CDI/ECU Problems
Posted: 31 Oct 2009, 10:18
ALL CRMs have 'CDI' units located under the seat.
Mk1s have two control units. One for the powervalve (by the exhaust, on the side of the airbox) and one 'CDI'. Generally these very rarely break but can occassionally be bought on eBay or more often Rinkya.
Mk2, 3 and ARs have one unit. Unfortunately these do develop faults from time to time. Mk2 units do come up regularly on eBay; but ARs much less frequently. There are almost always Mk2 & AR CDIs on Rinkya but it is currently very expensive to get one to the UK, mainly due to exchange rates. It goes almost without saying that a new CDI, though currently available from Honda, are very expensive. Mk1 and Mk2 are no longer available from Honda.
Mk3 CDIs seem to be less prone to failure but are more rarely available second hand.
There are Mugen versions of Mk3 and AR CDIs but they are generally even more expensive. One new AR Mugen unit was sold for the equivalent of £750 on Rinkya last year. They are, in my opinion
, not worth investing in for a small increase in power over standard - more pose value 
. A little more over rev and a little more midrange. See graph -
(2nd gear - 6th) -
It does happen that owners mistake other faults for CDI failures. Amongst these are:
Regulator/Rectifier faults - Poor, or intermittent supply of electricity makes faults appear as though CDI. BUT if you have got a CDI fault then it is often the Reg/Rec that has caused it. You do need to check this before you replace your CDI.
Sticking powervalve or non-operative powervalve servo.
General wiring faults/shorts.
Lack of consistent electricity from generator.
Mk1s have two control units. One for the powervalve (by the exhaust, on the side of the airbox) and one 'CDI'. Generally these very rarely break but can occassionally be bought on eBay or more often Rinkya.
Mk2, 3 and ARs have one unit. Unfortunately these do develop faults from time to time. Mk2 units do come up regularly on eBay; but ARs much less frequently. There are almost always Mk2 & AR CDIs on Rinkya but it is currently very expensive to get one to the UK, mainly due to exchange rates. It goes almost without saying that a new CDI, though currently available from Honda, are very expensive. Mk1 and Mk2 are no longer available from Honda.
Mk3 CDIs seem to be less prone to failure but are more rarely available second hand.
There are Mugen versions of Mk3 and AR CDIs but they are generally even more expensive. One new AR Mugen unit was sold for the equivalent of £750 on Rinkya last year. They are, in my opinion
, not worth investing in for a small increase in power over standard - more pose value . A little more over rev and a little more midrange. See graph -(2nd gear - 6th) -
It does happen that owners mistake other faults for CDI failures. Amongst these are:
Regulator/Rectifier faults - Poor, or intermittent supply of electricity makes faults appear as though CDI. BUT if you have got a CDI fault then it is often the Reg/Rec that has caused it. You do need to check this before you replace your CDI.
Sticking powervalve or non-operative powervalve servo.
General wiring faults/shorts.
Lack of consistent electricity from generator.
.