Gearbox prob on VFR400 nc30

[Deftones]

Bought my VFR400 nc30 3 months ago. Gearbox was really stiff and heavy, and once it was warmed up, had to rev it to get into neutral - there was no other way. The owner assured my all VFRs had bad boxs. After riding my buddy's nc30 i knew that wasn't true, his was sublime compared to my clunkbox.

Anyway, I adjusted the chain tension, and clearly without enough freeplay i rode it a bit. Next thing I know, when hammering it through first and second, the bike gives a massive jolt. Spoke to a guy and he said I've stuffed a bearing in the box and the bike is trying to jump out of gear. I think he's right.

Appparently, the engine's gota come out to repair the box .

Before I commit lots of time and money to doing this, is there anything else I should try? Any other options? Also is it OK to ride it in this state? Am i damaging the gearbox by continuing to use it?

Appreciate the input

[finpos]

May not be all bad - trouble changing gear and getting it into neutral might be as simple as a clutch adjustment problem.

"massive jolt" is subjective, it may just be jumping out of a hurried gear change or the dogs on the gears slipping for the same reason.

Was it a one-off, is it working ok now?

finpos.

[Cillit-BANG]

Yes, it is perfectly normal for it to be imposible to find first gear. It is a common and normal fault. If you turn the ignition off it will flick straight in though!! You can sometimes get it when rolling to a stop, but sat still it is very unlikely.

The gearbox in general though shouldn't be stiff and heavy. They are usually quite sweet little boxes, although you often have to be quite 'positive' with your gear changes to keep it from popping out of gear.

As for the jolt, no idea I'm afraid. Taking the gearbox appart is never going to be a quick job though I'm afraid.

[Kickstart]

Hi

Before diving into the engine, make sure the chain is adjusted properly and well lubed. Same for the clutch cable. Change the oil (and make sure you use the right grade of oil).

And most importantly, clean up and lube the linkage for the gearchange. Make sure the gear change lever is free to pivot.

All the best

Keith
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[Deftones]

finpos: definitely acceleration causes the jolt, its like the whole bike jumps, or like the chain suddenly takes up slack. this is no hurried gear change problem. its happens a lot, even when not under hard acceleration.

cillit-bang: i can get it into neutral be reving it, thats not a problem.

keith: chains got 25mm freeplay now, well lubed as is clutch. VERY good and expensive semi-synthetic oil in the engine. when you say linkage, do you mean suspension linkage?? if thats so, there is a complication: wishbone on the bike isnt stock - its a modified longer one coz the previous owner was really short and heavy. i am quite light, so the bike handles terribly and cant lean and feels heavier than it is. i assumed this wasnt related to the 'gearbox' problem.

i thought linkage just related to suspension and handling. was planning to get a stock wishbone to sort the handling. wot do u guys think?

BTW is there anything i could check on/in the gearbox without taking the engine out? like home maintenace level stuff

[Kickstart]

Hi

No, I mean the linkage from the gearchange lever to the gearbox. My FZR600 has a habit of this starting to stick (on that the gear change lever pivots on the inside end of the footpeg).

Doubt the suspension linkage would have an effect, but check the chain isn't catching on anything with the suspension compressed (with the swinging arm in its normal position accelerating will extend the rear suspension, but get the suspension compressed and accelerating will compress it even more).

Lastly, also worth checking for play in the rear sprocket, often caused by wear in the cush drive (ie, lumps of rubber that the sprocket mounts through to the wheel) which can easily cause a nasty gearchange.

All the best

Keith
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[Deftones]

The suspension is so hard that id have to go on an all macdonalds diet to be able to compress it

nc30s dont have a cush drive because they're race replicas.

will check the gearchange lever linkage

Thanks a lot Keith

[Kickstart]

[Nath]

I was under the impression the swinging arm on the nc30 is almost identical to on the Bros, and that certainly has a cushion drive.
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Hard livin', hard luck.

[Kickstart]

[finpos]

If the sensation you are getting is that of the chain jumping teeth over the sprockets and it's only in one gear, it's usually a sign that your dogs for that gear are worn. Unfortunately, every time it slips like that, it knocks another lump out of the dogs and it quickly deteriorates.

That is an engine out job, and it's normally a sign that the whole engine is worn to near the end of it's life. Eliminate all the more obvious, external stuff first.

finpos.

[Deftones]

Keith, definitely can't see any rubber between the sprocket and the hub or whatever it's bolted to. I lubed the external linkage too.

Finpos: don't scare me like that!! And I am no hooligan rider. Anyway, can you please explain to me what the 'dogs' are? "knocking lumps out the dogs" means nothing to me.

I've got he Haynes nc30 manual, and there is a part which details removing certain external parts of the gearbox without removing the engine. It looks like quite a job, so I'm thinking of finding a decent mechanic to do it.

Would appreciate it if someone knows of a link to an explanation gearbox problems like mine - that would help me understand.

[Kickstart]

[finpos]

Dogs for dummies :

https://auto.howstuffworks.com/sequential-gearbox1.htm

The trouble is when they do slip, the gear becomes disengaged, the engine has no load so and the revs up really quickly, until the dogs manage to hit each other again (with a bit of a thump). This is all usually over in less than a second. Unfortunately, when the dogs do thump into each other, they tend to damage each other a tiny bit (they are VERY hard metal), and this damage accumulates to the point where they can't maintain any drive at all

From what I've seen, the reason that the dogs fail is because the selection mechanism hasn't been working well first. Sounds like you are experiencing that to some extent. If it is doing it a lot, I think I'd be tempted to stop using the bike.

finpos

[kingnathski88]

I have the same bike, doesn't like neutral at all, yet if you turn the ignition off, it flicks straight into neutral. Also when i go from 1st to 2nd it sometimes gets stuck in neutral, but thats probably down to my dodgy gear changes

[Deftones]

Wanted to ask something else: is it OK to use the bike like this? Someone mentioned it is damaging the box every time it tries to jump out of gear. I try and ride softly so it does this as little as possible, but it invariably does jump.

So what do you guys think? OK to ride, anything I could do to minimize damage?

[Kickstart]

Hi

It probably is damaging the box, but on the other hand the bits it is damaging are likely the bits causing the problem.

All the best

Keith
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[Deftones]

Lol, does that mean it's a good thing?
So if I use it does that mean at some stage the gearbox will no longer work?

[finpos]

I can say empirically, yes

finpos.

[Deftones]

Hi again all!

I have decided to take the bike to a shop with workshop facilities. The gearbox jumping is becoming chronic, as well as the clutch slippage and I want the original size wishbone put back in.

Anyway, the mechanic told me that it may not be necesary to put a new gearbox in. He said it may just be a selector that needs replacing. This sounds much better than more expensive quotes I've got that includes undercutting the gears and putting entire new boxes in.

Considering that the box was bad before, and that I probably stuffed by running my chain a bit tight (and with a 41tooth - 1 extra - sprocket), is undercutting/new gearbox necessary?

Or is it possible I just need to replace some parts?

Thanks

[finpos]

The cost is in the amount of labour involved in tearing the engine apart and putting it back together. When you consider that, paying the extra 100 odd quid for the new gears or to re-work the old ones is worth it just so you're sure you won't have to do it again.

In my opinion, I'd be very wary of someone who says they can fix this type of problem on the cheap. It's a big job.

finpos.

[Blau Zedong]

There is no quick fix for this. Anyone telling you otherwise is a liar. A mate of mine had a simillar problem on his NC, although i think his did it in 3rd or 4th for some inane reason (its usually first or second that suffers due to crap stunting and abuse). Solved by part exchanging it for something else (he was / is a trained bike mechanic and even he wanted nothing to do with it).
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Deftones]

I get that it is a major job. What I'm saying is the mechanic said that it's possible that only a part or two needs replacing. How likely this is, I don't know.

What appears more likely, and expensive, is a complete repair. I guess that would entail replacing parts and undercutting the gears, although I'm not sure on the latter.

BTW it is definitely jumping in 2nd gear, probably 3rd maybe 4th too

[Blau Zedong]

Your mechanic is probably right in that the damage is confined to a few worn parts, however you won't be swopping these without splitting the crankcases.
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Deftones]

Are you saying that simpling getting to the worn parts is going to be costing me, because other parts will be destroyed in the process?