Having an issue with my 87 zilla. Seems to burble or cut out in the higher RPM. Did this when I bought it. So I replaced the stator with a aftermarket one. It still did it. Had the motor gone through due to the crank bearing pockets being worn out. Broke it in well and I always assumed it was just rich jetting. Well, dropped the main down from a 620 to a 560 and it didn't change much. I can see though that the color of the spark plug is getting lighter with the leaner jetting. I have an EGT gauge on it and it isn't running any hotter with the leaner jetting. SO I am assuming it is an electrical issue. Are there any common ignition parts that go bad on these quads? Like a coil or CDI box? I have a couple more CDI boxes laying around but I can't tell the difference between the 250 and the 500 cdi boxes. I don't see any numbers or stickers on them. I got them in some parts lots that I bought and it is a possibility they could be 250 boxes. I am going to ohm out the coil and cap tomorrow when I bring my meter home. Plug gap is at .018. Pipe is new at time of build so that shouldn't even need a repack yet. Starts right up and idles good. Runs fine through the midrange.
Are you running a stock reed petals on the 87?
I have had problems on some 1987s that have had the reed stops bent to increase the reed lift potential. It does not help the power but will make the engine misfire at around 7600 RPM. The engine behaves like it is an electrical problem or too big of a main jet. It is reed float and can be eliminated by using thicker reed petals or a progressive type of overlay between the reed petal and the backstop.
I never would have thought of that. Thank you for the reply. I can only assume that they are stock pedals. I will pull them out and find out for sure though.
Pretty sure 250 and 500 cdi boxes are the same. More info on motor please, pipe, carb other engine mods. That jetting sounds really rich unless you have some crazy built motor.
badmoon, I just noticed your signature saying under your skull pic lol THAT is some funny chit
Jerry did up the motor a while ago. Has his HPR 19 pipe, bored out stock carb, full porting. Dropping the jet really didn't change the way it ran so I don't think it is jetting. also running sunoco 110 24:1 dominator oil. I have some reeds on the way for it and am going to put them in and see how it runs. Currently have the stock reed cage in it and ordered some of Jerry's modified v force reeds for it.
the timing curves were different on the zillas. i have a manual in the shop that lists the advance at a certain range.
Well, I switched out the reeds for a set of custom v-force reeds. The sputter up top is gone and it runs a lot better now. Seems to pull harder bottom to top. Even put the 620 main back in it...The reeds that were in it sure seemed to open really easy.
the timing curves were different on the zillas. i have a manual in the shop that lists the advance at a certain range.
Chris, can you get that information on the CDI differences?
I heard that on the 500'a the 87 is different than the 88-90?
I also heard the 250/500 boxes where swappable?
Can someone dispell the rumors?
Thanks
85-86 lt250r cdi have a totally differnt timing curve
Somewhere down the road suzuki superseded the cdi boxes to be the same. I had a 250 cdi box on my hybrid for a few years and no issues. I swapped them out a year ago cause I baught a zilla and parted it out just to do it. Butt synonym doesn't know the difference
the timing curves were different on the zillas. i have a manual in the shop that lists the advance at a certain range.
Chris, can you get that information on the CDI differences?
I heard that on the 500'a the 87 is different than the 88-90?
I also heard the 250/500 boxes where swappable?
Can someone dispell the rumors?
Thanks
Any word on this?I need a CDI for a 500 and am curious if I can use a 250 CDI in its place?Curious if the timing curves are different?