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Rob Bellamy

XT 250 1981 - Non starter - Help!

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Hi Everyone,

I have bought a 1981 XT250 for $360 off ebay that is a non starter. I have no knowledge of the history of the bike but it doesn't look like it has started for a long time and it has been maintained using bodge methods. I have a clymer manual and enthusiasm.

Problems:

  • Kick starter has no decompression cable.
  • Cam chain tensioner is missing.
  • The timing was completely off.
  • The electrics have been messed with. Indicators / brake light have been removed, only remaing light is the headlight. In general look butchered.
  • No battery.
  • Sticking clutch - my intuition says this might fix itself once the engine warms up and has been running for a little while.
  • The most worrying thing is that the engine has clearly been opened and messed with by some mope who has lost engine bolts for the head and covers and even a few threads have been stripped.

So far I have done:

  • Cleaned and rebuilt the carb with new jets and gaskets
  • Checked compression - 150
  • Spark - big and blue
  • Checked all valve clearances - good
  • Removed rotor and stator to check timing - all good
  • Fresh fuel + Start ya bastard + Fuel to carb flows freely.

What happens:

Currently when kick starting the motor the kick start backfires and dominates my foot and leg. I have tried bump starting it with some success however it only runs for less than a few seconds before stalling and it does not respond to the throttle. This may also be due to a sticking clutch which doesn't let me disengage gear to stop it from stalling. The other worry I have is that the engine despite only running for a short period is not responding to the throttle in anyway.

Next Steps:

  1. When I rebuilt the carb I found that a plastic washer was missing from the drawings I have from the Clymer manual. It is a white plastic ring that sits in the bottom of the float chamber. I am not sure how crucial this is to functioning of the carb.
  2. I am thinking that if I have a decompression cable on the kick start then I might be able to get it started in neutral with the kick start.
  3. Otherwise I am thinking there might be a wiring issue considering the butchering it has clearly taken. I read somewhere that incorrect wiring would enable it to start but not rev up which seems to fit with what is happening.

If anyone can tell me why everytime I try to upload a photo it comes up as a broken link let me know and I can provide images to each of my points.

If anyone has any feedback I would greatly appreciate it as I am unsure on how to move forward.

Cheers,

Rob

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Hi

Your list of things that have been carried out should allow the engine to start,

What worries me is that you said the ‘TIMING CHAIN TENSIONER’, was missing, if the engine has been turned with this missing then the inlet/exhaust valves will stay in their position until the tension has been taken up and not close under the spring tension quickly enough to miss the piston,

If this has happened you might find that the piston has hit one of the valves and bent it. Hope not because this would be annoying to fix,

Also you I think you say the kick starter kicks back when you try to start it,

This could be a sign that the timing is still out (valve timing as well as ignition)

I would check for compression and try to get a look into the combustion chamber to look for signs of piston/valve contact. If all ok and compression is good then I would dry crank the engine slowly by hand with the ignition plug out several times to ensure that the valve/ignition timings remain correct, then go to the ignition (good spark at the right time)

If after this the bike fires and runs for a few secs then I would go back to the carburettor,

By the description you give the engine needs to be stripped down in anyhow to undo any previous mistakes made (stripped/missing threads/bolts) so spending too much time on an engine that might go pop at any time would not be productive. Until the engine has been overhauled.

Good luck

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Hi Rob,

Dropping that motor out & having a good look into it on a bench would more than likely save you alot of grief....believe me, I know this 1st hand.....with my XT6.

Nayruf is on the right track by suggesting you check into the valve timing first.....if your tensioner was missing when you got it.....good chance that cam-chain has jumped a tooth. Not a difficult task to correct....plus, if the motor is out of the frame, you can check the combustion chamber easier.....and have a look into the clutch while you're @ it. Pull those clutch plates apart....clean & re-oil them before re-installing.

Regarding the carb.....make sure your choke is working properly as well.....tends to help more when starting cold.

Also, make sure & get a tight seal @ the intake rubber.....can also cause back-firing.

Don't get discouraged.....it's well worth it in the end.

Good Luck ;)

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