Gas Gas 250 Pro Starts And Runs But Choking Its Self

[thats_a_five]

Choking

What year is your bike? The rear silencer has changed over the years. You removed just the rear silencer, right? You can run the bike without it to test. It will be loud but if it revs freely you will know the plugged exhaust is the problem.

My bike is a “TXT Edition” not a “Pro” so my silencer is different although the basic principles are the same. To clean it, you have to remove the rear cap. I had to drill out 4 rivets, yours may be held on with bolts. Take off the cap and look for a metal screen. It is probably very plugged with black, oily soot. Soak the screen in solvent (petrol, diesel fuel or parts cleaner – no smoking!) then scrub with a wire brush until you can see through the mesh of the screen. There is a perforated metal pipe that goes through the silencer to the inlet. This pipe is surrounded by “packing” that quiets the noise. This packing is probably also pretty saturated and the holes in the perf pipe may also be plugged with soot. I would clean the pipe and replace the packing while you have it apart, although these will not cause the choking, just the plugged screen will do that.

[thats_a_five]

cant suggest where its coming from the coolant it looks like it from bottom of engine is there a specific order the hoses go on and the o rings are brand new on cylinder head

Coolant Leak

Water will always drip down so the leak could be up higher, just running down and dripping off the bottom of the engine. The sequence that you install the hoses should not matter. Were the hoses new or did you reuse the old ones? Reuse is OK – just make a habit of inspecting them for wear from rubbing or age cracks or splits. Check that the hose clamps are tight.

How big was the puddle on the floor? Every time I top up the radiator on my bike it will spit some out the next time I run it. Not much but it was concerning until I collected and measured the amount. About 1 spoon full, so I stopped worrying and now only top it up every couple months.

If you use colored coolant, you should be able to see where the leak is. Fill the rad, run the bike up to temp, shut it off and watch as it cools. Use the paper trick to follow the drip up to its source.

[dombush]

Jason

The coolant leakage and the "choked up" issues may or may not be linked. Right now my hunch is that they are probably not. Reason is that a bike will run normally (not under load) for a minute or so before overheating.

Water leakage.

Try to trace the source of the water leakage by working up from the point above the "puddle". Without belittling the problem it should be quite easy to spot the source as long as you use some anti-freeze that leaves a trace and doesn't evaporate.

Unblocking of the exhaust

I like the idea of running the bike very briefly without the rear silencer section, as although noisy it will prove the point. If you suspect the silencer section is blocked I suggest that you disassemble the silencer as follows:-

• Drill the heads off the pop-rivets that hold the end cap to the silencer body and punch the remains of the rivet into the silencer.
  
• Remove the end cap to reveal the silencer screen tube and the absorption material.
  
• Remove the absorption material from around the screen tube and then pull out the tube (it might pull out anyway)
  
• Note the orientation (radial and top end / bottom end)
  
• Inspect the screen tube for holes / collapsed sections / blockages etc.
  
• ********repair as necessary*********
  
• Replace the screen tube into the silencer
  
• Pack new silencer material around the "in position" tube using a long rod. Careful not to over compact the material.
  
• Replace the end cap ensuring the exposed screen tube locates into the and cap recess.
  
• Re-rivet the end cap in position using correctly sized large head aluminium pop-rivets.
  

Materials costs are likely to be £5-£10 for the absorption material and £2-£3 for some large head aluminium rivets (assumes you have or can borrow a pop-rivet gun).

Dom

[jason1987]

hello everyone who has helped me i took exhaust off earlier and stuck a rod down and bashed the exhaust a bit put it back on bike and big bang bosh kicked bike up took it down road and now runs sweet so im guessing that this was the problem thanks sooo much e to everyone your the best all of you

[thats_a_five]

Good to hear that you got it running. Keep your feet up!