Hi there.I'mnew to this forum, but I'm sure thats no excuse, and hopefully you'll forgive me...

I've been riding CBR F's for about 10 years now, and am loathe to try anything else.
I have afull fairing(ed) 1990anda semi-fightered 1993 model.

Anyhoo, I won't beat around the bush.It's the1990 model that has recently started having issues starting, and I thought I'd ask here if anyone might have any ideas?

A bit of background:
The bike is serviced every 1 years. New plugs, filter gets cleaned etc, etc. Every 6 months it gets an oil change (5w-40) irrespective of how clean it looks. Carb hasn't been serviced for about 2 years.

Just recently, its been struggling to get going. (here's a link to a vid on yootubeI did of how sick it sounds - http://www.youtube.com/watch?v=kfgqjgIeoqk ). Now, its not like this all the time. Sometimes it kicks over straight away, but mostly, i'd be lucky not to run the battery flat first. As it is, I've had to jump off a booster these last few mornings just to get my sorry butt to work...

To me, the starter motor sounds extremely weak, but was rebuilt about a week ago because thats what I thought the problem was. As you can tell by the vid, the starter motor appears to be struggling, and even though it was rebuilt, it is doing exactly the same thing. So I'm sure, even though it sounds bad, the starter motor is not the problem.

My partner reckons it sounds like a wheezy old man...

Diagnostics so far:
The battery is a Yuasa about 6 months old and appears to be charging ok at between 12 and 15 volts over 4500-5000 revs, so theRectifier appears to be doing its job.I've ruled out a dodgy battery or rectifier...though the battery has been charged a dozen times over the last month. A new one is on the bench being juiced and slow charged, but am not keen to connect it up yet until I have found what the problem is.

Both ignition coils and the leads are in good condition. Spark plug caps fit tightly, and plugs are 1 week new and clean. Resistance readings measure as factory standard = Ignition coils are generating a strong pulse. Spark tests done to verify reading, and all plugs put out a good spark.

Compression is up and equal across all 4 cylinders.

The only real problem I can see is the starter relay switch, which appears to have burnt out the connector-pin casing. All the wiring between the battery and the starter motor is ingood condition. All the grounds are good and clean.

I have heard that it may be a problem with the starter clutch? Is that what it sounds like?

I'm hoping there is enough information here and on the vid for an experienced rider/mechanic to be able to diagnose it better than I have.

This is my daily commuter (100k's round trip every day), and I'm keen to get it reliable once more.

Thanks for looking.

 

battery need more juices to start.. charges it within 30 minutes and dont unplugged the charger when u start it..

 

If you have strong spark it's not your CDI or coils.
Reg rec,stator are fine too.
I'd suggest two possible causes
1 Dirt in the carbs - if they haven't been cleaned in a while, clean them thoroughly.
2 Starter clutch plates. MUCH bigger job.[X(]
3 Dodgy battery - try this FIRST
Is your choke sticking ?
If the bike bump starts easily, chances are it's no 2[X(]
Can be done with motor in the frame - Bazman and Kaska have both done it, but you need to know what to do.
Best I can do is give you the manual, see Blackbears below.
I have a 90, too.Good luck

 

Cheers Shadow.

The battery thats in the bike seeeems to be okay. It holds a charge, is strong for a while, but then it does begin to wane quite significantly. So I've got a new one on charge but won't be able to pick it up til Monday.

The choke is free and dandy. No problems there (apart for some slack in the cable and no adjustment left).

I'll get the carbs off tonight and give them a good scrubbing.
I spoke briefly with Bazman today on the phone. (He's the guy that put me onto this forum[sm=smiley20.gif] and he indicated it sounds like the starter plates. I suspect, after everything else, this is what I'll end up doing.

Thanks for your comments.

 

hey, thanks for your comments Typhoon. Could you elaborate? I don't think I know of this method. Isn't in unsafe to leave the charger plugged in and connected to the battery when you are trying to start the bike?

Or have I completely got the wrong end of the stick?

Cheers

 

Get a new battery...........
With the right charge,right amps.
You have to have the correct battery type ie;not some cheap generic copy.

I had the same issue with my beast in the winter months,because i had a crap battery in it .

 

unplugged the charger when motor start in a second and its not safe also if u leave the charger to the battery , we have to use our common sense..

 

Hey Stu.

Just looked at the Vid and the news isn't good.But all is not lost.

I've flicked you an e-mail.

Cheers.

 

cheers. common sense sounds good to me.

 

I would not rule out the R/R. When the diodes start to fail, they let juice leak back to the alt. and drain the battery. To check this, charge the battery and check the voltage. After 24 hours check it again. If the voltage is still 12V the problem is not the battery. Now install the battery and walk away for 24 hours. If you see a voltage drop the R/R is at fault.

When the diodes are weak you will still see 14-15 volts when the bike is running.

Be careful when using a battery charger. You can over charge a battery and ruin it quickly. When charging a battery, remove the cables and check it. When you get to 12v stop charging it.