Problem with first gear

[jim328]

My bike will go into first no problem when cold, just snicks straight in, however once the bike is warm it is a real struggle. However, if I put the bike straight into second at a standstill it goes in fine. Once in gear it stays there and goes between gears just fine except second to first (goes from first to second no problem). I have checked clutch adjustment at lever and indicator under engine and indicator is where it should be. I have taken the cable out and lubricated it, it moves freely and I have checked routing and that is fine.

Any ideas what could be causing problem?

[fret not]

How many miles on it?  Have they been easy or "spirited"?  Has the bike ever been down on the shifter?  Could be bent or worn shifting fork or shift shaft mechanism.  Unfortunately that stuff is pretty deep inside.

[jim328]

Mileage is unknown but best guess is about 30,000km. The bike had replacement gauges on it that were broken then i put some more on. But working through regstration records 30,000 would be close. I bought the bike as a "barn find" it had been sitting in the owners shed for 13 years. The motor runs really well and doesn't burn any oil. All I had to do was replace the waterpump seals and usual fixes for carbs, starter clutch and starter motor seal, but I have no idea how the gearbox has been treated. The shift lever and associated mechanism is quite worn and there is a fair bit of free play. ie I can rattle the lever around a fair bit on the shaft. Would this cause the problem?

I suspect you may be right about having to go deep into the motor but am hoping someone can offer me a miracle cure because after spending so much time working on the bike now I just want to ride it.

[inanecathode]

Adjust the clutch (start at the cover, go to the lever from there) get that shaft play figured out (shouldnt be loose at all) and you'll be right as rain.

[Lucky]

this tends to be more towards finding neutral, but something else to consider, i just went thru this with my wifes bike yesterday:

I normally adjust the connector on the shift shaft so that it's a few degrees from straight up. then adjust the linkage so the shifter is where i like it. this helps finding neutral A LOT.  it may help in your case too.

--Lucky

[fret not]

Jim, is there any serious rash on any of the shifting components? (lever, linkage, shaft end, etc.?)  It may turn out to be just adjustment or choice of lubricant viscosity, but check the obvious things first.

We used to say "check the easy and obvious stuff first", but you still need to check everything until you find the problem.  Make a list and follow it.

[jim328]

Thanks guys, there is no obivoius signs of the bike being dropped. I will check adjustment. I misread the manual regarding adjustment, I didn't realise that the cable had to be slackened off at lever first. So will give that a try tonight.

[jim328]

Over the weekend I adjusted the clutch as per Haynes manual which slightly improved gearchanges, and stripped the shift lever linkage, the adjustment bar turned out to be bent so I straightned it and set it up as per Lucky's instructions.

Now it will go into first gear if at a standstill I go  second it will then go into first. It will go through the top fours gears brilliantly.

Are there any gearbox experts out there who can tell whether it is likley to be bent shifter shaft or something deeper in the gearbox?

[Rikugun]

Jim, Is this bike relatively new to you and if so, has the shifting issue been there since you got the bike?  If the problem just arose recently, what happened just prior to it shifting poorly?

[jim328]

I got the bike in non running condition, has taken a while to get the bike back on the road. However, when I first got the bike running the problem wasn't apparent, it was only after a couple of rides that it became an issue.

[Walt_M.]

When this thread first started, I suspected a bent shift fork inside the gearbox. Since you found the bent shifter rod, I think it is even more likely.

[jim328]

Can I fix that without splitting the crankcase?

[fret not]

You can deal with the shift shaft by removing the clutch cover, but the shift forks are deep inside.  If your other gears seem to work nicely then it is probably not the shift shaft, as the ratchet works all the gears and would most likely have the same or similar difficulty with the other shifts.  More and more likely to be a shifting fork, so learn to live with it if not too difficult or open it up and replace the bent parts.  It is also possible though not likely that the shifting drum is worn for that troublesome shift. 

One other possibility comes to my mind, that one or more clutch plates are warped and causing drag when the clutch is disengaged.  This would make the slow speed shifts clunky but in high speed shifts the parts are moving so fast they are more likely to find "home", which is why you can shift without the clutch when going fast but not slow.  I don't recommend shifting without the clutch.  With the engine off and the gear engaged, if you pull the clutch in can you push the bike easily?  If the clutch is dragging this will show it.

[Rikugun]

It seems odd that something like bent forks or warped plates would just happen without some cause. Is something being left out of the narrative? A weekend at the drag strip? Loaned the bike to a friend for a vintage road race event? Wheelstands from 1st to 2nd via powershifting?

Also the exact symptoms are unclear. When an attempt to engage first is made, is there grinding? Or, does the shifter just refuse to budge?

However, if I put the bike straight into second at a standstill it goes in fine. Once in gear it stays there and goes between gears just fine

Is that to say it pops out of first put if you start out in second it stays in second?

[jim328]

 To clarify how it will go into first. Second from neutral or first is no problem. Snicks into gear and stays there. If I try to change directly into first it simply won't go or if it does jumps straight back out. If bike is in neutral and I change into second at a standstill the bike will then click into first nicely and stay there and then change to second once on the move no problem. If I come to a stop and go into neutral it will not go into first at all, if I then select second sometimes it will crunch sometimes not but once in second it will then go into first and back into second no problem.

Being a 400cc version it is lower geared so will take off in second without slipping the the clutch much. So I might ride it as is for a while.

[Rikugun]

I'm no transmission expert but I don't see the problem resolving itself. I'd be a little concerned about further damage as well. Walt, does this still sound like a bent fork? Do you know if that fork handles another gear change? As Mike stated, you'll have to split the cases if it turns out to be fork related. Mikes suggestion to look under the clutch cover may be a better first step. You can get to many components from there - outer basket, inner hub, springs, plates, pressure plate, push rod, inner portion of the shift shaft and it's associated arms and springs, and the end of the shift drum and pins.

Actually the first thing I'd suggest is doing a clutch adjustment one more time using your manual. When you had all the external linkage apart, was the circlip in place that keeps the shift shaft from moving into the engine? And finally, if in neutral at a stop, if you use your feet and push ahead to get the bike rolling then attempt a shift into first, does it go in?

[QBS]

Try this and see what happens.  From neutral, pull in the clutch lever and press down on the shift lever as if you are attempting to select first gear.  Keep the pressure down on the shift lever as you gradually ease out the clutch lever and see if the bike won't go into first gear.

[treedragon]

One thing to check, see if any of the linkage arms are hitting on anything.

I had a similar problem when I was adjusting  for my size 12 feet and riding position. Sometimes it would go in, sometimes almost, a lot not, as I recall I had a non standard bolt combined with different than standard lever position which resulted in it hitting on something, it wasn't immediately obvious.

[fret not]

This is beginning to sound more like a bent shifting fork.  Or an accumulation of wear and/or other damage of several parts involved in the gear selection process.  As long as it goes nicely into first from second just make a habit of doing that.  If you have trouble getting into second then I would think the clutch is not completely releasing for one reason or another.

[Walt_M.]

If you can't get it with linkage adjustment and it turns out to be the shift fork, be prepared to put some new gears in it too. The bent fork will lead to worn engagement dogs. You will have to split the cases to get to it. And Rik is right, it will not fix itself and will probably get worse. Put in a magnetic oil drain plug and check for any unusual amount of metal filings. Another good diagnostic check.