My ZXR250A Project Log

Just wondering how much work is involved. While I have the motors off may change the good one for the unknown condition one. From the looks of the manual it seems pretty simple, unscrew, pull out and replace. That actually the case?

 

Thanks Kiffsta, appreciate the tips

 

Both engines are now out and prepping for the swap. Stripped both sets of carbs and re-jetted my good set for the A model engine. Unfortunately the sump plug on the A model engine is totally buggered. Looks like it was drilled out at some point in the past (the bolt is 40% larger than it should be!) and undoing it to drain the oil this time shattered the thread. Hopefully I can jump use the good sump of the C model engine and save some pain there.

Assuming I can get the sump swapped and sort out an appropriate gasket maybe... just maybe... I'll get it back together tomorrow

 

Don't even know if a timesert would work but I'll have a better look when I get it off. I mocked up an "extremely accurate" image of what it looks like has happened when you look from outside. It's like half of it it snapped completely off, maybe it was over tightened at some point.

Mock normal:


Mock Broken (on my replacement engine)

 

Yep that's the plan. Gasket $11 nice and easy

 

Updates:

Got my hands on a sump gasket Sunday from Bert @ BK performance. Pulled the sump off easily, little bit of muck on the oil pickup but nothing compared to what I expected, can't have been the first time the sumps been off. Set about degreasing the motor... lovely job... but looking a lot better.

Then onto some other general odds and ends then. Most of the exhaust studs came out so had to locktite those back in, put a new set of plugs in. The old plugs were warn out but had no tell-tale damage on them. New(er) sprocket, vacuum lines etc.

Got the engine into my frame, hooked everything back up, swore a lot getting the throttle cable and carbs back on as usual. Was all ready to go and then..... primed the carbs... fuel everywhere! Awesome. It's coming out of the carbs so they'll be coming off again tonight and getting another look over. Oh and the blinkers stopped working too! But at that point it was 9:30pm and was done for the day, hopefully just a fuse.

Anyway will make another attempt this arvo, fingers crossed. Got to love old bikes

 

Ok so trying to get her to start now. Does not want to bite. Add a little bit of choke and it backfires out of exhaust and back through the carbs, nothing explosion worthy.

If I remember correctly that indicates wrong order on the plugs. So can someone confirm for me that on the A model it's still

(left to right)

1 to 2
2 to 4
3 to 3
4 to 1

Should be, same order they came off this engine when I pulled it out of the other frame. If you've other ideas of things to check/try please advise too. Each plug is sparking, leads, caps, coils are in good condition.

 

Ok then my order is wrong. Coil orders have always thrown me off. Strange though as I just set it back up identically to what I unplugged it from the running A engine as. Thanks Grey

 

Woohoo! Good to hear the sound of a running engine again. Silly me swapped the coils back to the right order and the bike fired up first go!

Seems to be a bit of a rattle coming from somewhere at the moment. What do you guys think? Cam chain? If I need to spend some money on this engine I will be. Not keen on blowing up an A model engine.

 

Thanks. Good idea with the CCT prob a good thing to do anyway. I'll start putting it back together slowly now. Electronics are going haywire so that'll be the next thing to worry about. Got to get another roadworthy shouldn't have let it expire haha!