another thing to try

Graeme,
I went to a 17T front sprocket and noticed a 13% improvement at cruising speeds. if by performance you imply rapid acceleration rates, then going to a 17T front sprocket is the wrong thing to do even though it improves fuel economy. I have not yet seen what the change will to to improve the top end performance (velocity).
Regards,
Brian

 

I'd be interested to hear:

a) what slip on you purchased or if there is one specifically available in Canada that I should consider to improve performance and economy

b) what jetting should I go to now that I am riding in a diffrent climate

Since moving from Calgary, AB to Kelowna, BC I am not getting as good of mileage. I did a carb sync, but suspect that jets may be in order.

Both are fairly dry climates with Calgary elevation being 1048 metres (3440 ft) and Kelowna being 429 metres (1407 ft)

How expensive are the slip ons? jets?

Thanks for the thread!!

 

Sorry, I am a nub. I just got my carbs rebuilt, cleaned, and tuned. Would these gas saving mods require the carbs to be retuned or sync'd again?

I get about 42 mpg, and I was hoping for 50

 

Nightviper,
None of the mods I've done have affected or included the carbs (except fitting a K&N air filter)
All the mods were 'intended' as performance mods, but they appear to have had a benificial effect on fuel economy as well.
The best explanation I can come up with is that each mod had released a little extra power, so I need to use less throttle (and less fuel) to achieve the same, or better, performance.

 

economy with "power" mods

Graeme,
if you'll re-read Bolserst sticky on modifying carb needles and measuring A/F ratios, I think he hit it on the head. at much over 1/2 throttle, the stock ZR runs really rich. A/Fs as low as 11:1. Presumably (guessing here) to keep from an overly lean condition as folks "hot rod" their zr by freeing up exhaust flow (slip ons, etc.) and tweaking the induction side (holing the airbox etc.). by making these "power" mods, you're actually leaning out the mixture a bit so you get better economy. Max power is 13:1 A/F with best economies near the 14.7:1 stochiametric ratio (however 14:1 is about as lean as the stock K comes, and only in the 1/8 - 1/4 trhottle area). much after 1/4 throttle, the A/F heads down to 11:1. So my guess is that the K engineers figured we were all going to mod our exhaust and intake anyway, so they saved themselves some warranty/reputation issues and just over-riched the thing for the majority of the throttle opening. If you want to leave the induction and exhaust systems stock, you can probably do what Bolserst did and improve the drivability a bit w/o reducing mpg much.
best regards,
Brian