Battery ?

[gonzo 2,211]

Now I got the serow running again ! It’s starts ok , (kick start) and ticks over ok when it’s warm ! But won’t rev out ! I read something on you tube of someone having the same prob  and he cured it by fitting a new battery, just checked voltage on mine @12.5 v , bike hasn’t been used for a couple months. Do I buy a new battery ?  Ta chaps ! 

[fj_stuart 4,753]

I'd say no. I've had a lot of duff batteries over the years and none stopped a bike revving. I can't see how it would. More likely carb, ignition, etc.

[Viator 1,526]

Hi @gonzoat 12.5v the battery sounds good. If the connections onto the battery are nice and clean I would pay attention to the other end of the earth lead first, take it off, clean it and reattach. However it sounds more like lack of air or a fuel +/- issue, try running it with the air filter off. If you have had the carb apart is the main needle in the correct place?

 

 

[Andy m 23,543]

What's it sound like when revved? What colour's the plug tip it choped during an attempt for revs? It indeed sounds more like a carb issue to me. 

 

I assume the petrol is new? St.Gretathyol at 6 months old has all the pyrotechnic qualities of Australian lager.

 

If you do think battery, you can always start it then connect jump leads to a fully charged car battery or another bike rather than buying one.

 

Andy

Edited August 7, 2023 by Andy m

[gonzo 2,211]

15 hours ago, Andy m said:

What's it sound like when revved? What colour's the plug tip it choped during an attempt for revs? It indeed sounds more like a carb issue to me. 

 

I assume the petrol is new? St.Gretathyol at 6 months old has all the pyrotechnic qualities of Australian lager.

 

If you do think battery, you can always start it then connect jump leads to a fully charged car battery or another bike rather than buying one.

 

Andy

Mot and carburettor work done by a so called local professional , followed by a substantial invoice, I’ve done the valves and are now spot on . Was advised by a mate with 30 Yamahas not to use e10. These early Yamahas need e 5. So tank now is 1/2 full of fresh petrol, so it’s a fault finding process. Lucky I got a Honda to ride ! 😳

[Andy m 23,543]

If it runs on E5 it can be made to run on E10.

 

There is less energy in the watery rubbish so you need to jet accordingly, especially with open pipes and air filters. While you are at it you can replace all the bits of rubber it'll attack if left long enough.

 

It's a question of how easy it is to get proper petrol and how many miles you'll do to justify the upfront costs.

 

I'd always want to fault find using Esso E0 or similar, it's one less thing to factor out.

 

Andy