Issue with bike when its wet

Mrdodge7 · L Plate Warrior Joined: 13 Jan 2021 Karma :

CBR 125R 2014

Its mainly when its wet, it rides fine no issues, when I get to where I'm going and stop, it idles at 1.5-2k RPM but skips/misses revs then eventually cuts out. This is only when its raining or been raining.

Any ideas what could be causing it? Just trying to narrow it down a bit so I dont have to pay a mechanic too much money just for diagnosis! Its going in on Saturday for new chain and sprockets and possibly to fix this issue.

jaffa90 · World Chat Champion Joined: 06 Apr 2016 Karma :

May help.
https://www.bikechatforums.com/google.php?q=+Honda+CBR+125+keeps+cutting+out+in+the+rain

doggone · World Chat Champion Joined: 20 May 2004 Karma :

Moisture round HT leads and/or plug cap(s)?
Such things can be difficult to diagnose if it's not that damp in other block connectors or even sidestand cut out.

steve the grease · Crazy Courier Joined: 26 Jan 2018 Karma :

Try narrowing the plug gap down a bit - or maybe splash out on a new plug. If the plug is a bit tired or the gap too wide , the ignition system has to work a bit harder to make it work.
This can show up any weaknesses in the insulation when it rains. When it does misfire and play up, try spraying the coil/ lead/ plug area with WD40 or similar, it may improve.
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All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....

Mrdodge7 · L Plate Warrior Joined: 13 Jan 2021 Karma :

I've recently sprayed the plug and cap with WD40 as it rained so bad the bike wouldn't even start lol, it did fix that problem, wondering if it could still be that? I think I'll get the mechanic to whack a new spark plug and HT lead and a new cap anyway for peace of mind.

blurredman · World Chat Champion Joined: 18 Sep 2010 Karma :

Touch the ht lead in various places and get a shock to determine wherebaouts the problem is occuring. Could just be some moisture in and around where the HT lead goes into the coil, or perhaps cap.
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S, 1979 MZ TS150.
Current: 1973 MZ ES250/2 - 18k, 1979 Suzuki TS185ER - 10k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 40k, 1989 MZ ETZ251 - 51k.

stevo123 · Nitrous Nuisance Joined: 10 Aug 2004 Karma :

if you run it in the dark you have a good chance of seeing the high voltage jumping to ground.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

My enfield started stuttering when I applied the brakes in the rain.

I eventually worked out that water was pooling in a fold of my waterproofs then when I braked, it would slosh out and drop into the air filter -located directly under my right thigh- and make the bike stutter.

I solved the problem by sticking my leg out a bit when braking in the wet.

the point being. Water is getting in somewhere.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.