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WR250F Throttle Bogging...?

Joined
Nov 28, 2006
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#1
Hey guys,

I'm the second owner of an '03 WR250 and I took it out for a spin the other day after a month or two in the garage. It started right up on the first kick with the choke pulled out, then I warmed it for a bit before pushing in the choke. The idle speed was a little high so I tinkered with that a bit, and then, with the idle hovering and ever so slightly oscillating, I put on my helmet and plunked down onto it.

It was in neutral already, so I flicked the throttle to rev it up, just out of habit I guess. The result was less than appealing. It bogged and died immediately. I started it again, tried to rev it and the same thing happened. Third time, I tried opening the throttle very slowly and it lagged a little, then suddenly revved up to where it was supposed to be.

That's not how it's supposed to run! Up until now, it's always had immediate response to my throttle.. Now this is happening.

What could it be? I haven't had to tune this baby at all so I don't know what's wrong. Maybe somebody could help me with a simple explanation and possible culprits?

I recently changed the air filter to a brand new UNI filter, btw. Everything else I haven't touched.
 
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Oct 19, 2006
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#2
Let's see, it's sat for months and bogs like it's lean. Could it possibly be gummed up jets?
 
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#3
you warmed it up so it would be the carb.

but if it lagged then i would warm it up more.

my bikes tend to lag if they arent warm
 

ghunter

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#5
Could also be bad gas or a combination of a gummed up carb and bad gas. During the summer in the Los Angeles area gas goes bad in plastic containers very fast due to the heat. If I don't use all my fuel on a ride, it will stay in the bike to a maximum of two weeks before I drain it and use it in the kid's quad.

You might try draining all the old gas out and using it for your car/truck/lawnmower and putting in fresh fuel AFTER cleaning the carb.
 
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#6
I've never cleaned the carb or done anything with the jets. Which would be easier/less expensive? I'm thinking about taking it to the Yamaha shop nearby and asking if they can show me how to do it.
 
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#7
pidro_el_pirata said:
I've never cleaned the carb or done anything with the jets. Which would be easier/less expensive? I'm thinking about taking it to the Yamaha shop nearby and asking if they can show me how to do it.
It's not that bad. Loosen the clamp on the intake manifold and the one on the air box boot and twist the carb clockwise as far as you can. This will expose the float bowl and screws that hold the float bowl on.

Remove the float bowl and it will expose the jets. Most likely your pilot or idle jet is clogged. Also remove the little plate on the bottom of the float bowl and clean that area out and inspect the diaphram for damage. That is your accelerator pump.

Remove all the jets and clean them until you can see daylight through the holes. If you do not have a service manual, you should buy one. It will explain how to do these and other things yourself and save you from having to take your bike to the dealer.

If you have never checked your valve adjustment, this is the first thing you should check. If the valves are too tight, the bike won't idle right. Refer to your manual for this also.

Good luck. :cool:
 
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#8
Inoperative accelerator pump?

Chris
 
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#9
I'm thinking of stopping by my Yamaha shop and having one of the guys show me as he does it. I'm not experienced in this at all, and I don't want to screw anything up.

How much would/should a carb cleanup cost? And how about a jet job? I'm looking for a price range to expect.
 
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#10
pidro_el_pirata said:
I'm thinking of stopping by my Yamaha shop and having one of the guys show me as he does it.
How much would/should a carb cleanup cost? And how about a jet job? I'm looking for a price range to expect.

You would have to call your local shop. They should have a flat rate for that.

Prices are usually around $60.00 to $85.00 an hour.

If you watch it's $90.00 to $100.00 an hour. :ohmy:

If you help it's $150.00 up. ;) :laugh:
 
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#12
my yamaha dealer said that they can completely rebuild the carburator and have it spotless for 100$ canadian.
 
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#13
pidro_el_pirata said:
For both or individually? A carb cleanup and a jetting job are two separate things in dirt bike land, right?

Right. But your carb should not need re-jetting. Just a clean out.