MrKaizer

The OEM ones are, the aftermarket ones seem to be the same length for in and ex. Do you mean they swapped them on accident or on purpose? If the latter, did they state a reason? Did you notice any difference?

I just wasn't sure how important the lenght of the guide is. As in, how far it protrudes into the airstream. Because this probably has some impact on how much it can cool the valve. But if they are doing it for racing it can't be that bad. And yeah, the "racing spec" is a bit of a problem, having to ream/hone the guides. I'd be happy with using OEM stuff, but like I said, that seems hard to find in my neck of the woods. I'll just have to see how far I'll get. I didn't realize the GS and Z motors were that similar.

Hi folks, I noticed that some online shops / manufacturers use the same part number for valve guides for GS1000 and Z900 (for example APE VK900). Additionally, in said APE kit, all the guides look the same (no difference between intake and exhaust). This leads me to assume two things: I can use Z1/900/1000 valve guides (OEM or aftermarket) in my GS1000. I can use OEM intake guides on the exhaust side, even though they have a slightly different shape. Is this correct? My reason for asking: Exhaust valve guides seem to be hard to get in Germany. But I still have two for the intake side and there is a shop that sells guides for the Z1.

I didn't write this clearly, sorry. I'll definitely do the valve clearances before I ride any more! But I'm hoping I won't have to do a full head rebuild, valve seats and all, yet.

This is a really good idea, I'll try that. I did a compression check before checking the valves. The result was 9 - 10 - 9 - 9,75. I will do the head eventually but was hoping to be able to ride a few more kilometers before I have to take the lid off.

I've had my sidecar GS1000G for a few hundred kilometers and finally got around to checking the valve clearances. I couldn't even get the 0.03 mm feeler gauge between 6 of the 8 shims/cams I was able to get some of the valves to within spec with shims I salvaged from a donor motor. But the math suggests that there was no clearance at all! For example, I went from a 2.50 to a 2.40 shim and got a clearance of 0.05. So there was 0.05 mm "non clearance" before? Am I measuring wrong? I'm using the guide from BikeCliff's website. I'm wondering because I could not imagine an engine running like that...

Your measurements were spot on, thanks again! I was able to print some more prototypes and they fit inside the airbox and over all four carbs very well. I made the CAD files parametric, so it should be possible to make carb boots for the GS850, too. They seem to be hard to get as well. But I still have to make some adjustments to make them more "printable", 'cause it all went really sideways when I tried to print them in some other flexible material. I was goin to post the current version here for now but the forum software doesn't seem allow .stl files. So I'll probably upload the files to thingiverse or printables once I'm happy with them. Btw, is there a "proper" technical term for carb boots, so people can find them?

gs7_11, thanks a lot! But now I have to ask: Which one is which? I'm assuming the one with the bigger distance is for the GS1000G, right? Could you please also put a ruler directly to one of the holes, for the inner diameter? I assumed the same. Thanks for the heads up.

Hello everybody, I recently bought a GS100G with sidecar. She runs but there are a lot of things that need addressing. One of them is the rubber tubes (boots?) between the carburetors and the airbox. They have shrunk massively and are rockhard. After weeks of searching I was lucky and cmsnl had one in stock, but it feels like this was the last one on the planet. That's why I'm trying to make them myself. I used the new one to make a CAD model and the prototype looks promising (sorry about the off-brand color, it's the stuff I had available ). But now I need some exact measurements from the airbox that I can't get because the rubbers on mine are glued in and I would like to keep the bike in running condition until I have a full set of rubbers. It'd be really cool if someone who has a GS1000G airbox kicking around could measure the following things: Material thickness of the airbox Diameter of the holes for the rubber boots Distance of all the holes to each other If anyone is interested I can publish the CAD-files once they are done so other people can print them as well.