The old 4 pot has always had an issue when taking off using all of it's 1800 muscle and what happens is that it goes and holds, goes and holds until about 4000 rpm then it's all gravy. I bought it like this, sold it like this and then bought it back still like this and now it's on 150,000 miles.
It's a pretty unmolested engine which has done town rides most of it's life but now it's getting it's legs stretched so I want to sort it out. One thing I've been looking into is the adjuster unit or DISA valve as it's more commonly known. These are quite prone to failure at 80-100,000 miles, even self destruction and ingestion causing horrific internal engine damage. So at the current mileage, I thought I'd look at replacing it!
Usually these take on a rattly type noise which gives their expiry away but mine makes no noise. Could it be the cause of the wobbly acceleration issues? I have found that if I hold the revs whilst moving at 3-4000 rpm it is at it's worst and this appears to be the magical range that the DISA operates.
The part is a touch over £200 from BMW so would it be worth removing it and having a butchers at it's condition or just outright replacing it? I'm warming to the latter just because of what it can do when it all goes wrong!
Here's a technological picture:
It's a pretty unmolested engine which has done town rides most of it's life but now it's getting it's legs stretched so I want to sort it out. One thing I've been looking into is the adjuster unit or DISA valve as it's more commonly known. These are quite prone to failure at 80-100,000 miles, even self destruction and ingestion causing horrific internal engine damage. So at the current mileage, I thought I'd look at replacing it!
Usually these take on a rattly type noise which gives their expiry away but mine makes no noise. Could it be the cause of the wobbly acceleration issues? I have found that if I hold the revs whilst moving at 3-4000 rpm it is at it's worst and this appears to be the magical range that the DISA operates.
The part is a touch over £200 from BMW so would it be worth removing it and having a butchers at it's condition or just outright replacing it? I'm warming to the latter just because of what it can do when it all goes wrong!
Here's a technological picture:
