Honda city express losing power

[JohanR]

It's not like it had a lot to start with...

It's been running fine since I've had it, about 8 months. On the way to work this morning it got about 4 miles into the 8 mile trip and then sporadically lost a bit of power. Never really enough to show on the speedometer, and would recover after a few seconds.

On the way back it was doing it from cold. It felt very sluggish to accelerate, and couldn't get above 25 mph. It can usually get to 30, at least on the flat.

I did wonder if it was one of the brakes applying itself. the front drum was cool after the trip, and the back slightly warm. I don't know what it's usually like, and it is right next to the exhaust...

What should I check, starting with the easiest, and hopefully, most likely.

I'm a complete novice when it comes to vehicles. This might be a good place to start learning.

(I found the spark plug, but have no spark plug spanner to extract it. I'll have to get one first thing tomorrow. Once I've done that, I'm out of my comfort zone!)
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[andys675]

probably a build up of carbon in the exhaust
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Some people feel the rain, others just get wet.

[JohanR]

The exhaust is now off.

From looking at other threads de-carbonising it is basically a case of filling it with a solution of caustic soda overnight. Apart from being careful with the caustic, are there any subtleties I missed?
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[Martay]

Id certainly try a new spark plug. Might be worth cleaning the air filter too if you're de coking the exhaust.
They are quite sensitive to compression, there's not alot to begin with, which is a sign engine wear could be setting in.
Check the condition of the auto choke pipes around the carb. They're hidden from view and i found mine runs like a dog with them disconnected. there is a small rubber round filter in amongst those pipes, open it up and bin the tiny piece of foam. It seems to choke the auto choke!
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Eat well, poo hard
Drives: Cavalier 2.0 16v
Rides: Slightly ratted Honda City Express

[Tbag]

I had this kind of problem with my Old CG,

It was almost like i was running with the choke on.. No power whatsoever (No that it had any to start with )

I ran some redex through it and added a fuel filter, It runs fine now.

[JohanR]

Exhaust filled with caustic soda overnight, and emptied this morning. Lots of lovely black gunk came out.

There's some water still inside, not much, but I haven't been able to tip it out yet. How important is it to get it all out? Will it be expelled by the exhaust, or will it sit there and rust?

I'll clean out the air filter next.

Spark plug on order, here's the old one:
https://stampsworkshop.co.uk/misc/bike/spark_plug.jpg

According to the book, it's the right colour. The insulator appears to be missing a bit at the tip though.

Redex... Seems to be split opinions about this, but by all accounts it won't do any harm. I'll try that after the spark plug.
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[JohanR]

It actually worked, the bike is working as well as it ever did. I wasn't really expecting that.

I did over torque one of the bolts holding the side panels on, and snapped the head off when putting it back together. Time to buy a bolt extractor...
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[The Shaggy D.A.]

Welcome to Yak shaving, want to clear your exhaust and end up buying bolt extractors