TX650 valve adjust and decompression actuator.

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rustyrescue

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Hi, I have been a bit quiet lately, anyhow I have had issues with the TX dropping out on right cylinder after a bout one mile..starts great, idles great, runs great in garage then take it out and about a mile in it starts popping on right hand one, then drops out except the occasional kick in pants for a split second as it picks up. Lots of pops on over run.
It runs a boyer electronic ignition.
I have gone through bike, and the only issue I found was very tight valves on the offending cylinder so I hope this could be the problem.
My manual seems to have an error on clearance for inlet, says 0.076mm (.033") I think it should be 3 thou on inlet? ans 6 thou exhaust.
Also the decompression lever on the exhaust valve.....how much slack should be in the cable? I have not found that in manual yet.
Thanks
 
Last edited:
maybe a float valve issue. nothing else is dynamic enough to shut you down after a mile
 
I did wonder, but fuel seems to get there. I wondered if the valves being so tight was causing loss of compression when they get proper warm and expand. I have stripped/checked the carbs (Keihin by the way) which are near enough new. I am not sure I have the float level right, perhaps a bit low but they are both the same.
 
yeah tight valves might do that. so could a failing coil or resistor cap or a stray condenser in the electronic iggy. or oil fouling...
 
rustyrescue said:
Also the decompression lever on the exhaust valve.....how much slack should be in the cable? I have not found that in manual yet.
Click to expand...

My XS2 has the same compression release as your TX. When I first built my bike , the belief was that the early bikes starter wasn’t as strong as the later models, so the factory added the compression release to help it out.
What we ( @Jim ) realized was that the starter is the same across all models, it was never changed. The starter really doesn’t need the assist. I have it all in place on my bike and it still is started with the little finger lever, but I have the cable backed off and it doesn’t actuate the compression release at all. The engine turns over smartly without it and fires right off.
 
OK, so it has been out and it still drops out on the right cylinder after a mile or two. So it is not the valves as they are now set spot on.
I doubt the electronic ignition is cause, because when I got home it sat in drive on one cylinder, pulled HT cap off and no change in engine but get a spark earthing from plug cap to ground.
Replaced it and pulled left cap and engine stopped.
It is a wasted spark system so I will switch HT leads/coil connections so if it is ignition linked it should move to left cylinder.
I dont believe its fouling a clean or new plug in under 2 miles.
I am beginning to wonder if it is carb related.
 
Funny you should say that, I just pulled them before seeing your comment and even took piccies! Left one looks ok..brown on core after only about 3 miles, sooty around edge but not much of a run. The right one, sooty/black. Better than before I did valves when it looked almost unused!
 
I know the carbs are spotless inside....near new too. I removed and looked in when I bought bike. I may switch carbs over! after the switch coil output over test!
 
This may sound pedantic ;) but open float bowl drains run some fuel through into a catch pan, what do you see? :geek:
 
I will do as you say and let you know...........thanks for your help and interest, I can usually sort these things out pretty good but this one is causing some thinking.
 
I had a misfire once that I traced down, to of all things, a loose negative battery cable. Unfortunately, I didn't discover it until after I pulled and cleaned the carbs, lol.
 
OK, no you are not being pedantic at all. So first I drained each carb and got a similar small quantity of petrol out of each one. Then I opened the fuel tap on each one and indeed the problem side barely trickles and the good side runs well.
So it does seem like needle valve or fuel tap/tank restriction.
I am a little confused why the problem side spark plug is black/sooty when it is evidently lean/no fuel tho! Thank you again.....this is why we all share experiences on forums. I would get there in the end but it is more fun and quicker to share ideas:)
DSCN1913[1].JPG
DSCN1912[1].JPG
 
Yesterday: Went to start the Radian for the first time this year. On prime, choke on, crank crank, crank, grr crank crank, GRR! Pull plug add carb cleaner to cylinder check spark SOLID, crank crank crank, ARRGG! Go get catch pan going to start opening float drains get some fresh gas in and THAT's when I noticed I had added an "extra in line" fuel shut off last year, OOPS, Brm, brm and purring like a kitten. Getting gear on to take it out and THEN Allison shows up with helmet and off she goes. Sheesh!
98173641_10218230910507714_3763016612634951680_o.jpg
 

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