Team-BHP - Honda CBR 250R : Answers to some commonly asked questions

Quote:

Originally Posted by Sutripta (Post 3024127)

Actually it is even easier to make clutchless gearchanges, esp. downshifts, in a car compared to a bike. The sequential shift pattern in a motorcycle is not relevant in this regard, the lack of a well defined neutral between every pair of gears is. Cars have a well defined neutral position.

Regards
Sutripta

P.S. Ever wondered why in a DSG, downshifts take longer than upshifts?

Anyway before it becomes a controversy, here's my take on clutchless gearchanges:
Can it be done - Yes
Will it damage the gearbox - If perfectly done, IMHO, no.
Should one do it regularly - No. Because doing it perfectly 100% of the time is very difficult. And when you don't get it right, you are damaging/ causing extra wear and tear on the gearbox.

Sir, if I understood it correctly, a clutchless shift is easier in a syncromesh? On paper, it certainly seems easier though as one can play with the throttle in neutral so that the engine and transmission speeds are in sync before the gear is slotted. Will try this out on my car next time. On my bike, I normally do clutchless upshifts without any 'thud' or detrimental effect to the gearbox.
And with regards to the postscript, I'm guessing its because it takes more time for the DSG to rev up the engine to sync with the lower transmission ratio. Please do let know if that is the correct explanation as I'm not quite aware of the mechanicals of a DSG. Thanks in advance.
(Apologies for taking this grossly OT)

I didn't have any experience with bikes till I bought the CBR, so I used to downshift the 'commuter' way, ie, without rev matching. Reading up about rev matching while downshifting here prompted me to try it out.

What I did was- clutch in, blip the throttle while braking and downshift at the same time and release the clutch smoothly after the downshift. Am I doing it right?

I feel that the biggest plus point while rev matching is that the gears no longer clank or thud occasionally as they used to while I downshifted the commuter way. The bike slows down smoothly without any jerks- almost like an automatic. I think that this reduces the strain on the tranny to a good extent.

However, I find that this takes a fair amount of my concentration. It takes a lot of practice to do this effortlessly but the satisfaction of executing a smooth downshift is worth it. Time to find some really secluded roads and practice carefully till it becomes like a second nature.

Evilmessiah ; You have said everything yourself. Once you master it, nothing like it. Don't sweat too much over it. The way you are going, in another few days,you will almost perfect it.

Keep practicing & keep learning. The best riders still are evolving & learning. Its a never ending process.

Cheers! :)

Quote:

Originally Posted by sukiwa (Post 3033649)

I recently rode a 6 month old 250R having 6k Kms on odo. Idle rpm was high compared to test bike I had tried at dealer.
If idling rpm can't be changed, how is this possible? OR was it poor maintenance for that bike?

I'm not sure about the CBR 250R but the Ninja 250R has an idling screw which can be tweaked to adjust the idle RPM.

Quote:

Originally Posted by sukiwa (Post 3033649)

If idling rpm can't be changed, how is this possible? OR was it poor maintenance for that bike?

This is why you should go through the first 4 posts before asking questions; this has been covered there in detail - http://www.team-bhp.com/forum/motorb...ml#post2994976

Quote:

Originally Posted by aargee (Post 3034002)

This is why you should go through the first 4 posts before asking questions; this has been covered there in detail -

Thanks for pointers.I was aware of initial FAQs, wasn't aware of updated posts in Dec '12.
Anyways, this was a used 250R ABS that I was checking. I have decided to let it go.

Lovely post I must say ! This has been instrumental in me enabling me decide go for a CBR 250r and I have given away my Custom RE 350 (Drago) and am set for the buy. Tri-color (ABS) it is for sure. One dilemma remains - The 2013 color scheme on the tri-color looks a more appealing and I am awaiting the same. Would any of you on this forum have any idea of when this new color scheme is being launched ? There have been various posts on the colors but no information per se on the arrival date.

Looking forward to any information to enable me book the ride !!

Thanks,

Srinivas

Quote:

Originally Posted by Srini76 (Post 3047004)

Would any of you...enable me book the ride !!

For now, there's no concrete news about the new color schemes to be launched in India; there're so many other news (rumors rather) floating around, especially after the launch of 150R & 250R naked versions, 500 F/X/R, about the possibility of these launches. So the color scheme news has almost become old now. But I do agree with you, the new HRC color scheme looks fabulous (even the red) than the current ones.

Tks for your kind words & glad my posts were of any help to you :)

Quote:

Originally Posted by n_aditya (Post 3024136)

Clutchless upshifts are easier than downshifts (and less harmful to the GB and engine) since there will be lesser load on the gearbox and engine during upshifts. If the revvs are matched correctly (blipping the throttle) then you can seamlessly shift up without using the clutch.

how does one blip the throttle without the clutch pulled in? What am I missing here? please elaborate. I always had the habit of bliping the throttle during down shifts, but with the clutch pulled in. :)

Quote:

Originally Posted by naveenroy (Post 3068629)

Hello Aargee. Are you sure it is 14mm? I bought a socket wrench and a 14mm attachment for it but it doesn't fit the nut?

Yes I remember it's 14mm; let me check once again for you today evening; I hope what you bought is a socket-wrench type tool

Quote:

Originally Posted by YaeJay (Post 3068735)

how does one blip the throttle without the clutch pulled in?

Avoids jerking

Quote:

Originally Posted by aargee (Post 3068907)

Yes I remember it's 14mm; let me check once again for you today evening; I hope what you bought is a socket-wrench type tool

Avoids jerking

Still does not answer the question! rev matching is more of a jeepy thing when we dint have the synchromesh. Always helps with bikes when you want to down shift with bikes, and upshifts if the gear box is shot. But, the blip happens with the clutch pulled in or pedal pushed in. My confusion was about 'blipping' when a gear is engaged.

rev matching, blipping, double clutch, gas in the clutch etc etc were all pretty common at one point of time.

Most modern bikes don't have false neutrals, most accept an up shift without the clutch.

In those days, it was not about jerking, but getting the gear engaged!