Intermittent spark

Questions regarding the DR750

Intermittent spark

Postby Gavinnash25 » Tue Apr 09, 2019 7:14 am

Hi All

Bought the bike from a farm in pieces. Put it together but had no spark.
Please note that I am not a mechanic, but have tought myself one or 2 thing through youtube and google since I have bought this bike
I took it to an auto electrician and he mounted a dc cdi Chinese unit and explained that the coil on the stator was not giving power to the original ac cdi. The bike is running fine on the Chinese CDI but tend to run a little bit hot and loses a bit of power at higher revs (assuming this is because of the timing on the cdi.)
I always wanted the bike to run with the original CDI so I had the coil on the stator rewired and bought a second hand CDI from ebay. With the rewiring of the stator the wires was shortened abit and when refitting the stator I had to rotate it back about 30 degrees to make it fit, but thought it should be fine as the stator does not affect the pickup. The bike still starts fine on the Chinese CDI, but when I change to the original CDI and sounds like it wants to start, short little burst about a second or 2. I checked the spark on the sparkplug and when the bike turn over there is no spark and suddenly abit of spark and it looks like a strong spark and this keeps on repeating. I have the same symptoms on my old origenal CDI
I have to mention that with the Chinese CDI the bike will only start when the kill switch is in the off position and the original CDI works on run.
I have gone through the wiring and everything is correct, side stand is bypassed, neutral switch is working
Any suggestions would be appreciated
Virgin - be gentle
Virgin - be gentle
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Re: Intermittent spark

Postby BigBob » Tue Apr 09, 2019 8:42 am

The Big series are not noted for giving trouble with the CDI, in fact it`s almost unheard of.
Occasionally the pick up coil can go down and this usually a result of human failure ie connecting up wiring wrong, but again, this is very uncommon.
The system is also essentially very simple with very few components.
The stator/pick up/CDI are the same on the 88/89/90 models and completely different on the 91 on models.
I`ve no idea what is wrong with your bike as I would have to go over everything with a meter to check and with a problem like yours it would be total conjecture to make any sort of suggestion.
Clearly what set up you have is not working and I can`t help feeling that messing around with Chinese components is not the way to go.
Is there anyone close by that can lend you their stator just to check?
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