Newbie with a 1981 GS400S

[400s]

Greetings,

This is my first post in this forum but I have learned more about motorcycle maintenance from reading threads here the last few days than I ever thought I would and I could need some advice.

I recently purchased a 1981 GS400S in Vancouver. From what I understand the 'S' model was never sold in the US so there is little information on this specific model online, other than in japanese, where rosetta stone has only gotten me so far... I bought the bike from someone who didn't know what 'res' stood for on the petcock and so naturally no manual or help came along with it. Nor did any maintenance history, but from the looks of it I don't even know if it has a maintenance history. I have downloaded some manuals from other models the same year but do not have one for my model. Does anyone out there know of any ways the 'S' model is different from other 80-81 models? Does anyone with an 'S' model want to educate me on things I should look out for?

Other than a stint with a 50cc dirtbike when I was 16 I do not have any experience with motorcycles and playing with carburetors and valves intimidate me slightly. Luckily I like getting my hands dirty and am endlessly patient so I think with some practice this learning experience of owning a motorcycle curves right up my alley.

Initial concerns:

The airfilter was completely disintegrated, I replaced it and replaced the sparkplugs because as a result the bike had been running rich for who knows how long. Does this warrant an investigation into other parts of the bike?

When the engine warms up it tends to stay around 3000 in idle for a while then slowly fall until the engine dies. I think this is a result of an airleak which would make sense because the airbox boots are looking warped and the o-rings are trying to escape. With this situation (even after replacing the airfilter), I am considering just replacing the whole airbox with k&n pods. Is this a good idea? I know performance will increase a bit but does it have other effects? If I were to do this I assume I will need to re-jet. Can someone tell me exactly what pods and what new jets I would need? (I just recently learned what pods and jets are)

The tires are cracked and I'm going to have them replaced. This and the condition of the airbox o-rings makes me concerned other rubber elements on the bike are due for replacement, what parts are the first to go?

Lastly, and this is primarily a BC legal concern. The bike only came with one mirror, on the left hand side. Am I allowed to drive like that in BC?

I like this bike as-is and am positively surprised, even in its current condition, by its performance. That being said, if anyone has any easy and cool tips of things to do with to increase performance/looks it I would love to hear it.

Ride on,

[tom203]

Welcome... to the fun! As you have noticed on this site, carb cleaning is a religious experience and a must do. Personally, if you aren't interested in fiddling with carbs (other than proper cleaning !), I'd avoid pods and stick with airbox. If you haven't already followed the link to Basscliff's, do so- incredible resource of info.There is lots of maintenance to catch up on. Endless patience will come in handy!

[pete]

Welcome! Definitely sounds like you have an intake issue of some sort there...

However, to help you out with parts etc., you actually have what's referred to in the US as a GSX400 which has an 8 valve head instead of a 4 valve head.

I believe they may have roller bearings on the crank rather than plain bearings too, although I could be wrong.

There are a few guys around here with experience with them, one of whom is SVSooke who lives in Sooke in Canada there somewhere.

This parts source may have fiche for your bike as it's in the Netherlands and I'm pretty sure they had that model there:

http://www.cmsnl.com/

[SVSooke]

Yes Pete I'm just across the water in the Victoria area.Born and raised in Vancouver so I know it well!
Now to 400s.Nice looking bike!You are missing the small S fairing but the bar end mirrors of the S are there.Mirror broken on one side?No this bike was not in the US and other places .It is the same plain bearing bottom end as the GS450 with a TSCC 4valve 400cc top end.US got 450S models.BassCliff has the Haynes manual for these http://www.mtsac.edu/~cliff/storage/...450_Haynes.pdf .
Personally I'm not a fan of pods and would stay away from them on a "weird" bike like this.Doubt you could get it to run right without doing a lot of jet changing and fiddling around.
Carbs are not as hard to do as it seems.Lots of tutorials on BassCliff's site.May want to post up in the GS owners area and introduce your self there.That will get you BassCliff's Mega Welcome for yourself.
Nice to see another BC GSer.Have fun!

[400s]

Mirror

You are missing the small S fairing but the bar end mirrors of the S are there.Mirror broken on one side?No this bike was not in the US and other places .

Thanks for pointing out the mirror, this photo was taken by the previous owner and I guess it must have fallen off since. My left side mirror is loose also, the threading is gone inside the handlebars. Any suggestions to how I can attach it properly?

[pete]

You can get a helicoil kit which will let you drill the hole out and repair it with a thread insert.

Alternatively, being the left side means you should be able to get a replacement clutch lever bracket.

[Smokinapankake]

That looks like a tail piece off a 650. Are they the same?

[pete]

Nah I think the 650 is a one piece that goes along under the seat whereas the 450 has two side pieces under the seat and the duck tail separate on the back.

That's definitely the right 450 part on there...