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Weak spark ?
Posted: Wed Jun 13, 2012 7:29 am
by 2manymadmonkeys
Bike is now a none runner it does spark some times is this the cdi unit if so which ones fit will most fit I've seen one off a gsxr750 or are they all different my bike is a gk76a 1992 import 400 it says on it
32900-33c70 bb7240 ?
Re: Weak spark ?
Posted: Wed Jun 13, 2012 8:38 am
by gsxr400 91
Im pretty sure if the cdi were at fault you wouldn't get a spark at all. As far as im concerned the cdi is either good or bad . Never in between ??
Just for information tho Cdi can be picked up from ebay either second hand or there is some in japan offering a de restricted cdi but requires the BB----- number and charges £100+ for them....do they work ??? Im not sure .
As for the spark providing your gettin a spark at all four and correct voltage should be ok . Idealy we all want a bright blue spark but i get a yellow spark and isnt very bright either. . . I too were concerned but found this to normal according to several people and mechanics . Id expected a huge spark like a cars sparks but nope these are alot more fainter .
Again i would make sure all spark plugs are ok and battery is fully charged. Check the condion of the caps and ht leads. Check the coils. If all is good that side then move to the cdi and generator. Checking correct voltage.
Thats just electrical..... If all seems ok check is fuel getting through to the cylinders? Is the cylinders dry or being flooded. Do a compression test to check condtion of cylinders. This tool can be picked ip from ebay or local machine mart. Very hand to have.
Theres lots to go over a good afternoons work or so...
Start here ... Thats my advice.
Hope it helps mate. Keep us updated.

Re: Weak spark ?
Posted: Wed Jun 13, 2012 9:05 am
by 2manymadmonkeys
Nice one will have a look today
Re: Weak spark ?
Posted: Wed Jun 13, 2012 10:11 am
by 2manymadmonkeys
Battery is new and charged orange wire on coil is reading over 10 volts all ok so far the sparks are a year old but not been used in a year and are cr8e so I have some cr8ek in the post
Re: Weak spark ?
Posted: Wed Jun 13, 2012 4:32 pm
by gsxr400 91
Sounds good so far. Check the coils not just the orange wire. Then just see what happens when you try the new spark plugs.
If all is ok after that start looking a fuel / carb side of things. Some one recommended a bump start or easy start fluid just to see if will fire that way. . .
All the best mate
Re: Weak spark ?
Posted: Wed Jun 13, 2012 4:59 pm
by 2manymadmonkeys
How do I check the coils had all the plugs out look like 2/3 are bright spark but at the same time? And 1 and 4 are weak whenever they feel like sparking ?
Re: Weak spark ?
Posted: Wed Jun 13, 2012 5:09 pm
by gsxr400 91
You may havr to remove the coils as im not sure if there is enough space to do so on the bike. You check both pins at bottom then one at the top against the ones at bottom sort something like that... Again check you tube should be a vid on how to. . .
As for the spark on 1 & 4 could be just as simple as the plugs or caps or leads them selves.
Re: Weak spark ?
Posted: Fri Jun 15, 2012 8:27 am
by 2manymadmonkeys
I'm getting about 1 ohm on the coil if I'm checking the right bit
Re: Weak spark ?
Posted: Fri Jun 15, 2012 10:26 am
by 2manymadmonkeys
But I'm not getting a reading from the coil to the spark plug holder ?