Things I would like to know about CBR250RR

**djleigh** · 28th April 2006, 08:01

(1)Well i can think off it there is a sticker on my bike that says
Cam Gear Train dose any one know what this means or what it dose.

(2) For the people out there that own these bikes how dose yours idle not how many rev but is it smooth or sound like it has lumpy cams like a car would idle if it had lumpy cams.

(3) Where is the air filter and where is the oil filter.

(4) What do you pump your tyre to fornt and back.

Sorry for all the questions just trying to learn about bikes because i know more about cars.

Thanks in advance.

**Two Smoker** · 28th April 2006, 08:05

Originally Posted by djleigh

(1)Well i can think off it there is a sticker on my bike that says
Cam Gear Train dose any one know what this means or what it dose.

(2) For the people out there that own these bikes how dose yours idle not how many rev but is it smooth or sound like it has lumpy cams like a car would idle if it had lumpy cams.

(3) Where is the air filter and where is the oil filter.

(4) What do you pump your tyre to fornt and back.

Sorry for all the questions just trying to learn about bikes because i know more about cars.

Thanks in advance.

1: Cams are driven by gears, not a chain...
2: It should idle smoothly...
3: Airfilter is under the tank in the airbox, the oil filter should be just behind the headers attatched to the main block (all my bikes are like that, so im assuming)
4: try 32-33psi front, and 34-36 rear...

Hope that helps

**FROSTY:Me** · 28th April 2006, 08:07

you dont have a cam chain so gear cams not chain. Tyres --start with 32 front 37 rear..Air filter is up under the tank inside a plastic box. Oil filter I remember beeing bottom front of motor. Memory serves they were a pretty smooth idling bike -surging may indicate need for4 a service -but they are a high revving bike so can sound "cammy"

**djleigh** · 28th April 2006, 08:15

thanks yeah the bike i think idles smooth as in it dose not spike or any thing and reves up smoothly and gose like a rocket from what i can tell but hey its my first so i guess it would seem like a rocket to me and not some other gus with more experiance but it just sounds cammy when idleing and a nother thing i noticed is if the bike is cold and i start it it ok but if I pull the choke up and start it it wont start and if it running and I pull the choke up it stalls any ideas about that

**SimJen** · 28th April 2006, 08:26

The lumpiness could just be the carbs needing a balance

**djleigh** · 28th April 2006, 08:34

yeah when i got the bike from the shop i asked them if they had done that and they said yes and it had a full service

**kiwifruit** · 28th April 2006, 08:35

Dont take the gear cam train sticker off!
just my 0.02c

**djleigh** · 28th April 2006, 08:37

haha yeah dont plan to

**Bend-it** · 28th April 2006, 08:41

DOES, not dose

Sorry, it was driving me nuts... a dose is 1 serving or course of something (commonly medicine). For example, 1 dose of antibiotics.

DOES is the singular of 'do', Eg. They do; he does; it does; "does anyone know..."

Also, it says Cam gear train, not chain. A train of gears makes sense... meaning more than 2 gears linking the cams...

**djleigh** · 28th April 2006, 08:45

haha oops bad spelling that one always gets me and yeah the sticker does
say Cam Gear Train thats what i said at the start

**imdying** · 28th April 2006, 08:51

Compared to a car, the cams are incredibly 'lumpy', most bikes sound pretty lumpy if you're used to cars. Cam gear train is the reason it sounds like a sewing machine... no chain, only cute little gears spinning their nuts off

CGT wtf

**bugjuice** · 28th April 2006, 08:53

The oil filter for the CBR250 is different to most other bikes. If you look under the engine, there's 2 bolts. The lower bolt towards the back of the engine is the oil sump plug, the bolt in front that holds a round plate up into the engine is the filter. It's a cartridge filter. Drain the oil out first, then undo the filter. Install a new filter, stick the plug back in, then fill via the screw cap on the right side of your engine, just by where your shin would be when riding. Have a look in there, and that's your clutch

Fill up with about 2.3l of oil (if memory serves me right, there's a sticker on most CBRs that say how much, but it's in jap squiggle. The first number is for oil only, the second is for oil and filter, and the third is for dry/rebuilt engines), and check how much oil is in by using the dipstick on the screw cap.

The spark plugs are real fun. You'll have to drop the radiator and get at them from the front of the bike, bloody awkward. Everything else, everyone has covered.

**Bend-it** · 28th April 2006, 09:02

Originally Posted by djleigh

haha oops bad spelling that one always gets me and yeah the sticker does
say Cam Gear Train thats what i said at the start

Yeah, but the other people are posting stuff about chains... just pointing out that your post reads 'train', not 'chain'.

**TwoSeven** · 28th April 2006, 10:21

The correct term I understand is "Cam gear train" and refers to a set of complete set of sprockets called cam sprockets that make up the cam gear train (the part that links the crank to the cams).

There are two basic implementations as I understand things- the more common is the use of a cam chain to link the camshaft gear sprockets to either the crankshaft sprocket, or the clutch outer sprocket. The less common setup is to replace the chain with a set of 'cams' (sprockets) instead. Later model cibby 250s use the latter [sprocket] method (I cant remember if earlier models used cam chains).

Off the top of my head I seem to remember that the cibby 250 has the large primary gear sprocket on the end of the clutch basket (its about 86T I think) with two smaller sprockets running off of it - one being the crankshaft sprocket and the other being number one cam drive sprocket. Then there should be numbers 2 and 3 cam drive sprockets and then the camshaft sprockets (there may be an extra sprocket to drive the inlet cam but cant remember).

I think that the main reason why cam gears are used instead of a chain in bike engines is to increase the precision of the valve timing at the higher revolutions (think 18k rpm or so).

As I understand things the noise primarily by caused by backlash and change in angular gear velocity of the sprocket causing the teeth to come contact each other then separate - ideally they should always be in contact (same way you get noise from a worn chain and sprockets, or worn cam chain in bikes that use those).

On the earlier models I think the oil filter is underneath the engine beside the drain bolt and is of the paper type with a cover held by a single bolt. For some strange reason I have it in my head that the later models have the metal canister type on the front of the engine behind #4 cylinder.

Air filter is under the tank, and also i seem to remember there is a different design between the earlier and later models. Perhaps I am confusing it with the 600.

In general a motorcycle engine should not hesitate when idling (or running), that is there should be no pause between plugs firing (should be a tat tat tat tat tat tat constant type noise), however, if its not warmed up properly or out of balance etc, then you may get a slight pause (tat tat tat tat pause tat tat tat tat - kind of like a pulsing or thrumming noise) - I never used to worry too much about it.

I've found that the usual starting procedure for a cibby with a good battery is no-choke, no-throttle, pulse [starter] catch [with throttle - but dont blip] and hold [at 3-4k rpm] til its warmed up [84C]. If the bike has been standing for a very long time, or if its a really cold morning (sub 10 deg), then a little bit of choke may be required until the engine is warmed correctly. Everyone has their own starting procedure tho so its swings and round-a-bouts really.

Just my thoughts.