 21 inch's

[chad502ex]

Originally posted by 44oEX
on the dyno run in 5 gear 85 +MPH what was your gearing with the 21 inch's

440ex, i run stock 15-38

Chad502ex.com