Project XL185/CG250 swap

[XLsior]

Edit 42P 135M was the winter tune.


I have installed 38P 138M jets. still 4th needle clip.

[XLsior]

Might be the nail in the coffin for the this CG250...

[XLsior]

So the OG $80aud basket case used CG seems to be on the way out...


The blown headgasket ordeal might have been to much for it and it's giving up.


Oil is sweating out of it and the clacky bottom end is knocking on heavens door.


So I have some options...I while back I picked up a few used chonda engines after my catastrophic head gasket fail...


I used some parts of a Dukar CG250 to save the OG engine...So I have the option of using the Dukar core and bottom end and swapping parts over from the OG....However the Dukar looks about as abused so its a toss up how long that will hold up...


I also have some smaller displament 200cc CB/CG chondas...unknown quality.


And finally the gem being the 169FMM CB250 that appears newish* and I got to turn over after finding all that was wrong was a stuck intake valve...The issue being the valve/cam cover fouls on my modified XL350 fuel tank...


But it might be possible to dent some clearance...


Not what I had planned for the weekend as I am now in a position where all my vehicles are pit stopped for some reason.


I will try the 169FMM first...

[XLsior]

Got the 81 frame out for a test fit before committing to installing the CB250 into the 92 frame.


Would appear to fit no issue but looking under the tank the CDI and inner tank wall are likely kissing, but its close enough that I'm ok shaving 1 side or love tapping the other to call it doable.


With that information I proceeded to rip out the tired old heart 'again' and bolt in the 169FMM


Got it in before sun down.

[XLsior]

So I got the 169FMM running...


Good news is that it runs and all gears work...


Bad news is that the clutch is stuck and there is significant blow by...


So its seen some action.



It hot starts pretty well so I'd say the compression is fair and the blowby might improve with more use as I suspect the cylinder and rings might be rough from neglect/sitting.


However Is it worth investing more time and effort into?



I am inclined to use the Dukar CG250 core and swap all the bits over from the busted bigend CG250 OG...


Sorry for thumb in vid shot...Honestly all the gears shift and there is neutral...

[XLsior]

So now I had to establish if indeed the bottom end was bad...


after removing the top end on the clacker and comparing it to the Ducar...


I came to the conclusion that they are about the same...


Nothing jumped out suggesting the crank or rod was bad...


So with that piece of insight I have elected to keep running the OG.


Seeing as I went this far I opted to install the 70mm DYNOP flat top piston and send it...


it's just gotta last 6 months of small errand work...and maybe a 700km return trip at Christmas.


Then it can keep leaking oil and collect dust under the house...


The 169FMM will likely go into the 81 frame. As i would have to modify the tank and header pipe to make it fit in the 92 road bike.

[XLsior]

Pulled of the flywheel cover to see if there was any signs of contact wear or loose items...all looked ok.


rocking the flywheel by hand the clack felt like it might be coming from the other side...


So off came the clutch cover. things looked clean but feeling around there was noticeable slop in the clutch basket...


I took the clutch cover of the Ducar parts engine to cross reference...


And well this is what happened

[XLsior]

While I had the top end deconstructed, Seemed like a last hoorah upgrade opportunity with some parts I had...


New valves and springs.



and grinding a little more clearance on the flat top piston seeing as I had shaved the head and was using a metal head gasket.


Also discovered the AN fitting I had used to shorten the oil cooler lines had failed, So potential major oil leak remedied with a spare long cooler pipe...

[XLsior]

So the Zongshen turns out to be a 7 plate clutch with a small oil filter slinger. The basket is shot.



the Ducar has a 6plate clutch with a large slinger.



I have installed the 6 plate clutch and larger oil slinger into the Zongshen engine without issue, All the gasket kits I have only support the larger slinger.


I do not want to spend money on a new 7 plate clutch basket.



Cleaning the Ducar clutch cover to install as it fits on the case no problem but is required to engage with te 6 plate and clear the larger oil slinger...


So the take away is, not all CG250 engines use the same clutch and slinger configuration.


But the friction disks are the same so no harm in buying 7 if you're unsure.


Though if your clutch cover has a bulge around the slinger its likely a 6 plate.


Fingers crossed this sorts out the clacky clacky pop pops

[XLsior]

After installing the 6plate I got curious and decided to crack open the 169FMM and the 2 remaining Loncin 200cc CG/CB engines...


The 2 loncins have different clutch baskets and less plates...(incompatible)


But it turns out the CB250 has a ZS 7plate and small slinger...In excellent condition albeit some sticky disks



Well I decided to uninstall the 6plate from the CG250 and install the 7plate and put the 6plate in the CB250. /swaparoo



I also found that the clutch covers worked and cleared plate/slinger configuration. So I could keep covers factory original.


I believe both the CG and CB 250s now have working clutches.


the Ducar is now just a parts holder...


However for whatever reason now my clutch cable is too long... So looks like the wallet is getting stung anyway.


Still after 2 days of grime I feel like there's 2 decent running engines...


Well hopefully the clack clack is gone with the sloppy basket binned...I cant think of anything else that might cause it beyond splitting the case...

[XLsior]

Welp...put it all back together and hit the button...


clacky clacky still...


Through the process of elimination I can only assume its the cam that's dusted and the followers are making harsh contact as the noise is not coming from the valve cover...


Another day of faffery...


Will get it sorted out at some point...Least everything else seems to be updated...

[XLsior]

So now with a suspect cam issue being a possibility.


I tore down the Loncin CG200 to inspect the cam and gear, which looked fine.


then I took of the flywheel and cylinder on the OG for the upteenth time, using the engine tip foward tactic.


Looking at the cam nothing was suggesting damage that would create the clack...but the gear looked a bit chewed up...


So I checked the cam followers in the cylinder and they also looked ok...


But then I noticed the spring washer had left the stage completely...It was installed, which implies it failed and fed the gears and probably settled in the sump or oil screen/cooler.


Anyway I replaced all the bits with left over better bits and installed the cam/gear from the Loncin CG200 into the OG as the parts are the same.


Also noticed 1 of the push rods was slightly bent...Might explain the rich pop popping...


So out of 4 pushrods I managed to find 2 straights.


Put it all together again and fired it up...much better normal valve tick and less cam clackery.


So a running result with a refreshed clutch bonus ...Should be 'reliable runner' now.

[XLsior]

So I got the new Clutch cable installed and did a few laps of the yard before taking a trip down the hill for basic shopping essentials.


2/3 down the engine goes blurgh and konks out on the side of the road.


Doing the diagnostic rounds of spark and fuel and then coming to terms with it being a compression issue I lifted the valve cover to find the intake pushrod had snapped in half with both halves falling down passed the cylinder...


Well I might have tempted fate or jinxed myself with the 2 out 4 unbent push rods...


Called my local friends and neighbor to see what options I had before ditching it and taking the bus...


local friend was out of town but said he had an account with a tow company so would arrange a pick up if i didn't mind kicking rocks for an hour...


I said it's better than pushing a bike for an hour...so waited.


The trip of shame and back into the garage for another round of off with the head, cylinder, flywheel and cam gear if i cant fish out both halves of the push rod with a magnet.



I have ordered some new beefier replacements...Stock push rods might not be able to handle the new springs.

this project bike sure likes whooping me...


At some point this bike has to become reliable right?


Think its Main Van time again...