Exhaust[ion]

This is what it should look like…

...a bike capable of crossing continents. Unfortunately at the moment it would struggle to cross the driveway…

After 78,000 miles, mostly in harsh conditions, it needed a complete strip down. These bikes are capable of massive mileage, but as with any metal object, require occasional TOTAL REFURBISHMENT! Rust has begun to set in. The two most effected components being the lower fork-brace (i think that’s what it is called)...

And the battery cage. To start with, I removed them and stripped the rust and paint. The fork-brace was easily re-sprated with Hammerite…

The battery cage is being given an anti-rust treatment before being painted. Removing the battery cage revealed some alarming rust on the Ohlins shock absorber, which cost me £800 only 20,000 miles back…

One of the great things about the R100 GS Paris Dakar is that it was designed to be worked on out in the cuds. The tank and seat clips off in seconds, and the few body panels and crash protectors are cleanly bolted in place. If only removing the exhaust system were so easy. I need to take them off to get at the sides of the lower part of the engine. The down pipes also desperately need replacing, with holes starting to appear in the left hand pipe. The struggle was mighty and prolonged. The down-pipe nuts came off quickly, using the special BMW tool…

This was good news. No serious force can be used to remove them, as this would strip the thread on the engine (expensive). I had expected to be able to simply pull out the down-pipes as a pair, but unfortunately they were seized into place. To progress further I removed the silencer (and attached pannier frame), with the Y-piece still attached. I then tried to seperate the two down-pipes at their crossover. Unfortunately, the left pipe was seized into the crossover. However, it was so rusty that it started to disintegrate. I had no choice but the snap it in half, leaving a rusty shell within the end of the Y-piece, to be dealt with later. Once this was done, I could carefully twist the down-pipes out of their ports.

Here’s the broken down-pipe…

With the pipes off, I could inspect the state of the lower part of the engine. What a mess! It looks as if at least one push-rod seal has blown. This would explain the disappearing engine oil.

After covering up the open exhaust ports and the electrics, I started to apply Gunk engine degreasant. The first application had only a small effect…

I now have to get all of that gunge off, and then start cleaning the black dirt out of the pitted surface of the engine. I will also use Autosol to give a shine to everything. The frame has more rust than expected, so that will need to be treated as well.

And this is only the start! The pushrod seals need to be replaced. I suspect that a new timing chain is also required. This is all only a temporary fix. Next year I plan to get it professionaly refurbished and powder coated.

Robert O'Toole : 22 Nov 2006 20:50 |  Tags: Bmw Gs Motorcycle Travel Travel Travel And Motorcycles Travel Writing Writing |  Comments (1) |  Report a problem