SPECIFICATIONS - HONDA CBR250RR MC22

General Specifications

Consumables Specifications

Below is a list of the relevant sizes of the common consumable parts and maintenance items from the bike.

Tyres

• Front: 110/70/R17 54H

• Rear: 140/60/R17 63H

Sprockets & Chain

• Front: 17T

• Rear: 52T

• Chain pitch: 428

Lightbulbs

• Headlights: 2x H4R

• Park lights: 2x T10

• Indicators: 4x BAU15S

• Taillights: 2x BAY15D (1157) - offset

Further information - Tyres and Headlights

Tyre size options

It is increasingly difficult to find a rear tyre which is 140/60/R17, with 140/70/R17 being much easier to find. The difference between the two sizes relates to how large the large the sidewall is, and consequently the outer diameter of the tyre. As both tyres are R17 (17 inches), the inner diameter, which is relevant to the size of the rim the tyre is being placed on, remains the same.

If you fit the 140/70/R17 rear tyre to your MC22, the overall difference in tyre diameter compared to the standard size is +4.67%, resulting in a generally equivalent size discrepancy between your speed and what is indicated on your speedometer. Now, when your speedometer indicates 60km/h, you will actually be travelling at about ~62.7km/h. At an indicated speed of 100km/h, you will in fact be travelling at ~104.5km/h.

Some other things to be aware of with fitting the slightly larger tyre are that: 1) your odometer will also be underrepresenting the actual distance you have travelled, which although relatively marginal at ~4%, is nonetheless relevant if you rely on the odometer to determine when to refuel, noting the bike does not have a fuel gauge; and 2) your overall gearing will also be longer, which may affect acceleration, fuel economy and top speed.

Headlight options

As you may have noticed, one unusual part in the motorbike is the headlight bulb, whose size is H4R. These differ in sizes to standard H4 headlights, with the spacing of the tabs on the headlight differing between the two. H4R bulbs are rated for 12V 60/35W, rather than typical H4 bulbs which are rated for 13V 60/55W.

Why does it matter, you might ask? While the high beam wattage is the same, the low beam wattage of the H4R bikes is lower. That is likely the reason why the H4R bulbs use a different fitting, so you don’t unintentionally put higher wattage bulbs in.

While that probably doesn’t matter as much today with modern cars and motorcycles, the MC22’s electrical system is well known for not being particularly robust , including frying the left hand side light switches after a period of time if you use H4 bulbs, rather than H4R. Clearly the bike’s wiring and other electrical components weren’t designed to withstand high current.

Led Headlight bulbs

With the options for direct H4R bulb replacements being exceptionally limited outside of getting standard replacements (which have the poor light output and lifespan limitations of Halogen bulbs), you may consider modifying an H4 LED headlight bulb to fit.