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1987 XR600R Starts good cold, not so good hot...

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Hello everybody. My 1987 XR600R is having a slight issue with not wanting to start once it has run a while. It also doesn't really like to idle once it is hot. I make sure it has enough oil in it every time I ride it. I really love this bike even though I haven't had it a while so I would really like to get it to run well for me. I know these twin carbs have an adjustment for the opening of them but I don't know how to mess with that to try to fix it. Any information would be helpful. 

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Woah wait that makes sense... it doesnt want to start with the choke on, does that mean the choke is ALWAYS on right now? Damn i feel dumb now... so how do i reverse it then? ive had the carbs off and i bought a jet and gasket kit for them and installed the new jets. 

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I've had a couple of those bikes in the past, and had similar issues when they warmed up/got hot. The stator was failing. You might need a new or rebuilt stator

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so i looked on some other forums, one harley forum about a bike not wanting to run when hot blamed a ground wire on the issue. now thinking back, right before the bike died, like literally less than 5 seconds before it stopped running, i went through a large water puddle which may have gotten water splashed up under the seat where my ground wire is. could that be my issue?

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Cleaning won't do anything for it. There's nothing to clean anyway , it's bathed in oil.

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A tight intake valve will make starting a nightmare, especially when hot.  A too-high float level can also cause starting problems when the engine is hot as it will richen the A/F ratio.

I LOVE those old twin-carb XR600s...  They were BEASTS!

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Fuel, air, spark

Fuel and air- too rich and it'll be hard to start hot.

Cracking throttle might help a little.

Weak stator when hot or pulse generator resistance going up when hot are 2 other usual suspects to go along with what's been stated.

Make sure choke plate has been updated!

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Fuel, air, spark

Fuel and air- too rich and it'll be hard to start hot.

Cracking throttle might help a little.

Weak stator when hot or pulse generator resistance going up when hot are 2 other usual suspects to go along with what's been stated.

Make sure choke plate has been updated!

87 twin carb = no choke plate. Fuel enrichment circuit type choke.

 

The rest of this post is spot on.

 

 

 

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16 hours ago, VortecCPI said:

A tight intake valve will make starting a nightmare, especially when hot.  A too-high float level can also cause starting problems when the engine is hot as it will richen the A/F ratio.

I LOVE those old twin-carb XR600s...  They were BEASTS!

I had the same year as well as some others.  I have an xl600 that was one of the first batches.  My neighbor sold it to me for a great price.   Floats were high,  wouldn't start hot.  4300 miles.  I had seen it on lots of others.   set the floats set the valves.   I am assuming you have adjusted the fuel screw?   a 15 dollar multimeter will tell you lots about your coil and stator.   

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A good diagnostic I forgot is to shut the fuel off about 10-20 seconds before you shut the bike off. Drains the bowls down a bit.

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