1VJ kickstart gets stuck/very hard sometimes

[Leo44]

Hi everyone,

Whenever I go and try to kickstart my 1VJ (following the usual procedure, so go through the strokes slowly until you hear the "click" from the decomp mechanism, then kick) I find that sometimes the kickstarter pedal comes to a hard stop, not on compression stroke though, seems quite random, to "unstuck" it, I have to weigh in on it, after a couple of seconds of putting almost all my weight on it, it "releases" itself.

The decomp mechanism is adjusted, around 1mm of play at the little lever on the rocker cover, I can see it move whenever I use the kickstarter, so I don't think there is any issue there. Valve clearances are adjusted, 0.10mm intake and 0.15mm exhaust.

Starting the bike using the e-start works fine, even though the one-way bearing is on it's way out. it doesn't get hung up and it doesn't have any issue turning the engine over.

I read on other posts/forums that it might have to do with gears meshing due to worn out bushing within the kickstarter mechanism, others say that the timing chain might be getting hung up on the crankshaft cog or tensioning rails, but I'd think that it would cause a hell of a mess if that was the case, or some sort of bad noise at least.

None of the post regarding this issue have a conclusive answer/update so I'll probably have to go with the good old trial and error, but if anybody has any advice/experience with the same issue, any help would be truly appreciated!

[donnybach]

Ideally the official distance when at tdc is 0.5mm, I don’t measure, just ensure there is the minimum free play with touch. You may have too much slack.
Starting, I go through about 3 cycles with ignition off and throttle wide open. Gets everything primed and ready.
Then ignition on, bring it to beginning of compression, pause, kick.
If it hits a dead stop, it’s probably started at the wrong point, missed the compression.
I’d re measure at TDC before anything else is played with.
Also did the lever reset fully before kick?

[Leo44]

Ideally the official distance when at tdc is 0.5mm, I don’t measure, just ensure there is the minimum free play with touch. You may have too much slack.
Starting, I go through about 3 cycles with ignition off and throttle wide open. Gets everything primed and ready.
Then ignition on, bring it to beginning of compression, pause, kick.
If it hits a dead stop, it’s probably started at the wrong point, missed the compression.
I’d re measure at TDC before anything else is played with.
Also did the lever reset fully before kick?

You mean measure at TDC for play in the decomp lever? Just after it releases I imagine, because if it's during the compression stroke, it should have no play since it should be in tension to keep the exhaust valve open.

To see if it's actually a compression/no decomp issue, I could remove the spark plug and see if it still comes to a dead stop. I'll try both and report back.

[donnybach]

T is lined up on end of compression stroke, according to manual, after setting valves.
Not viewed the action, but I’d guess it’s held open on stroke but closed at TDC to lower pressure in the cylinder.
Not near the bike but I’m sure I’ve replicated this when maybe I haven’t cycled the whole “length” of the kick on priming so it’s not all come to rest in the correct position, lever, gears etc.
Usually when I have no room, or slip. A bit like me being out of sorts until I’ve had a brew in the morning.

[Peen]

I find the same with mine sometimes, kickstart fitted to a 3aj, figured its just something binding when not doing the full swing correctly and needs a bit of a push to free off, as you say, it doesnt feel like its the compression stopping it. Its done that since I fitted the kickstart probably 20,000 miles ago and never caused an issue.
Maybe its just a 'feature' of this kickstart design?

[Leo44]

I find the same with mine sometimes, kickstart fitted to a 3aj, figured its just something binding when not doing the full swing correctly and needs a bit of a push to free off, as you say, it doesnt feel like its the compression stopping it. Its done that since I fitted the kickstart probably 20,000 miles ago and never caused an issue.
Maybe its just a 'feature' of this kickstart design?

I doubt that it’s a design feature, for me this issue popped up after a top end rebuild, so I probably messed something up while putting everything back together. Maybe the lever on the rocker cover, maybe the cable, god knows, I’ll dig deeper.

[monala]

What you’re describing really does sound more like something intermittently binding in the kickstart mechanism itself rather than a decompression or valve issue, especially since the e-start turns the engine over normally. Worn bushings, sticky idler gears, or damaged kickstart shaft bearings part can let the gears mesh at a slight angle and occasionally jam until enough pressure forces them past the tight spot. Since the one-way Mud pump bearings is already failing, I’d also inspect that whole side carefully because debris or excess play there can sometimes affect engagement behavior. If the timing chain or guides were actually hanging up badly enough to stop the kickstarter dead, you’d usually expect noise, inconsistent running, or much more dramatic symptoms by now.