Re: Yamaha FZ 25 Owners Reviews and Experiences

Will do, I'll post the results tomorrow.

In stock configuration, the FZ does 100 (speedo indicated) at ~6500rpm, I assume people want it to do 100 earlier in the rev range to reduce engine stress. But this configuration makes it very usable and fun to ride in cities.

Re: Yamaha FZ 25 Owners Reviews and Experiences

Counter intuitive, when you over-gear you're making the motor consistently pull more load which translates to more stress on components.

Re: Yamaha FZ 25 Owners Reviews and Experiences

I have a doubt. Is the final reduction ratio directly related to these. For example, the Apache 160 4v and 200 4v both have the final reduction ratio of 3.461 (45/13) but the primary reduction is different (3.095 for 160 4v vs 2.818 for the 200 4v) and the top gear has a ratio of 0.880 in both the bikes. So the overall reduction ratio in the top gear is 8.583 for the 200 4v and 9.426 for the 160 4v. At 5k rpm 160 4v does 63 kmph while the 200 4v does 70 kmph.

Interestingly enough, the NS 200 also does around 70 kmph at 5k rpm. So it must also have an overall reduction ratio close to that of the 200 4v. But the NS 200 has 14-39 sprockets and hence a final ratio of 2.786. Infact, after this point, the NS 200 pulls more easily than the RTR 200.

What I think is, the overall reduction has more to do than just the final reduction ratio. Please correct me if I'm wrong.

BTW... At what rpm do you shift??

Re: Yamaha FZ 25 Owners Reviews and Experiences

You're right as far as primary ratio goes, but that is not all there is to it which is how the thumb rule of maintaining 3.00 at the final drive came into existence, the variables relating to load cannot be listed out on paper due to its nature plus we do not have the option to alter primary ratios, though from what I've seen they're more or less the same for most motorcycles if any variance is present then the same would be due to difference in number of gears or load spread per gear.

Normally I shift within the 4~6k range, on stock gearing even for regular riding the shift would happen between 6~8k RPM's, as anything under 5k RPM i.e 80 kmph in final drive would lead to light pinging.

Though the above is just an estimate I like to crack open the throttle now and then, especially on overtakes etc, so at times I'd be bouncing off the limiter before considering upshifting, the reason my FE remains decent is due to me keeping the throttle input in check in spite of maintaining higher RPM's.

Re: Yamaha FZ 25 Owners Reviews and Experiences

Is it somewhat similar to riding with a pillion??

Re: Yamaha FZ 25 Owners Reviews and Experiences

Let me make it simple for you. When you undergear, the engine revs fast hits top speed faster but loses out on acceleration. When you overgear the engine, you lose the bottom end to an extent, improved mid and top end range meaning the engine accelerates slower and top speeds are improved. Usually a thumb rule is to go one or two tooth in either of the sprockets.

With a bigger sprocket, you have more torque, bottom end pull, the vehicle accelerates faster, gives you the feel good factor.
With a smaller sprocket, the engine pull slowly, gains in mid range and top end acceleration is improved and gives you comfortable crusing without straining the engine.

Cheers!
VJ

Re: Yamaha FZ 25 Owners Reviews and Experiences

More or less but with a pillion you can always drop them off whereas when you over-gear the load remains consistently present and goes up in increments of the primary reduction.

With the stock sprocket setup of my P220 i.e 36/14 there were some uphill roads(Sabarimala) I could not climb from a standstill in first gear with a pillion and luggage without straining the motor and burning a lot of clutch with the revs nearing peak torque.

With the same gearing my chain and sprockets needed to be adjusted frequently as any P220 owner would know, as most users change their first set around the 20k km's mark, after undergearing to 40/14 my motorcycle has done 13k km's until now and the chain has not been adjusted even once, I've just checked the same a while before as I have a ride planned for tomorrow.

The only downside I see now is that it is easier to break traction at rear, either when downshifting or accelerating hard. And when I've got the top box on and its fully loaded the front end becomes a tad lighter on hard acceleration in lower gears. Plus that also translates to earlier tire replacements, though I don't think of that to be a matter of concern.

So in short, undergearing has not affected my FE adversely if not the other way, my top speed remains more or less the same at 130+kmph fully laden, I can cruise 60~70kmph in final overdrive at 4~5k RPM's fully laden without any concern as a jab of the throttle would send me shooting to triple digits in the blink of an eye which when compared to earlier is like day and night as anything below 80kmph would cause pinging and to overtake I'd need to drop 2 gears. So you can say its working well for me.

Re: Yamaha FZ 25 Owners Reviews and Experiences

I was aware of the outcomes of overgearing and undergearing but the highlighted part was why I posted the question. As aswinprakas said earlier, it is counter-intuitive that undergearing puts more stress on the engine and drive components.

Re: Yamaha FZ 25 Owners Reviews and Experiences

Thanks for the explantion bro.

Re: Yamaha FZ 25 Owners Reviews and Experiences

That's exactly the reason. Oveegearing too much without understanding the very usage would mean poor rideability. Stunt bikes are supremely overgeared to make use of all the power, and yes the bikes are tremendously stressed, right from drive train to the engine.

Poor torque bikes undergearing is recommended
Torquey bikes overgearing is recommended.

Cheers!
VJ

Re: Yamaha FZ 25 Owners Reviews and Experiences

I guess you got the terms mixed up.

Stunt bikes are under-geared, not over-geared.

And engine/exhaust note is not an indicator of stress which is what makes things counter intuitive.

The easiest indicator of stress is pinging, as this means that the motorcycle is under load that it is finding hard to overcome, at that time, the cylinder, con-rod and bearings are at maximum load, this can even be under 4000 RPM's, whereas when you undergear a motorcycle, you get more power at rear wheel, you would be running higher RPM's but that doesn't necessarily mean that the motorcycle is under load as the motorcycle runs most optimum at the RPM where it makes peak torque.

So on an overgeared motorcycle would be under more load even at sub 4000 RPM's as comapared to an undergeared motorcycle at red-line speeds.

Re: Yamaha FZ 25 Owners Reviews and Experiences

Absolutely right, missed the finer details there. Thank you for correcting me. But yes undergearing done right for the right motorcycle won't stress the engine. Too much and the above falls true, pinging, or more appropriately called as lugging which are crucial.

Cheers!
VJ

Re: Yamaha FZ 25 Owners Reviews and Experiences

I think sprocket swapping would also depend on the particular bike and engine characteristics too.

Re: Yamaha FZ 25 Owners Reviews and Experiences

Sprocketing is a cheap and effective way to increase or increase the final ratio of a given motorcycle within a set parameter. Now, each motorcycle as you've stated right, is tuned differently, w.r.t to its inherent power and torque metrics, and so are the primary and the final ratios. The one we can tinker with, are the the final ratios. Undergearing or overgearing, it's each individual's preference. Tourers prefer more taller gearing or overgearing for a relaxed engine and city runners prefer lower gearing or undergearing for that additional torque.

Splendors to Apaches many bikes overgeared for a relaxed pace, especially the Apaches which are overgeared often.

Cheers!
VJ

Re: Yamaha FZ 25 Owners Reviews and Experiences

Could you give your feedback now since you'd have ridden thousands of kms by now. Planning to go for this set you chose

P.S. Don't quote the entire picture set. Remove all pics before quoting.