85 X won't run for more than a few miles

This has me perplexed. I took it out a few weeks ago, and it sputtered and quit on me after about 3 miles. I assumed this was the dreaded coil issue, so I spent the day today upgrading to the Dyna Coils and rebuilding the leaky petcock. To my delight, it fired right up after the new coil install. I let it idle for about 20 minutes while I went inside and got my riding gear on.

It's exhibiting the same behavior as before the new coils. In fact, it broke down at exactly the same place. Maybe it just likes that gas station. It takes off just fine and pulls strong, but after a mile or so, it starts to get lower and lower on power until it just won't run anymore and sputters out. Just had the carbs rebuilt, petcock is rebuilt, I know spark is good... what else could it be? Any ideas from anyone?

 

Check the vent in the gas cap. Try riding with the cap open a bit.

Kenneth

 

Hey Kenneth,

Thanks. That's a good idea. I hadn't thought of that. I'll try it tomorrow and see if it's nice enough to get me home.

 

When it dies are you checking that it still has spark? Ignition parts can fail when they get to operating temperature.

 

Mlew,

No, I hadn't checked since it was up to operating temp as it sat and idled before I left. I thought that was good enough. If I can get it to run long enough to get home tomorrow, I'll try tooling around a little in the driveway to see if I can get it to die on me again.

 

Also make sure you have good flow out of the petcock and through the inline filter. Try it in prime, and then "on" but you will need to put some vacuum on the petcock to open it....or you just disconnect the fuel line and start the bike up. It will idle for a while on the gas in the carbs and will show you how much fuel is getting to the carbs.

Sounds like it is starving for gas once you put some load on it.

 

Hopefully it will run long enough to get home. When it dies next be prepared to see if it still has spark and fuel. Cary a spare plug ,screwdriver and hose. A volt meter or test light to see if you have lost power to the TCI. When the moment comes hook up the spare plug and try to start. If you have spark great, then hook up a hose to a carb and open a drain to see if there is fuel.
Its just a process of elimination.

 

How many miles on the bike, and has it ever had the valve clearances even checked? Although the interval is greater on an "X" they still need to be attended to. A bike with a bunch of tight valves will behave the same way.

 

Just over 13k on the bike. I've never checked the valves. It started right up and ran like a champ on the way home. It started raining so I'll have to try everyone's suggestions out tomorrow.

 

Ouch. Although the service interval is greater, I suspect the requirement for an initial check on the valve clearances was something quite a bit less than 13K miles. Don't put it off.

 

I bought it with I think 8k on it. It had been meticulously cared for. I will check this weekend and let everyone know what I find.

 

If the Bike "Cranks-over" after that few miles it goes before quitting, ... odds are its a FUEL Delivery related situation.

Check the FUEL Level in the Tank.
Try to run the Bike on PRIME.

Bring along a Spare Spark Plug.
When the Bike Quits, ...
Unplug the No.-4 Plug and Plug-on the Spare.
See if you have Spark.

Rule-out the OBVIOUS.
Get some fresh gas.
Charge the Battery.
Pull the Plugs and see what the Plugs tell you about how the Bike is running.

 

i agree with above... if my bike doesnt run for a few days... i will get like 2 miles down the road, and die with no warning.... i usually pull the filter off one end, and set it on prime.... and she will take off.... i sometimes switch the petcock at my infamous die point and it will fix itself before it fails.... so in my not so smart opinion, id agree with either cap vent, filter, or petcock.

 

It does turn over after it quits. I had just put a fresh gallon or so in the tank. I was already running on PRIME to eliminate the possibility of low fuel. I did pull the boot off plug #4 and could hear it arcing. (Those new Dyna coils are strong!)

Filter is new. Plugs are new. Battery was just charged. I just rebuilt the petcock thinking it or lack of spark was causing this behavior before. I guess I'll try having a friend follow me in a car in case it quits on me, but taking it for a ride with the gas cap open to see if that solves the problem.

If it is the gas cap, how hard is it to rebuild? Will it be pretty obvious once I take it apart?

 

I never have done one... doesn't look too hard though.. unless you get a new one. I replaced petcock and all that stuff too... I was thinking it may be a vac issue... because once I pull the filter and put it back on... she works... but prime eliminates vac so I don't know. When she dies... and your cranking... check filter to make sure fuels comming in and leaving filter. Obvious when they r dry and obvious when its flowing. That would eliminate a few things. Also.. if carbs are clean... were they synced? I cleaned my carbs and a float fell out.. easy to skip torque and run into probles. All it takes is 1 bad apple

 

If you are running a Inline Filter ... CHECK it!

A Full Inline Filter is a Warning that the Filter might be BAD.

Remove the Filter.
Determine the direction of flow.
Blow through it.

L@@K at the various imprints on it.
Made in China = Bad.

 

Rick.. sorry to jack the thread but check out my keep on knocking but you can't come in. Need ur help

 

Partial Success! Owed too much to the "It's too obvious, so that can't be it" department. The fuel line was about an inch and a half too long, resulting in a little loop when you put the tank down. Fuel was getting stuck in there and I guess the vacuum wasn't enough to get it through the loop and into the engine when it started to die.

That said, it still tries to die after a few miles. It will just sit at about 1500 rpms no matter how much throttle I give it. It does this for about 20 seconds, and then *poof* it starts working again. It stumbles a bit above 4k when under load, but otherwise runs normally.

I'm ecstatic that I was able to get it to go past the dreaded gas station and then some. I filled up with gas and drove for another 5 miles or so but it looks like rain and the bike is still not running quite right, so not wanting to push my luck, I came home.

 

Oh, and Rick, I checked the filter. It's fine.

 

I had a similar problem. It turned out the way my fuel line was routed with it's filter created and air bubble in the filter and blocked the line. Exact same behavior.

 

Ok, I'll try rerouting the whole line tomorrow and see what I get. Thanks!

 

Success, finally! Yesterday I rerouted the fuel line and changed from a 90 degree filter to a straight one, and it's now running like a champ! I put 100 miles on it yesterday and I'm happy to have it fixed with a few weeks of good riding weather left!

Thanks a million for the suggestions. This was a weird problem and I wouldn't have gotten through it without the help!