MC-250-54B Timing Chain Replacement

[smorkle]

I adjusted the valves when I had it apart the first time. Only had 27 miles on the adjustment before the chain broke. I can't imagine that it needs adjusted again this soon. I will if the clattering persists.

[JR]

Yea I know it sounds stupid but now that you have had it apart and back together again it could be off! The valves especially the exhaust valve are really picky on the linhai.

I just finished mama's today was being irritable and the intake was fine exhaust closed up and I adjusted her's at 200 miles and it now has 1500 and in that short time the exhaust closed! It now runs like a scalded ape and I also just put in 12 gram sliders! Man it will haul but up the hills! Hey if ya ever think about a ride on the Pig Trail again you might think about those sliders, with that extra HP you will gain a tad with the sliders for that two up with GF!

I also adjusted the valves on my 250B as the long ride to Dallas and back made it irritable too after 5500 miles now, again she runs like a scalded ape! LOL JRR

[earlwb]

Way to go Smorkle. That is a great idea on how to deal with the camshaft timing chain. The pictures are excellent.

jrryan, there have been cases where the exhaust valve stretches when heated up as the engine is running. Usually it goes away after a while, but it can be a PITA having to adjust it from time to time. many years ago, valve adjusting was a standard ritual of ownership for motorcycles. Some motorcycles were notorious for needing the valves adjusted a lot. of course i remember a piece of crap old Jaguar car that I owned for a while, that I swear, needed the valves adjusted almost every weekend.
But in the past there were scandals where a batch of scooter engines had valves that stretched too much on the owners. Bad valves that weren't manufactured correctly. One had to adjust the valve gaps very frequently, almost daily it seemed.

Way back in the dark ages when I was a teenager, i worked at a car dealership, and they had a machine they used to machine the valves. one step was to grind a little off the end, so you could adjust the valve gap. of course a valve job entailed lapping the valve into the valve seat, so it might sit a little deeper, thus making it too tall to adjust the valve gap with. But valves on the cars of the period would stretch over time. So the specs had a minimum and maximum valve length and specs on when to grind off the end as needed.

[JR]

Yep Earl know exactly what you're saying and one of the engines that needed adjusted pretty regular too was the old Chevy 235 with the solid lifters! Ya always knew when you started them up as in the clacky clack! LOL

So far on my 250B now with 5500 miles on her I've done it twice both thimes the exhaust valve was tight! No gap at all! Intake was fine the second time! On mama's 250A I checked them for the heck of it with 300 miles again exhaust vavle closed and again yesterday and the exhaust valve hd .001, almost closed but Smorkle's scooter has 5000 miles on the valve assembly so they could be loose too especailly with this new higher compression piston and head so he'll just have to run it for a spell and then see! JRR

[smorkle]

I rode it some today and it's still clattering a bit but not as badly as before. I think the problem was month and a half old gas. Time will tell.

I took about a 40 mile ride and it's running hotter than before. The fan is kicking on at about 7/8 of the gauge and kicking back off at about ¾. Used to it would kick on at ¾ and kick off at ½. The last time I drained the coolant I had this problem too and it eventually worked it's way back to normal, but it is a slight cause for concern.

Also, it's making a noise on the right side of the motor. Kind of a ticking noise. I can't isolate the exact spot where it originates from, but it is definitely there and something new. I can't find an LED display counting backwards to zero so I don't think it's gonna blow up. At least not in the traditional sense.

I'm still gonna ride with these guys tomorrow and see how it acts. If I break down I'll have plenty of help.

[xy260t4]

good luck smorkle"hopely no problem straight tire riding.

[smorkle]

Well I'm back from my ride today. Pushed it a little harder than I would have liked to, but I made it home in one piece. I discovered that I had just a little more air in it before I left and, after adding some antifreeze, it ran a little cooler than yesterday. It's still making the ticking noise but it doesn't seem to be affecting anything so I'm gonna wait on figuring out what it is until later. Perhaps whatever it is will present itself.

[xy260t4]

GLAD IT RODEFOR U BRO,HOPELY U FIND THE NOISE PROBLEM AND IT JUST MINOR.ONELOVE PEACE

[noetzkahuna]

Is there any common technique for removing the oil seal that sits on the side of the timing chain?

[wile]

They do sell Seal pullers, but you can use those tiny screwdrivers and pick at it that way. Once you get part of it to stick out then you have it made. Also as your picking at it trying to get it to move out push to rotate it as you pull out.
Wile