| Author | Message | ||
     Bigdog_tim |
Can someone describe how a clutchless upshift works (technically)? Just curious - - but what is different that enables it? | ||
| Tijuanajack |
Basically the same way it works on a car. The syncros are set for a specific rpm range. When you are within that range you can disengage the gear and as long as you are with in that range still you can slip the transmission into the next gear smoothly. You can even down shift using the same technique. Semi-truck drivers use this technique as it is very tiring to be pushing in that clutch on the rig when in traffic jams. Race cars use this technique as well but their syncros are designed the same but for higher rpms while some have the multiple clutches setup for their specific race. I'm not sure if you wanted a more technical explanation. Toby | ||
| Cheshire |
a clutchless up shift is best performed with modern conveniences like power commander's shifter module, but technically all that is required is that you unload the gears smoothly for a moment and shift. It takes practice, and if you do it wrong, it can cost you, but I've done clutchless upshifts on an SV for a long time without issue. I've tried it on a M900 also and that was a little harder to modulate, and on an XB9 and that was pretty difficult. There's a very real flywheel to get used to in the latter's case. happy first post! W | ||
| Bigdog_tim |
Thanks - I was looking for a technical answer. I have never even tried clutchless on my XB12R. I did all the time on my GSXR 750. | ||
| Zac4mac |
Kept my fingers on the heated grips and warm this winter. That aluminum clutch lever gets COLD. 3rd and up is ssssssmoooooth. add - straight-cut gears? Z (Message edited by zac4mac on March 25, 2008) | ||
| M1combat |
I don't think there are sycros in a sequential trans. It works by unloading the gears when you let off the throttle. | ||
| Jlnance |
It works by unloading the gears when you let off the throttle. Do you have to unload the throttle on the 1125r? :-o When I was riding one at VIR I'd just hold the throttle and pull up on the shifter, but it's not like I knew what I was doing. I was just testing out a feature. I hope I didn't turn their transmission into mush.  | ||
| Blublak |
Hey Jim.. I found that the smoothest way to do it is to load the shifter (toe under the peg pushing up on it, it won't shift while you're adding power) then 'Almost' blip the throttle. All it takes is a half a second of let off and the 1125 slips into the next gear.. Then let your toe drop completely away from the shifter so the lever settles and then (if need be) you can do it again. Sooo.. Steady throttle, press up with toe, rock throttle a little and voila, up shift done! | ||
| Ratbuell |
+1 with Blublak. On my tubers and on the 1125r demo bikes, I'd preload the shifter peg and when needed, I'd just barely *twitch* off the throttle, and up she goes. Had to get out of the way of a merging semi this morning on the way in, having ridden the porker FLH for the last few weeks I forgot how well the ol' S2 will get up and go when you tell it to, and preload-shift to boot! | ||
| Xnoahx |
preload the shifter under throttle and throttle off then on again as quick as you can, it will shift wonderfully. | ||
| Baggermike |
So if you can preload the shifter and use this method under wfo riding and when the bike hits reline and the rev limiter kicks in the bike should shift? | ||
| Dentguy |
So if you can preload the shifter and use this method under wfo riding and when the bike hits reline and the rev limiter kicks in the bike should shift? Yes. It will work the same way as the electronic/air shifter works by cutting out ignition for milliseconds and unloading the trans gears. As for preloading the shifter. It will work, but not a good idea. Preloading the shifter is putting excess pressure and excess wear on the shift forks. If they wear enough and they will over time, it will start popping out of gear. Not to mention the whole shifting without a clutch and not using an electronic/air shifter. It does work, but eventually you start to wear out the dog engagements (not synchros, it doesn't have those) by rounding off the corners, shift drum and shift forks. Learn to use the clutch well (not that you don't) and you will be happier in the long run. Please don't try to downshift without the clutch as somebody said earlier. Not a good idea. (Message edited by dentguy on March 25, 2008) | ||
| Cheshire |
In a motorcycle gearbox, the gears are straight cut and nonsyncronized. Incidentally, the worst gearboxes to clutchless shift are synchroed boxes. When you alter a car's box to sequential or straight cut, you usually remove the syncros and install intermediate gears called dog gears. These are sort of crash gears in between that accelerate the main gears until they are going the same speed. On your bike, the gears are more than likely straight cut nonsynced... and that's great, there are less parasitic losses in straight cut gears. But... Straight cut gears require much closer rev matching, and on a bike like the Buell (aircooled) the motor winds up and slows down too slowly to make clutchless shifting a very safe practice without a lot of skill. I'm not sure what you mean however by a technical description. I suppose you could say that when you are upshifting and chop throttle the hair's instant that you upshift, the motor decelerates, matching gear speeds with the next gear in the line (or damn near) and if done correctly, this can be smoother than using a clutch, although I'm really torn between this and "clutch banging" or simply pulling and releasing the clutch very quickly as I'm shifting just to not risk the sever driveline lash that a failed clutchless shift can cause. On a bike, the biggest failure point in clutchless shifting is often the shifter forks, because some tool (like myself) has the bike setup for GP shifting and forces the shifter down into the next tallest gear with more force than is required and broadsides a gear rather than lining them up. The shifter fork snaps, and you get lots of metal floating around in your engine/gearbox... technically this is called no bueno. Incidentally I downshift my sv more readily without the clutch than I upshift it. With such a fast revving motor, it's pretty easy to match revs. I agree entirely on never preloading the shifter. Once again, gotta show your shift forks love. (Message edited by cheshire on March 26, 2008) | ||
| Bigdog_tim |
Hi Cheshire, I got pretty much what I was looking for. At my Inside Pass day, I overheard many riders talking about how the 1125R tranny was different from prior Buell's with clutchless upshifts being one of the key features. I have never even tried to shift without the clutch on any of my Buell's. On my GSXR - I did clutchless upshifts all the time (when riding spirited). I was looking for what was different at the transmission level that made this bike "an easy clutchless upshift". I suspect I will stay with clutch banging - as it is the way I rapidly upshift on my other bikes (have sold the GSXR - so only a Buell/Harley garage now). | ||
| Baggermike |
Big dog what is your technique for doing clutch less up shifts on the 1125R. Mike | ||
| Bigdog_tim |
Hi Mike, Actually, I don't have one. I started this thread to learn from others what makes a tranny "ok" to upshift without a clutch (and of course, to not damage anything). I don't race (but do enjoy a spirited ride). The fractions of a second banging a clutch costs in time compared to the cost of replacing a bent shifter fork have pretty much convinced me that I don't want to try clutchless upshifts on my 1125R or any other Buell bike I own. My GSXR - well - that was bought as a wreck and I pretty much thrashed it even more until I sold it. That being said, on the GSXR, I simply blipped the throttle and shifted. No preload was necessary and it just nicked up to a higher gear. I am sure that was faster than banging the clutch - but again - I don't race and those fractions of a second don't matter as much as the cost of replacing a broke thing (or my pride for causing an operator error). | ||
| Garrett2 |
baggermike - the 1125R is no different from any other bike, i treat the shifting the same as on my tuber, just off the throttle and it goes it like butter. nothing too it i wouldnt worry about breaking something - ive done it literally hundreds of times on my tuber with ZERO consequence. dont be affraid of it. | ||
| Baggermike |
Thanks Garrett I was asking about shifting with out letting off the throttle and thought that the bike was made to by one of the post, I will be drag racing and want something to shift real quick so I was thinking of rigging up something like an ignition killer on up shifts, I got other things to figure out way before that. Mike | ||
| Crashcourse411 |
XB's are not Sportsters. As long as the primary is kept adjusted and your foot is more than something used to bash at the lever there is no problem. I ride the crap out of my '03 9R and as long as you pay attention to detail on maintenance there is no problem at 11000 miles of it. Don't get me wrong, this is not a Honda trans by any means of the word, but it is much better than right shift XLH's from the '60s. I run synthetic 20-50 in the trans and change it every 3k. I also adjust the primary to the tight side, and the clutch till the lever has just a little play. As long as the primary is unloaded the trans will shift without issue. But if done incorrectly you will get stiffer shift after a while. | ||
| Dentguy |
Baggermike, There are two kinds that you could use for drag racing. One kind kills the ignition from a switch mounted on the bars for hand operation or a shifter mounted switch to cut the ign. when you shift manually. The other has a push button that will shift for you (with a cyl. mounted to the shifter) and cut the ign. at the same time just by pushing a button mounted on the bars. | ||
| Baggermike |
Thanks Dent guy I know of them but there are none yet for this bike, so for drag racing I have to have a kill tether in case of something bad, I was also thinking of a small button to press as I make a shift so I do not have to let off the throttle, I also have a few other idea's. Mike | ||
| Crashcourse411 |
To kill electronically it is as simple as purchasing a stand alone ignition kill and connecting it to a micro switch on the shift linkage. These have adjustable kill times and are to be connected to the ignition. I prefered killing the fuel instead, otherwise exhaust is filled with unburned fuel and you get a really loud pop when the ignition comes back on. Connecting it directly to the shift linkage allows ever shift to b clutchless, but it does not hurt anything to use the clutch when the switch is in place. Hope this helps Our application was approximately a 80ms kill time but that is not a sure thing. It all depends on the application. | ||
| Baggermike |
I seen this on the other buells but the 1125 does not have a shift linkage, so maybe a kill switch on the bottom of the toe shifter that would have to be rpm sensitive for finding neutral. Mike | ||
| Dentguy |
Mike, I saw one that bolted right to the shifter and didn't need a linkage. It is made for bikes that don't have a shift rod. | ||
| Dre99gsx |
In my experience, clutchless upshifts rounds your gear dogs much much quicker than using the clutch. I wouldn't recommend it for street riding. | ||
| Baggermike |
Dent Guy can you give me the web site that you seen it at. thanks. Mike | ||
| Dentguy |
PM sent. Didn't want anyone to think I was advertising. I didn't really read much about it or how it hooks up so I don't know if it will help or not. Good luck. (Message edited by dentguy on March 30, 2008) | ||
| Dentguy |
Mike, Sent you another PM. Looks like maybe a no-go. You could call them and see if anything is in the works. | ||
| Baggermike |
I post websites all the time were I see the items people are looking for, I am not making money off this and just relaying info on were to buy, I know lots of good stuff but do not have anything myself to sell and if I did I would pay to do it. Mike | ||
| Dentguy |
Mike, Hope you didn't take that the wrong way. I just didn't want anyone to think I was advertising something after reading the stuff going on in the "My custom exhaust" thread. Had nothing to do with you. | ||
| Reepicheep |
I replaced the 2nd gear pair on my M2 after about 20k miles, thank God it had a cartridge transmission. I'd never do a clutchless shift on my XB... I would have to split the cases to replace worn dogs. I know import sportbike guys say they do clutchless shifts all day long without hurting anything. I had a friend that ran an independent import repair shop as well, and he made a lot of money replacing bent forks and worn dogs for those guys. Every time I stopped in there he had some Japanese sportbike in pieces replacing transmission parts... Do the 1125's have cartridge trannies? | ||
| Dentguy |
Reepicheep, I think you would have to split the cases on the 1125. As for the clutchless shifts. As I said before I am against them unless there is a computer cutting the ign. at a precise time to unload the gears and shifting for you at the same precise time (still not that fond of that). I just don't think a person can do it consistent enough and it will eventually cause damage. I have seen too many damaged and worn pieces to count due to this. I also know plenty of guys who have sworn that it doesn't hurt anything, but most haven't owned their bikes long enough to let it catch up to them and maybe it never will. Unless somebody is a pro racer and in many of those cases they probably will not be paying for their own rebuilds, I just don't think you will save enough time to offset the possible damage for it to be worth it. Call me old fashioned, but I like the whole clutch thing. | ||
| Baggermike |
Hey Dent Guy I did not, I was just telling you that it is alright to post something like where to get hid lights, seats, grips, and other things on websites, it is just passing on info not selling, I just wanted to let you know that I think it is alright to do this thence I have not been told not to, all I am doing is trying to help others with what I know, and not making any money from doing this. I ju Mike | ||
| Baggermike |
I read that the electric shifters do not hurt the transmission, I do not know if this is true, I have tried shifting with out using the clutch and feels weird, it also feels weird not having my two fingers on the levers which is how I ride, so I am using the clutch to be on the safe side, I am not racing anyone so that spit second does not matter. Mike |
