SYM Owners Forum

Scooter Models => HD125 => Topic started by: Jolly Roger on July 08, 2019, 06:16:35 AM

Title: Starting issue
Post by: Jolly Roger on July 08, 2019, 06:16:35 AM
I have an Evo 125 with a starting problem. When it has been stood for a few hours or overnight, it takes maybe 10 cranks or more to get it started. Within a couple of hours of it last running, it starts immediately.

The battery is fine and the plug is sparking well. This leads me to believe that it is a fuel feed issue, but once fuel is in the float chamber, it should stay there until the next start! There is no petrol smell or evidence of a leak.

In the manual there is mention of an auto bi-starter. Not sure what this is, or what it does, but could this be the problem?

Any advice would be appreciated.
Title: Re: Starting issue
Post by: Jolly Roger on October 04, 2019, 09:49:30 AM
I have an Evo 125 with a starting problem. When it has been stood for a few hours or overnight, it takes maybe 10 cranks or more to get it started. Within a couple of hours of it last running, it starts immediately.

The battery is fine and the plug is sparking well. This leads me to believe that it is a fuel feed issue, but once fuel is in the float chamber, it should stay there until the next start! There is no petrol smell or evidence of a leak.

In the manual there is mention of an auto bi-starter. Not sure what this is, or what it does, but could this be the problem?

Any advice would be appreciated.

I have still not solved this problem. The auto bistarter is a kind of choke that enriches the mixture for starting. Could it be this? Otherwise there is a unit in the fuel line, close to the filter, which has a feed to the carb, but also has another tube to the engine which I think could provide a vacuum to draw fuel to the carb. Does this make sense? What is this unit called? Could it be faulty and result in the starting problem?
Title: Re: Starting issue
Post by: Tromper on October 05, 2019, 12:40:02 AM
Yep.  It could be.  The Auto bistarter (choke) is a notorious problem on small bikes with carbs.
Might just need ti clean it up a bit.  Mine's a bit fussy on one bike, I just live with it, & start it on the center stand with little bit of throttle when it's cold.
Could also be a vacuum leak of some kind, or a more general need for carb cleaning, but I suspect you're on the right path.