Hi all, I'm knee deep in the process of swapping motors on my KLX250sf, and I wanted to know if you guys have any pro tips for me.

I have gotten to the point where everything is off and the motor has been broken loose in the frame, but hasn't been pulled out. Tomorrow i'm going to lift it out of the frame with dad (any tips on good ways to do this would be appreciated too), and put in the new (used) motor.

Any suggestions on cleaning/degreasing/lubing/loctiting etc. would be awesome, also would like tips on engine oil, coolant, first start after being oil-less and sitting for a while.

please and thanks!

 

If the motor has been down for quite a while I would leave the plug out, or not connect the plug wire and hit the starter for about 10 seconds 3 or 4 times with about 1 min between running to pump a little oil around the system.

 

So an update, I successfully completed my first engine swap

I ended up reusing the engine mounting bolts, even though the manual said to replace them. Has anyone done this before and can confirm the bike was fine after doing this? I used blue loctite and torqued them to spec.

I used blue loctite on practically everything that was connected to the motor/frame.

Thanks so much for this awesome tip. I made sure to do this prior to starting the bike up.

I left the rad cap off to bleed the system, and noticed that some sort of dirt was collecting at the top of the rad cap. I'm going to flush the coolant out again with deionized water a couple times and then refill.

I noticed the bike was idling a bit high (slightly over 2000rpm), and had a slight fluctuation increasing and decreasing by about 200 - 300 rpm. Vacuum leak somewhere? I made sure to put the carb boots on properly and tighten them up securely. I am going to adjust the idle screw to lower the idle of the bike and see if the problem sorts itself out.

The header was glowing red after being left to idle for a while. I read up on how this was apparently normal?

I have yet to do any tuning, but the bike was previously running a 351 with twinbros header/pipe and no airbox lid. Currently running a stock 250 with stock exhaust and no airbox lid.

Previous owner said it had a Dynojet 128 on the 2nd notch (I still need to read/learn more about what that actually means), but I figured the bike would run rich if anything considering what it was tuned for and running previously.

Finally I ended up putting anti-seize (the silver stuff used on brake caliper bolts) on the sprocket where moly was recommended because I read something online that suggested it. I think that may have been a mistake, and got moly instead to put on, but have yet to do it. I will do it before running the sprocket though. If i'm not mistaken I need a solution that's 1 part moly 1 part engine oil? What do you guys usually do when swapping sprockets?

As usual, any advice, tips, etc. are greatly appreciated. I don't really know what I'm doing, but I'm trying and learning as I go.

 

Did some more work on the bike, figured I'd share an update.

Flushed out the cooling system well today, no more dirt in the system!
One thing I did notice was steam coming from the rad cap if I revved the bike up a bit. Does this mean I need to change the rad cap?

Fixed the idle, and found it was holding quite steady. It would go up/down by about 100 - 200 rpm depending on how hot the bike was, but it held steady when it did. I'm happy with it.

The header stopped glowing on idle. I think this was attributed to the warmer day (6 degrees as opposed to 0, Celsius ofcourse), as well as the lower idle. It did glow red if I revved the bike up for a bit, but cooled off when I laid off the throttle.

I have decided I'm going to leave the bike tuned the way it is for now, and tune it when the weather warms up.

I did some further reading on the anti-seize, and a few sources claimed it was alright to use on the sprocket. I decided to let it be for now, and torqued the sprocket on per spec. This thread scared me https://www.kawasakiforums.com/forum...r-story-42562/. I also cleaned and lubed the chain, adjusted it and torqued the rear wheel back on to spec.

I really can't wait for the season to start...

 

Was the steam consistent or just when for a minute and then stop? The anti-seize do you mean you put it on the sprocket retaining bolts?

 

I will try again today and report back on how the steam looked. From what I saw it was right on hitting the throttle to rev up, and then dissipated.

For the sprocket, I mean I put it on the counter shaft on the engine side. I also put it on the rear of the engine sprocket, and now that I think about it, that may have been a mistake.

 

Anytime I have something that slides over a shaft splined or keyed I put antisieze on the shaft. I've fought way too many stuck sprockets pulleys taper locks ect of shafts not to.

 

Don't know never heard of putting anti-seize on the spline?

 

I feel confident in using it after doing more reading, as it apparently helps reduce wear on the countershaft splines. I also think it wasn't a bad idea to use on the threads for the countershaft nut because there's a physical lock in place (bending down the washer onto the nut), preventing it from backing out.