Help with troubleshooting a poorly running 125.

[DrAlf]

A friend of mine acquired a Honda CLR125 a few weeks ago. Seeing as I found the bike, I now find myself being in the unenviable position of being responsible for its running and maintenance – obviously.

The bike has started running rough – it won’t idle with the choke off even when warm. At the top end of the rev range it splutters and generally runs poorly barely managing to hit 50mph. This all seems to have started since the bike was dropped about 2 weeks into ownership. Whether this is related I don’t know.

Having discussed this with a few technically savvy tossers at the Cotswolds do last weekend I’ve been advised to check for water in the carb. The bike is being dropped off on Saturday. Is there anything else I should check? Grateful for any ideas or thoughts – Ta

 

[Ogmios]

Was it lying idle for any length of time?
I'd strip the carb and clean it, drain tank (see what the contents looks like - could tell you a lot ) and clean the fuel filter.
Some (a capful or two) 'Redex' in the tank and try again.
Good luck and keep us posted.

 

[Timpo]

Take the carb off, check the jets are clean but do poke metal objects through them. Main jet, pilot jet, emulsion tube and associated galleries will all need a looking at. (Myself, I don't mess about, just replace the pilot and main with brand items, you know they're right then. http://www.allensperformance.co.uk/products.html).
I'd measure the float heights whilst there and also check that the balance pipes are clean, these are the breather pipes that hang from the carb body.

Also check that the battery leads are clean and contacts are good either end of the cabling.

Let us know of any findings.

 

[DrAlf]

Thanks both, so it looks like I’m in for a day of carb stripping and tank inspecting on Saturday. Should be interesting. I’ll let you know how I get on

 

[ahutcheon]

check the jets are clean but do poke metal objects through them.

Sorry to be picky about a likely typo, but did you mean DON'T poke metal objects through them? I appreciate I know just enough to be dangerous, but I always went with a bit of nylon bristle or maybe soft brass wire for poking through jets on the grounds that anything harder might damage/enlarge them. Maybe I'm about to learn something?

 

[Timpo]

Sorry to be picky about a likely typo, but did you mean DON'T poke metal objects through them?

Whoops, yes it's a typo.......

 

[(RIP) Kaister]

valve clearances

compression check

 

[Lord Snooty]

I'd start with checking the plug and HT lead. Sometimes it is the most obvious and simplest fix. Best of luck.

 

[Toad]

http://www.motorcycleservicesshipstononstour.co.uk/

 

[DrAlf]

Thanks all I’d already figured out the typo Battle commences tomorrow – I’ll have Mike on standby for when it all goes wrong Toad