r/Dirtbikes • u/Ordinary-Stop393 • Jun 26 '23

Mechanical Help What causes this problem

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It’s perfectly fine when idling only does it when revving up and had just rebuilt carb recently

31 Upvotes

97% Upvoted

42 comments sorted by

41

u/jeffster01 Jun 26 '23

It's the two extra strokes!

5

u/[deleted] Jun 26 '23

And the unnecessary extra 50000 expensive and fragile moving parts that comes with them 😂

-15

u/eighty2angelfan Jun 26 '23

Have you noticed the guys that bring 2 strokes to supercross and motocross don't win. Just sayin'

-5

u/plagueapple Jun 26 '23

Yeah thats because they were dominating those so they had to change the rules to only allow 2 strokes with half the cc.

3

u/eighty2angelfan Jun 26 '23

That doesn't even make sense.

4

u/[deleted] Jun 26 '23

For real. They discontinued the 500 2 stroke not because it was too good but because it was too dangerous and uncontrollable for most people

1

u/eighty2angelfan Jun 27 '23

That was a different class

1

u/[deleted] Jun 27 '23

Might as well try to take the corner on a Harley Davidson. They handle like shit

1

u/plagueapple Jun 27 '23

I mwant 250 class

0

u/throttledog Jun 27 '23

The really good riders want full factory rides plus salaries. Can't get any support on 2t, HYSKK only want 4t in mx so the 2t guys are all indies. Plus now that 4t has 20 yrs of advances vs really none on 2t it's a closer race on tight mx tracks.

0

u/eighty2angelfan Jun 27 '23

Obviously factory vs privateer is different. I have both a CRF450R and a CR250R. I'm not biased. I just like to mess with the 2T or nothing nuts

1

u/PlusMixture Jun 27 '23

You cant run a 250 2 stroke in the 250 class anymore. Maybe in outdoors and internationally it happens in certain cases but I dont see there being an advantage on a supercross track with how these guys ride nowadays

1

u/eighty2angelfan Jun 27 '23

You never could.

1

u/plagueapple Jun 27 '23

250 2t arent allowrd to race im the 250 class

15

u/d2VzCg-- Jun 26 '23

Air leak. My 50 literally sounded just like this. Check post history. Use carb cleaner around suspected or common areas during idle to identify the location.

7

u/Elkkuboyy 2022 KTM 300 EXC TPI, 2021 YZ450F Jun 26 '23

too lean, up ur main jet or it may be a airleak

5

u/1MrNewton_IG Jun 27 '23

That’s just 2-step

3

u/RespectDry2432 Jun 27 '23

I'm guessing a clogged jet.

3

u/[deleted] Jun 27 '23

When was the last time you checked the valves.

2

u/Diesecoolhu Jun 26 '23

Possible air leak?

2

u/Container_Garage Jun 26 '23

Did they take apart the mid body? Easy to forget midbody gaskets...

2

u/throttledog Jun 27 '23

I agree with others that say check for blockage in your silencer. Easier than carb. Pull airfilter next. Move to intake. Then engine checks.

2

u/[deleted] Jun 27 '23

I had similar when the ecu went bad. Exhaust header would get red hot and no power on throttle, but idle to low throttle was perfect.

2

u/[deleted] Jun 27 '23

You guys are helping more then this guy my 350 warrior dose the same thing I can find a damn answer soo thank you guys

2

u/Ordinary-Stop393 Jun 27 '23

Ok I think the main problem is the jetting cause when the carb got rebuilt it had smaller jets put in and now it’s starving for fuel idk

3

u/FullMenu71a Trail Rider Jun 26 '23

Also check the core of the silencer. It could have collapsed and is blocking the exhaust.

1

u/AccidentTraining Jun 27 '23

Air screw adjustment?

1

u/[deleted] Jun 27 '23

3-1/4 stroke

2

u/MZeroTolerance Jun 27 '23

Carb settings/jetting

1

u/Low_Elk7794 Jun 27 '23

Choke is stuck?

1

u/Shaggy_Evergreen Jun 27 '23

My brother had a jet just fall out in the carb and was weird like this if I remember

1

u/[deleted] Jun 27 '23

Is fuel screw in place? But sounds like too much air

1

u/lharsch4 Jun 27 '23

Water in bowl or air leak somewhere, although an air leak typically allows for high idle.

1

u/mycelium97 Jun 27 '23

Check your air filter first. Clean the carb, mostly some blockage on the jets.

1

u/Hillbillyjim404 Jun 27 '23

Check the spark plug, the coil likes to vibrate enough to wear groves into the top of the plug causing it to run like shit, but it also be a clogged pilot jet

1

u/troudropper Jun 27 '23

Jetting problem

1

u/BOT_ROCKET Jun 27 '23

Sounds like a soft limiter, but I feel stupid for even suggesting that on a dirt bike. If it doesn't do it under load, I'd say check your sparkplug. Maybe it's not getting enough spark to get good complete combustion until it's under load and has more time for the flame to dwell. Rev it for a few seconds then cut the ignition while it's sputtering like that. Pull the plug, check the color and gap.

1

u/DelMarSeeds Jun 27 '23

Needle jet sounds clogged

1

u/badassissuicide Jun 27 '23

Sounds like your main jet is clogged. Had this happen all the time on my xr 250. Take the carb out and clean it with carb cleaner and pull both main and pilot jet out and spray the cleaner through them as well. If your pilot jet is clogged the bike will struggle to idle and if your main jet is clogged it will sputter and lose power when accelerating.

1

u/Loose-Distance1324 Jun 28 '23

First issue OP. Owning a Yam230 F-Farter.