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2009 G450X Valve clearance check and ajustment

ScottM604

Super Moderator
Before I started to check my valve clearance I read the service manual from bmw and i have to say although it is very clear and well layed out there is a key piece of information missing, the size of the valve shims used on this bike. I looked high and low on the internet and found nothing, so I am going to post all information I gathered during my little adventure into valve system of this rare and interesting bike.

The first thing i found was the service manual tells you to remove the radiator, to do this you have to drain the coolant. Doing this every time you check the valve for me is a pain in the .... so i just removed the bottom mounting bracket and leaned the rad against the forks. You need to remove the front fender to do this.

The next step is getting the engine at TDC on the compression stroke. first i took out the spark plug this makes the combustion chamber vent so there is no compression making the engine easier to turn. Second put the bike in 5th gear and use the rear tire to turn the engine. (this trick came from a friend) the bmw is easy to get to TDC because on the cam shaft gears there are small holes that are witness marks, simply have them facing each other and level with machined top surface of the head. Make sure you put the sparkplug back in or you could drop something into the combuition chamber .

Next lock down the engine at TDC the manual tells you to use their special TDC lock down bolt. The tool is $6.00 at my local dealer Part # 116570, however they did not have any in stock so I made my own. I used a M8x40 bolt and machined down the end to 5.25mm in diameter for the first 5mm of the bolt.It works great. Although some say you dont need it at all, my view point is that for just checking the valve clearance you don't need it but it is nice to have because it puts the engine in the exact same postion every time, and if you need to make adjustments it is a must. You really dont want to end up with the crank shaft turning as you are removing or installing the cams and cam chain. Everything may look fine but the valve timing will be out and this can cause the valves to hit the piston.

Now for the important bit. The exhaust valves use the very common setup of bucket over shim (bucket tappet in the service manual). The shims are 10.00mm in diameter and range in thickness form 2.3mm to 3.00mm in 0.05mm incriments. You can get a universal shim kit or buy indivdual shims from a BMW dealer. The next part is where it gets interesting. In between the cam follower and the valve is the shim. The cam follower is the arm that is depressed by the cam to activate the valve. The shim is a semi sphere, it is best described as an 8mm ball bearing with a flat ground on it. The flat side sits on the valve and sphere mates into the cam follower. They range in thickness form 4.60mm to 5.70mm in 0.05mm incriments. The only place to buy them is from a BMW dealer and you guessed it they only sell them indivdually at about 8.50 each. This being said before you start a valve ajustment call your local dealer and confirm that they have a full set of intake valve shims in stock.

I only had one intake that was out of tolerance and the process of getting at the shim was not too bad. The first thing the manual forgets to tell you is to release the cam chain tentioner before removing the cam bearing cap. Make sure you remove the cam shaft bearing retainer rings before removing the cams as they can fall to the bottom of the cavity that houses the cam chain. When you remove the cam shafts start with the intake. Lift it up and towards the exhaust cam shaft then remove it from the cam chain, now take out the exhust cam shaft. The manual tells you to remove the exhaust buckets with a rubber suction cup Part # 113251, this tool is $70.00 at my local dealer. Like the TDC bolt it was not in stock but i ordered it in and it did not shown up in time so i just used a mechnics magnet to remove them. Be very gentle when pulling them out. If you have good luck the shim will be sitting on the valve, however, if you have bad luck like me they will be stuck to the under side of the bucket with oil. If this happens dont bump the bucket because the shim can fall off into the head. Next the manual says to "flip the cam followers clear" this is a bad idea. The intake shim is very small and mostly round and could go anywhere if you do this. The best way is to just gently lift the cam follower while having a magnet ready to grab the shim as soon as it is free. The installation of the intake shim can be tricky as well. I put a bit of oil on the flat part of the shim and set it on the valve then I pushed and wiggled it around a bit. This makes the shim stick to the valve. I then very quickly set the cam follower back on top to hold it in place.

A word of advise: keep notes of your measurements so if there are any issues in the future it will be easy to find a solution. Note the following: starting valve clearance, size and location of shims, shim changes, and your ending valve clearance.

This ends my painful journey of what I thought was going to be a peaceful day of working on the BMW.


If you have any questions or comments please post a reply or PM me


Scott Miller
aka the tool (that means im useful right!)
 
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AlexBC

New member
Thanks so much for posting! I will be doing mine at the end of the season and this will be very helpful.

How many hours were on your bike when you dove in? You mentioned you only had one intake out of spec, how far off was it? How were the exhausts?
 
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ScottM604

Super Moderator
Thanks so much for posting! I will be doing mine at the end of the season and this will be very helpful.

How many hours were on your bike when you dove in? You mentioned you only had one intake out of spec, how far off was it? How were the exhausts?

The head was rebulit just before I got the bike. So the head had about 50 hours on it.

My one intake valve was at 0.13 mm the spec is 0.05mm-0.12mm
Both exhaust valves where in the middle of the spec i can't remeber what the spec is off hand
 

Jamel

New member
The head was rebulit just before I got the bike. So the head had about 50 hours on it.

My one intake valve was at 0.13 mm the spec is 0.05mm-0.12mm
Both exhaust valves where in the middle of the spec i can't remeber what the spec is off hand
Hey guys i know its been awhile but does any other bike use the intake valve as the bm g450x
 
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