Hi folks.
my 1990 cbr1000f is having starting issues. I thought initially it was a battery problem cos it was turning quite slowly or intermittently but then i found a website where a guy posted a video of his bike and mine was exactly the same. on his bike it was his alternator damper clutch that was faulty.

However yesterday i took it to my buddy's house who checked the electrics and we found the battery voltage to be 12.3v standing, then when i hit the starter it drops straight to 8.2v and the bike has trouble turning. When the bike is running the voltage at 5000rpm is within the normal recommended range and all lights work etc.

the weather in the uk is really cold at the moment so could this be the cause of the issues. would a new, properly initialised battery be the problem solver.
my own thoughts are that it is worth £30 for a new battery to check rather than the £220 for the damper clutch.

your thoughts please
thanks
grim

 

Can you try and start the bike with a jumper battery? If you attach a known good battery with the same results you might have your answer... Just use a battery of simular amp hour..... putting a car battery inline might overcome any starter clutch issue.

 

Yep, I would definitely hook it up to a car battery (with the car not running).

Make sure you have good connection between the jumper cables and both batteries, and see how it starts then. If it starts ok, you know it's just a shot battery.

Has the bike been sitting for a bit? Is it hooked up to a battery tender? (or optimiser, or whatever)

These bikes really need a good charge to start correctly.

 

this vid was the one that i found. my bike sounds exactly the same.

i hooked the bike up to a car battery but all this did was to make the starter spin faster. the bike sounded like it wanted to start but there just wasn't enough juice in it. the bike had been stood for 6 months prior to me buying it and had only done 100 miles on the new battery from march 09. i used it everyday and it became progressively harder to start as the days went by and now i get nothing except this horrible whine that is in the video.
it is not hooked to an optimiser at present but I intend to get one in the next few weeks. i think it is just a process of elimination. it bump starts just fine even from cold.

 

definitely a low battery issue. anytime you have less than 9 volts, you cannot troubleshoot any further until you get a known good battery. What was your charging voltage at 5k rpm? Also keep in mind that the charging system is not charging the battery until you get higher in the rpm range due to all the electrical systems on the bike. If your bike starts fine with jump cables and another battery then it's your battery. put that thing on a charger.

 

Starter damper IMO
A bit of a pig but you can do it yourself
Look in the how to section - good writeup.
I've done it, so has Naga Thai and others (hi Martin) and none of us are bike mechanics. Just takes a bit of time is all.................Check www.mrcycles.com
starter damper much cheaper than 220 quid.............

 

£220 was the estimate for the part and labour inc vat.

the part itself new is £117 from david silver spares in the uk. Think I will try a new battery first as this is the cheaper option. Probably needs one anyway so no harm done if it isn't the battery. Battery voltage at 5000rpm is 14.9 if I remember correctly so hopefully everything is good as far as alternator goes. I really hope however that is just the battery cos it will mean lots of headaches avoided by not having to change alternator damper lol.

 

I hope you get your hope, but............................

 

well a new battery has been fitted and it started fine from cold but i ran it to normal operating temp and attempted to restart it and it sounds like battery is dead again. dont know if it is alternator clutch or what but this is the last resort as far as repairs goes. i will do it if i have to but want to dis count other possibilities first. charging voltage seems fine but wondering if there are rectifier ignition unit issues