GSXR400 GK76A Problems starting and revving. HELP!

[raywilby]

Hi guys, im a noobie.

I bought my lovely little gsxr400 1990 gk76a in sept and it has had a lot of work done to it to get it on the road as it was used as a track bike. It rode lovely and always started first with no problems.
Recently the stand decided to sink into the ground and the bike fell over and ever since the bike is a pain to start, wont rev properly (twist the throttle open and the bike dies). I cleaned the plugs up, checked the coils and cleaned the connections up, I have very good sparks, good compression, fuel is getting to the carbs. I have iridium plugs in them cr9ex (I think).
I had a spare pair of carbs come with the bike which were in good nick and the ones that were on them when I bought the bike the red wire on the tps had broken (came out of the tps so I cant even solder it back). Took it to SeaStar motorcycles and they said the spare carbs with out the tps on it will work fine. So I believed them, but I have been told by a mechanic that the tps needs to be on the bike to run properly. What are the effects of not having it on the bike? Will it ruin it?

Cheers

Ray

[Variablevalves suck]

Hi Ray,
Good to hear from another gixer owner. Sounds like you upset the carbs when it fell over.
It might be something inside but i would check the mounts and air box for air leaks before taking them apart.
If you have an SP with TPS then it will have 35mm carbs, the non TPS carbs will be 33mm and will work but will probably give less topend. The TPS allows the cdi to give different advance curves for part and full throttle so is worth keeping- can you post up a picture of said tps, where has the wire broken? we maybe able to use one from another model.
Chris.

[Jaicen]

I'm not certain, but I think that the TPS needs to be on the bike for the timing to work correctly, because the SP model has advance/retard curves built in to the CDI.
Sounds to me like it's over-fuelling. Pull your carbs out, and check the float bowls. You may find that one or more of the float bowls are stuck. That happened to me, and caused petrol to spew out when the bike was running.

[raywilby]

How will I tell if my bike is an sp or not?
I will check my bike over in the morning.

Here are some pictures of the tps




And here is my little beasty


Cheers guys,

Ray

[raywilby]

Had a look at my bike today and checked over the bike for air leaks and thankfully there wasnt any. Managed to break away some plastic on the tps to get the wire bare and im just about to solder it up. The bike started up when I connected the wire together with a little bit of choke and petrol started leaking from the overflow in the carbs which means I have a bad case of over fuelling. Going to take it to my friends house who is an mechanic and have a look at them and sort them out properly and hopefully it will work this time.
I will get a closer picture of the tps and where it has broke before I solder it.

Cheers guys,

Ray

[Fast lane]

I bought a Suzuki gsxr 400 gk76a...i have now purchased 2 cdi's and she simply does the same thing...swing swing swing slight rumble and then a bang...neighbours have even complained thinking it was gunshots...cam timing is perfect, she has beautiful compression what else can it be?she did have a fire on board when i bought her so im not sure if they altered the wiring...but she is amazing spark...this defies all logic of how a motor runs??!!compression spark and fuel.....any ideas....

[Variablevalves suck]

@ Ray- you cannot simply boplt the tps sensor back on and expect the bike to run spot on. They have to be set up using the two different ohm reads for open and closed throttle. Ther is a percentage used between the two readings and i do not have the readings used for the gsxr4. There is a big write up about tps on the banditalley site for the 1200 bandit, this may give you a percentage to try.

@ Fastlane- are 100% the cdi you have is the correct one for the year of bike? as pre and post 93 bikes have different cdi's and triggers. Youi would need a trigger + cdi if changed and the misfire is the end result if not!