Every now and then i come across situations where i find it hard to locate the information i'm after, so i thought i would dedicate this portion of my web site to providing the information i eventually work out after hours of investigations.
I bought a 1985 Suzuki DR250s and it unfortunately only lasted 4 days before it lost spark, after testing a few bits and pieces i come to the conclusion that it had a fault with the CDI unit ( Capacitor discharge Ignition ). After several phone calls looking for a second hand one it was becoming apparent that back in thier day the CDI units for these bikes failed quite frequently and as a result no second hand ones from motorbike dismantlers around NZ were available. New CDI units were available from Japan at a price close to $600 + GST + Freight , workshop manual's were also hard to locate for that year of bike and they too were ex Japan at a cost of $145+GST. I finally come across a place in New Zealand that used to make brand new Hyperpak CDI's for this model bike back in the days when they were popular, that business is Electronic Research and Development ( ER&D) which is run by Wayne Gum and he made me one up for 1/2 the price of a new one.
Important warning please read Unfortunately the CDI Wayne Gum from Electronic Research and Development made me up sparks at the wrong time which results in the bike now being hard to start and backfiring like a shotgun, he then sent me down a second CDI just in the case the first one was faulty and the second one didnt spark at all. I would like to mention at this point just as a warning to others that i have dealt with hundreds of buisnesses over the years and i can quiet honestly say that Electronic research and development or ER&D as they abbreviate them self as would have to have the worst customer service skills i have ever struck. After paying just under $300 to get a CDI made, a week and a half later the first CDI eventually turned up but was faulty, another 3 weeks and several phone calls/faxes/emails later and a replacement CDI was sent down which was also faulty. This was frustrating on its own but i then spent another 4 weeks after that making endless toll calls and emails trying to get a hold of Wayne Gum to resolve the issue and never ever getting a reply. After weeks of frustration i managed to locate a second hand CDI which got my bike going again. In total it took me just over 15 weeks from the date i paid ( thats almost 4 months) to get a refund from ER&D and not once during that time had he ever replied to any of my phone calls emails or faxes, absolutley appauling service in my opinion and i'm not the only one, cause a little research over the internet shows that someone on Ebay that also bought a CDI off him also took 4 months to get a refund. So my advise is to stay well clear from that business.
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DR250 Ignition
The Ignition system on this bike relies on several other components to function properly and therefore below i will explain the test procedure required to narrow the problem down to a suspected CDI. I don't have any test procedures for testing the CDI as such and from what i read even if you had a workshop manual it may or may not give you a test procedure, therefore by eliminating everything else you really only leave the CDI at fault.
The main components relevant to the ignition system are, Magneto ( found in the left hand side of the housing of the motor ) also the pick up coil ( found in the same place and also called pulse coil or trigger coil) , The CDI unit ( Usually the black box mounted on the frame under the tank and has seven wires coming from it) , the igntion coil, and spark plug. Before ordering a CDI you need to do the following.
Remove spark plug and earth it to the frame or motor, kick the motor over with igntion key on and kill switch off and check to see if you have spark. If no spark then find the 2 wiring plug to the magneto and disconnect them ( the 4 pin plug from the magneto will go to the CDI, the other plug goes to the lighting system.. The Magneto should have 2 plugs, one plug that has 4 wires to it and then 1 plug that has 3 wires from it and includes a pink wire.
Magneto / Stator
4pin plug wiring code is : Black with a white tracer ( B/W ) = Earth wire Red wire ( R ) = Power source (high speed circuit i believe ) Brown wire (Br) = Power source ( low speed circuit ) White wire (W) = Trigger wire |
Test Procedure is :
With a Digital multimeter test the resistance (ohms) of the Magneto coils
| Pick up coil | W - B/W you should have approx 50 - 90 ohms |
| Power source | R - B/W you should have approx 5 - 9 ohms |
| Power source | Br - B/W you should have approx 3 - 6 ohms |
| Lighting | Pink - B/W you should have 1 - 4 ohms |
All your resistances should be within these specs if not then you have a fault within your magneto/stator. A extra tip is to also test all these readings whilst "lightly" tapping the magneto housing with the "wooden" end of a hammer just in case the windings have a intermittent break in them.
Ignition Coil -
Disconnect the wiring plug from the CDI that goes to the ignition coil it should be a 2 pin plug.
Black ( B ) = primary wire Black with yellow tracer ( B/Y ) = second primary wire |
Test procedure is :
With a Digital multimeter check the resistance readings across both primary wires, you should have a reading of approx between 0.5 ohms and 3.0ohms
Test the secondary windings by inserting one test lead from your multimeter up the spark plug HT lead and the other lead to a ground connection you should have a reading between 15 Kohms and 25 Kohms. Once again its a good idea to also do the same test whilst tapping the coil with the handle of a hammer or some other non conductive tool. If all of the above tests are within the recommended specifications and yet you still have no spark then it would be a fair assumption that the CDI unit is at fault.
NOTE: These coils are different to several other motorbike coils in the fact that the secondary windings get tested from HT lead to ground and not from HT lead to a primary wire