Engine Cutting out.

I have an odd one, or maybe not.

I went for a long ride today, and at about 20 miles the boost guage starts getting erratic, and the engine begins to miss. It is almost like it is running out of gas, but the boost guage doesn't make sense.

It get's so bad that I can't maintain speed and have to pull over. It then dies altogether, and wont immediately restart.

I play with it, turn on the primer and flood the carbs. Then hold the throttle wide open and get it started. It is now running nearly perfectly, with just a very slight miss. Prime off, petcock in run position.

I decide to turn around and go home. The bike runs great, boost guage and boost working fine, everything is fine.

However, at about 20 miles it does the exact same thing again, just like before at 20 miles.

The bike turns over, but wont restart.

I then hit the prime again, crank the engine for 3-4 seconds, turn off the prime, wait 10 seconds and it starts right up again, and runs fine the 2 miles home.

It is very odd. The boost comes on as low as 4K rpm, normal is 5K rpm. The boost guage is bouncing all over, and the bike begins to miss. Just a little miss (or starve for fuel), at first, then it gets progressively worse for about a mile, then basically dies.

I suspect a build-up of crud in the wastegate is causing the turbo to add boost prematurely, and it is starving the bike for fuel. But I am wondering if any turbo owners have had a similar issue?

Jim

By the way, this evening it started up and ran fine for the 5 minutes it took to put it in the garage.

 

Sounds like your fuel petcock is clogged up. Take them apart and clean them, look at the plastic fuel screen tube in the petcock they like to clogg with varnish after a while. If you have an external filter ckeck it also. There are sometimes filter screens in the needle and seat assembly , they may be clogged. Sounds like the fuel flow can't keep up with the demand.

 

Wow
In my first reply says I am a biber wanabee, How incorrect, I'v been on XJ/XS bikes for 25 years. How can I change it.

 

I thought about that, and will definitely check it. Maybe crap is getting stuck to the screen, then when I shut down the engine it dislodges from a lack of fuel flow draw, and starts working again.

Makes sense.

I need to figure out how that effects the turbo boost though?

Jim 8)

PS To get rid of the "Biker Wannabe" you need to post more! :lol:

 

could be a vacuum leak. Starts leaking. boost gage goes nuts petcock starts to close without vacuum.

could do the starting fluid trick. but it could damage your bike if done wrong.

Rob

 

Plausable!

What would make the vacuum start leaking after 20 miles, and with the bike fully warmed up, but not when it is cold?

Is the wastegate vacuum operated?

Jim 8)

 

hmmm. I have a similar problem with my Turbo. When I ride for about a half hour, it starts sputtering a little as if it's running out of gas. It's never died on me though. I switch the petcock to reserve and ride for a few miles, then back to run and it's fine. I was thinking that the petcock was probably needing to be replaced, but I'm thinking harder now. None of this is associated with boost on mine though. It seems to kick in around 4.5K though that seems to wander a bit. If you find your problem, please post the solution!

Greg

 

So maybe this is a common problem afterall?

I'll do some research, and some experimenting, and get back to you.

Does anyone know the procedure for cleaning out the wastegate? I thought I saw it somewhere, but can't find it again.

Thanks,

Jim 8)