1vj wont start

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darcynaboo
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Joined: Sat Mar 07, 2026 6:34 pm
What Bike or Bikes Do You Own?: XT600 1VJ and BMW F650gs

1vj wont start

Post by darcynaboo »

I bought this as a barn find. It had no compression so never started. We have stripped it and re~built it. The top end has been rebuilt and the carb cleaned to an inch of its life. Compression is now great, new spark plug and good spark and new battery. But it just wont start.. Any ideas why it coughs and fires twice then cuts out. Scratching our heads wondering if anyone has experienced this?? I do have a video but cant seem to attach to this post.
charliext1vj
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What Bike or Bikes Do You Own?: 2 XT600s -1VJ, BSA Bantam Trail, CRF1000, BSA B25 if I can find all the bits!
Previously Owned Bikes: too many to list - XT600s, cr500, KTM 990 Adv, VFR800, RDs, DTs
Location: Bath, UK

Re: 1vj wont start

Post by charliext1vj »

Hello,
It could be a number of things and this is a good forum to seek the experts but not probably not me?!

If you have a good spark that's half the battle!
But you say carb is clean it may still be the issue.
But in the first instance I would go for the Carb inlet rubbers as these fail frequently and basically they leak such that the fuel mix is far too weak.
I would see what eazy start does either around the carb rubbers and/or direct into the carb mouth.
You say top end rebuilt but what is the compression value?
Is the decompressor cable too tight? are the valves leaking.
Process of elimination good luck (Jo?)
Charlie
donnybach
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What Bike or Bikes Do You Own?: tenere 1vj
Tenere 700
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Location: Cardiff, UK

Re: 1vj wont start

Post by donnybach »

Throw a load of easy start in the carb intake as described on the tin, and try eleccy start, or kick (try both). If it fires temporarily it's the carb or fuel supply. Then you can delve a bit deeper.
darcynaboo
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What Bike or Bikes Do You Own?: XT600 1VJ and BMW F650gs

Re: 1vj wont start

Post by darcynaboo »

Hi, the carb has been off again and checked, all good and the carb rubbers are new. Valve clearance checked again- all good. Easy start tried - no change. Great spark. Great compression. Starter coil and electrics checked. Going to check the cam timing again and if that is ok and it still wont fire im going to cry 😭.
Scumfrog
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Re: 1vj wont start

Post by Scumfrog »

Possibly choke plunger assembly knackered.
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