Yamaha Thundercat Won't Start On Cold Morning

[Guest]

Hello

I have a year 2000 Yamaha Thundercat and on cold mornings it won't start. It starts fine in warmer weather or if it has been run for a few minutes (once you get it started). Obviously this is not ideal when im trying to go to work at half five. The bike seems to turn over all right and Ive checked the battery which reads 12.8v. When I can't get it started I can bump start it and it will run fine. It also seems to idle a bit lumpy at first. Any advice would be appreciated because Im starting to lose faith in the bike. Also I should mention it is kept outside and isn't under a cover.

Regards Richard

[Tango]

Welcome to TMBF mate.......pop over to the newbies section and introduce yourself to the gang......

Ok.....is the choke working ok? Dunno this bike, but if it has a manual choke check the cable and adjustment as a first pass......

[acting_strange]

"can bump start it" could also possibly mean that the starter is starting to draw too much current from the ignition system....earthing or worn motor problems...

[eastanglianbiker]

i would be looking at starter motor drawing to much power and starving the cdi stopping it sparking and bumping it give all the power back to the electrics

[Stu]

could be a battery on its way out

check the voltage whilst cranking the bike over if its below 10v replace it

If you have access to a car and jump leads an easy test is to jump it off the car without the engine running

if the battery check out ok or it still does it hooked up to another battery then I would check the choke on the carbs and check settings on them and get them balanced up too

also might be worth changing the plugs

[buggerit]

Sounds daft but could well be the battery my battery read 12.5 and my optimate said green for good. Anyway I read in my manual a fully charged 12v battery should have13- 13.5v. I bought a cheap one incase it wasnt that but I had the same issues until I put a new battery in. The 1v more on the new battery must have been yhe difference! Not sure if it makes a difference either but I dont put my lights on until the bikes running now either. Try and borrow a battery if not buy one and worse case you have a spare which in winters always a good idea!!

[Stu]

Anyway I read in my manual a fully charged 12v battery should have13- 13.5v.

 

I think you might have read that wrong its around 12.5 -12.7

13-13.5 will have been with the bike running

[Tango]

Gotta agree with the guys here......most likely is the battery......but check the connections are tight first before splashing out on a new one.......

[buggerit]

Ive tested it after I charged it off the bike it hits 13v plus, just checked the manual and it just says fully charged over 13 discharged 12.3 could just be my bike though. But there was definitely a difference as after the optimate charged the new one I tested the old and new against each other I remember the old one was around 12.5 ish and the new one was a little over 13. I tested it again not long ago as my alternator went too! It hit 13 then. Im just glad mines working bloody hate the charging circuit!

[Stu]

if your testing a battery after you have just charged it you will have what they call surface charge and thiss will drop off over a period of time and will settle to just over 12.5

each cell only holds 2.1v and they are six cell batteries so 6x2.1=12.6v

have a read here http://en.wikipedia.org/wiki/Automotive_battery

[Guest]

Thanks for the advice I will try the jumping it of the my car next time it doen't start (probably tomorrow morning) and see if that helps.

[Adam]

If you do buy a new battery go for a gel on they're better for cold starts. I'd highly recommend Motobatt gel batteries they're slightly more expensive than acid ones but well worth it.

[Stu]

If you do buy a new battery go for a gel on they're better for cold starts. I'd highly recommend Motobatt gel batteries they're slightly more expensive than acid ones but well worth it.

 

lol a motobatt is not a gel battery they are an AGM battery (absorbed glass matt) its a type of sealed lead acid battery

but I totally agree get a motobatt if you need a battery they are great and come with 4 terminals if you ever need to add extra wiring

I run one on mine

[Fozzie]

Sounds like the battery is out!

After charging to get rid of the surface charge just leave the lights on for a minute and that will sort you out. The guy who did my mot showed me this when I had a similar issue!

Batteries are cheap enough, lob a new one in. As a 13 year old bike I imagine the starter could also be starting to wear out.

[Guest]

Sounds like the battery is out!

After charging to get rid of the surface charge just leave the

led lighting on for a minute and that will sort you out. The guy who did my mot showed me this when I had a similar issue!

Batteries are cheap enough, lob a new one in. As a 13 year old bike I imagine the starter could also be starting to wear out.

Yes battery issue..I had similar problem last winter and need to change the battery