BMW Luxury Touring Community banner

1 - 6 of 6 Posts

·
Registered
Joined
·
90 Posts
Discussion Starter #1
My 2001 K1200LT (39k miles) developed an intermittent fuel leak over the past couple of months. Very strange to me is that some days I smelled raw fuel, most days none at all. Nothing visible to trace it too. If it happened at all, it would start upon initial takeoff and usually tapered off during first few miles. Weird! Never considered it to be life theatening - but not good. Only consistent pattern was that it seemed to occur in the morning after I skipped a day of riding (a rare occurrence).

Yesterday morning it happened again, only this time when I arrived at work there was obvious dirty oil/fuel splashes all along the lower left fairing, across the shift linkage, and up on the left hardcase... and big UH OH... down onto the exhaust pipes - this is way not good - "Houston we have a [potentially serious] problem!"

Since I knew from experience that it only happens it when cold, I road it home from work that afternoon without any incident - though I kept a close eye on my lower left side for the flamer effect.

"Stupid is as stupid does."

Took her all apart last night and discovered a huge mess of fuel(?) up on throttle bodies of cylinders 1 and 4. Throttle body of cylinder 4 was a real mess, still covered in something wet and shiny. In looking back, I did recall a bit of a mess on throttle body #1 during the 36k, but had no idea what that was all about.

Took a time out to come read the current and archived message boards for wisdom - didn't find anybody having trouble with injector O-rings. Poor searching skills? I don't think I'm that unique. I then went back to the garage and removed the fuel rail and all the injectors and looked them over real closely - no visible signs of damage, cracks, etc.

Put a light coating of heavy grease on the O-rings of all injectors, cleaned on port in manifold and reinserted injectors and fuel rail. Hooked her all up for a test - no leaks. Stressed the rail manually while exercising the throttle - still no leaks. Good enough to avoid riding the cage to work the following morning. :)

No trouble at all this morning. Road her to work naked...not me silly, the bike.

Picked up a set of new injectors O-rings at the dealer today for about $30 bucks and will install them soon.

My theory: I suspect that in my zealous desire to clean the injectors after replacing the throttle cables [during a recent 36k service] that I neglected to lubricate the injector O-rings and they were drying out and shrinking when left idle for a couple of days.

Questions:
1. Has this happened to you?
2. Am I fooling myself into believing it is the O-rings when I should be suspecting something else?
 

·
Registered
Joined
·
90 Posts
Discussion Starter #2
O-Ring Follow-up

Replaced all 8 O-Rings on the injectors over the weekend. I just took my time and was patient through the process. Using small dental-like tools helped me maneuver the O-Rings off and on. Took a little time, but not too tough.

While I had the bike open I decided to check and balance the throttle bodies. Sure enough they were out of balance, with cylinder #2 considerably lower on the vacuum scale. Just getting at the adjustment screws was a job for small fingers, small tools and a little patience. I used a Carbtune which I had from years ago - it sticks from time to time, but worked well enough for me to finish the job.

She runs more like a sewing machine than previously - a definite improvement. I notice in retrospect that the engine used to stumble a bit around idle. The stumble now appears to be gone.

That is all for now. Take care y'all.
 

·
Registered
Joined
·
699 Posts
Can someone give a quick explanation on how to balance the throttle bodies? I've done many tuning jobs on old British cars with a Unisyn or even three feet of garden hose. I suspect the principle is the same, balance the air flow, but how do you do it on the LT and what tools do you use to measure the flow.


Also, I've heard mention of balancing the injectors on a flow bench. Here I'd guess you are trying to align the fuel flow rates through each injector to be equal. Anyone have a better description on this. And, are these two procedures worth the effort for normal everyday riding?
 

·
Registered
Joined
·
607 Posts
McAllister said:
Also, I've heard mention of balancing the injectors on a flow bench. Here I'd guess you are trying to align the fuel flow rates through each injector to be equal. Anyone have a better description on this. And, are these two procedures worth the effort for normal everyday riding?
Fuel injectors are pretty much set at the factory for flow rate. I wouldn't attempt to tamper with that at all.
 

·
Registered
Joined
·
13,451 Posts
But the throttle bodies can be adjusted.

Be sure the bike is up to operating temp, put a four hole vacuum mate on the nipples on the fuel rail (after removing hoses), loosen locknuts and balance.

Here's a write up from one of our overseas friends:

First you have to remove the Tupperware on the left, right, radio and the lower spoilers.

When you then remove the cover of the right fan ( and connect the connector of the fan back again ) and lift the tank, the throttle bodies are accessible.

You remove the vacuumlines and connect the Vacuummate (that’s the one I used).

The fourth cylinder is the reference cylinder. Now you start the engine and let it warm up.

Now you can register the amount of vacuum of each cylinder, and you can adjust.

I’ve synchronised a few LT’s this way with great results. The engine runs a lot smoother and there are significant less vibrations around 4.800 RPM.

Now, what do I adjust. When you look at the first three throttle bodies you can see a screw that’s being locked with a nut. The screw and nut are sealed with blue Loctite. Frist you remove the seal by releasing the nut on cylinder 1 – 2 – 3. Then you can adjust the amount of vacuum per cylinder by screwing the screws in our out, with a running engine. Once these are at the correct setting, you lock the screws again with the nut and some loctite. You will find out that those nuts are quite difficult to reach.

When this is done, you check the settings again, so that you are sure that they haven’t changed while you locked the nut.



100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3
 
1 - 6 of 6 Posts
Top