Project: 1987 Honda CH150

[cbolling]

Pretty cool. You do good work.

[Nihon Newbie]

Originally Posted by scootrboi

I have a 1984 125 Elite, which is a similar scooter. I bought it new in 1984 and gave it to my wife when I got my old scooter 'up to standards.' The 125 only has 11,000 miles on it, mostly from the 1980s. It has been an almost trouble free scooter. The final drive gave out at around 7000 miles because I didn't know it had one. We stored it for 17 years and I had to clean out the tank and do other things to the fuel system to get it going. But it runs perfectly now. I don't think I would have persevered the way you have, I find the Honda hard to work with, but it is a rugged scooter with lots of pep, and gets excellent fuel economy. Sometimes over 100 mpg. With your attitude (positive and determined) you will probably be well rewarded for your efforts. The Elite is a good design with no nasty quirks. Do what you can to keep the exhaust studs from seizing, a broken stud precipitated the worst episode in that scooter's history.

It's always so cool to hear of people having their own unique experiences with the same model vehicles I own! Thanks for the tips and info.

Originally Posted by Wentwest

The 87 150 is maybe the best all around scooter I've ever had. It has 2 weak spots that I have run into that can cause strange problems.

The CDI develops some kind of problem internally and can cause sudden shut downs that will just stop the engine with no warning at all. A couple of minutes later it starts right up and runs fine. Everything will check out perfect, it will run great and then it will stall. If that starts to happen, buy a new CDI. Lots of people say get only a Honda part, but remember that they are all 25 years old and they all can break the same way. There are loads of Chinese reproductions all over the internet for $10 to $20, and they work. If you don't trust them, buy 2.

The other thing is the bystarter that helps with cold starts. If it fails it mostly still starts easy when it is cold, but it's hard to start warm, and gas mileage goes down and your top speed drops. There's a ton of info at www.ch250.net. In the tech tips there is an article about bystarters. Also you can search through the CH250 group on Yahoo. Mechanically these 2 machines are almost identical, just a bigger displacement engine.

Great machine anyway.

I've read a lot about both issues, and have even considered buying a spare of each, but knock on wood, mine seems to be fine at the moment, and I'm honestly not sure how long I'll own the scooter, anyway. I am yearning big time to get back on the track, and to do some long, fast road trips. I love wrenching, but given my current situation, I can't afford to keep the scooter and buy a sportbike, too. In the meantime though, I am enjoying the hell out of the thing!

Originally Posted by cbolling

Pretty cool. You do good work.

Thank you, sir. I'm a bit of a home brew type of mechanic, but I strive to be thorough.

[Nihon Newbie]

Finally pulled the valves out. Had to buy a cheapo overhead valve spring compressor at Sears, which promptly broke as soon as I started trying to use it...Worked out in the end though, and I didn't break anything, yay! Had a hell of a time with the intake valve, as the collet halves were totally, utterly stuck, forcing me to jig everything upside down to tap the valve face itself to loosen the jammed collet halves. No macro lens for my camera, but the collets had somehow managed to actually put 4 tiny, tiny dents in the valve stem, which prevented me from sliding the valve out. Had to use a small file to carefully deburr those dents before I could extract the valve. Madness! I guess it's a good sign that the .002" clearances in there are tight as ever.

Sorry I didn't take any before pics of the valves, but suffice it to say that the exhaust valve had a ton of crud and crap on it. Intake looked ok. I polished up the dome on the cylinder head, and took to toothbrushing out the exhaust port after smoothing it some with a red 3M pad. Everything is within spec measurements, thankfully, so I guess tomorrow I'll do a quick solvent wash and stick the valves and springs back in. In the meantime I used a cotton swap to coat the stem seals, valve guides, and valves in new oil to inhibit any overnight corrosion.









In that last shot, intake is on the left, much cleaner. Exhaust still looks dirty, but I cleaned it as best I could without damaging the valve face.

[Warney]

Some fine lapping compound and a few minutes back and forth will clean the exhaust valve and seat like new.

[Nihon Newbie]

Originally Posted by Warney

Some fine lapping compound and a few minutes back and forth will clean the exhaust valve and seat like new.

Oh cool, thanks! I didn't know you could do that intermittently just to freshen that up. Sounds good!

By the way, anyone have any advice for how to prep the bottom of the cylinder head? Sanding on glass seems to be popular...

[Nihon Newbie]

So stoked with my pile of tiny Honda parts, and materials for the rebuild!!! A local automotive shop let me use their impact screwdriver to remove the seized Phillips head screws anchoring the stator and failed pulse module, which was my last issue of disassembly. Big thanks to them!

Lapping compound, sheet gasket material, Xacto knife, Hondabond, new piston rings, new cylinder, pulse module, new wrist-pin circlips, new exhaust gasket, new exhaust nuts, new base + head gaskets, new SS fasteners for the stator anchors, and clean gloves, lol!

First thing, I need to verify the fitment of the new cylinder and gaskets. Next, I'll need to start tracing and cutting gaskets for the CCT, and the stator/pump cover. Tomorrow I'll be removing/cleaning the stator, then swapping it and the pulse module into the replacement stator cover with the new fasteners. After that, I'll start the valve lapping process, wash out and dry the head again, reassemble the cylinder head, and maybe if I have time, start stacking parts to work out the squish with the new gaskets, ensuring that everything is stacking up properly.

The valve lapping suction handle thingy is way too big for these tiny valves, so I think I'm going to stick a piece of plastic hose on the end of the valve stem and just spin and pull from the other side, by hand.

I'm still researching 2 things: a) if I'm supposed to apply anything heavier than motor oil to the valve stems/guides when I put the head back together and b) how best to clean, flatten, and prep the gasket mating surface on the head...

Lastly, what say you all about re-using the original cylinder? I don't have a bore gauge, so I'm not sure on its exact ID at the moment, but I'm tempted to keep this brand new cylinder as a spare, and re-sell it whenever I sell the scooter. It has 19,000 miles on it, and looks to be in pretty good shape.

[Warney]

I've used a piece of dowel rod and hot melt glued it to the valve, worked fine. This guy has the mojo going on.
http://www.youtube.com/watch?v=fhXsH12Rg6s

[Nihon Newbie]

Originally Posted by Warney

I've used a piece of dowel rod and hot melt glued it to the valve, worked fine. This guy has the mojo going on.
http://www.youtube.com/watch?v=fhXsH12Rg6s

Ha! I watched that same video earlier. I've been on Youtube most of the day going between watching F1, and researching all the stuff I need to do to my engine. So awesome being able to look and watch people doing it, instead of just reading about it.

News: My cylinder showed up in the mail today, but unfortunately, it is not an OEM part. This was not made clear in the listing, so I'm pretty pissed. I suppose I could re-sell it, but since it's not a factory-available part anyway, I guess I'm back to square 1 on the head gasket dilemma. The one that came with the eBay cylinder is of very different construction from the one I pulled out of the motor. There is no lip that seats down into the coolant jacket, and there is no fiber layer on the outside whatsoever. I'm not one to deal with parts misrepresentation lightly, so I'm kind of freaking out again.

I guess I'll be back in contact with Gaskets to Go over in Thailand, as I have read about many a satisfied customer of his, after they had him custom make 1-off head gaskets for their bikes...

I was so stoked earlier, thinking I would be riding this weekend...

[Warney]

Contact Jack at jacksscootershop.com, he is a good fellow who may be able to get you fixed up.

[Nihon Newbie]

Originally Posted by Warney

Contact Jack at jacksscootershop.com, he is a good fellow who may be able to get you fixed up.

Thanks, I'll definitely give that a shot tomorrow.

[bykpimp]

This is a neat thread!!! I was working for Honda when these scooters were new and it brings back some great memories!!! I've got my ole CH150 Deluxe (forgets year, 85, 86? ) sitting covered up out in the drive. The exaust gasket thing brings back memories. 9 out 10 were missing when these scooters came in for a service. Love the pics in this thread as well!!!

[_cy_]

got two CH150 or CH125 parts scooters. both has complete engine/tranny, wheels, etc. let me know if you get stuck and need something

[Nihon Newbie]

I cut out some new gaskets for the CCT and the stator cover, though I only made the stator one as a template to send off if I ever need the gasket actually made, as it would have to be heavier duty than this thin fiber paper stuff. I only need to cut out one more, for the base of the new cylinder. I guess after I have the head machined, I'll try using the MLS head gasket that the cylinder came with...I also removed and cleaned the stator itself, before swapping it into the replacement case cover, then I did a final clean and lube of the water pump impeller shaft and its bearings. Learned a valuable lesson about why you shouldn't use anything but snap-ring pliers when removing snap rings...

I spent a whole day on the head last week. Really hard to get any decent pictures, but I "ported and polished" it. I sanded the intake and exhaust runners, removing the fat lips of aluminum casting flash where the runner meets each valve seat ring, as well as smoothing the walls of the chambers. I polished the domed part of the inside of the head, as well as lapped the valves. Now I need to file down the welds on the muffler from when I repaired the break, have the head milled flat, and install my new valve seals, which unfortunately won't be here til January 4th. :/ Theoretically, after that, I should be a go for reassembly of the whole scooter. I'm thinking I'll run it for a day with the first oil change, drain it, fill it up again, and maybe run that second oil fill for a week? ...Thoughts on that?

Originally Posted by bykpimp

This is a neat thread!!! I was working for Honda when these scooters were new and it brings back some great memories!!! I've got my ole CH150 Deluxe (forgets year, 85, 86? ) sitting covered up out in the drive. The exaust gasket thing brings back memories. 9 out 10 were missing when these scooters came in for a service. Love the pics in this thread as well!!!

That's awesome! I think I would love working for Honda. This is definitely my first experience with all this gasket nonsense, both for the head and for the muffler...It's definitely a heck of a lot of work to be putting into something this old, but it's a great learning experience!

Originally Posted by _cy_

got two CH150 or CH125 parts scooters. both has complete engine/tranny, wheels, etc. let me know if you get stuck and need something

Thanks so much,I'll definitely keep that in mind!

[Nihon Newbie]

So, I took the cylinder head to an engine builder in town...The owner is a bit crazy, but still a sharp machinist. He spent a while looking it over and checking for warpage across the deck...I started getting nervous, then after a very, very long conversation about RA finish levels, and gasket composition, he declared it was just fine, and in no need of being machined! Didn't want to charge me for his time, said come back if I ever needed anything down the road. Super stoked on all this.

Not stoked on still having to wait another week for my stupid backordered valve stem seals...ha

[tcjames.yu]

I rode through Xindian Taipei today, sunny day.