1987 Honda Elite CH150 Performance Question

[max57]

Originally Posted by Prodigium

I have a '87 CH150. It has given me 85mpg in light riding, not goosing it all the time. My top speed is 10mph faster than 58mph. I've GPS'd my speedo @ 3mph low and pegged the needle at over 65mph today, so that was 68mph. I wish i'd had my GPS with me. It was pretty exciting. This engine responds well to opening it up for better breathing. I've removed the twisty intake tract and replaced it with a K&N filter on the carb. I've also opened up the exhaust a tiny bit. That's all I've done. Next, I'm opening up the muffler so that the outlet is as big as the head pipe. The outlet has less that half the area of the head pipe... the engine is choked. I also have a head I ported and polished and matched the intake manifold to the intake port, and head pipe to exhaust port.

My CH125 goes 57mph.

[pradecki]

Thanks for the advice guys. I was able to spray some wd-40 where that shaft goes into the rear brake from the outside and then just worked the lever arm back and forth for awhile to get it rotating nice. Brake works well now, I got lucky and never had to take the rear tire off.

I think this spring time I am going to rebuild that carberator again and maybe buy a new bystarter. When I winterize the bike in a couple weeks here I will check the fuel tank for rust. It feels like the fast idle isn't set right. Now that I have been riding it for a couple weeks I am noticing how if the bike is fully warmed the engine really runs well, like I can go up this steep hill by my house at 35 or 40 mph no problem, but when the engine is cold at wide open throttle I can barely do 25 mph and the bike loves to stall at stop lights. Its weird because when initially rebuilt the carb I tested the bystarter and it warmed up when I applied 12 volts and the little shaft moved as it heated up, so I thought it was working fine.

[max57]

My 84 125 sat for 17 years. I found it necessary to clean out the fuel tank of several cups of rust. Low grade metal of course. Then I replaced the auto fuel valve under the tank, unplugged the tiny slow jet, and replaced the bystarter. It still only starts at 45 degrees and up, but otherwise it runs like new. The slow jet is really important. It can run without it, but having an authentic idle is a big improvement.

[dorus]

Installing mikuni vm26mm carb on my Ch150. Any one done this... jetting recommendation ?

[nerdydaddyo]

I have a 1985 Honda CH150D that struggles to start from cold, and often will have this low, rough idle that if not maintained by the throttle, will eventually die out. I have warmed the scooter up to completely warm and still have the issue regardless of temp. I have done everything; cleaned the fuel tank, clean carburetor, spark plug, fuel filter, air filter, oil change, new belt, petcock assembly (includes new fuel screen), all vacuum hoses, carburetor mount (the rubber one infamous for failing), breather separator assembly(all new), new muffler gasket, new battery, tested the bystarter for resistance (a perfect 0.5 ohms), all fuses check out OK, and all wiring is intact and free of damage. When I start it, it takes several tries, and once i get it going, it has puffs of white smoke at first while warming up, and maybe its because its just cold outside right now, but once its warmed up, no smoke. When I pull the spark plug, its wet, but the bike only has 870 miles on the odometer. Any help would be greatly appreciated, because as you can see, I have put A LOT of money AND time into fixing this, and my woman is livid with me right now that it STILL cannot be driven. I plan to do a compression test next (waiting on 12mm adapter), but in the meantime, I'm open to suggestions. Thanks.

[outofcontrol]

So did you buy this scooter not running? or is this the same symptoms it had when you bought it?
You said it starts hard even when it's warm, but does it run well when it's warmed up?
How did you clean the carb? did you rebuild it?
What are your current carb settings?
What's your elevation/latitude/ave. temp?
Did you check the valves?

There's so many things that it could be. With 870 miles on the bike, I'm guessing the carb needs to be rebuilt. There's a bunch of rubber O-rings in there that have probably hardened over the last 25 years of sitting around. And just the slightest layer of lacquered fuel will change the way the bike runs.

It's taken me about 20 carb rebuilds to really understand how to clean a carb. Taking the bowl off and spraying carb cleaner in there might not be enough. I would buy a cheap $17 rebuild kit from eBay and use most of it on your carb. Strip down the carb to only metal, and boil it in water for an hour before you do the rebuild.

This might free up a passage in the carb you're not seeing, or seal up a passage that's leaking.

A faulty bystarter can be a bitch too. Pull it out and touch the leads to the battery and see if the little metal pin and collar on the end move out after about 90 seconds. It only moves about 1-2mm, so measure it. But if it was faulty, you'd probably have running problems, not starting problems.

Oh, and welcome to the forum. You might get more attention if you start your own thread instead of hijacking this old one. But it is amazing that the best advice on the CH150 is buried here on an adventure bike forum.

-Kevin

[nerdydaddyo]

Per your advice, I'm moving this to a new thread with the same title as my first post. Thanks again.