Pointy won't rev past about 6k?

[ska_authentic]

Hi,

Hoping someone can help, went out on the bike after work today and was fine for a good 30 mile ride on fast twisty roads. Went to tesco, and when I got back on bike it suddenly felt like it was losing power as soon as it hit around the 6k mark, just wouldn't rev anymore.

Got home, revved in neutral and it revved right through the rev range. Left it for an hour and went back out to have a look, all connections looked fine, everything tight etc but struggled to start, turned it off and then wouldn't start again as if battery is flat. Power to light etc but everything dies when I hit the starter.

So, question really is will a bad battery (or charging system) cause these symptoms and stop it revving properly?

Battery is currently on charge so I can't test the voltage etc but I do have a meter and can test in the morning. I hope it's just a feckd battery as it obviously the easiest thing to replace!

Thanks.

[Bibio]

when were the plugs last changed?

[ska_authentic]

Thanks for quick reply!

About 3500 miles ago. That wouldn't explain the dead battery though would it?

[yorkie_chris]

Yeah voltage weirdness can cause odd running. Check the charging system when your battery has some oomph back into it.

[Bibio]

ahhh i read the post but not fully. sounds like an electrical gremlin. there are a few test you can do but i'm not expert enough to help go threw them. might also help if you tell us what bike and how many miles it's done.

[Scythe92]

When mine did this it was an ignition coil gone bad.

[ska_authentic]

It's a pointy; k4 with just over 30k.

Would ignition coil lead to battery also dying?

Both problems have happened simultaneously so to me it seems the wierd running must be attributed to whatever has gone wrong with charging/battery just wanted confirmation that bad voltage could stop it revving fully. It got to around 30mph and maybe 6000rpm then just wouldn't pull but the hour prior to that was perfectly normally

[Bibio]

yup bad battery can cause all sorts of problems if it's old good chance its past its best. might also be a bad earth or ignition.

[ska_authentic]

I've only had the bike for 12months and the dealer reckoned he had put a new battery in although I obviously can't confirm that. From what I'm reading they should last a good few years tho right? Maybe the charging system is faulty. I will run some tests in the morning when it's charged.

[Beetrootkiller]

Cheapo batteries will not stand the test of time and if that's what they put in then 12 months down the line it could well be a fecked battery!

[yorkie_chris]

Even the cheapest crap should last more than a year if being properly charged.

[ska_authentic]

About 2 months ago I actually ran aload of tests and charging system did appear to be working, I was having issues with rear light blinking with indicators (solved by replacing light unit). I Recieved advise on here to test battery voltage, voltage whilst cranking and then again at 3 and 5k. I also did the earth leak test.

I will do all that again this morning but the battery has just came off the charger so I'm going to let it sit for an hour as I was advised last time!

[ska_authentic]

It does appear to be a cheapo battery tho I.e not yuasa/Bosch etc, it says "poweroad" on it

[ska_authentic]

Ok, Thanks for all the help so far; some results:

Battery: 13v (1hr or so after unplugging charger)
Ign on: rapidly falling
Cranking: 11v
Idle: 13.8v
3000rpm: 13.8v
5000rpm: 13.8v

Headlights dont get brighter with revs (very sunny not easy to see!)

Earth leakage: 0.01 (negative battery terminal to black lead)

Stator: 68vac across all 3 connections

Thus, stator seems to be working correctly yes? So suspect reg/rec however why is the voltage increasing from ign. Off to idle? But then not increasing with revs?

Can a reg/rec work at idle but breakdown under load perhaps?

And finally would this have caused the poor running/inability to rev yesterday?

Thanks again!

[yorkie_chris]

Does it maintain 13.8V with headlights?

[ska_authentic]

Its a pointy so lights are always on automatically. The last time I did these tests though the voltage increased to 14 @ 3k and 14.2@ 5k....today no change at all in relation to rpm

Ps. The reading may be a tad artificially high as the battery had only been off the charger for a little over an hour

[ska_authentic]

I've actually got the reg out of the bike does anyone have a link as to how to bench test it with a meter is that possible?

[yorkie_chris]

Nothing worthwhile to do with them.

Might be slightly low then, check for voltage difference across the live and neutral wires between reg and battery see if any charge is going AWOL on the way.

[ska_authentic]

I've ran the test again this evening after giving the battery several hours left in the bike. It's now idling at around 13v and increases to 13.7v at about 3k and stays there regardless of revving harder.

It should be above 14v yeah?

So is this the stator not putting out enough power, the reg/rec not letting more than 13.7v through or the battery?

Does the test on the stator wires (all 3 results were 68vac) confirm that this is working correctly?

Its clearly not overcharging anyway so does this mean it would be safe to take it for a spin tomorrow? Just to see if now the battery is full it will rev properly on the road.

[speedyandypandy]

rec/reg is busted me thinks, 14.7V would be a good charging number.

[ska_authentic]

Morning guys,

Ok so Ive just been for a spin, 10miles or so and bike ran like normal revving freely through the rev range in all gears. This seems to confirm the original issue was electrical and the fully charged battery has sorted it.

I am going to order a reg/rec and see if the voltages return to +14v.

Do they break down under load? As it seems to be increasing voltage at idle and then slightly with revs but only upto a max of 13.7v. Perhaps when out on the road its failing completely when it's under load or too hot?

Thanks

[ska_authentic]

Hi guys,

Regulator installed today and bike is now idling around 13.8v rising to around 14.4 when revved upto 5k. So seems all good yeah?

Thanks for your help.