Project 1994 ZXR250

End of year update ..... I'm going to try use less words and more pictures

Carbs are back together and bench sync'd using a round feeler gauge. Diaphragms seating issue resolved by cleaning any trace of INOX around the rim and trying numerous times to get a consistent 'woosh' across the 4.



Carbs bagged up and stored while I move on to other things ... I wanted to check the valve clearance and leak test the motor and, i also wanted to clean the rest of the motor before I went ahead and found these adjustable feet which served as a carb intake plug, also found 16mm chair tips to block the crankcase breather hose.




after yet another wash (I've fast forwarded a few steps here in stripping the rad and cam cover):



Dropped the oil which looked pretty good - appears like good quality red stuff and no real particles to speak of. Coolant wasn't too bad either.

Picked up one of these to do a leakdown test, I figure I can use the adaptors and buy a higher PSI gauge with a check valve if I want a compression tester also.



CR8E plugs were found to be installed instead of CR9E's




Today was clearance measuring day, below are the results - I will check again to make sure I measured correctly.



One thing i'm not sure is the cam timing marks - I believe this should be #1 TDC on the compression stroke, however I'm not convinced the cams are lined up correctly.... I also noticed that depending on the crank position, the chain is noticeably tighter and looser - apart from a tensioner or chain issue, I don't see what else could explain that.






Last pic shows where the chain has given the cam cover a little kiss.

 

Happy new year everyone!

Thanks @Linkin for the advice. Chain ordered (un-jointed).

I'll check the tensioner for wear, I wasn't able to locate the specs in the service manual though. If the body does wear i might be best to replace it as a unit - anyone know if a ZR250 (Balius), OEM part 12048-5002 is compatible?

 

2022 update 1:

I ended up measuring all valve clearances a second time and quickly became very confused as all the valves had seemingly tightened up ! As it turned out, in reality they hadn't moved at all - the feeler gauges I recently bought have imperial and metric values printed on them and I was reading the imperial values by mistake ... turns out I fell into the same trap during round 1 on a pair of valves also. The old saying "measure twice, cut once" is still valid !

A quick spreadsheet to minimise mathematical errors was definitely a good move. Keeping track of what came from where and placing the new shim in the allocated tray was my best friend during the process also.



I leak down tested the engine while the cams were out, interesting process and my take-away trick is a nitrile glove on the exhaust is a good indicator for exhaust valve leakage. I also had to McGyver a thread adaptor as the one supplied with the kit did not want to thread in to the spark plug holes after it's first use. I ended up dismantling a spark plug and using JB weld to join the original M10 x 1.0mm adaptor to it.
There was some air leakage across all cylinders but the majority of the noise seemed to be coming from the crankcase (rings). I'm not too concerned with the leakage from the valves at this stage in that the engine hasn't run for numerous years and none of the valve clearances were 0.0 mm, or should I be concerned ?

 

Missed a couple of pics.

Mr Glove



Shims going in (I installed spark plugs immediately after taking this photo!)

 

Before I undo the cam holder (I like how the tightening sequence is stamped in it BTW) ... is it 28 or 29 pins between the inlet and exhaust timing marks? It appears i have mistaken the 9 for an 8 in the service manual.

I'm pretty sure i need to rotate the inlet cam CCW 1 tooth....

Cheers

 

Cam timing sorted. Valve cover soda blasted and painted the little discs that hold the oil seal against the cover.
Coil On Plug wiring done, I made some small lacing bars out of 10mm square aluminium to mount where the original coils sat so the wiring is secured:





Rad fan shroud is being 'relieved' as the coils foul on them - think 25mm hole saw...


All cables lubed:


I also discovered the RHS clip on bar is bent - NOS bar on the way:

 

I decided to dig into the cooling system a bit more as I wanted to paint the pump cover to match the freshly painted stator cover. Impeller has some errosion on it but I think it's still usable. @GreyImport - I noticed you have a shiny new metal pipe that connects the hose from the water pump to the hose going to the cylinder. Is that a home made job ? I might have to do the same as the one I have is starting to fall apart. Is it just mild steel ?

 

Thanks mate. I actually bought a welder I didn't need a while ago - sounds like a learning opportunity !

 

Been a while so here is a status update:

• Flywheel cover and water pump housing(s) blasted and painted

Freshly baked ...

• Homemade gaskets as I was hoping to not wait for parts to come from Japan, as it happened I needed to wait for a new mechanical seal and a couple of other bits anyway. Also, I haven't tried making them since high school.

• The exhaust headers ... I was going to paint them but there is a local guy that does cerakote so I took the easy option and splurged on that instead.

• I needed a way to prop the front end up so I could take the forks and triple clamps off, I bought a bit of square tube and solid round bar, drilled some holes in the right places and inserted them into some axle stands. Works Ok, stable enough

• Forks are currently apart, waiting on new seals to come in. I also used my TIG welder in anger for the very first time (it's actually the first time i've TIG welded anything - the quality of the job shows). I made a fork cylinder holder out of a bit of 25mm tube and some nyloc nuts. Fork oil is nice and dirty

• And lastly, I'm giving the brakes a full overhaul - definitely something you want to have some faith in