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Feb. 8th, 2011

Just before we bought the house I'd noticed that the Rockster was making a lot more noise on the right side than it should. gordonmessmer and I popped the right valve cover to do a quick adjustment and found that the right intake valve was out of spec. Way out of spec. In the 2000 miles since the last service the valve gap had widened by something like 0.5mm. I tightened it up for the time being and only rode it once more to get it to the new house.

Last weekend I finally got the time to open up the engine and take a look. After two trips to Sears for more tools as well as a good deal of swearing I finally got my answer. The intake pushrod was short, by 0.57mm compared to the exhaust. Now you'd think that this would have been the result of a deteriorating pushrod end, or some other calamity. No actually. All I need to do is replace the pushrod. But "How" I hear you saying "does a pushrod get shorter without the ends wearing?" Here's how:



The one on the left is the original exhaust pushrod. The one on the right is the replacement I bought. They are both the same part number. Do you think that perhaps BMW figured out that the old one wasn't cutting it? Anyway, they are damn near the same weight. The old one weighs in at 11.18g while the new one is 11.90g. Seems worth the extra .72g to not dissolve into the engine oil. Anyway, I've ordered 3 more as I might as well do all 4 at once and save myself the trouble in the future. Not worth opening it all up again.

Comments

( 5 comments — Leave a comment )
torpidai
Feb. 10th, 2011 09:15 am (UTC)

The intake pushrod was short, by 0.57mm compared to the exhaust.

I'd have questioned if they were meant to be identical lengths myself.
matthew
Feb. 14th, 2011 05:46 am (UTC)
Based on what I know of these types of engines, the pushrods are generally the same length. When I checked the parts diagrams I found that they are the same part number, so they should be identical.
atypia
Feb. 14th, 2011 03:21 am (UTC)
The new version looks like piercing jewellery.

INitially this entry read like you were talking about the house making noises. I was confused :P
matthew
Feb. 14th, 2011 05:47 am (UTC)
I thought the same thing! "That looks like one wicked piece of piercing jewelry"

Huh, I did say that the house was making noise... I'l uh, go fix that :P
cooncat
Feb. 15th, 2011 01:42 am (UTC)
Interesting.
They really have the same part number? It's more common for changes this extreme to have slightly different part numbers or at least revision numbers, the newer superceding the older. That the pushrods were the same part number seems very un-German to me...unless the old part number has changed and the supercession is obscured from the general public, which would sound like Der Korporation indeed.

Then again, my BMW just came back from the shop with an updated warranty repair for a failed warranty repair from two years ago, and I believe the campaign numbers on the two invoices are the same.
( 5 comments — Leave a comment )