k4 GSXR 600 starting issues

Ok I am new to working on motorcycles but have worked on cars for years, well anyways I decided to do a motor swap on my bike. I got a K5 600 motor completed the swap. I used the upper throttle body assembly from my motor on the K5, well when I tried to start it it would Backfire act like it was gonna start then nothing. I took the plugs out let it sit for a day then put in new plugs. I connected it all up and tried again, I had to open the throttle about 1/2 way and it started. As soon as I released the throttle it died. I asked some people I know, one said soak the injectors in seafoam to clean them. They might be dirty and not supplying enough fuel, I havent tried this yet but has anyone had this issue or know of any other things to try?? Please help

 

Have you fitted the connectors onto the injection unit the correct way round

 

can you explain alittle more, Im not sure what you mean by connectors to the injection unit. Do you mean where the fuel line runs from the tank to the fuel rail

 

I think it might be the TPS that is mounted on the black box on the end of the throttle bodies. If you took any of that loose from the throttle bodies it will have to be reset. Its spring loaded and mounted to the end of the secondary butterflies. You will need a multimeter to get it set. That is if you took that stuff loose from the throttle bodies when you switched them out.

 

good idea on the TPS, i didnt take it off but it was all unplugged. How would I go about reseting it? I got off work early today so I went home and played around with it for a bit, I did adjust the screw that controls the idle and got it to stay on with the idle around 1300. I did notice that it had a slow throttle responce tho, it would go through the RPM's slowly, not super slow but slower than normal. TPS would make sense with that as well. Thank you guys for your help!!

 

Are you familiar with using a multimeter? If so its fairly easy. The TPS has 3 prongs inside the plug. You connect a multimeter to the outside prongs and check for resistance. It should read 1600 or similar depending on what you have the multimeter set on. It will read in ohms. You then loosen the screw and rotate the TPS clockwise until you get the right reading. You'll have to open the airbox and push the secondary butterflies all the way closed then get the reading. You might have trouble getting to the prongs because they are inside the plug between the frame and throttle bodies. I used two female blade terminal connectors like you would use on speakers. I took all the plastic insulation off and crimped them down so they would slide over the pins and stick out the bottom of the plug. That way you will have something to touch the multimeter probes to.

 

yeah im pretty good with a multimeter, thanks for the info. You just taught me something new! I will give it a shot and hopefully it will fix the issue. I will post up the results tomorrow!

 

If you have any problems just PM me. I'll help the best I can.

Edit: After doing some searching, my info is based on the secondary TPS whixh is mounted on the STVA( black box on the end of the throttle bodies). The info on setting it is right, it just might not fix your problem. Also, there should be a white alignment mark on that from the factory. I'd check the alignment on the marks before I took it loose.

 

ok i used the multimeter on the TPS and got a reading around 1680, it bounced around a bit between 1670 and 1700. Is this close enough or does it have to be adjusted?

 

deff need more info on exactly what you did. Took just the motor out and put a newer motor in? the TPS rarely moves and it needs the special torx screws to remove. Do u have a power commander? Is the fuel line pinched somehow?(common problem)

 

I assumed that since he swapped the throttle bodies that maybe he removed the STVA, not knowing the TPS was spring loaded.

 

I didnt remove the stva, Its attached to the upper section for the throttle bodies, injectors and fuel rail. I will check the fuel line, i never thought of that. I dont have any power adders except for a bolt on muffler.

 

Check the vent lines on the bottom of the tank as well. I had to pull mine back down after I would lift the tank on my 04. It would pull them up as I lifted the tank, then they would kink when I would put it back. I had to reach under the bike and pull them back straight.

 

ok well i checked the fuel lines, pulled the vent lines straight down. It will start and stay running now but it still kinda acts up when intially starting, I have to finish the clutch adjustment but getting it running was my main priority. Once i finish the clutch i will take it for a ride and let you guys know the outcome, thanks for all the help

 

Dont know why,but if u have another ECU try that. Sometimes during swap it can somehow get shorted out. I have chased many problems like this and sometimes it was ECU.

 

Is it throwing a code?

 

yeah it had the c28 code but it was reading that before, i would just adjust the 2ndary butterflies and it had no issues. it starts up and runs, it still seems very sluggish but i couldnt give you and accurate statement because the clutch still isnt adjusted properly. It is a pain!

 

This is your problem. The connections inside the STVA are bad. Typical problem on the 04/05 Gsx-Rs. I missed a race because of this before. That code being thrown kicks the bike into limp mode, which causes it to not rev over a certain rpm. With the secondaries not opening right, the bike will have trouble starting. Ever tried to start something without choking it first? Kinda the same principle.

 

It is common for them to kink if you install the line backwards.

 

You can safteywire the secondary butterflies open to help uerself out. There is no need for them. I did this with my street/trackbike. It took me forever to track the problem down. FOREVER! There is a test that you can do to make sure they work correctly. I forgot exactly what it was but basically you take the tank off and airbox. Turn the key from the off position to the on postion and the butterfly valves to a diagnostic test. Do a search on gixxer.com thats where I found the info I beleive. The secondary butterfly valves rotate one way then another or something like that. I will see if I can find the exact process.


Saftey wiring was the quick and easy fix. Alot of people just remove them. Only way you can tell they are removed is when you take off from a stop light it bogs for a split second. But once you get use to it you don't even notice.