hi a mate has a 8k rpm flat spot it wont rev past it .
he has 1990 fl but a 1987 fj cdi would this be the problem
any help would be great thank you

 

bump ... someone must know even you yanks !!! sorry

 

1. stock or aftermarket exhuast?

2. any airbox mods?

3. any jetting mods?

4. are carbs working properly?

5. does engine idle properly?

6. any intake leaks?

7. check coils? plugs? wires?

cdi could be a problem but also could be jetting at higher rpms. engine could be starving for fuel.

 

at the minute just need to find out about the cdi is the fj compatable with a fl engine .
exhaust is race air box is modded .
but as his is the same as mine apart from the cdi i thought this would be the best place to start but thank you for your reply

 

are you using a 87 or 90 wire harness. there are minor differences and that could be the case with the cdi.

 

dont know about that / how would one check that ?

 

get a service manual that shows both wire harness schematics. i know for sure that the alternator is different. but i am almost sure that the cdi between both years is different. i'd have to check.

 

i misspoke. alternators are the same but the pulse generator is different. also, the cdi is different between pre and post '88 models. could it be that your wiring harness is from a different year from the engine? if the engine is a 90 then somehow it must be running a 87/88 wiring harness. you should really look at the wiring schematic and check it against the wiring harness and especially the cdi. if it all looks kosher then there is a slight possiblity that it is related to another part of the electrical system that is not as obvious. i won't get ahead of myself until you say otherwise on the cdi.

 

Thanks for starting up the thread lloydie.. and for all of the replies so far..

Wealth of knowledge on here

It appears that the CDI's are different..

I have ordered a new CDI for a 1991 fl which should be the same. Its also coming with the full wiring loom..

Could the CDI have been causing this problem?

Will have a look over the loom this evening to firm up which year bike its from..

Cheers peeps..

 

The wiring loom in the manual for the 600's seem to be the same no matter what year..

I think the loom may be form a 1000...

So hopefully with the new loom and cdi will help..

Loom should be with me on thursday so can fit it then and let you know..

I don't think the issue is to do with the airbox as I have tried lots of configurations.