Not sure if this belongs here, but I figured it's not Z-400 related so here goes.
My son has a 2006 LT-Z 50 that he trail rides with me on my 400. It's a neat little bike but one of the drawbacks it has is that it REALLY lacks power. Even for a little kid's bike. The bike comes stock with a throttle limiter and clutch limiter, and after junior got better with it I took the clutch limiter out. Now the throttle limiter is backed way off, but the bike still has trouble with hilly areas or ruts. The biggest problem is the built in rev limiter. It never lets the engine spin long enough to build any speed or power. I called up my friend who is a mechanic at the dealer I bought the bikes at and asked if there was anything we could do to get a little more out of the mini. He scratched his head and said he hadn't really seen any performance parts for these, but he'd see what he could come up with. He called me up the next day and said he wanted to try something out. It seems that the CDI box off of one of the new Z-90 bikes is an exact fit for the 50 in every way. The wiring harness requires no mods and the box will physically fit perfect. He checked the wiring diagrams and the box is exactly the same except it has a rev limiter that is so high that this bike's clutch will never reach it. It took about 32 seconds to replace the box and then we tried it out.
The results are good. The bike isn't any faster, but because of the increased rev, you can gain a lot more speed before the hills where the old rev limiter would cut in. I had to reset the throttle screw because junior wasn't sure where to stop
![Image]()
. Heck, I even rode it and saw the difference.
So if you have one of the new 50's and are looking to increase performace, look at getting the 90 box. So far, so good.
Thanks for the help, Aaron. One of the best mechanics I know.
Jerry
My son has a 2006 LT-Z 50 that he trail rides with me on my 400. It's a neat little bike but one of the drawbacks it has is that it REALLY lacks power. Even for a little kid's bike. The bike comes stock with a throttle limiter and clutch limiter, and after junior got better with it I took the clutch limiter out. Now the throttle limiter is backed way off, but the bike still has trouble with hilly areas or ruts. The biggest problem is the built in rev limiter. It never lets the engine spin long enough to build any speed or power. I called up my friend who is a mechanic at the dealer I bought the bikes at and asked if there was anything we could do to get a little more out of the mini. He scratched his head and said he hadn't really seen any performance parts for these, but he'd see what he could come up with. He called me up the next day and said he wanted to try something out. It seems that the CDI box off of one of the new Z-90 bikes is an exact fit for the 50 in every way. The wiring harness requires no mods and the box will physically fit perfect. He checked the wiring diagrams and the box is exactly the same except it has a rev limiter that is so high that this bike's clutch will never reach it. It took about 32 seconds to replace the box and then we tried it out.
The results are good. The bike isn't any faster, but because of the increased rev, you can gain a lot more speed before the hills where the old rev limiter would cut in. I had to reset the throttle screw because junior wasn't sure where to stop
So if you have one of the new 50's and are looking to increase performace, look at getting the 90 box. So far, so good.
Thanks for the help, Aaron. One of the best mechanics I know.
Jerry
