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Discussion Starter · #1 ·
Hello, I hope everybody is doing good, haven't been around in a while even though I check the forum from time to time. Spring is almost here!!

I think I'm developing bad habits and I hope someone will talk me out of it. :p First I've discovered clutchless shifting a couple of months ago. What a revelation! Makes shifting really smooth, I'm addicted... but I hear it could be bad for the bike so I'm trying to wean myself off of it. I should, right?

Second is: it's been relatively cold this Winter in the DC/Baltimore area, but I still rode my bike to work (almost) every day. I keep it in the garage and it starts right up every morning like a champ even if it's like in the mid teens outside, but I wonder if I should let it warm up more than I do. Typically I'll fire it up (w/ choke of course), let it warm up (not too high) while I put on helmet, gloves, backpack and tank bag or whatever, then reduce the choke to very low (just enough to keep a solid idle), and then I go (partly because I don't want to let it run with the garage door closed and breathe the exhaust, and I also don't want to let it idle with the garage door open and bother my neighbors with an idle engine in the background, I typically leave at 6:40 am). The ride through my neighborhood is slow (< 25 mph) and short (like 3-4 mins), so I'm not pushing it. If it's really cold I keep the choke kind of low for 2-3 minutes, sometimes more (basically until I get out of the neighborhood), if it's not I turn it off quickly. Is it bad for the bike/engine to run with the choke on for a couple of minutes? And if it is, why?
 

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Clutchless shifting was discussed here some years back, can't put my finger on it at the moment. Problem is the engine has to transition almost instantaneously from the proper rpm for one gear to the proper rpm for the next gear. No doubt you've found that you can downshift pretty much as easily as you can upshift. IIRC the concensus was that the "shock" to the mechanism outweighed the possible reduction in wear to the clutch.

Your choke usage sounds appropriate. Using more choke than absolutely necessary may cause it to be running a bit rich, but, especially when it's cold out, you won't be doing any damage.
 

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Discussion Starter · #3 · (Edited)
Thanks. To be clear I've only done the up-shifting, haven't tried the down but from what I read it's trickier, and for some reason I'm not really tempted to try when slowing down (I use engine brake and using the clutch is nice to control it). So I guess if you're doing the upshifting at a reasonable rpm (ie you don't push the rpms too much) and the drop in rpms the engine experiences to move on to the next gear is not huge it's not that bad? Potentially? And the drop gets smaller at higher gears? What components would be affected? Is it the gears? Or parts of the engine itself? Is that why some people (I think it was ancientdad) mentioned using something to briefly shut off the ignition (I think that was the ignition in another thread)? To sort of act like you're using the clutch and let the engine rpms slow down without being 'forced'?

Honestly the transition between gears from going clutchless is super smooth. To me that's the appeal really I guess. It's hard to be that smooth using the clutch... maybe because I almost never push the rpms when I do it, and on the NH the gears feel pretty close anyway, I mean by the time I hit 40-45 mph I'm in 5th gear... it's like butter! Just pull lightly on the lever, roll off the throttle and bam, you're on the next gear without even really feeling it!!
 

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Olivier,

Yes, this has been a cruel winter. Not particularly snowy or bitterly cold, but long and uncomfortable. :( These next few days are much anticipated!!!! :D

I am no authority and do not intend my OPINION on this to be taken for anything other than what it is.
Whether using the clutch or not, individual style in said application can have as much variance as simply saying I do or don't use it.
I believe there is little difference between holding the throttle steady and stomping the shifter drag race style and pinning the throttle then dumping the clutch and wheeling away from a stop.
The "shock" to the entire system is little different. However, the entire movement of the (clutch) pushrod from totally engaged to totally disengaged is only several thousandths of an inch! Somewhere in the neighborhood of 1/8 of an inch at the most. feathering the clutch as opposed to a full handful may not allow full disengagement, but does allow the plates to slip alleviating the "shock."
Even if totally ignoring the clutch lever, judicious throttle application mitigates engine "shock" of the new ratio.

Very simply, the way you shift whether with or without the clutch, has as much impact as whether or not you are using the clutch. The key is remembering that we ARE talking about 40+ year old machinery! Machinery that was generally intended to be used with the clutch. As the bike appears to be your primary transportation, perhaps due diligence in prolonging its reliability outweighs convenience. ;)

Choke use is totally at the mercy of dictating conditions. That said, an optimally operating engine is designed to run with the choke off. Factors such as cold or a sick engine can be nursed along with judicious use of the choke, but the goal is still to not need it. :cool:


That's MY opinion. Other's may vary.
 
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LOL..... At 45 MPH I'd on have JUST shifted into THIRD gear on a stock CB 175......

IF you aren't at least getting to 6500 RPM you haven't hit the max torque point yet......6500 to 8500 is where these engines are happiest
 

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Discussion Starter · #6 ·
:-D I occasionally push it, but rarely. Mine doesn't have a tachometer so it's hard to tell... I may install one at some point since they're so cheap on eBay, I just wonder how accurate they are...
 

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I think we tend to baby engines more without a tachometer so don't be too down about it.

I'm curious how your mileage has been this winter, are you still seeing the 85mpg you mentioned earlier?
 

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Discussion Starter · #8 ·
No (>.<), after I hit a best of 82 mpg at the end of January, my last 2 fill-ups since have been 76, and then a measly 63 yesterday. Boo. Maybe that 82 was just a fluke, average has been 68 since I've owned the bike, I suppose that's not bad though (the Saab gives me like 23 mpg :-D). Either that or something has happened that I have not noticed and is impacting my mpg. But I think the 82 was probably just a combination of maybe under-filling the tank somehow and riding like a grandpa :-D.

The data in fuelly has the CB250 '07 at around 62 mpg average. So I think I'm good...
 

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Understood. Don't forget that those cold weather warmups with the choke closed are using up more fuel than average warm day cold starts do.

Oh, did you by chance change out your spark plugs for the ones specified in the FSM for cold weather riding in temps below 41F? Its on page 1-13.


That may help with cold starting and warm up times.
 
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