What Are The Causes Of Poor Shifting In Motorcycling?
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- Опубликовано: 15 янв 2018
- Kevin Cameron explains why you should buy a junk motorcycle and “play” with it-in this case, the transmission.
Most of the problems with poor shifting are traceable to causes outside the engine. It’s quite common for people, attempting to adjust the height of the shift pedal to suit the limits of their ankles, to get the linkage in such a state that it cramps against itself when you make the shift and doesn’t push the shift claw far enough to fully engage the gear. So if you have a shifting problem, it’s a good idea to look first in the external linkage, especially if you’ve recently made a change.
Inside the engine, engagement of one gear to another takes place when one set of dogs is pushed into engagement with another-the two gears now rotate as one. The space into which the engaging dogs can fit determines how much time it takes to complete a shift. So it is better for rapid shifting to have fewer, rather than more, dogs. Wide spacing between the dogs allows more chance that the gears will promptly engage. For this reason, eager racers of an earlier era used an abrasive cut-off disc to saw out every other dog.
On the other hand, touring riders-and other people who are going to spend time on and off the throttle in traffic-are annoyed by the large “clunk” of backlash from dogs that have a lot of space between them. One way in which some designs have dealt with this is to have six dogs but every other dog cut down to half its original height. The initial shift is made in a condition in which three dogs are engaging three dogs. Once the engagement is made, the backlash is quite small because of the half-height dogs.
I have spoken before about the shift from first to second, which is a difficult one because of the speed difference being larger than from second to third and so forth. Quite often the engaging dogs on second gear get rounded off by spirited shifting. All it takes to fix it are new parts. If you want to shift that way-bang ’em through, clutchless shifting-there may be a cost. But if we’re real enthusiasts, we don’t mind replacing gears, do we?
Another set of problems comes about from either pushing the shift drum too far, in which case the gearbox jumps into a neutral of the ratio you were selecting or kicks back out of the ratio to which you were shifting. There’s an eccentric pin in the assembled engine that determines how far the shift arm can move. Sometimes I found that adjustment was not correct. When I corrected it, I could see the claw pushed the drum almost into the next position. The rule I found was that the shift claw should stop pushing about a millimeter before the shift drum drops into its next locked detented position.
At one point in my early days, I had a bike with a Burman gearbox, which, instead of having dogs, had fine splines. That was valued by some riders because it had almost no backlash. But it was the scourge of people who wanted to shift quickly because there was so little space between one spline and the next, which offered very little time for a rapid engagement. In general, those Burman gearboxes with splined dogs were not for the sporting rider.
All of this stuff makes sense to you after you’ve played with it a lot. For those of you who are interested in doing this sort of work, get yourself a junk motorcycle and play with it. It’s the only way you’re going to get familiar with what the parts actually look like.
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Развлечения
This man has forgotten more mechanics than I will know in ten lifetimes. Truly wonderful. Ought to have his own channel guys.
As always, awesome. There are people with a lot of knowledge. But very few can share it so well. Thanks Kevin. 👍👍
Wow, didn’t know you did these videos. Been reading CW since 1976 and read tons of your great articles. So cool to see you doing this. I remember when I was 14 and tried to talk to people about your topics and no one ever knew what I was talking about both back then or even today. Learned a lot from you over the years and appreciate every bit of it. Your knowledge has always amazed and inspired me. Thank you Sir!
Great video! Very true that poor shifting is often caused by something outside the engine. The tip about the shift lever being installed incorrectly is really useful. I've also found that poor drive chain tension or a loose clutch cable are two other common reasons why my bike will shift poorly.
G'day Kevin, some don't like the music, some do, my two cents...it adds that nostalgic touch to the way you explain the inner workings of the mechanical world, bloody awesome!
Top-Drawer. Thanks Kevin!
The man is brilliant!
NO SHIT
indeed
Amazing to have you sharing such great knowledge here on RUclips! Thank you
"... a disturbance to your momentum." Kevin, that is the quote of the year. I love it. Thanks for the great vids. Always enjoy them.
Thank you for sharing your experience and knowledge. It truly is a gift to new riders and experienced riders whom are interested in learning about all the sounds and vibrations taking place between their legs as they progress down the road.
This video is pure gold!!! 👍
I remember bikes back in the 80’s when most were 2 paw shift forks and straight cut gears with crappy clutches. Modern bikes shift like butter. We used to take TZ250 gears and remove all the burrs on the lead of the gears, polish the forks and chamfer the dogs lightly with a stone.
So awesome! I have three junk motorcycles. Learning so much! Never knew that about the dog spacing, makes total sense about rapid shifting versus gear lash. Love the part about "only existed in theory" when you thought about what might be wrong with your transmission. Reminds me of Zen and the Art of Motorcycle Maintenance.
Thanks for the thorough, clear explanation. Helps me for sure.
I did really enjoy this video, very well explained by a very skilled man. The reasoning and experience is impressive!
Thank you, Mister! Brilliant!
Very helpful video. That was a lot of trouble you went to, on the little Kawasaki you mentioned, Pulling off the head and cylinder barrel and splitting the cases just for an intermittent shifting problem, and you'd have to have bought a fresh new gasket set for that.
I have your Sportbike Performance Manual on my bookstand and refresh myself ofn it every now and then!
Thanks for the video lots of good info
Thanks 4 sharing knowledge
Great video! I am a long time fan of yours!
Thank you Professor
Thanks for posting ! Was interesting.
Your videos are very informative
Thank you Sir 👍🏍
Kevin Thnks for your mechaTours!
Great info! Music made me change channels.
A great vid as always
I learning a lot of your videos! Very good to explain . Have my first bike now, gs650g katana and have this problem when im going from 3 to 2 gear. I think it happens from 2 to 1 gear too. I know i was thinking right when im ending up in this video
This dude has a big brain!
Where did they find Kevin? I just don't think they make people like this anymore. A gentleman and a scholar
Wow, just amazing (as usual) :-)
Very well explained, tx
I've been having some issues going from second to third on my Mean Streak. Every once and a while when I really dog it, it doesn't like to go to third and I felt a bit of grinding. I have a feeling the dogs might be a big rounded (or something weird is going on with them), but the bike is an 02 and I just recently purchased it. Hopefully it's just rider error and I can fix it by making better and more accurate shifts. Either way this video was really informative and explained really well. I feel like I understand a bit more what is happening in the gearbox.
".....Not that you'd want to do anything about it".....
Well said.
Can you do a video on centrifugal clutch motorcycles, usually those of
Please make a series of Cycle World t-shirts with Kevin's likeness on them. I will buy one immediately.
Awesome.
This certainly helped me better understand transmission. Yet I still don't understand why my 82 XJ 1100 jumps out of 1st gear into neutral when the engine hits 3 grand. This really stinks when I cannot fix it myself (I just don't have the skill to do it) also finding someone to crack into a 30+ year old transmission for a reasonable price is near impossible. This issue really drives me nuts and is one of the major reasons why I don't ride as much as I would like to. Also I don't have enough money for my dream bike a Triumph Rocket 3.
I had just problem with my kawa z750. After tyre change (were still factory tyres 😀 bike is from 2004 and 2000 miles) 5 and 6 gear didn't go in. Needed to relift lever several times to engage next gear but didnt have false neutral. It had just chain too tight. Loosened it to 30mm and now works fine. 25mm is minimum slack. Maybe gearbox is still too crunchy because low mileage.
I got familiar with shift shafts and shifter pawls by buying an 800XC.
I wore the dogs down in my “spirited” 1st and 2nd shifting on a first gen FZ1, so much so than on one aggressive shift up to 2nd, it dropped back to neutral suddenly and in kicking it back up, broke the gears. Until I watched this, I’d never fully understood why.
I have a Gen 1 Yamaha R6 that is notorious for losing 2nd gear. This video is great but I’m curious if the dogs get rounded off during clutch ups, or if it’s really just power shifting without the clutch? I’m trying to avoid this problem. Thanks
Hi Kevin,
My new Honda monkey sometimes fails to upshift from 3rd to 4th! It takes a second try to get the job done! All other changes are fine, and I don’t ever get false neutrals.
It is as if the mechanism does not fully re set after the 2nd to 3rd upshift, so when you attempt the 3rd to 4th upshift it doesn’t move the parts it should! Any thoughts or guidance you can offer would be appreciated!
It has only done 1000 miles so wear in the parts should not be a problem?????
hi,,is it possible to replace crankshaft size and flywheel to a smaller to make a shorter piston stroke for more power?,,does it affect my electrical voltage because the stator will rotate more and create higher voltage than the regulator and rectifier can handle?
Can someone help please??? What i would like to know is .do you know when you accelerating and you want to go up your gears as fast as you can soemtimes it feels like the chain slaps when you relaise the clutch but I'm sure it's when the dogs aren't lined up then when u relaise clutch it sorts itself out and makes a little nock is that bad for the dogs ? Or can they take that
As usual I enjoyed Kevin's explanations and stories, and I learned a few things. As usual the music sucks big donkey balls. No background music would be great, but at the very least pick some music that doesn't sound like an LP of the Donnie Darko soundtrack that skips every 10 seconds.
Should have mentioned bent shift forks, very common.
Your session were bucket of knowledge but due to mic the voice sometimes become too much low and can't understand.Please do something if you can do. Thanks
Is the jerkiness between on off throttle that people complain is from bad fueling is caused by a large gap between the dogs?
Jenkins Bradbury I know my jerkiness happens when my chain is too slack and out of adjustment.
I wonder how many false neutrals before damage occurs?
Have read your books, enjoy your u tube bits. But please cut the back ground noise. Thanks.
Hello Mr Kevin, I'm learning a lot from you amazing information and knowledge, did you experience or knowing a motorcycle kawasaki 650 2019 abs have a lot vibration from engine it buy new but something is wrong do you think can be a camshaft problem or same time a clutch im feelings vibration all the body not to smooth wile you ride this is normal thanks very much?
Sorry, right now is 1000 miles
The latest trend of quickshifters and their long term effect on gearboxes does cross my mind.
I was wondering about that. I have a factory quickshifter, and do seem to get more missed shifts from 1st to 2nd over time. Adjusting the linkage helped, but I wonder if the clutchless shifts are wearing the gears faster than normal.
Just asked Google. Turns out Kevin himself has answered this question :) www.cycleworld.com/2015/07/03/ask-kevin-do-motorcycle-quickshifters-have-negative-effect-on-gearbox-life
1st to 2nd you are also jumping across neutral. Never used a quickshifter
Aaaaargh, that 'music'!
I we are real enthusiasts, we don't mind changing a gear. I'll frame that and put it on my wall.
if done right clutchless shifting won't be a problem.
I admit the music kinda sucks, because of that i pay more attention to what he is explaining and that makes it work. Great job lots of info
im old and thinking les is more .... i want a automatic.. lol
Did any of Kevin Cameron’s Kawasaki’s ever win an AMA road race championship??!I was racing back in the day, Club level, AMA amateur races, I did win six championships, two national championships riding Yamahas...(Not under the name hairy lime)...I followed the news, I enjoyed reading about me in cycle news, but I don’t remember reading about any of Cameron’ prepped bikes winning championships.. I remember Duhamel winning, Nixon, Roberts, Lawson, Baker,spencer...tuners like Carruthers kanamoto,Pops Yoshimura machines winning.. but I don’t remember Cameron bikes setting the pace..
I guess the old saying applies here,
those that can, do..
Those that can’t, teach
A friend of mine bought an H1R used. Gary Nixon gave us a line on where to get it from a buddy of his in Pennsylvania .. I think the price was $2000 including lots of spares...The crankshaft had some miles on it, it needed to be replaced...Cameron was supposed to be the so-called Kawasaki expert or someone that worked for him was. My buddy (brother-in-law)called Cameron in Boston and secured a rebuilt crankshaft. Cameron said he would not ship it, it’s too delicate and too risky to send such a Percision piece in the mail,
So my buddy and I hopped in his brand new Vega, and drove from ohio to Boston and picked up this precision rebuilt crankshaft personally from the great man himself...The crank so perfect that it could not ever be trusted in the hands of a shipper.
That was before President Ford lowered the speed limit to 55 mph. We drove from Ohio to Boston and back in 22 hours with the fresh precision rebuilt crankshaft.
Well,the joke was on us....When we went to put the crankshaft into the H1R cases.. it didn’t fit. Not even close.It’s not that the crankshaft was too long, or the incorrect crankshaft, or the bearings were the wrong sizes, or that the cases were wrong. It was that crankshaft was so out of true, it wouldn’t even fit in the open cases ...Looked like the prop split case with the triple crank in this video. The rebuild crank was not just a little bit out, it was way out, it actually would not sit all the way down into the engine cases that’s how far out it was.. and that’s why I am wondering if machines that Cameron prepped ever won a championship,or even won a race?? I’m wondering what the finishing rate of his machines that he prepped is/was...I can’t say that I remember any of his machines winning,
That was over 45 years ago that my buddy and I did that grueling nonstop trip, at times driving at 90 miles an hour in that little cramped Vega, eating potato chips , and washing them down with Mountain Dew bought at 10 minute gas stops..We were in a big hurry to make it to the next race.
We ended up getting the crankshaft trued .. and the machine race ready for Loudoun.
The reason we ended up with the H1R, was because, they were mot the bike to have anymore...The bike to have was a Yamaha. Gary Fisher waxed the entire field on a 350 Yamaha that year at Loudoun..I ended up owning the dinosaur H1R..I took the engine out of the H1R, and put it into a Suzuki X6 and drag raced it. It turned 9.9 1/4 mi.. then I ended up trading it away for an S2...I traded the entire chassis to Eric Buell (we were both mechanics at the same Yamaha/Honda dealership then) for a Kawasaki 350 big horn dirtbike. Eric put a big single Kawasaki 2-stroke motocross engine in that chassis,I think he actually tried to race it but I don’t remember how he did.One of the magazines back then actually did a story on it.I still have the Sandcast case close ratio five-speed chrome bore cylinder H1R engine somewhere I think...maybe I traded it for something The engine really wasn’t any good for anything. You couldn’t put it in a street bike. Change that, of course you could put it in a street bike, but I wouldn’t ..
But getting back to my original question. When I saw the video and that triple two-stroke engine case on the bench in this video, I was wondering if anyone out there knows if any of Cameron‘s machines ever won a Championship, or even won a race??How about finished on the podium?? I’m only wondering about that, since I experienced firsthand the quality of his work.
Back in the 70s and 80s when I raced, there were always guys that thought they knew more than the factory. They were always porting this or raising this exhaust port or shaving this piston skirt ,using this carburetor or lengthening the stinger on the expansion chamber, always tuning,changing something, and making their bikes slower or less reliable in the process.
I did that my first year road racing, Of course I blamed the machine because I didn’t win week after week the first year.the machine I went to the track with I did every hot tuneup tip that I read about in the magazines. Most of the time I would change four or five things at the same time.And every race the bike was slower. Towards the end of the season, I seized the machine three times in a row and quit racing...
After I cooled off over the winter, I went back to the track the second year with a box stock machine. I swore I would never change anything to do with the way the machine runs ever again. I did relocate foot pegs, put quality suspension components on, changed overall gearing, and re-jetted depending on elevation. But I never changed the timing, the compression ratio, the transfer ports, the carburetors, I didn’t even smooth out the transfer ports. I did make sure that the base gaskets did not intrude into the transfer port flow path, and I balanced/matched the weight of the entire piston/ring/wrist pin assemblies.. I never undercut the dogs in the box, I never used Champion spark plugs, I ran 10 weight oil in my gearbox, I put five weight oil in my wheelbearings, I converted to the skinny chain and sprocket‘s, and I pre-stretched/broke in new chains before I put them on the track. I was on a team in a 24 hour race one time, we started the race with a brand new chain, and at the first pitstop, it was my job to lube the chain while they were gassing the bike. That brand new chain was never broken, the chain lube sizzled on the chain and it was turning blue. We put the old chain back on that 750 Honda during that 24 hour race on the very next pitstop. When we took that new chain off, it had seized links. Lesson learned.
Anyway, I left my machine engine, specs, timing, as it left the factory. I ended up winning four championships in a row, and two national championships on that box stock machine. So don’t believe these guys that think they know the secret little tips that will give you a quarter of a horsepower here & there. The factory knows More than these guys that havent proved anything. Leave it alone and learn how to ride. You can’t learn how to ride if you’re trying to make your bike run better but only making it slower or blowing it up every other week. You have to be 100% confident in your machine. And if you’re experimenting every week, your confidence is not going to be near 100%..Do as the factory says, not with these hacks that write for magazines say..
I read in one of the magazines someone wrote a question asking why their tires wear out on the left side more than the right. That expert answered the question . For everyone to read. The expert in the magazine said, have your frame checked, there’s something seriously wrong with your machine.
The correct answer to the question why do my tires wear out on slightly on the left side of the tire more than the right, answer: roads are crowned so the water will drain to the curb. You are riding on the left side of center when you are going straight down the street and your tires wear out slightly on the left side sooner than on the right side. All Street bikes with two wheels tires ware out the left side 1st.. everybody’s frame is not bent, as the expert at that magazine implied. It wasn’t Cameron that wrote that, ever since that crankshaft butcher job, I never read a word he wrote..
Aaarrgghh...the music!!!! PLEASE, PLEASE KILL IT!! The videos are brilliant. The purpose of the music seemingly to ruin them?!
What's up with the creepy music. I expect Pennywise to pop up at any time.
Why soo many dogs? 2 dogs f
Very interesting and informative, BUT please loose the annoying music! Does it make the video better and more interesting? Certainly not,!
please, please change that harry potter backsound music
Keep it.
Background music annoying and unnecessary
Now I know why my Kawasaki has a shifting issue from first to second. It often stops in neutral and I have to double shift. It is annoying.