Running problem....

I've just got a 97 CB500V, and it's doing my head in ! now this the 3rd i've owned and i've never had one let me down before.

It start's and runs for about 10 to 15 mins, then the rev drop and it die's, at this point the starter circuit and neutral light go dead, no light and no power to the starter button. Leave it for half an hour and all is well. The vent on the petrol tank appears to be clear, its doing my head in.

I've replaced the 3 pin diode, changed the CDI, the coils are reading within the specs, reg/rec is working.

Any ideas, cheers Ernie.

hello,

Have you tried the battery ..? is it getting enough charge..?

and are the battery terminals nice and clean?

Its a good new battery, so that's not a worry and the charging system is working as it should. After sodding about with it some more, i'm starting to think in may be on the cut out circuit, but all the switch's are working...

Ok .. Ive had a similar problem on a customers bike where it was a coil problem.

From what you have said its sounds as tho your coils are cutting out when they get hot and when they cool down they are fine again . I'm not say that this is your problem but it's worth checking out.
Once the bike cuts out check your spark .

Cheer's Kwakboy, i'm still not convinced the coils are the problem, but i'll be replacing them anyway, i can't work out why the stater circuit go dead when it stalls, so today if the weather stays nice, i'm going to by-pass the cut out switches and see if it makes any difference .....

Might be worth checking the reg/rec again to be sure having just read this post.

Yeah. i read that post, the battery is not being drained, the reg/rec seems to working as it should, whats confusing me is the start circuit going dead, when the engine stops.... all the cut out switch's have been tested and are ok, i'm waiting for some coils to turn up , so i'll see if that helps....bloody electrics ! i'll keeep you posted.

If you have access to a good, larger battery (probably a car battery would do) and some longish leads, trying running it with the larger battery in circuit rather than the standard one.

If the problem persists it is definatyl not your standard battery, if it goes away then it *is* the battery....

Also - once the bike has stalled, you should have a check around with the multimeter - check that bits that are supposed to be earthed *are* earthed and that cables that are meant to be 12v *are*.... I wonder if there is a duff cable somwhere that is working when the bike is cold but fails when it gets a little warmer?

Cheers eternally, i check when i when the replacement coils turn up

Ernie the dwarf wrote:Cheers eternally, i check when i when the replacement coils turn up :)

Don't mention it; i'm just guessing at what might be wrong ;)

Well the coils turned up this morning, fitted and working which is nice..checked all the main connections and earthing points, bypassed the cut out switchs.....hoorah she live's but only for 10 mins bugger and blast. So i checked the ignition pick up readings a tad low, so i've ordered one up, with luck that will sort it. This bike will be renamed the money pit

Ignition pick up fitted, no change but after much digging and poking around the loom, i have the 3 yellow wires from the alternator have been some what overheated and have melted. So a new rec/reg has been ordered..........i hate electric's all the reading are spot on,,,,,they lie oh yes they lie.....

What a nightmare Ernie, I'm glad to hear you're cracking the problem though

Woohoo she lives , got a new pattern replacement rec/reg from Cardiff Motorcycles Ltd, only £24:95 A bargain considering the price of the used ones on e-bay......now i can sort out all the little things to get it past it's MOT,,,,How hard can it be and cheers for the suggestions Folks.

Well done mate!

Well the saga continues, on the plus side she's running well, the front end is off about to put some new seals in the forks and fit some gaiters, on the minus side i need to replace the cooling fan and possibly the rad, not's not leaking or damaged but the lower fan mounts are badly corroded to the point of breaking if i try and remove the bolts, i have a spare fan from one of my FZX's so i think some weapon grade bodgeing will the next step....Hoorah

I feel your pain, I got a 2nd hand fan off ebay which wasn't too rusty & a delkovic rad off ebay. Check the earth wire for the rad fan while your at it; this screws to the top mounting point on the fan and is probably floating free!

I've removed the fan which, snapped the both the bottom mounts off the rad bottom doh ! the fan surround is as rusty as the Titanic, the fan motor is dead, so i'll be making some new brackets and fitting my spare fan from the Yam, which is about the same size. So a fun weekend ahead

Enjoy, I hope the sun shines for you!

Are fans repairable? I spent the weekend helping a friend with his recently purchased 1997 CB500.

Amongst other issues, his fan fuse had blown. We replaced it and the fan made a DREADFUL grinding sound for a few seconds when I shorted it. The circuit is still OK, but the fan isn't turning now. I'll take it off next weekend when I have more time. As with most of them - it's rusty as hell!