sparxooo Posted September 10, 2020 Posted September 10, 2020 (edited) Hello peeps! Background: Car driver for 11 years, have rode a motorcycle on 4 separate occasions now (CBT, lesson, two rides of my own bike). My 2006 Yamaha YBR125 is being a bit of a pain in the rear when changing gear (see what I did there?) - to go from first to second it will sometimes get stuck in neutral. Double declutching (letting the clutch out, and then pulling back in) sometimes helps, other times I have to come to a stop, and fiddle with the lever until it finally decides to go into a gear. This is particularly annoying when pulling out of a junction, and going up a hill - getting half way up and having to pull over because it's just not happening (although it let me practice a hill start :P) It will also go from first, into second - pull whilst maintaining the throttle, but then when the throttle is released it'll slip back into neutral. I have *double checked* i'm not resting my foot on the lever at this point (I originally thought this, so lowered the shift lever a bit, which has done nothing except make it difficult to get my bleeding foot under it... The other gears seem ok - and when on the center stand it will shift through the box the majority of the time ok (releasing the clutch every time - you hear a little "clunk" as the clutch engages). My plan for tomorrow is as follows: drain and replace engine oil (I don't know 100% what oil is in it - it was freshly replaced by the seller a month ago) with 10W40 motorcycle specific oil double check chain slack (although I checked this not long ago and it was between 20-30mm) double check clutch cable free play - it does fully disengage when the lever is fully in check the shift lever is in the right position Is there anything else I should check for/do? I am aware i'm a new rider and so some of this may be technique - hence why I found a straight and double checked that it was dropping back to second of it's own accord. Once it is in second, it will stay there (and shift back to first/neutral fine and generally behave itself). Edited September 10, 2020 by sparxooo
Moderator Cynic Posted September 10, 2020 Moderator Posted September 10, 2020 Honestly, ride it. Motorcycle gears can be tricky to sus, my vmax can sometimes catch me if i go from 1 st to second too slowly when crawling in traffic. You will learn to give it a nice clean flick rather than a push. Sounds odd but when it clicks you will understand. YBR125s are legendary for being all but unkillable, i have personally been alongside an SR125 (same motor) at 80mph (slight downhill), considering the gearing was stock god only knows what the rpms were, that bike had over 80k miles on it.
sparxooo Posted September 10, 2020 Author Posted September 10, 2020 46 minutes ago, Cynic said: Honestly, ride it. Motorcycle gears can be tricky to sus, my vmax can sometimes catch me if i go from 1 st to second too slowly when crawling in traffic. You will learn to give it a nice clean flick rather than a push. Sounds odd but when it clicks you will understand. YBR125s are legendary for being all but unkillable, i have personally been alongside an SR125 (same motor) at 80mph (slight downhill), considering the gearing was stock god only knows what the rpms were, that bike had over 80k miles on it. So far i've ridden around my estate, and up to a car park to practice - on the way is when I really noticed it playing up and also in the car park - so ended up riding around in 2nd and just using the clutch (great for practicing clutch control!) most of the time, including pulling away in 2nd, and figure of eights in 2nd too. I just don't want to use 2nd for everything and get lazy on the gear changes for when I go to a bigger bike (if). Points taken on board - i'll still check everything tomorrow and the clutch cable adjustment - but plan for another ride tomorrow eve when it's quietened down.
sparxooo Posted September 11, 2020 Author Posted September 11, 2020 (edited) Just to add info from todays ride: Keeping upwards pressure on the lever whilst letting the clutch out makes changing 1st - 2nd work 100% of the time. 2nd-5th works 99% of the time (more my technique maybe letting me down here) without holding the shifter up/down. 2nd - 1st is much more difficult - it feels like you're at the bottom of the box, even keeping slight pressure on the lever before bringing in the clutch doesn't help it. Once at a standstill, it'll sometimes go to 1st, or then go to neutral / a false neutral - a slight sharp tap on the lever then will make it go into 1st - but it will most of the time NOT do this whilst moving, and you will have to stop fully / rock the bike. Edited September 11, 2020 by sparxooo
Moderator Cynic Posted September 14, 2020 Moderator Posted September 14, 2020 Remember there are no syncros on a bike. The gears locate on dogs not splines. When the gears are loaded they naturally want to stay in place. It's what stops it jumping out of hear. 1st is rarely if ever changed into while riding. When you change to second you are changing up 2 gears effectively. (n is a gear position). This change takes time. Breif granted but if you are not going very quickly the momentum you lose will stop the gear engaging properly. Biggest piece of info. Don't worry about looking a tit! Stalling or any of the other possible cock ups available. You will do it. Now way round it. Just ride. People have crashed thinking they have to be perfect. If you started learning Russian, could you be fluent in a couple of hours.
sparxooo Posted September 18, 2020 Author Posted September 18, 2020 (edited) On 9/14/2020 at 12:43 PM, Cynic said: Remember there are no syncros on a bike. The gears locate on dogs not splines. When the gears are loaded they naturally want to stay in place. It's what stops it jumping out of hear. 1st is rarely if ever changed into while riding. When you change to second you are changing up 2 gears effectively. (n is a gear position). This change takes time. Breif granted but if you are not going very quickly the momentum you lose will stop the gear engaging properly. Biggest piece of info. Don't worry about looking a tit! Stalling or any of the other possible cock ups available. You will do it. Now way round it. Just ride. People have crashed thinking they have to be perfect. If you started learning Russian, could you be fluent in a couple of hours. You're right - I know i'm only early in my riding career! Adjusted the clutch cable again today, replaced the perch as the mirror thread was damaged and the adjuster was a bit wobbly (pretty sure the bike has been dropped onto its left side previously). Tightened the mid-cable adjuster so there wasn't so much adjustment needed at the handlebar end - at the lever I wound the adjuster out until the lever had no free play, then wound it in 1/2 a turn which left about 10mm free play. Ride out to the car park where i've been practicing - perfect. Gears selected fine all the way there. Being a bit more positive on the lever now. The clutch bite point has now changed (obviously), and is taking some getting used to. Going all the way through the box, slowing and going 2nd to 1st, working fine. 15 minutes later after arriving - 2nd -> 1st and 1st -> 2nd is doing it again... 12-15 mile ride planned for tomorrow, so will see how it goes! Edited September 18, 2020 by sparxooo
Moderator Cynic Posted September 25, 2020 Moderator Posted September 25, 2020 That will be the oil warming up. Just about every motorcyclist wont bother with all the down changing faf of 2nd to first, even 3 rd to first when coming to a stop. Hell i have gone from top to first sat at the lights before because the change caught me on the hop. You just ride up to your stopping point and ( ideally while the wheels are still turning a little ) in the last few moments before you stop, just rattle down through the box. It works as well stopped, 1st can sometimes need you to rock slightly, that should illustrate than it can be a troublesome bugger till you get the hang of it.
sparxooo Posted October 14, 2020 Author Posted October 14, 2020 (edited) So, an update on the whole situation. My dad rode my bike around (used to ride 30+ years ago) and had the same issue. Speaking to a friend he said to take the clutch cover off and check the internals. My theory is the bike has been dropped onto the gear lever and it's forced it down, forced the pin (right hole) through the bottom of its hole, and also broken the post for the spring - it's then been repaired with weld, but does not hold the pin tight enough. (You can see the scuffs on the bottom of the casing by my oily rag). As you move the gear lever, the pin moves - just enough - that the gear selector does not return to it's middle position (and as a result, does not then latch onto the gear cammed wheel thing). This may be slightly more exaggerated than when the clutch cover is on, as there is a boss on the clutch cover - however the pin doesn't actually touch the boss even without a gasket in place (estimated about 1-2mm between them as stuck a dab of locktite on the end of the pin and put the clutch cover on - didn't mark the cover). The selector lever also appears slightly bent, with lots of play in all directions in the moving end, and also the little post to the left of the moving end (which looks to force the cammed wheel into the correct position on its return). Changing gear (turning the cammed wheel by hand) is smooth, no excessive force required at all, and if it does get "stuck" between gears, spinning the output shaft slightly lets the gears drop in (which I believe is normal). Only way to truely fix this is to replace the engine casing - but i've also found that i've successfully managed to shim the pin with a piece of aluminium can on the bottom. Gears then work as they should (whilst disassembled). Hopefully if that shim does ever come loose, it's soft enough that it'll just get a bit mangled by anything it comes into contact with, or just collect below the mesh. Just waiting for a new shift shaft to appear, and will reassemble. Hopefully that fixes at least the 1st/neutral issue! Also have a new shift shaft main spring (just in case mine isn't strong enough), along with some replacement oil seals and some fresh 10w-40 Shell Advance 4T AX7. Also found *lots* of gasket sealer bunging up various little oil galleries? under the clutch cover and floating around inside, so have meticulously cleaned all that up, and cleaned up the cover mating surfaces as best I can. Edit: And i forgot - even after all the warnings about the clutch ball bearing - I still managed to lose the bloody thing! Luckily only 25p to replace Edited October 14, 2020 by sparxooo 1
Moderator Cynic Posted October 16, 2020 Moderator Posted October 16, 2020 Wow, didn't expect that. Must have gone down in just the wrong way. No other tells of an accident.
sparxooo Posted October 16, 2020 Author Posted October 16, 2020 (edited) 8 hours ago, Cynic said: Wow, didn't expect that. Must have gone down in just the wrong way. No other tells of an accident. Thinking back - newish bar ends (the universal type), and actually new bars too at some point - they are not OEM as they don't have the dimple for the switch assemblies to lock into. Having a little bit of entertainment trying to fix it in all honesty - I like fiddling with mechanical stuff. It's a 14 year old bike so has the standard few broken trim fixings on the removable covers, and some cracks to the rear fender. I do feel it was made to look "pretty" by some of the previous owners, and parts somewhat thrown at it (frame fully painted, new clutch, new chain and sprockets, etc). All a learning curve, and I certainly know what to look for in my next bike! A complete transmission rebuild isn't off the cards if my repair works (then fails) - at least I may be able to fix it the right way instead of bodging... Edited October 16, 2020 by sparxooo
Moderator Snakebite68 Posted October 23, 2020 Moderator Posted October 23, 2020 I was going to suggest getting someone experienced to try a bit of clutch-less shifting to see how it took it... If you like 'tinkering', before you replace the casing, you might consider trying to bore it out and sleeve it! Kind of a more permanent version of the tin can shimming you've done so far. Even if it ultimately doesn't work and you replace the casing, it will be a good learning exercise...
sparxooo Posted October 25, 2020 Author Posted October 25, 2020 (edited) On 10/23/2020 at 7:47 PM, Snakebite68 said: I was going to suggest getting someone experienced to try a bit of clutch-less shifting to see how it took it... I have tried this - it helped the 1st -> 2nd issue (but I can live with it if this doesn't fix that issue), but not the downshift issue. On 10/23/2020 at 7:47 PM, Snakebite68 said: If you like 'tinkering', before you replace the casing, you might consider trying to bore it out and sleeve it! This has also been mentioned - as have the low temp aluminium "brazing" rods (essentially brazing the pin when it's in situ), or at a stretch tig welding the pin in. Edited October 25, 2020 by sparxooo
sparxooo Posted November 2, 2020 Author Posted November 2, 2020 As a bit of an update - it appears to be fixed. Haven't managed to get much riding in (and back to work tomorrow), so hopefully from Tuesday next week i'll get a long run in. Removed the pin and re-inserted it with a good 15mmx10mm piece of Alu can to shim the bottom. Whacked that in with a rubber mallet and it slid home quite nicely. New shift shaft also has much less play on the end than the old one. Re-assembling the clutch, "why is this bolt just continuing to spin and not tighten up?" - aah balls it's broke... with a small 1/4" ratchet. After much swearing I managed to drill through from the other side which span the broken bolt out through the top just enough to grab with pliers. I found an equivalent bolt in the stash and used the existing washer. I adjusted the clutch as per the service manual (set so that the clutch lever on the engine has its mark on the arrow), however this means that I can *only just* get the clutch cable re-attached at the lever end (then attaching to the engine casing). I can set the required amount of free play at the lever though - just a bit tight to get on. Did wonder if i'd slightly maladjusted the initial clutch adjustment but it doesn't seem to be slipping at all. Result: Gear change buttery smooth, no slipping back into neutral from 2nd, and no stuck/floppy lever at any point. Gears much less "clunky" now than before (most noticeable when going to 1st from neutral at a stop) so the clutch adjustment may also have had something to do with it!
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