GSX 400E -83 chopper

[MotoX]

So, looking in the service manual I can see a slight difference (which might not be so slight?). The Main Jet on my bike is 120 and should be 117.5 according to the manual. All other things is according to the service manual as long as the bike is a GSX400EX and not GSX400ET, and frankly I don't know, so should be a GSX400EX right?

[hampshirehog]

Beware the manual!

Which part of the world is listed on the front page (or 'early pages') of the manual? The carbs do vary a bit depending on the market - usually the US bikes were set up to run leaner than the rest of the world so your bigger 120 jets might be standard in Sweden.

Edit: Just checked and if your bike is a GSX400 1982 (SZ) European model it should have 120 mains.

[MotoX]

Beware the manual!

Which part of the world is listed on the front page (or 'early pages') of the manual? The carbs do vary a bit depending on the market - usually the US bikes were set up to run leaner than the rest of the world so your bigger 120 jets might be standard in Sweden.

Yeah it's a Haynes Manual printed in England.

Oh well, the thing for me to figure out now is what parts to change in to for my setup. If I can I will go with some sort of headers to the carbs and will probably weld a washer into the exhausts to restrict that air. So with the exhausts hopefully being like original in ways of air restriction I "only" have the air to the carbs to wory about. I guess I could make the headers tight but should probably need to rejet the carbs anyway right?

Should I change every one of those parts mentioned in previous post or just a few special of ones when i rebuild the air intake this drasticaly? Or do I simply have to test it out and change after testing once the rest of the bike is finished?

[hampshirehog]

Yeah it's a Haynes Manual printed in England.

On behalf of the English members on here I apologise for the Haynes manual. They are useful for lighting fires though.....

The chances of you being able to use the original carb settings if you are chopping the exhaust / throwing away the airbox are remote - even if you do start making restrictions etc. You will have to either run the thing on a Dyno or do plug chops to tune the carbs in when you're ready.

[MotoX]

The chances of you being able to use the original carb settings if you are chopping the exhaust / throwing away the airbox are remote - even if you do start making restrictions etc. You will have to either run the thing on a Dyno or do plug chops to tune the carbs in when you're ready.

Yes, plug chops is what I intend to do when I'm finished, but to take a chance on some sort of baseline, do I change every of the 5 components listed to the next part with richer mixture or do you normaly just change some of those parts when greatly added air is introduced to the mixture?

[MotoX]

On behalf of the English members on here I apologise for the Haynes manual. They are useful for lighting fires though.....

Also don't appologise for the Haynes books, maybe they have faults but it's often better than nothing right?

[hampshirehog]

I would start it up and see how it goes using what you've got already. Chances are you'll just end up changing the mains, maybe the pilots (not the pilot air jets, though you might) and maybe shimming the needles.

You've only got 2 of each so it won't cost much to chop and change.

[hampshirehog]

Also don't appologise for the Haynes books, maybe they have faults but it's often better than nothing right?

As long as you know what not to follow etc. Haynes are famous for missing out crucial bits and spend pages telling you how, for example, to remove the engine and then only one paragraph on how to rebuild the gearbox. Plus they do get their years mixed up.

Have you looked on Cliff's page to see if he has got the original Suzuki manual?

http://members.dslextreme.com/users/bikecliff/

[MotoX]

I would start it up and see how it goes using what you've got already. Chances are you'll just end up changing the mains, maybe the pilots (not the pilot air jets, though you might) and maybe shimming the needles.

You've only got 2 of each so it won't cost much to chop and change.

I have started it up right now, though with open pipes and not with the washer in the exhaust, it is running lean enough to missfire with the pilot screws 2 turns out. Also it dies without chocke until it is plenty warmed up. Other than that I couldn't tell you. Also it stalls a bit when it is warmed up.

Oh well, I gues I'll just be patient and complete the bike first then and then plug chop my way to perfection Interesting thing you said about the needle though, do I shim it up? Don't I buy a new smaller one?

[MotoX]

Have you looked on Cliff's page to see if he has got the original Suzuki manual?

I downloaded the one I could find, which was a Haynes one I havn't looked through the linked pages though, might spend some time another day scrolling through those.

[psyguy]

I think, spare yourself some trouble and get Dynojet kit for 1100 (8v), or for 850. It comes with air jet restrictors, adjustable needles and 3 different main fuel jet sets. Airjet restrictors I don't think you can get anywhere else from but Dynojet. The OEM needles in your carbs are likely adjustable (unlike for the USA market) BUT Dynojet needles have a different taper to them so are a better option.
Dynojet may be willing to sell you 1/2 kit, i.e. for two cylinders.

Then you've got all the parts you need for fine tuning.


The diaphragms are not sold separately but only with the piston and cost you through the nose OEM. I seem to remember seeing them available aftermarket... but where...? Anyone?

[pete]

BassCliff has a Clymer manual on there as well, get that one and don't use torque figures from the Haynes, I stripped one thread for the gear changing arm in the crankcase because they had twice the torque rating figure listed

[salty_monk]

Not available aftermarket... At least not unless you have a full machine shop to modify the slides to fit the new ones! Someone here did... GregT perhaps??

[psyguy]

discovered that one membrane has a hole in it.

you can buy a rattlecan of sprayable rubber that you can use to fix the membrane if the damage is just a worn out membrane that's got very thin - but if there is an actual hole then that won't work

[MotoX]

you can buy a rattlecan of sprayable rubber that you can use to fix the membrane if the damage is just a worn out membrane that's got very thin - but if there is an actual hole then that won't work

No actually you can see that it is worn out and that there is still an ok mesh in there. So that should be fixable with that spray?