So during and after yesterday’s downpours my scoot was running like garbage. Hesitating and no power. I could barely get up to 59 kph. I go to my local shop and he takes it for a spin and says, “No problem. I got it up to 70”. I ask him why it was running so bad in the rain and he says that lots of scooters have that problem. It’s OK. When it dries out it will run fine.
I’m thinking it’s time to change scooter shops.
So from someone with some actual mechanical knowledge, what’s causing it and what needs to be done to fix it. I’m suspecting the hesitation is a carb issue because that happens even when it’s dry with increasing frequency. But why the rain problem?
Help please.
The same thing happened to me. It was pouring heavy, I start riding, and when I come to a stop, the scooter dies and is unable to start.
Long story short, I had to ride my bicycle to run my errands yesterday in the rain, and to go to work.
After it cleared up, I rode my scooter in the evening…
I have no idea why this is. I didn’t have this issue before… It is motivating me to buy a KTR asap though…
I’ve been wanting a motorcycle for a while, and have been debating about a 250cc, etc…
Now, I just want a decent bike.
Is that cover on the filter sealed tightly? I don’t know if that’s the problem but I’ve had power issues whenever that cover doesn’t fit tightly.
water clogging up the air filter (ensure your air filter is new and lightly oiled, and the air box or air inlet aren’t funnelling water into the filter area)
water covering the HT lead and spark plug and providing an alternative ground route, especially through a layer of dirt (clean the outsides of all your HT leads, perhaps remove any dirt from the cylinder head, use a spark plug grease around the boot of the plug to prevent current leaks).
run a carb cleaner through the carb to open jets and passages, and assist in removing any water that’s collected. This is not a spontaneous change that happens only when it rains, but it does contribute to your carb running badly all the time…
it is not a universal problem, probably more related to design of the air intake and cable routing, etc., on some models
I also have this problem with my Hartford. But I hate issues that fix themselves so it’s difficult for the mechanic to troubleshoot.
Re: Rain makes my bike run bad
Postby urodacus » Yesterday, 08:18
"water clogging up the air filter (ensure your air filter is new and lightly oiled, and the air box or air inlet aren’t funnelling water into the filter area)
water covering the HT lead and spark plug and providing an alternative ground route, especially through a layer of dirt (clean the outsides of all your HT leads, perhaps remove any dirt from the cylinder head, use a spark plug grease around the boot of the plug to prevent current leaks)."
Good info…
How do I do that? How do I ensure water can’t get to to the filter and what not? Can you show some pictures or illustrations so I know exactly what I need to do?
you can’t do much about the design of the bike if it’s built that way, but you can check that everything is in place and there are no missing panels, baffles, etc.
if the air intake is pretty much open to the elements, you can perhaps rig some kind of splash guard so that the water thrown up by the front wheel doesn’t get sucked straight into the air intake.
The oily filter thing retards water entry through the filter. It also traps more dust, dust that often passes right through a sponge and then abrades the piston and cylinder lining, leading to premature wear. Of course, on a piece of crap scooter, that’s normally neither here nor there as they’re disposable items in many people’s opinion.
(If you have a paper air filter, don’t oil it. Only oil a sponge one!)
[quote=“urodacus”]you can’t do much about the design of the bike if it’s built that way, but you can check that everything is in place and there are no missing panels, baffles, etc.
if the air intake is pretty much open to the elements, you can perhaps rig some kind of splash guard so that the water thrown up by the front wheel doesn’t get sucked straight into the air intake.
(If you have a paper air filter, don’t oil it. Only oil a sponge one!)[/quote]
My biggest problem is when my bike has to be parked outside in the rain. I looked at the air filter and it doesn’t look like it’s sealed very well. Perhaps this is the culprit.
Badly
[quote=“jaame”]Badly[/quote] 
this is a common problem - I was informed that it was to do with air pressure and the automatic choke. you see it happen all the time - even here where they park inside
[quote=“kjmillig”]So during and after yesterday’s downpours my scoot was running like garbage. Hesitating and no power. I could barely get up to 59 kph. I go to my local shop and he takes it for a spin and says, “No problem. I got it up to 70”. I ask him why it was running so bad in the rain and he says that lots of scooters have that problem. It’s OK. When it dries out it will run fine.
I’m thinking it’s time to change scooter shops.
So from someone with some actual mechanical knowledge, what’s causing it and what needs to be done to fix it. I’m suspecting the hesitation is a carb issue because that happens even when it’s dry with increasing frequency. But why the rain problem?
Help please.[/quote]
shouldnt run badly in the rain, that sounds like bull.
my scoot ran badly only when it was under water.
but make sure to get a new air cleaner and a new spark plug and perhaps a distributor?
Distributor on a single cylinder engine? Does it really have one? Why would it have one?
My spark plug and boot are only 3 months old. I haven’t checked the air filter yet but will do that in the next day or two. Even when it’s dry outside, the hesitation is still happening at speeds above 55 while cruising even after running a bottle of cleaner through it. I’m still guessing carb needs work or replacing.
[quote=“kjmillig”]Distributor on a single cylinder engine? Does it really have one? Why would it have one?
My spark plug and boot are only 3 months old. I haven’t checked the air filter yet but will do that in the next day or two. Even when it’s dry outside, the hesitation is still happening at speeds above 55 while cruising even after running a bottle of cleaner through it. I’m still guessing carb needs work or replacing.[/quote]
Thats what i thought too, but its called “bai ching” and it works like a distributor. IF your scoot is backfiring especially.
anyway it shouldnt run rough because of rain.
get a better mechanic
distributor because even tho single cylinder it acts as spark timing, which is still needed. unless u have electronic ignition.
With the rain these last few days it’s getting worse. I’m taking it to a new mechanic this afternoon. The second half of my 16 km commute this morning in the rain had me down to 40 kph. :fume: :fume:
Thanks for all the information!
Yep. Went to a different mechanic and suggested that maybe it’s the air filter. He asked if I had been though any particularly large amount of water, what it was doing, etc, took it for a short test drive, and agreed that the air filter was the first guess but he’d check out other stuff as well if needed. Then opened up the air filter and it was trash. Replaced it for $180 and the scooter runs like a champ. :bravo:
NOT going back to the first guy…ever. I’ve been going there for 2 years but I will not return. :fume:
told ya to check the air cleaner (filter element).
glad u got it sorted. A good mechanic is worth A LOT
If you haven’t had your HT lead replaced for a while, then do so anyway. The HT lead will break down over time and cause current leaks as suggested. It’s so cheap to replace, along with the spark plug, and you can improve your performance and fuel economy at the same time by doing away with the old one.
[quote=“tommy525”]told ya to check the air cleaner (filter element).
glad u got it sorted. A good mechanic is worth A LOT[/quote]
A good mechanic is GODLIKE if he does 10Km roadside rescues from his shop 
and as suggested, AF, sparkplug, sparkplug “mushroom head” , most common 3 problems.
Glad to hear changed the air filter worked for you.
I had almost the same problem, when it was raining heavily or had just rained heavily, I had problems with my scooter running. It would often just turn off when I was waiting at a red light or just accelerating from a red light. If I did manage to get my scooter going from a red light, there was no power loss.
It was just scary having your engine die when the light turns green, as I’m sure a lot of you can understand. Especially if you aren’t on the far right of the lane.
I was told by my friend at the Kymco warranty shop in Hsin-Chu (or is it Hsin-Ju) that the “Ignition Coil” is often the problem in my case, even on new scooters.
I went to my scooter parts distributor in Jubei and ordered a new ignition coil with a new spark plug lead for about 680NT and put it in myself. It’s a real easy job, just take out the seat and compartment, take off the 2 nuts holding down the ignition coil and disconnect the 2 wires that connect it and the spark plug lead.
After changing my ignition coil, never had problems with the rain since.
However, with your scooter, I can easily see that the air filter that would have been the problem. Often when scooters don’t have much power and have problems getting upto 60+km/h, check your air filter and the air box if it’s properly sealed.
Found this out the hard way after I took apart my carb to clean it and my air box. When I put it mostly all back together, with a new air filter, I didn’t put the cover to my air box back on and tested my scooter and couldn’t figure out why the engines RPMs had troubles going higher or being steady over 3000. Ended up taking apart my carb again to
see if I messed something up. Everything looked fine, so I put the carb back on and this time put the air box cover back on, and that fixed my engine RPM troubles.
I guess lastly I’ll finish up with what tommy525 called a “distributor”. In my shop book for my scooter, it’s called a “CDI unit”. It controls the firing of the spark plug, which gets it’s timing from the alternator/generator. Most scooters have them, even if they aren’t fuel injected. My isn’t fuel injected and it has one.
I know when I saw the word distributor, I saw a picture in my mind of what they used a long time ago in cars and motorcycles. A round thing with your spark plug lead(s) coming from it and inside a bar that would spin around to make contact with the lead(s) to deliver the spark. Can’t remember when they stopped using those, as I only got into
engines in the past five years or so.