GSXR400 running problems - help!

phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

Hi, ive recently purchased a gsxr400 gk76a model. When i accelerate, it usually picks up well but then starts to lose power temporarily before picking up again, making for a very frustrating ride. I thought it could be the plugs or coil connections? also theres a rubbing noise coming from the front wheel and it could be the bearings but again im not sure? any help or ideas would be appreciated, cheers

sagiliam · Could Be A Chat Bot Joined: 26 Mar 2006 Karma :

Hi, firstly, just for future reference. Post problems in "the workshop" section. Dont worry about it now, a mod will move it for you Thumbs Up

Have you tried changing your spark plugs yet to see if theres any difference?

LS

Matt06 · World Chat Champion Joined: 18 Nov 2006 Karma :

Check you're spark plugs and see how clean they are. You might need to give them a clean.
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

sorry mate i didnt know where to post it, its my first post. But thanks for the replies. Ive been told it could be running rich or lean but ill inspect the spark plugs when i can get hold of a plug socket, cheers

Teaman · World Chat Champion Joined: 01 Dec 2004 Karma :

if you have a center stand use it then lift the front end off the ground, I pack bits of wood under mine and rest it on the engine. This way you can spin the front wheel. do so and listen carefully, it could be disks rubbing or you hear a grating noise if its bairings.
if its bearings theres bound to be a bit of play in them, by getting aomeone to hold the bike turn the wheel to the side and pull it then push it a few times to check for play, you might pick up some play from the forks here, if so check them, (its a recently bought bike remember, owt could be wrong)

as for the power loss, check your plugs, the fuel system, the carbs (not sure if its got carbs tbh, these are basic ish checks)
my gpz 900r did the bogging down when I was rev happy, turned out to be the carbs and also the fuel line, previous owner had fitter a fuel filter, handy but slowed the flow,

have fun,

Stu
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Matt06 · World Chat Champion Joined: 18 Nov 2006 Karma :

NSR Mick · World Chat Champion Joined: 26 Jun 2005 Karma :

It'll be running rich, there are some o-rings in the carbs that are famous for perishing.
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NSR Mick · World Chat Champion Joined: 26 Jun 2005 Karma :

Also does is the air filter in good nick and a genuine Suzuki one as they run like a dog if you mess with anything fuelling related.
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Wafer_Thin_Ham · Super Spammer Joined: 18 Nov 2005 Karma :

It could just need a carb balance if it's fluffy in some places.
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

hi, cheers for all of the replys. Ive had a little look in the carbs and couldnt see any o-rings. Unless everyone is referring to the diaphragm style rubber things which are visible as soon as tops of the carbs are removed? otherwise im blind or the o-rings have just completely disintegrated. hopefully not

NSR Mick · World Chat Champion Joined: 26 Jun 2005 Karma :

The o-rings are under the main jets and or the emulsion tubes.
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Matt06 · World Chat Champion Joined: 18 Nov 2006 Karma :

I am currently in the process of changing/replacing my O Rings on the same bike. Got 2 of the 4 O rings I need delivered today.

You might find this website useful - https://tonysleep.co.uk/gsxr400carbs

It tells you everything about fixing possilbe carb problems with the GK76a. Mainly being the O Rings Rolling Eyes

. The pictures should help with finding them aswell, they are quite small.
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

cheers mate that really helps Thumbs Up

did you take your carbs off to do the o ring replacement or did u manage to do it with them on? i can get access to the screws with a stubby philips head but im worried incase i round the screw heads with the carbs still on, are they easy enough to remove?

Matt06 · World Chat Champion Joined: 18 Nov 2006 Karma :

You have to take the carbs off to replace the O Rings. There isnt really any way to get at them otherwise. If you follow some of the stuff on that site for getting the carbs off they should be easy enough to get out. The main thing that helps is to remove the airfilter so you can get some extra space for the screws. Oh and yeah, the philips screws around the carbs are shit and shape like butter but its mainly due to the age of the bike. Should still be able to get them off though. Try some WD40 Cool

.

Hope this helps.
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

this is annoying me to no end. Ive just been fiddling about with it, got the tank and seat off, battery case and battery, airfilter... and i feel pretty stupid asking all these questions but theres absolutely no room to access anything.

Matt06 · World Chat Champion Joined: 18 Nov 2006 Karma :

With all that stuff off you should be able to remove the carbs. You dont need room if they are out of the bike Cool

.

What are you trying to access?
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

im trying to get the carbs out but theres just no access to the jubilee clips and there tubes and wires galore. plus i havnt got the actrual airbox out, its just the element. the air box looks like it cant come out cos its wide at one end and looks like it wont be able to come out from betweek the frame?

NSR Mick · World Chat Champion Joined: 26 Jun 2005 Karma :

Theres a large coathanger thickness type clip that holds the carbs into the airbox. Pull it out and the carbs go back into the airbox.
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phill_sumner · Nova Slayer Joined: 17 Feb 2007 Karma :

cheers, ive got the carbs off and managed to get the screws off (some with a hacksaw blade, i had to sit there using just the blade to saw a slot for a flat head driver to get them out) but anyways....got some stainless allen head bolts to replace them with. What i was really wanting to ask was (this is aimed at the guy who gave me the link to a website telling me about the o rings, very grateful for that) but where is the slide holder as im supposed to change an o ring in that aswell, cheers