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Author: Subject: Cooking rectifiers - must give it up.
Banana

posted on 2/3/17 at 03:49 PM Reply With Quote
Cooking rectifiers - must give it up.

So my third rectifier will be in the post box when i get home and i can't afford to cook it.

It all started when i moved my battery/ecu/rectifier to the foot well, and very soon after the battery stopped charging.

New rectifier acquired, and all was well again whilst ticking over on my drive (14.5v ish charging across battery).
So i drive 1/2 miles down the road, and notice my on board volt meter is reading 11.8 - 12v. So i get home, test with a multi meter and the battery is not charging.
'It must be over heating' i thought - So i relocated the rectifier out of the foot well to its original position in the engine bay, on a piece of ally with heat paste under it.
Started the car - and no charge..
Found the 30amp fuse had blown in the starter relay - thought that would sort it - fuse replaced, and still no charge.

So im guessing i fried the rectifier (could this really happen driving for 5 mins? It was bloody hot mind)

I have a new rectifier at home now, and im going to fit it OUT of the foot well this time, with some new heat paste. But i cant help worry im going to damage it..

Stator is putting out between 15v and 40v ish.
Admittedly, all the rectifiers in question have been ebay £15 ones, but these have never been a problem for me before.

Any suggestions on this problem?

The three yellow wires from stator - Haynes doesnt state what order these should be, im just going on the original arrangement. Does this matter?

Thanks guys.

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adithorp

posted on 2/3/17 at 04:37 PM Reply With Quote
I think the 'blade rectifiers are a known weak point. There's an upgrade people do from another motor but I don't recall where from. Do a search and you should find it here somewhere... or ask AndyBates. The order of the three wires doesn't matter AFAIK; Having good cooling and heatsink is important though and putting it in the footwell probably didn't help. I wouldn't trust ebay parts for this as theres so many fakes being sold there.





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Wadders

posted on 2/3/17 at 05:16 PM Reply With Quote
If not done already it might help if you take the charge wire from the rectifier direct to the battery positive.
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r1_pete

posted on 2/3/17 at 05:28 PM Reply With Quote
It would be worth checking the stator out too, the resistance between any 2 yellow wires should be the same, about 5 ohms from memory, but check.

None of the yellows should show any continuity to ground, and it doesnt matter which reccy wires you connect them to.

I cant remember whether the blade uses an energiser feed, if it does it too needs checking out for end to end continuity and isolation from ground.

There is a reason the rectifiers are popping you need to find it,

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Kev99

posted on 2/3/17 at 05:56 PM Reply With Quote
If i remember right its the cb250n rectifier u need this sorted my problems out on my old blade engine

Also move it into an air flow area to help with the cooling and a nice alloy heat sink plate helps

[Edited on 2-3-17 by Kev99]

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Banana

posted on 2/3/17 at 06:48 PM Reply With Quote
Yes, good idea on a direct feed to the battery. That will help with the elimination process.

I have done the alternator testing as per the Haynes manual, and all seemed OK. I will revisit that before installing this one though..

CB250n rectifier? Tell me more!

I shall be going ott and fitting a CPU heat sink/fan to the underside of the ally mounting plate this tiume around..

Rectifiers are very simple bits of kit, so even these cheapy ones should be up to the job. When you find out what is actually in them, it makes buying a genuine one even more painful..

Thanks for the input..

[Edited on 2/3/17 by Banana]

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mark chandler

posted on 2/3/17 at 07:14 PM Reply With Quote
Have you got a big battery or a little bike battery?

A car battery will draw to much current and kill the rectifier, standard blade sits in cold air under the seat and is a weak point on the bike.

I got one off a Ducati with a big heatsink that sits up front with lots of cold air after a couple of blade ones failed.

Cb250 can be 6v so make sure you get the right one if going that way.

[Edited on 2/3/17 by mark chandler]

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kingster996

posted on 2/3/17 at 07:20 PM Reply With Quote
Fit a Yamaha R1 rectifier. Make sure it's bolted to a nice flat area as a heat sink.

You can also add a PC cooling fan to help.

Honda VTR 1000 used to suffer the same issues so have done the above to great success.






I used to be indecisive, but now I'm not so sure

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02GF74

posted on 2/3/17 at 08:11 PM Reply With Quote
rectifier - 6 power diodes mounted on alloy bracket I is what I did for my Z1000; cheap as chips, literally as in micro chips; sadly it was the regulator that was not regulating so bought a complete unit for a zx600 or similar from ebay, which is awash with rectifier/regulators.

Fitting the unit on a heat sink and a fan should help or fit the correct engine which come with alternators already fitted with internal fan to cool the regulator






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CosKev3

posted on 2/3/17 at 08:15 PM Reply With Quote
14.5v is high at idle.

Yamaha manual test figures for a R1 are at 4-5000rpm IIRC,as stators don't make much at lower revs.

At idle on my R1 with a car battery it sits at circa 12.8v,once revving above circa 3000rpm it's between 13.5-14.2 volts.

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CosKev3

posted on 2/3/17 at 08:17 PM Reply With Quote
Pretty sure I've read the CBR1000RR rectifier is a popular upgrade for a early blade?
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Banana

posted on 2/3/17 at 08:50 PM Reply With Quote
You're right Kev, that 14.5v was when i blipped the throttle.

I've got the correct bike battery for a Fireblade from Tayna Batteries. Ironically, it originally had a car battery fitted, and all these problems started after fitting a bike battery and sticking it all in the foot well.
This makes me think it is an overheating issue, but i'd have thought it should have lasted longer than 10 mins..

Im going to double check all the readings, and give it another go out in the open this time. I'll gamble with another £15

In regards to other models, i would think most big 4 cylinder Jap bikes could interchange rectifiers.

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MikeRJ

posted on 2/3/17 at 10:28 PM Reply With Quote
quote:
Originally posted by Banana

Admittedly, all the rectifiers in question have been ebay £15 ones, but these have never been a problem for me before.



Do you mean second hand genuine Honda reg/rects or new pattern Chinese parts? If the latter then they are notorious for failing, and there are even fake parts around that are mostly full of sand.

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Banana

posted on 2/3/17 at 10:34 PM Reply With Quote
Ha, well the sand worked for 5 minutes in that case. The guy had sold a few hundred of them, and im not sure you can class them as 'fake' as they are not being sold as genuine Honda..

I did think about a second hand genuine vs cheap new, but im convinced me/my car are at fault.

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kingster996

posted on 2/3/17 at 11:21 PM Reply With Quote
quote:
Originally posted by Banana
Ha, well the sand worked for 5 minutes in that case. The guy had sold a few hundred of them, and im not sure you can class them as 'fake' as they are not being sold as genuine Honda..

I did think about a second hand genuine vs cheap new, but im convinced me/my car are at fault.

You might not be at fault. If you are using older model Blade rectifiers they are notorious for overheating.

Just fit a bigger finned one (like an R1 type) and it will save you spending £15 a pop on copies of crap designs that failed to work 15 years ago






I used to be indecisive, but now I'm not so sure

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ko_racer

posted on 3/3/17 at 11:58 AM Reply With Quote
I'd say you are likely using the older shunt type rectifier the suffers from overheating issues on various bikes.

The newer MOSFET type rectifiers are much more reliable and product much less heat.

From memory the part numbers usually start with SH for shunt ones FH for MOSFET types.

Try and find one that is a matching output/load to the one you are already using.

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Toprivetguns

posted on 3/3/17 at 05:15 PM Reply With Quote
This problem haunted me for months. In the end I purchased a new OEM rectifier and improved the cooling, along with buying a CTEK battery trickle charger to keep the battery in good condition.

Also inspect the wiring from the stator to the rectifier and check the correct resistances as per the manual.





Only drive as fast as your angel can fly... !

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MikeRJ

posted on 12/4/17 at 09:01 PM Reply With Quote
quote:
Originally posted by ko_racer
I'd say you are likely using the older shunt type rectifier the suffers from overheating issues on various bikes.

The newer MOSFET type rectifiers are much more reliable and product much less heat.

From memory the part numbers usually start with SH for shunt ones FH for MOSFET types.



The 'SH' parts use SCRs (Silicon Controlled Rectifiers) and the 'FH' use MOSFETS, but both types are shunt regulators. The MOSFET regulators run cooler since they have less voltage drop than than SCRs when shunting the output of the generator.

Series regulators are available, but they are much larger due to the increased power dissipation they must deal with, though they allow the stator to run cooler.

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