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Post by mik25nik on Mar 22, 2016 17:34:59 GMT
CDi Saga
Today my replacement cdi arrived from Rex's, in order to refresh my memory as to how badly mine ran on a 250cdi I started it up and ran it for a few mins, made a mental note and fitted the new unit. Pressed the starter and Zilch/ nothing /sod all, whatever you call it I had it. Refitted old unit and engine runs. Contacted Rex's who promptly replied:-
"What we often find is that a fresh unit draws a full load from the generator. If the windings are old it can cause loss of sparks. When you put an old unit back on the capacitor inside is unlikely to be able to absorb full power and therefore the insulation in the windings does not breakdown. This is a well documented phenomenon in cdi ignition. You need to make accurate measurements of generator resistance (only windings associated Ignition, report these figures to us using accurate multi meter"
Is it possible for me to collect these reading myself? if so how
A secondhand one is now looking quite attractive. |
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Post by srx600 on Mar 23, 2016 8:29:06 GMT
Is it possible for me to collect these reading myself?yes, if you have the kit.(Ohms meter / multimeter)... Its all been done to death on here. I'm rubbish at searching thought the forum web pages, otherwise I'd post the links. I'd read the Haynes manual and read thought the forum. Do a google search as well. As its covered lots on the internet. Think those guys are talking tosh...Off the top of my head there are different cdi's and if you have the wrong one pooh sticks.. The 'A' donates the earliest models of 400N CDI and are the ones that I have often found to have trouble with.
Never had trouble with a 'C' or 'D' marked item.....................improved versions perhaps ? 
Read more: honda-superdream.co.uk/thread/1692/400-cdi#ixzz43iIRjiAQ
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Deleted
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Post by Deleted on Mar 23, 2016 15:05:57 GMT
You can very easily measure the resistance readings with a half decent multimeter. Basic figures are in the Honda manual, but if you read Rex's test document on his site for the 250 generator- they are a bit of a wide tolerance. And Rex does not expand at all on what readings to expect from the 400 generator. Maybe he will if you give him your readings?
Sounds a bit of a getout is my view. I do wish he would stop selling individual items of a complex system and then blame everything except the part he has sold? If the CDI can pop the generator, the generator can pop the CDI, the old generator does not work with a new CDI, etc. etc.
What you want is to send off the whole lot and pay him 20 quid to test it all, recommend the best course of action- rewind genny, replace CDI or both and deduct the test fee from that- then guarantee the whole lot will work when you get it back.
I'm fed up with this CDI lark. The only 2 400 CDI's from Rex I know have been fitted (Dave's and mine) were fitted to bikes with no existing fault? But that isn't the normal way of things- you order a replacement when you have a problem.
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Deleted
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Post by Deleted on Mar 23, 2016 15:18:28 GMT
You can very easily measure the resistance readings with a half decent multimeter. Basic figures are in the Honda manual, but if you read Rex's test document on his site for the 250 generator- they are a bit of a wide tolerance. And Rex does not expand at all on what readings to expect from the 400 generator. Maybe he will if you give him your readings? Sounds a bit of a getout is my view. I do wish he would stop selling individual items of a complex system and then blame everything except the part he has sold? If the CDI can pop the generator, the generator can pop the CDI, the old generator does not work with a new CDI, etc. etc. What you want is to send off the whole lot and pay him 20 quid to test it all, recommend the best course of action- rewind genny, replace CDI or both and deduct the test fee from that- then guarantee the whole lot will work when you get it back. I'm fed up with this CDI lark. The only 2 400 CDI's from Rex I know have been fitted (Dave's and mine) were fitted to bikes with no existing fault? But that isn't the normal way of things- you order a replacement when you have a problem. This may sound brutal......but I'm in brutal mood. My advice is to ignore these CDI's and seek a genuine used replacement which is not stamped with an 'A'.... Sorry, but how hard is it?? There are tonnes of good used and tested CDI's of this type in Germany and the States. As we've heard from MEMBERS OF THIS FORUM, this company does not do customer service - if he did then that would be different. Stick with the genuine item. |
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Post by Deleted on Mar 23, 2016 15:26:16 GMT
What's more, perhaps the 'Rex Speedshop' section of the forum be removed......I thought it was designed for him to come and help fellow members? Which doesn't happen.
So it is pointless.....
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Post by mik25nik on Mar 23, 2016 15:29:14 GMT
Thanks for that Crouchy
I bought the cdi from Rex's as it was clear that my bike did not have a 400 cdi on it, and I did not think paying the same price for a second hand one was a good move. Now I am not so sure, Having gone this far down the road I will contact Rex's re testing my generator.
I actually had a ride out on it yesterday and it really was not so that bad considering it is running on a 250 cdi.
Well I guess having gone this far it is back to my wallet
Regards
Mike |
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Post by mikef on Mar 23, 2016 20:47:12 GMT
Hi Mike.
I have an idea that may help. I have a spare SD400 generator. I have not been able to test it on a bike but it's resistances check out OK. If you would like to try it I could post it to you.
I see that you are a full forum member so you will have access to the service manuals. The resistance checks for the generator are outlined in there, but understand that if electronics is not your forte then it could be difficult to understand.
In defense of poor old Rex, I have to say that the CDI that I bought from him works fine on my SD400, it was bought to replace the original Honda part that had failed. As for his customer service I have no experience other than ordering the CDI and it arriving 2 days later. I would have to say that it is conceivable that Rex's CDI would not work if the generator had a certain fault but an original part would. I don't know in detail how the REX CDI works, but probably sublty different from the original.
I could explain the resistance checks in a bit more detail if you think it would help.
Just PM me your address if you would like to try the generator that I have.
Good luck.
Mike.
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Post by Deleted on Mar 24, 2016 7:56:08 GMT
What are the resistances actually though? Can you post the numbers up?
What is evident- you have to admit Rex is expert and knowledgeable enough to reverse engineer units that work. So I think he is right that the resistance figures given by Honda are too wide a range to pin down an age related fault. I think Honda were only intending to test and detect catastrophic failure with newish bikes.
What we need are accurate readings from bikes that are running fine now. I have discussed with Dave and we are going to log readings from our generators as we know both our bikes ran well with the old CDI's as well as running (better we think) with a Rex CDI.
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Post by srx600 on Mar 24, 2016 8:25:18 GMT
does any one know where they manufacture the rex cdi's?
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terryc
Forum Accommodation Specialist 
I'll put you up ,plenty of room in my box
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Post by terryc on Mar 24, 2016 8:27:19 GMT
Rex's speedshop make them not sure where they are located though
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Deleted
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Post by Deleted on Mar 24, 2016 9:01:38 GMT
Contact information
Customers can contact us by telephone, e-mail or post. It is advisable to telephone us first before making a journey to our premises.
Address Rex's Speed Shop
Unit 5, Russet Farm
Redlands Lane
Robertsbridge TN32 5NG
United Kingdom
Phone 0044 (0) 1580 880 768
Sales & Customer Service Kate
E-mail kate@rexs-speedshop.com
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Post by srx600 on Mar 24, 2016 10:08:26 GMT
I mean was it made in china? They may have designed them.
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Deleted
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Post by Deleted on Mar 24, 2016 10:10:38 GMT
No, I think he makes and pots them up himself....
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Post by mikef on Mar 24, 2016 16:32:15 GMT
Hi.
I have listed the values for generator coil resistances as stated in the Honda manual for the CB400.
They quote two figures for the resistances using two different meter types. I don't really know why. Resistance should be resistance, whatever instrument you measure it with to my way of thinking.
Green to white 400-500 (315-385)
Blue to white 75-130 (77-95)
Green to Brown 75-130 (76-92)
Green to Light blue 75-130 (95-116)
Green to Pink 120-180 (128-154)
One thing to remember is that if you are checking the coils when the generator is not fitted on the bike the light blue and the brown wire are earted via the fixed pulser body, so one lead of the meter will need to be connected to the body of the fixed pulser instead of the green wire when checking the brown or light blue wire resistances.
I will measure the resistances of my known working generator coil later this evening and post the results.
One thing that I am sure will make quite a significant difference is the temperature of the windings. If I get time I will put a set of coils in the oven and warm them up and see what difference it makes.
Mike.
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Post by wazzbo on Mar 24, 2016 17:37:16 GMT
When We test mine The bike will have had a 40 mile run to Paul`s so we`ll test it when I arrive and its at a normal running temp.
we can then test it when its cooled down and note any differences.
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