You would also need new heads to match the larger cylinder bore.Friends ,
I have a plan to bore up my R25 from 250 cc to 320 cc using R3 Cylinder , pistons and ring piston ...
Yamaha Indonesia not selling that items in Indonesia , anyone can help me ?
Yamaha Indonesia don't sell R3You would also need new heads to match the larger cylinder bore.
Maybe better to trade in your R25 for an R3?
In Indonesia we have several options for ECU replacement (Stand alone) , like Daytona (300 Usd ) , ARACER (525 Usd) .Im guessing you are located in Indonesia and dont have access to the R3?
If you're in a country where they sell the R3 Id say just sell your R25 for an R3. The cost of converting will likely be very high.
Not only is it Pistons/Rings/Cylinders and likely the cylinder head that are different, but I guarantee the ECU has different fuel maps. As well I know the throttle bodies on the R3 are stamped with the R3 model # so there could be a difference in those as well. I found an english copy of the R25 manual once but cant seem to find it again to compare other specs.
If you're really interested in doing it you might want to get in contact with someone in Thailand where the R3 is sold and is closer to Indonesia than the Americas
R25 has a 60mm bore/diameter in each cylinder. R3 has 68mm bore. So the diameter of the cylinder head areas where the valves are has to also have a diameter of 68mm.Yamaha Indonesia don't sell R3
You mean I must adjust the squish to new bore diameter ? ok ... Noted
but if I don't do that , what is the impact ? higher compression ?
In Indonesia we have several options for ECU replacement (Stand alone) , like Daytona (300 Usd ) , ARACER (525 Usd) .
yap , any source will do ... if the price still fit in my budget
waiting respons from Thai member
No its a displacement tax thingR25 has a 60mm bore/diameter in each cylinder. R3 has 68mm bore. So the diameter of the cylinder head areas where the valves are has to also have a diameter of 68mm.
The R25 head(s) won't fit on R3 cylinders.
As noted in another post, you would also have to buy a new throttle body assembly, which is larger for the R3 than for the R25.
None of these parts are cheap! That's why it makes more sense to sell, or trade in your R25, and get an R3, IF it's within your budget to do so, and if Yamaha Indonesia will start selling the R3 there. Seems strange that they don't sell it there when the R3s are MADE in Indonesia!!!!!! Is it because there is a limit on engine displacement size? Maximum is 250cc? Or is it just because the R25 is so popular, and such a huge seller, there?
Note: What's true for BP gas/petrol isn't consistently true across the wide range of gas/petrol brands available. A lot depends on which type of crude oil the refinery is starting with, Light Crude or Heavy Crude (including which oil field they are sourced from), the refining process(s) used and how the final fuel is blended.Also make sure your clutch is upto par. If not, you may get clutch slip at higher speeds.
If you won't change the gearing, you might actually see a drop in top speed, and mpg.
without the correct counterbalance, your engine might vibrate more, resulting in lower engine life span.
Without proper ecu mapping, you will be running way too lean, with possibly overheating as a result in extreme conditions.
You could somewhat fight off the lean, by fueling BP Premium fuel, which carries about 5% more energy per ounce of fuel than regular fuel.
It's probably the only thing you can do against running lean, unless you plan on running exotic fuels...