SP125 leaking petrol and engine flooding

[archthesheep Participant]

Hello all,

I got my first bike last week and have now passed my CBT so can ride around. We noticed that it started to leak petrol from the overflow pipe when the motor was off and after a bit of googling reckon its probably a stuck float that lets the fuel into the carburettor. As it seemed to still ride ok and its the bank holiday we decided to go for a short ride out anyway, less than 10 miles there and back and the bike seemed fine but then once on duel carriage way we presume the engine flooded and lost speed, it wasn’t being over worked for a new engine either; I was really careful about not revving it too hard. Everything was fine and i could just coast to the next junction without issue but I’d wondered two things:

1) Is this an issue that anyone has experienced before with their Sinnis’ (Or YBR125’s I guess, as I’m fairly sure its the same engine, made under licence)

and

2) Do you think that the theory of the float being gummed up is a fair assumption on a brand new bike?

Cheers

[ChrisM Participant]

May well be dirt in carb stopping float closing valve and keeping fuel at proper level, you might be able to “flush it out” by locating the drain screw which when unscrewed releases fuel from the carb, its usually just above a pipe at the lowest point on the carb. if you put the end of the pipe in to a jam jar, then open the screw you will collect the fuel which drains from the carb. It should bring any dirt in the carb with it, with petrol turned off it will just drain the carb/pipes and should show you if there is dirt in the carb in older bikes there will be all sorts of rust and particles. If you do it with the fuel turned on you will get more of a flush through. That would by my first roadside check, and may well solve it without taking carb off and apart. No smoking is advised while you do this!

[archthesheep Participant]

We’ve actually been turning of the drain screw, or what I’m guessing that is, every time we ill the engine to stop it leaking, though as it was brand new we took it back to the dealer and he thought the same as me so hopefully it should be back to running in the engine tomorrow

Incase you were interested apparently there’s some sort of anti corrosion or preservative spray on the inside of the tank that may have just flaked off a little bit and that was what caused the blockage.

[ChrisM Participant]

Sounds like dealer will sort, its one of those things with carbs, the float shuts a valve and it only takes a fleck of rust paint or anything. Always used to be turn off petrol tap when park up to stop any leakage, also stopped you turning to reserve then forgetting you were on reserve next time you were out then running out completely! Apache 250 has fuel injection, miss the old petrol tap with reserve.

[archthesheep Participant]

Just an update,

All sorted now and back to running in the engine. It was the float that needed reseting and apparently the timing of the engine wasn’t quite right either. Definitely runs a lot better now though

[archthesheep Participant]

Also, I don’t suppose anyone knows how hard it would be to change the gear shifting lever to a longer one would be? I found some online for about £12 +p&p and don’t really like the one on there at the mo, its one that you press on the back to go up and on the front to go down. The front is too short to get a boot under at all.

[ChrisM Participant]

Hi, not sure if you are wanting to replace with another heel and toe job, haven’t had a bike with one of those since my very first Honda H100a early 80s. Think they will be held on same with pinch bolt through “lever” if so can just remove bolt and wriggle off splined shaft that actually changes gear, just need new lever to have same sized hole and splines as existing one(although one I got myself off ebay had larger diameter and bodged in with bit of aluminium from walking pole, did pinch bolt up tight and holding ok, and longer lever is feeling much better) if not pinch bolt probably some sort of circlip on end of shaft to remove. Shouldn’t be to tricky Good luck.

[Sinnis Mike Keymaster]

The dealer will sort this out – very occasionally, where the factory have tested the carbs there is dirty residue left in them. This causes it to gum up and be a total pain. Contact your selling dealer, they should be able to resolve this