Hey guys and gals, I've been trying to pin down a problem for a few weeks now with no success. I've read countless forum posts to no avail so here I am. This post will be a bit long but I want to provide as much info as possible as this has me stumped.
I have a 2005 DRZ400e. Mostly stock besides the 'free power' mod and the previous owner opening up the airbox and drilling some holes in the stock exhaust to open it up (and make it way too loud).
When I bought this bike last year it ran flawlessly. The day after I bought it I left on a two week adventure through far north Australia. Unfortunately the stator was toast, but I luckily had a starter pack that got me through the trip. Other than that it was mechanically solid.
After arriving home I let it sit for a few weeks and after that the damn thing just wouldn't start. I got the stator professionally rewound and had them check compression for me. Low and behold the compression was terrible, so I pulled the top end apart and found that the piston rings were absolutely embedded in their grooves. I assume this could be the result of overheating, as without a working stator I was leaving the bike running as much possible. It took a lot of persuading and hot water to get them unstuck before replacing them, but the piston and cylinder looked absolutely fine.
So after this the bike started up straight away but wasn't holding idle. Knowing that I'd need to clean the carb I decided to purchase a carb rebuild kit along with a JD Jetting kit. Unfortunately my compressor has broken, but I was as through as possible trying to clean out all the circuits and replacing the clogged jets with the new ones in the kit as well as replacing all the O-rings and gaskets.
Currently my carb settings are as follows:
Float hight 9mm
Main Jet 155 (142 is stock)
Pilot jet 45 (stock)
Pilot air jet 60 (stock)
Mixture screw at 2.5 turns
And I'm using the JD blue needle on the 4th notch as suggested by the instructions.
Now after doing all of this the bike starts up perfectly and runs great at low speed but has a very weird problem. When I accelerate in any gear through around 1/2 to 3/4 throttle the bike falls flat on its face. It doesn't backfire, but it feels like it is starved for fuel and misses considerably until it gets to a higher Rpm and then it takes off like a rocket again. Never experienced anything like it before and the bike is unfortunately unridable because of it.
Here is a list of things that I have tested:
Petcock flows fuel fine
Replaced fuel with a fresh tank
Checked for air leaks - no change
Rode with choke on - no change/ worse
Rode with airbox cover off - no change
Disconnected RR - no change
Disconnected TPS - no change
I'm really running out of ideas here. I need to test if putting the original needle back in changes anything, but that will probably have to wait until next week.
A few other notes:
My battery is pretty much shot. It has enough juice to start the bike a few times but that's it. Is it possible for a dodgy battery to cause these sort of problems? I was under the impression that the bike gets its juice from the stator once running.
The mixture screw does not seem to do a whole lot. The bike will idle with the mixture screw all the way in, and will still idle with it out 3 turns. This doesn't seem right. I have an extended mixture screw on the way so that I can test it a bit easier.
I would appreciate any input as I am grasping at straws here.
Thanks in advance,