1981 GSX400f Cafe Build

[Guest]

Hi all,

I was recently given a 1981 GSX400f thats in quite a sorry state so I'm planning to make a cafe build from it.

The previous owner is my brother in law and he says the bike last fired around a year ago. Its been hacked and messed with by him since then and now I can't get a spark.

I have ordered a new ignition switch, two new coils and caps and new spark plugs.

Hopefully I can get her started and then I can move forward with the build.

Anyone have any info on possible common issues with this bike?

Attached pics of the bike when I got it.
IMG-20190521-WA0003.jpg
TIA
Sam

[Hardy43]

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[Hardy43]

IMG-20190521-WA0001.jpg
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[Hardy43]

IMG-20190525-WA0002.jpg
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[Hardy43]

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[steve murdoch]

Welcome to the site, Sam.
We didn't get that bike in North America so there is not a lot of info about them on this site.
Do a search and there are a couple threads.

https://www.thegsresources.com/_forum/showthread.php?247997-83-GSX-400-F-no-idle-dies-Need-some-advice&highlight=gsx400f

[Jedz123]

8 valve head on the 400 engine. We didn't get that bike state side although I would love to try one out!!!
From what I can gather same issues as other GS, keep an eye on the stators and R&Rs. Intake boots and check the valves too.
Other than that should be just as reliable as another GS twin.
Best and welcome!!!

[greg78gs750]

would love a little 4v 400....good luck, all the info is here if you look

[GregT]

Not a twin as some have suggested. The first of the 16V air cooled 400 fours. We got them here, I think they were sold in the UK and Australia too.

The common weaknesses are the usual age related ignition and general electrical gremlins but the main model specific problem is lubrication.
The oiling system is marginal so keep an eye on oil level - and use a good quality oil. It's a plain bearing bottom end so a synthetic or semi synthetic may be appropriate.

[Grimly]

Anyone have any info on possible common issues with this bike?

Beware the crankshaft oil supply - those 400F engines were notorious for doing in their crank bearings. All you can do is not thrash it (some hope, as it was a little thrashy bike thrashed by every previous owner) and feed it good oil.

The bright side is that if the engine is mechanically knackered, the GS550 lump will fit in that space.

[Hardy43]

Cheers everyone Ive had a look through some of the other posts I have found. Ive got the manual so I'm going to check the resistance in the rectifier and the signal generator. Hopefully I can get the thing started this weekend. Ive also bought a front end from a early 600 bandit and rear wheel, callipers etc which from what I have been told are quite an easy swap

[Hardy43]

Beware the crankshaft oil supply - those 400F engines were notorious for doing in their crank bearings. All you can do is not thrash it (some hope, as it was a little thrashy bike thrashed by every previous owner) and feed it good oil.

The bright side is that if the engine is mechanically knackered, the GS550 lump will fit in that space.

Cheers, If this engine won't start then I will just pick up a gs550 and drop that in. They seem to be fairly cheep to get hold of

[Hardy43]

Managed to get the bike started on the weekend, Had a few connections that needed replacing and some real bad earth points sorting. It runs great on cylinder 1 and 2, nothing on 3 and a little on 4. Runs fine on all 4 though when I hold a petrol soaked rag over carbs 3 and 4. Ive ordered a carb rebuild kit for it which comes at the end of the month so that should sort the fuel and non fire issue going to start rebuilding and prepping the bandit donor parts in the meantime