V/R cause rough running engine?

[89Fizzer89]

So my 89 FZR 600 has been running real rough. It seems to have a miss and runs like absolute crap at low rpms. I have gone through and cleaned the carbs, replaced the plugs and just found out my V/R is no good. Im gonna go through to process of fitting in the r6 version so i can get some more life out of it before changing it again. It is gonna be a few weeks before the funds come in to get one so im just curious if this could have to do with the reason it runs poorly? I know the v/r runs the ignition system, maybe im just reaching here hoping that i can finally solve the problem with a simple fix. Thanks for any advice!

[DonTZ125]

How did you realise your VRR has gone off? Did it fail high or low?

Once the engine gets out of low revs, does it pull cleanly to redline?

[89Fizzer89]

How did you realise your VRR has gone off? Did it fail high or low?

Once the engine gets out of low revs, does it pull cleanly to redline?

I used this flow chart to figure out it needed to be replaced. http://fzronline.com/wiki/lib/exe/detai ... charge.jpg
I first noticed a problem when my headlights would dim down and then brighten back up.

Yeah after it gets above 4k it runs much better. The PO said it had dynojets in it, im not sure if that has any relevance.

[DonTZ125]

If your lights dim and brighten with the revs, it sounds like the VRR failed low - is that correct? If that is the case, then this could very possibly cause rough running. The charging system doesn't put out enough juice to keep the sparks flying until 3-5k rpm; instead, you're running off the battery. If the battery isn't being charged, or isn't holding a charge, then you'll have problems. You're probably lucky you can still start the bike!

If you're still at the scratching head and planning stage for the VRR upgrade, I'm going to go into Used Car Salesman mode ( ) and point out that I make and sell little adaptor harnesses that make changing from a 4-pin to a 6-pin VRR a near plug-and-play installation.

This could still be a carb issue - how well did you clean the carbs? Did you just pull the bowls and spray some cleaner through the passages, or did you pull the jets and soak them, perhaps using some nylon fishing line? (It's sometimes easier to simply replace the pilot jets - they're cheap, and really hard to get properly clean)