Honda Sl125 stops sparking at rpm

Message
Author
Blankdeleted
Rookie
Rookie
Posts: 2
Joined: Tue Jul 26, 2016 3:57 pm
Real Name: *deleted
Sex: Male
My Motorcycle: Blank

Honda Sl125 stops sparking at rpm

#1 Unread post by Blankdeleted »

*deleted*
Last edited by Blankdeleted on Sun Jul 03, 2022 6:13 am, edited 1 time in total.

GS_in_CO
Legendary 300
Legendary 300
Posts: 300
Joined: Thu Jun 27, 2013 2:10 pm
Real Name: Ron
Sex: Male
Years Riding: 34
My Motorcycle: 1988 BMW R100GS
Location: Ft. Collins, CO.

Re: Honda Sl125 stops sparking at rpm

#2 Unread post by GS_in_CO »

Loss of spark under load (different from high RPM) can occur if the plug gap is too wide because a full charge of fuel/air mixture is more of an insulator than nearly-no fuel/air (=vacuum) so a weak spark or excessive gap can't make the jump at high power but it can at low power.

You might also have a gap in the conductor portion of the spark plug wire which you can't see which is contributing to an excessive gap problem.

I suppose that weak connections to the coil could give similar symptoms because at high RPM there is less time for the coil current to build up to create the voltage for spark so dirty connections or defective coil might give these symptoms too.

But check plug gap and plug wire first. They are cheapest and more likely than coil problem.
Ron

Current: 1988 BMW R100GS (the 'numberplate' model)

Past: 1987 Yamaha XT350
1983 Honda CB900F
1980 Honda XL185S
1979 Suzuki GS425E

User avatar
Johnj
Site Supporter - Platinum
Site Supporter - Platinum
Posts: 3806
Joined: Fri Nov 17, 2006 7:34 am
Real Name: Johnny Strabler
Sex: Male
Years Riding: 34
My Motorcycle: A Bolt of Lightning
Location: Kansas City KS

Re: Honda Sl125 stops sparking at rpm

#3 Unread post by Johnj »

The video says you need to look at the carb and or intake.
People say I'm stupid and apathetic. I don't know what that means, and I don't care.
Image
Always wear a helmet, eye protection, and protective clothing. Never ride under the influence of drugs or alcohol.

Blankdeleted
Rookie
Rookie
Posts: 2
Joined: Tue Jul 26, 2016 3:57 pm
Real Name: *deleted
Sex: Male
My Motorcycle: Blank

Re: Honda Sl125 stops sparking at rpm

#4 Unread post by Blankdeleted »

*deleted*
Last edited by Blankdeleted on Sun Jul 03, 2022 6:12 am, edited 1 time in total.

User avatar
Johnj
Site Supporter - Platinum
Site Supporter - Platinum
Posts: 3806
Joined: Fri Nov 17, 2006 7:34 am
Real Name: Johnny Strabler
Sex: Male
Years Riding: 34
My Motorcycle: A Bolt of Lightning
Location: Kansas City KS

Re: Honda Sl125 stops sparking at rpm

#5 Unread post by Johnj »

I'm sorry but you can't use silicone to seal the boot, buy new ones.
Did you replace the O ring between the carb and the engine?
There are many guide books on how to diagnose carb problems. The idle circuit is working but as soon as you twist in some gas (lift the slide) the engine dies (the needle isn't lifting off the seat) or bogs (the needle lifts too high) out. This could be as simple as moving the clip holding the needle up or down ONE notch.
People say I'm stupid and apathetic. I don't know what that means, and I don't care.
Image
Always wear a helmet, eye protection, and protective clothing. Never ride under the influence of drugs or alcohol.

Post Reply