250r motor setup? right or wrong

[Mark86250r]

Just got my 250r all back together after a long time. It just doesnt seem to run right. I got
fresh bore .020 over weisco piston cometic gaskets
Milled stock head
88/89 crank
spacer plate
sparks mx pipe/ silencer
cr 250 air boot
38 air stiker 160main 58 pilot
uni filter no lid on air box
200psi cold cranking

it just doesnt seem right
my main jet is a 160 which should be to lean but it is not
mabye I need fuel like 110
i dunno this is the only R I have ridden

[250rpilot]

1. you should be running race gas
2. pilot jet seems big, should be a 50 or 52.
3. main sounds close, maybe a bit lean. try 162 and 165.
4. needle is probably way off. tell us what is in it, and what clip position.
5. try gapping your spark plug to .018 and see if it helps. high compression can kill a weak spark with a wide gap.


thats all i can come up with from your vague description. describe your problem with some detail and we can go from there.

[wilkin250r]

"It just doesn't seem to run right" is WAY too vague. We need a lot more detail than that to help you out.

Why doesn't it run right? Does it idle fine? How about top-end power?

There are lots of different ways a motor "doesn't run right". Idle problems, high-RPM, low-RPM, sputtering, lack of power, poor throttle response, overheating. All of these can be "not running right", but they all have different causes.

You need to give us more detail.

[Mark86250r]

sorry my question was so vague. My 250r idles fines. Starts up well and has alright midrange.
I think it lacks some power in the upper mid to top end range.
My lt250r is my beater quad with an old motor and the LT shreds it up and that POS is also all stock. I don't get it?
It does not over heat
The plug burn is good and doesnt stutter

[250rpilot]

some may not agree, but i think your engine/pipe combo could be killing your power.

a 38mm carb is pretty big for a .020" motor, unless it is heavliy ported. also, with high compression, your top end overrev will suffer slightly. also, your sparks pipe is a low end pipe. it wont make too much power at the top end.

sounds like someone built that motor with MAJOR low end power in mind. your stock lt250r will outrev it for sure. plus, the lt250r had more HP from the factory.

i still say your jetting is way off, but is enough to make it run ok. those few ponies you lack could be hiding in the jetting.

[Teufel]

I would agree that part of your problem is that you have toomuch carb for the motor

[Mark86250r]

I agree I think the carb is too big so I tried a 36mm PJ carb.
It made a little difference. I mean i think this thing should have more low end than it does and a little more rev. I been playing with the plug gap and the jetting no luck yet. I ordered a new needle so hopelly this fixes it

[zedicus00]

a 38 airstryker is fine on that engine. u do definatly need race gas in that though it would prolly solve most of the problems. and jetting. that engine sounds like it is set up for low end definatly. a 35 mm airstriker prolly woulda been a better choice but being an as carb its not that bad. if u wanna run pump gas get a stock head gasket on that thing.

[beerock]

I feel the pilot is to big, big bores don't even use 58. the 38pwk is FINE for a stock jug. the Sparks MX pipe gives great bottom end but does fall off on the top a bit. but with the 38pwk you should have a good top end power.

Also, whats your gearing? with that setup id say 14/38 or 14/39 maybe your running out of gear?

With 200 static psi you could go all out and run full race gas, OR you could mix it 50/50 half, vpc-12(108 octane) and 93. it will save you some money.Also, the closer you run the motor to detonation the more power you get because your burning more of the gas charge. When you burn too much that results in detonaion.
Just remember when you mix 50/50 the jetting will be fatter then with straight race gas.I ran this combo on a motor for over 200 hours and used straight race gas in the begining. just by changing my mixture to 50/50 i changed my jetting by about 2-3 sizes down.

[250rpilot]

Originally posted by beerock
the 38pwk is FINE for a stock jug. the Sparks MX pipe gives great bottom end but does fall off on the top a bit. but with the 38pwk you should have a good top end power.

problem is, with a top end carb, and a low end pipe, you are getting the WORST of both worlds, not the best of both worlds. its pretty simple, really. an engine has to work together as a package, and the more things you have working against one another, the worse off you will be.

not trying to start anything, just pointing things out that some may not have picked up on.

i guarantee there is 5HP+ hiding in your jetting somewhere, it is up to you to find it. but you wont find it with a big carb and midrange pipe. it just wont work.

[beerock]

Your entitled to your opinion and so am I. I have run a 36mm,38pwk and 39mm pwk and a mx pipe and ive run the TT pipe also. Back to back with all carbs mentioned (doing some testing)The CSR mx pipe has tons of bottom end, so using a larger carb will enhance the top end, more then a smaller carb would. Yea so what you lose a little bottom, NOT ENOUGH to switch a carb and kill the top end even more. its not the WORST like you stated. I garauntee same cylinder same reed cage, mx pipe and a 36mm carb against a 38 or 39 the 38 and 39 will walk away from the 36mm carb all things relative and in proper working order. the 38pwk isnt working against the mx pipe it just changes the power curve.

besides this guy wants more mid to top end

mark, what reed cage are you running? have you checked the reeds? maybe there worn out? that would help with the bottom to mid snap. what about that gear ratio?

[JTRtrx250r]

If the guys running that much compression w/ pump gas...hes just waisting time trying to jet it, I went thru almost the same thing ...was running 50/50(110oct) w/ 210psi and just about pulled my wig out trying to get it to run right, after running straight 110(at 32:1) it got better, now I run 114 w/ my plug gapped at 0.018 and it solved my prob...but mines also ported etc

I say try 110 race gas, gap the plug down...and then jet for it and see where that gets you,(altho for a 38mm that does seeem like a small mainjet and a huge pilot)

all these guys know their R's pretty well, we all live in diffrent areas w/ diffrent altitudes, weather conditions etc, but the general guide-lines are pretty much the same, all we can do is try to help trouble-shoot w/ our own theories/opinions w/ whats described...and thats mine!:D

Good Luck w/ it:)

[250rpilot]

Originally posted by beerock
Your entitled to your opinion and so am I.

WTF is that supposed to mean? im just glad that you are here, and willing to share your knowledge, since you know everything and all.:rolleyes:

[Mark86250r]

Alright just through in a 55 pilot pet needle on 3 no lid. took it out for a ride to make sure my thoughts are corrects. Keep in mind Im at see level and it is 30 degrees out. Quad has bad low end
nice midrange and on the top end it is not that bad but not right.
Should I try a smaller pilot. Plug looks good. alright going to drag
SUZUKI VS TRX Ill be back

[beerock]

Originally posted by 250rpilot
WTF is that supposed to mean? im just glad that you are here, and willing to share your knowledge, since you know everything and all.:rolleyes:

It MEANS YOU have YOUR opinion and I have mine. in simpler terms, you have your opinion about using a mx pipe with a large carb and I HAVE MINE.Remember, you are the one that came out said its the worst set up. and frankly I BEG to differ. Another words im entitlied to my opinion. Do you understand that? I hope you do because I DONT KNOW if you do.

mark, what was that needle again a pet? perhaps a honda neeedle?whatever it is, it sounds like you might have the wrong needle. I would reccomend a keihn CEL needle. I switched my 265 to one from a dgh needle and BOY did it wake my bottom to mid, it was a night and day difference.

also mark you never answered my questions:
what reed cage are you running? have you checked the reeds? maybe there worn out? that would help with the bottom to mid snap. what about that gear ratio?

im just trying to figure out your enitre set up to help you.

I still think a 55 pilot is way to big for a stock jug. by the way is it ported?

[Mark86250r]

Hey Deerock, Yes my cyclinder is ported with a modifed head. I do agree that the 55 pilot is a little big but it is cold out here and it starts alot easier. My gearing is stock 13/39. I checked my reeds. They are boyseen reeds , a little worn out so I ordered a new set up. I also agree that the needle is off. So you are running a CEL needle. I know that some guys run a DEG or DEJ. Last night I did a plug chop and I was running lean. I took out my 160 and tried everysize unitl I ended up at a 175. What a difference It sreams on top now. I also swithced the needle to another honda one. I think it needed some more.
So I hope with some race gas and my new reeds and some more jetting I will be dialed in.
Well going to beat on the Suzuki

[beerock]

Ok telling me your gearing and that your jug is ported has a great affect.

First off, by a 14 tooth front sprocket!!!!!!!!!!!

second, the cel is a awesome needle for 250-265 jugs I said it before, I can garauntee it will totally change your bottom to mid power band

the pilot is still big man it can lead to fouling your plug at idle. go to a 52 and set your airscrew to 2 1/2 out

what reed cage set up did you go with?

with a ported jug nothing under 165 should be in your main. Do you see how the top end is coming alive as you let it burn the gas it is suppose to? YOU WILL NOTICE LESS BOTTOM END, but once you get the CEL needle it will come back! now you can choose whatever needle you want but curtis sparks swears by the CEL for there 265 and one of my friends changed to it and swears by it AND I swear by it too.

call up sudco for all your jets, needles, sparkplugs

http://www.sudco.com

also, when you were riding your bike did you notice any POPPING??? you might have not noticed because you have to keep the throttle locked to hear, feel it.

when you get the CEL(if you do) you are going to have to jet for 1/4 to 3/4 throttle. this is done by doing what i previously said, keep the throttle locked at 3/4 and check the plug(new plug) then half throttle and a little over 1/4 throttle. if you feel its sluggish at any of these positions drop the needle(raise the clip) if it pops at any position raise the needle(lower the clip)

before you do any of this you have to do WOT plug chops to make sure your WOT jetting is good if you dont get the jetting close on the WOT main then playing with the needle is useless because it all depends on the main.JUST make sure you completely warm up the motor so its warm when you touch the cylinder otherwise you could seize a piston in this kind of weather.

[beerock]

here is a needle chart If you notice the deg and dej are richer then the cel, which will end up shwoing a BIG power response.

the deg is a big bore needle, thats way off, the dej is closer but its still richer. remember you have to get the main right first.

[wilkin250r]

You porting and pipe will work against each other. A top-end port job and a low-end pipe will not give you the best of both worlds, it will give you the WORST of both worlds.

However, your carb and your pipe will NOT work against each other. The 38mm is not really a top-end carb in the same way that a pipe or porting is meant for top-end.

Your carb mixes your fuel and air together in the proper ratio. When set up correctly, it will do this at any RPM range, whether it low or high RPM, or a large or small carb.

Now, the difference is when you are CHANGING things, dynamic changes. When you go from 1/4 throttle to WOT. It's true that a larger carb will give you more top-end horsepower, but it won't give you less low-end horsepower, it's not like a pipe. A top-end pipe or a port job will actually reduce low-end power. Your carb does not. It can't. It's physically impossible, unless your jetting is off.

The advantage of a smaller carb is in throttle response. A smaller carb will respond right away as soon as you gas it. A larger carb will stumble and hesitate. The instant resonse will FEEL like low-end power, because you're almost always in the low-rpm range when you gas it, and you'll accelerate right off the line.

As long as your jetting is done properly, it's physically impossible for your carb to be fighting your pipe. Your carb will never decrease your low-end horsepower.

[stocktires]

I love threads like this, I actually took notes.
Bee, would that CEL needle work just as well with a Powervalve? Or would the dej be a better one?

[beerock]

Originally posted by stocktires
I love threads like this, I actually took notes.
Bee, would that CEL needle work just as well with a Powervalve? Or would the dej be a better one?

the cel is a pretty good needle for the stock jug. I have a pretty crazy port job in my jug so its mostly high mid to top end powerband. When i switched from a DGH needle to a CEL i gained ALOT of bottom end. See i use to foul plugs after 3-4 hours if i was in the 1/4 to 1/2 throttle range but 3/4 to wot the bike wouldnt foul the plug. when i switched to the CEL that problem went away and totaly changed my motors low end power.

for the PV i think it may be a bit lean, you could give it a shot though, dej may work better, you could by both and give it a shot.

[Mark86250r]

Hey Beerock thanks for the needle chart. Hey Sudco.com is an awsome site and I have ordered from them before I was just on there site. I checked out there needles and I am going to place an order this week.
I think that people think that I want some crazy top end power, which in fact I dont want. I want a good powered quad with decent power all around.
Well I have been tuning this thing more and more and It runs better everyday. I think now that I have gotten to this point my honda is a little faster than my LT250r now. This is good news.
Dont get me wrong though for a beater that thing moves. well it is 20 degrees out and the snow if falling like crazy, were supposed have 24 inches so Im taking the Lt250r out and the honda staying home.
Riding will be fun tonite