1978 GS 450 question

[racerxnico]

Hello,
A friend/ acquintance recently bought a '78 GS 450 which I finally had a chance to check out last weekend. I was mostly giving it a once over for her and noticed a variety of things wrong with the bike (not a big surprise considering that she got it for $400).

The biggest concern I have is with her front end. The forks are pitted and feel like they probably don't have any fluid in them. I'm going to put a post in the parts wanted section too, but I wanted to ask if anyone knows what other forks will fit. There is a pair from a newer 450 on ebay with the right price, but I'm not sure if they changed the front end geometry or fork diameter at any point over the life of the bike.

Unfortunately I didn't bring my micrometer over and didn't get the measurement either.

If anyone knows off hand that would be great.

thanks

[Nessism]

You might want to try polishing the stantion tubes to see if you can remove the rust without replacing the forks.

Regarding the bike and forks, the 450 wasn't available until 1980 so keep this in mind when looking for parts.

[8trackmind]

33mm...........

[BentRod]

you have a micrometer eh? would this be because you are a machinest/have access to a lathe? and how deep is the pitting? if its not too deep, you may be able to machine it out and refinish it. of course, you will need to retro fit the male end of the shock as well.

Not that this is really recommended (new parts alwasy good), but I'm cheep, kinda nuts, and know people, so if that option is possible, you may want to look into it.

[bgmart450]

78... You SURE that is correct? 1980 was the first year of the 450. Also I'd stay with the model type (E/S, L, T) to insure you get the right forks. You can check Bikebandit for exact fitment, or maybe hit up a bike boneyard with the fork you want replaced. A good one will help ya find what you need.

[racerxnico]

no '78? Huh, I was just going off what she told me. The bike itself doesn't have any badges on it and I didn't look for the sticker on the headstock.

'78 seems like it should be the correct year (or at least close). It has a rear drum brake. The seat hinges on the left side and there is a little plastic tool tray that hinges toward the back of the bike to access the battery. The gas tank looks like it had some sort of decorative plate around the gas cap. This is missing now and the gas cap has been replaced with a different one. This leaves a spring exposed between the front of the gas tank and the headstock. Maybe it's a 550?

Can anyone identify from these clues? I'm going to try and get over to her house next weekend to have another look.

As to the forks, I am not a machinist (I wish I had access to those tools and the skills to use them though). I'm probably miss-using the word micrometer. It is just the inexpensive tool for measuring inside or outside diameters with the thumb wheel for adjustment. The surface rust has been cleaned off, but the pitting is bad enough that I think the only thing that could save them would be rechroming. I am hoping that I can find a better replacement for less than that would cost.

[bgmart450]

If its a twin it won't be a 550 (all 4's I am pretty sure). I am pretty sure all the 450's had drum rears as well. Should have the displacement stamped on the engine, think mine is in the very front of the engine. Also I am pretty sure they use the engine size in the VIN (at least both of mine do).

[racerxnico]

right.

I haven't had a chance to go check the bike again, but I've gotten enought information that I'm pretty confident that it is a '78 GS400 (my mistake with the extra 50cc's).

Can anyone confirm the 33mm fork diameter on this bike?

thanks