Strange Problem...

[Loggy]

I've been having an intermittent problem with my bike that has only just started within the last month after 8,000 miles of trouble free running. To save time I've copied the posts I've made on XRV on here to get a wider knowledge base to see if anyone can come up with any suggestions.

28-08-13

Had a strange problem with the bike earlier this evening...

Went down to the garage a mile away and got some bits. Then rode the bike for about another few miles. Overtook a car and was doing about 60 when all of a sudden it lost power and sounded really rough. It didn't want to rev. Whacking the throttle wide open when it was running rough (one cylinder) it would occasionally kick in to normal running mode for like a quarter of a second and then back to rough again. Pulled up and it sounded like it was running on one cylinder. Limped back home and turned it off. Turned it over and it didn't start on the first attempt. Turned it over again and it fired straight away and ran fine.

I left it for a few hours and started it up again, it fired up straight away. I took it out for about a 25 mile run and occasionally ragged it and it was running sweet as a nut.

I thought it may have been fuel, but the tank was only 40 miles from full. It's got a facet pump fitted. Lights were bright when it was running rough. If it was valves or timing then it would be like it all the time, but it's now running sweet.

I'm guessing as it was running (pretty sure) on one cylinder and now the problem has gone away that I'm looking at something electrical. I'm leaning towards a coil pack that has started to break down. Has anyone else experienced this on their bike? Could a faulty pump cause it to run on one cylinder? I checked the starter relay a month ago and everything in that area is fine. Just really odd that everything is now fine again. The run of 25 miles tonight got the bike really warmed up and it ran fine, so not one of those problems that only seems to happen when hot. I'm really stumped...

Any suggestions from you guys would be appreciated...

Thanks



Then it happened again on, Friday 13th!!!

Okay, Friday the 13th has truely been a nightmare!!!

Took the bike into work this morning, running fine, and has been since the last time it played up. Fired it up to go home at 12:30 and she started fine. It ran for 10 mins and just as I was on the main road outside work the problem I had before came back with a vengeance.

She started to loose power as if the fuel tap was turned off and went on to one cylinder. I managed to get the bike to a cut out in the road where it died completely. After a few minutes I tried it again and she fired up but still on one cylinder. She ran rough as a dog for another 3-400yds and cut out again. I limped to a motorbike shop next to to work and had a chat with the mechanic and explained the situation. He got a temperature probe out and have now found out that it's the rear cylinder that stops working.

He then took the N/S plug cap off the rear cylinder and put in a new spark plug. The plug was sparking so it looks like it's not coil packs, HT leads or plugs as the engine should run fine on one plug.

I called work and they said if I could limp back to work then they would let me use a van to take the bike back home in. So after several short rides of 20mph and the bike cutting out every time I eventually got back to where I work and loaded up the bike in the back of a transit with the help of 3 other guys.

I got home and decided to try the bike again. This time she fired right up and no hint of the problem. Originally I thought it may have been crap in one of the carbs, but as the engine cuts out after a few minutes of running on one cylinder I'm starting to wonder if it's a fuel pump problem. The fuel pump fitted it a facet, but it does look pretty old.

Now as we checked the spark and that was okay and the fact the bike starts okay after a few minutes after cutting out I'm starting to rule out a blocked jet or carb as it would do this constantly. If it was coil packs then I wouldn't have had a spark, so either lifting the bike at such an angle dislodged the crap in the carb and it ran fine again, OR it's the fuel pump. The fact it runs after a few minutes albeit on one cylinder leads me to think this is a fuel pump problem judging by how long it takes for the carbs to re fill by gravity after being emptied of fuel and the symptoms of running out of fuel.

I will call Rugged Roads tomorrow. If they are in and have one in stock then I will chance a ride down in the morning and pick up a new Facet fuel pump and fit that on my return. At least it will rule out the pump. I will keep everyone posted.


I'm leaning towards a fuel problem as it's the same type of symptom you get if you forget the fuel tap is turned off and it runs out of fuel except it drops down to one cylinder. Could it be a fuel cut off relay shutting down power to the fuel pump? Could it be a bad connection?

To make matters worse, I've since been out on it this weekend and it's running sweet as a nut again.

Any suggestions greatly accepted.

Cheers,

Loggy.

[Mike54]

Spark plug cap

[Redmurty]

Crap in a fuel filter, had very similar on a old beemer I used to ride, would run fine then run onto one cylinder then run fine again. Lump of crap in a filter.

Could be worth checking

cheers Spud

[Redmurty]

Spark plug cap

yeah a good one to check as well

cheers Spud

[xtzrick]

Also check the power, signal & earth connections for your coils.
Sounds electrical to me.

Rick

[-Ralph-]

I'm having very similar problems with my XT600, only that's a single cylinder bike so the whole thing dies. Very, very difficult to diagnose something like that when it's intermittent.

It could just be damp electrics. Is it doing this only since the change in the weather? Was it raining at the time when it happens? Done any river crossings lately? Does the Transalp have a spark plug chamber drain hole in the side of the cylinder? Is that clear? Try giving your spark plug chamber, HT leads and coils a good soaking in WD40.

You said it did it first time on an overtake, then second time when you hit the main road outside work. Is it only doing this when you ask for power? That could point to a problem with the fuel supply so the carb bowls are draining empty when you open the throttle. Or it could just be a semi-blocked carb jet. Pull the petrol hose off the rear carb, stick it in a jerry can, and check you have a good consistant fuel flow. Then try stripping and cleaning the carb.

Is the fuel bowl float level correct? You can check that by putting a piece of clear pipe (I use fish tank air line) on instead of the drain hose, tie wrap it pointing upwards to the side of your fuel bowl, then with the bike on the centre stand open the drain screw. The clear plastic pipe will fill with fuel up to the same level as the fuel in the bowl, you can measure that level against the outside of the fuel bowl.

Don't bother answering any of my questions about rain, etc, it'll take you ages of writing posts that I don't really need to know the answers, but tell us as much as you can if there are any conditions under which the problem repeats itself.

[-Ralph-]

Pull the petrol hose off the rear carb, stick it in a jerry can, and check you have a good consistant fuel flow.

If not check fuel pump, fuel filter, hoses and the air admittance at the fuel cap (if you open the fuel cap and the flow improves, that's what it is, a vacuum in the tank).

Although you might expect all of these to affect both cylinders, not necessarily, because liquid will always flow on the easiest path, so if there's a fuel supply problem and the front cylinder is first on the supply feed, it will steal all the available fuel.

[Loggy]

The bike has two spark plugs per cylinder, so I would have thought if one was breaking down the other would take up the slack.

It's weird that it happens when the bike has been sat for a while, is cold, and has only been running for a few minutes. It's as if the fuel pump isn't running and it's using the fuel in the carbs before cutting out. But a phone call to Johnathan at Rugged Roads put a spanner in the works. He said that the Facet fuel pump, if it fails, stays in the open position. The first time it cut out I had only done 40 miles from a brimmed tank, so if the pump had failed, the bike should have run as normal as it can run by Gravity feed until down to about 3/4's of a tank.

The crap in the filter is a possibility. I've bought a new inline fuel filter. I need to take the tank off and check everything but haven't had chance this weekend as the weather has been terrible. I've also bought a set of new Iridium plugs I need to fit. I was also thinking of getting a new fuel pump (only £40) and fuel cut off relay (not so good at £60+)

Trouble is, while this problem is intermittent then I could end up replacing loads of bits, spending a fortune in the process trying to cure a problem that isn't evident at the time in the hope that I've cured it and just waiting to see if happens again.

Cheers guys.

[-Ralph-]

Trouble is, while this problem is intermittent then I could end up replacing loads of bits, spending a fortune in the process trying to cure a problem that isn't evident at the time in the hope that I've cured it and just waiting to see if happens again.

Welcome to my world

Before you start replacing expensive electrical bits such as coils, CDI/TCI units, etc, then see if there's someone over on the XRV forum that can help you out by lending you a working part from their bike/garage.

[-Ralph-]

PS, also worth doing a compression test on that rear cylinder and checking your valve clearances.

Also check your intake rubbers for splits that could be breathing air.