Project XL185/CG250 swap

[XLsior]

I was trying to dial in the PZ30 but was getting frustrated with the underside enrichment screw then the choke cable extension was not holding choke...

I decided to get my $ worth and just go for the Nibbi PE28FL upfront.

Maybe if i persisted with the PZ30 it would be fine but I was over the choke cable getting in the way in more ways than 1.

Anyway had to remove some frame material to allow carb slide cap access and rotation clearance.

After that got the bike running but still had the same papping on idle. Maybe my valves are worn....

upper rev range seems ok but 1/8 off idle is bogging and stalling...which assume is a lean condition.
My altitude is 500m or about 1600ft
So I currently have the needle at 4th notch and went from a 38 (stock) pilot to a 42 (I think this 42 was chinsy under size) and now a 45 which is definitely larger hole...

However my tank ran empty so think I kept getting out of fuel konk outs.

I'll fill up the jerry cans in a couple of days.

So tuning is on hold till then.

[XLsior]

So I tried 32 upto 48 on the pilot jets.
A/F screw is 2 turns out on a 38.

even with the smallest 32 jet I have at half a turn out it exhaust pops.

My spark plug keeps telling me its rich with dry black coking.

if i blip it will soot puff...

And as far as i can tell the main reason for the exhaust popping is mostly due to it being 'hiflow'...If i apply some back pressure the popping dissipates...So I don't think I can carb tune it away.

But from what ive searched it seems it not detrimental just an effect of de-restriction.

it does go away when its very rich but that's when the air screw is turned mostly in and the engine acts doughy.

However could it be as I suspected a valve related issue...took out the sparkplug and tried to get a photo.

intake valve easier to view...exhaust is a bit harder to see. But I don't believe seated valves should look like that.

So looks like I am taking the head off and doing a valve job to remove any doubt from my mind as to the reason if my fueling and exhaust popping issues.

[XLsior]

Tackling the head removal procedure in the XL185 frame.

Long story short engine had to be tipped forward on lowest rear mount.
Front sprocket removed to allow slack (will be applying blue locktite on those 2 sprocket plate retainer screws as they were less tight than ideal)

Anyway The conclusion is working on the engine in the frame is not so bad.

The head came off looking like a chimney sweep inside.

Inspecting the valves shows that the intake did look sunk compared to the exhaust valve when seated.

Made a valve retainer removal device from clamp, some poly pipe with a access window cut and a magnet held with a bit of wire...

Springs out bagged and tagged. 9getting them back will be the tricky part.

Valves slid out nicely.

Inspect exhaust looks....ok

Inspect Intake and... ho boy that looks like an issue.

Inspect valve seats in head...seems serviceable.

Take measurements order new valve kit ($17aud shipped)

Basic 2 compound lapping kit ordered...

Also ordered a new rotary tool to replace the last 3 rotary tools..(including a name brand dremel that died) So I can port finish the areas behind the valves as I already gasket matched the runners.

Stem seals were chalky so replacing those too.

Seeing as got this far, I also pulled the jug to measure the skirt O/D so i have a true reference measurement when i get the CG300 skirt machined down to size match. 72.8mm all the way round.

That intake valve might be another mystery solved to the car boot price paid for the engine and an explanation to the overly rich and popping run condition.

It's all a learning curve.

[XLsior]

72.8mm

[Moto1204]

Exhaust valve does look ok, yoy maybe correct on the intake side. I know in some old Honda service manuals you could measure the wear ring on the valve and see if it was either too large or small.

I’m right at about sea level with a full exhaust. Stock Honda 125 header to a modified Kawasaki Z125 mid pipe and two brother silencer. I also run a PZ30 carb with a pod filter. I can dig up my carb jetting specs if you’d like. Maybe a good starting point when you go back together. Best of luck!

[XLsior]

The intake valve itself is worn down to the bleeding edge...
The seats look ok, not worth a new head thankfully.

The carb tuning was not working on either PZ30 or PE28 due to the dicky intake valve throwing on overrich condition.

New valves and a lapping should correct any low compression/timing issues.

This should address the hard starting issues too.

And might have explained my 4* timing key assumption which now looks to be incorrect. So might try installing it again after a few miles/KM under my belt in due course.

[XLsior]

Got the Ebay rotary tool with with the extension cable.

So attempting at head porting valve seat side.

(Discalamer: This is my first time doing this)

Taped off the surface and added a decent amount over the valve seats as a protection layer against slips and chatter. also twisted some paper towel and plugged the valve stem holes.

When purchasing the carbide tips for rotary tools I recommend using for this sort of work get the multi fluted type shown on the left of my palm. The type on the right (best avoided) will chatter and jump and not do a very clean job at all.

I have intentionally left the bite marks on the intake side as turbulence. I am not prepared to dimple.

I used some sanding rolls on the exhaust side to help with flow...but i expect it to carbon up pretty quick regardless.

I won't say its a professional result, but it is better than before.

A decent amount of material was removed.

Got the new valves waiting for the lapping kit.

[XLsior]

Got the valve lap kit.

A life time supply.

The suction caps can be a bit hit or miss but if you spin and lift and return rather than try to start a fire back and forth it works better I found.

Few passes on both coarse and fine compound. keeping the stems clean and oiled.

easier to apply the paste with a finger tip while the valve is held in suction, a little dab will do ya.

Happy with the result. Can't be worse than before.

New valve stem seals and then managed to get the retainers back in.

Now to put it all back together again....

[XLsior]

So that completes a port and valve lap job.

[Bruces]

Looks great ! .Now ,finish that bike will you !

[XLsior]

Originally Posted by Bruces

Looks great ! .Now ,finish that bike will you !

'whip cracks'

[XLsior]

So put it all back together. Torqued and valve lashed.

had to kick it a few times to lick off on refueling.

Adjusted the A/F screw and idle. Definitely less popping but not entirely absent.

Got it ticking over nicely.

replaced seat.

1st gear, clutch out barely any throttle and off it went...

Had to relearn how to ride again...no muscle memory, stiff shoulders and death grip for the first 10 min.

hit a greasy patch and found the limit to the dunlop 605s...or probably just lack of riding skill.

My back yard is fine for 1st gear not enough to stretch out but I did try 2nd for testing purposes.

can confirm the digi dash speedometer xl185 adapter seems to be working as intended.

Any way after about 20min was getting more relaxed and the smile kicked in...gave it the beans a few times. can't complain about the power delivery from my novice point of view.

Almost there...The big hurdle has been jumped...Final stretch to the finish line now.

It will all come down to roadworthy inspection and the license plate.

[XLsior]

So after my test ride yesterday I rolled the bike out the garage and noticed 1 of the front engine mount bolts had vanished.

I am fairly certain I nipped up all the nuts n bolts.

But it appears the engine vibration might be to much for 30 year old wire wheeled Japanese Honda hardware.

thankfully Honda in their infinite wisdom used standard M8 threads so I had some stainless nylock nuts that replaced the old nuts.

However I now had the hope that the bolt had dropped down and not pinged off into the bushes...

I walked many laps of the yard and thankfully found the missing bolt on bare ground...washer and nut have gone to a better place...

Well it was a shake down test ride and lost the bolt in the backyard...not 20mins down the road.

Anyway the bolt is back.

[XLsior]

Bought a 31.8mm bicycle seat clamp.

With a bit persuasion it fit over the exhaust pipe slip coupling.

It doesn't really clamp/squeeze the pipe down right now..maybe with a few heat soaks.

Also I thought I needed to dremel down the inside lip...but in retrospect I think it would have worked better with the lip able to clamp on the inside smaller pipe...

But it looks legit which might address and road worthy inspection concerns.

Think it was about $3aud shipped.

[XLsior]

So while test riding, it was becoming evident my rear brake was ineffective...I was also getting a noticeable squeal from the hub while pushing the bike around and pressing on the foot brake was not really doing anything akin to brakes.

being so critical I had to get on the tools again...

It seems when I busted the original brake linkage which lead to refurbishing the pooched 81 donor bikes parts the shock load transferred inside the drum and snapped a brake shoe...

which explains the lack of friction...

Well I found the backup original shoes which still had enough meat on them and went over the drum and shoes with an 80grit scuff.

So making the bike stop should hopefully be resolved.

Original Japanese bearing seems fine...

I also made a dedicated earth/ground strap, As I was getting poor electric starter cranking and I felt the main loom was being asked to much for starting duty.

Happy to report the new ground strap has helped with electric starting immensely.