Morning all,

Drove the car into work today and whilst stationary in traffic the car started misbehaving...

Basically, the engine revs began to fluctuate and then eventually they fell to such a level that the engine had a large misfire (pop) and then stalled...

It started up ok afterwards, but it then continued to do this everytime I was stationary and just running at idle...

Another thing I noticed, was that whenever the engine revs began to fall, the battery charge warning light came on, but I'm not sure whether this was a cause of the problem or just an effect of the engine revs falling....

The carbs have been dynojetted and I'm running a pancake filter - but I've done about 500 trouble free miles since that was done...

Not sure what the problem is here ???

TIA

Matthew

what sort of rpm is the engine set to tick over at normally when warmed up?
I have (well had!) mine set to tick over at about 1500rpm. Maybe your idle needs set a little higher.

It was set to about 1100 - but I raised it up to around 1700 to see if that would help (or at least delay to onset of the problem), but unfortunately that didn't work either...

Sounds like your regulator/recitifier - common problem (achilles Hell) if not mounted in a well cooled position. i.e. behind nose cone on a heat sink! Hope I'm wrong! have a close look - if the unit is leaking or has any brown crudd around it - certainly found your problem... if not - check your plugs! Put in NGK iridium...

[Edited on 12-7-05 by Hellfire]

Thanks for the reply Hellfire.

I currently have a small PC fan mounted directly on top of the rectifier unit.

The rectifier is not however, mounted to anything that could be described as a heatsink...

How fragile are these units to heatsoak ??

I figured that the PC fan would have been enough to keep it cool.... although I have often been proved wrong in the past !!!

Thanks for the advice.

Matthew

PS. Already running NGK iridium - which I have checked and they look fine !!

have you mounted your heatsink to the finned side, or the flat underside? its the flat underside that needs to be against something that will dissipate the heat away, so thats where the heatsink / fan should be touching (with a bit of thermal paste to aid the contact). A PC fan on its own without a heatsink probably owuldnt be enough to cool it if it wasnt sitting on a solid bit of metal too.

[Edited on 12/7/05 by ChrisGamlin]

idle jets?

hi xy
i had this same problem a few weeks ago with my blade wouldmt idle ect misfire .it turned out to be the rectifer as hellfire was saying .i made up a alloy bracket i bought a modified unit of ebay plus put a commputer fan on the rectifer as well ,it still seems to get hot but has cured the problem

You can mount them in the
fridge it will still burn out.
Its all down to internal heat
not a thing you can do!Yep idle
speed is a cassic symptom. I
Think if you get 1000 mile out
of one your doin well.Look for
a tiny melt hole i its body or check
it out with a multimeter to confirm.
IN A WORD THERE CRAP!!!

Ive no experience of these regulators yet as my blade engine is still on the garage floor , but could the problem be due to using a car battery instead of a bike one?.If the battery was flat or low on charge it would sink a lot more current than a 17 ah bike battery and therfore fry the regulator.
Car alternators are voltage sensinng and adjust the field current to suit charge rate, the bike units do not and the total wattage flowing may be to high.
Paul

quote:

---

Originally posted by ASH3
You can mount them in the
fridge it will still burn out.
Its all down to internal heat
not a thing you can do!Yep idle
speed is a cassic symptom. I
Think if you get 1000 mile out
of one your doin well.Look for
a tiny melt hole i its body or check
it out with a multimeter to confirm.
IN A WORD THERE CRAP!!!

---

Ash, were you buying pattern ones possibly? They may be a bit of a weak point but the genuine ones at least aren't anywhere near as bad as you make out. As I said, I had 3 years / 6k miles out of mine without a problem and its still going strong, as have a couple of other mates who have blade BECs who have mounted them to something substantial to act as a heatsink.
Paul, you might be onto something there with the car battery thing, Im not sufficiently up on my auto electrics to understand how they work but it sounds feasible (I use a bike battery all the time)

[Edited on 13/7/05 by ChrisGamlin]

Chris no both were gen ones second
hand will admit,ive been lookin on ebay
at the redesigned ones at £65.Must say
tempted by another s/h one. Went round
bike dealers n they even say what grief
they give & suggested a 250superdream one as it as an extra wire that takes unused
voltage back in the loom so not under such
constant stress: unlike me.I have emailed
http://www.patternparts.net/ .See wat they
have to tell me.

My local bike breakers also suggested using a 250 Superdream reg/rec as they are more robust.

Andy.

Anyone got a 250 superdream rectifier
i can try!!!

Ive fitted a 250 superdream rectifier between the front wishbones where the body is open. Had no problem since, but the 3 yellow wires had to be obviously extended. These had to be soldered and in heavy wire to prevent overheating. Never had a problem since.

This 250 Superdream rectifier sounds interesting...

It's been mentioned that they have one extra wire which acts as some form of return loop for voltage supply.

How would I go about connecting this up to the original fireblade loom ???

Would it just connect back up to the battery +ve terminal ???

I have to agree that the Superdream rectifiers do look alot more 'substantial' even compared to the upgrade fireblade ones....

They also seem a little cheaper ?!?!?

Thanks

Matthew

Got my hands on 250 superdream
rectifier today good old bike breakers
in Sleaford and for only 20 quid.
Just in need of knowing were
to wire that extra wire (black)...
Lightning your my man

I'm trying to diagnose the idling problem futher..

I've checked the rectifier using the Haynes manual spec sheet and everything seems ok.

The car idles ok when cold and the battery sits happily charging at 14.7V.

The problem only starts to occur after about 5 mins driving..

Is it possible for the rectifier to overheat (which causes the battery charging voltage to drop down to 12 volts (ish) and hence cause the problem) and then return back to perfect working order when it has cooled down ????

Thanks,

Matthew

Just a thought, the fuel line doesnt run past anything significantly hot does it? What could be happening is that when stationary the fuel in the line is getting hot and vapourising in the pipe.

Chris, thanks for the reply.

Regarding fuel lines: Copper fuel lines run along the top of the centre tunnel and then 'turn right' away from the engine (IYSWIM) to the fuel pump which is mounted on the opposite side of the chassis to where the exhaust primaries sit... so I'd be suprised if this was it.

On another subject, whilst trying to diagnose the rectifier issue, I struggled to measure the specified resistance through each of the alternator windings. The Haynes manual states they should read between 0.1 and 0.3 (Ohmns) but I could only measure 0.0 Ohmns.

I initially thought that this could be where my problem lies, in that a faulty stator coil would cause my charging issues etc etc, but I still do get full charge from the alternator 'most of the time' and I am a little reluctant at commiting mself to removing them at this stage......

Looks as though I'm going to have to buy an uprated reg/rec and then stick it on a dirty great big heatsink !!!

Thanks for you help.

Matthew