South West Bikers | Motorcycle Forum

i have a gsxr400 gk73a and my main jets and needles are worn the jets are 97.5 and was wondering if anyone knows wat size should be in there and where 2 get new ones from and any idea on wat rear shocks fit as mines a bit knackered. many thanks

The manual i have for it available here http://www.korell.dk/Service_Repair_Man ... '88-89.pdf it says 102.5's but you might have a factory pro jet kit in it like i have and if so 97.5's are the right jets to go with the needles in the jet kit. If you want to get new jet's and needles you could buy a factory pro jet kit from http://www.factorypro.com/Prod_Pages/prods41.html or get a dynojet kit from busters accesories or similar. In the way of shocks you can get a fair few to fit if you try. A 1200 bandit shock or GSXR1100/750 slabslide shocks are popular and modern gsxr1000 shocks can be fitted with a bit of grinding although im not certain on exactly what will fit. What its best to do is have a look on ebay for shocks which look to have similar mounting points to your and ask the sellers to measure the distance between the mounts.

If you intend replacing jets then be aware that not all jets are calbrated the same way. Mikuni/Keihin numbers relate to flow rates, where as DJ numbers relate to hole size in the jet. IE Mikuni 97.5 will flow 97.5cc of fuel per minute, DJ 97.5 means the hole is 0.975mm diameter and is slightly larger than a Mikuni jet, so will flow more fuel.
You'll probably find the emulsion tubes are worn oval which leads to poor fueling. Main jets will wear but not very much. The action of the needle moving up and down in the emulsion tube wears the brass of the tube as the needles are usually made from titanium in aftermarket jet kits. This ovality of the emulsion tube prevents the needles metering the fuel flow correctly, and it is usually the tubes that need replacing rather than the jets or needles themselves. Speak to Robinsons in Canterbury for Suzuki parts, or Allens Performance in Nottingham for Mikuni/Keihin parts, or NRP in Manchester.