Motorcycle Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
So things have been great so far with my OLD but good looking 1984 Honda VT700C. In fact we just rolled past 50k miles. Honestly, I haven't had it for long, but today it just decided that first gear wasn't cool any more. When I got the bike earlier this year, I had the radiator fan repaired (hardwired actually -- thanks mechanic, I think) and I had the clutch line repaired as it was leaking at a mid-tube connection near the fork head.

I've ridden approximately 800 miles since, and out of the blue today, I lost first gear. The trans will shift through the other gears with relative easy, up and down -- but only down to neutral, of all places. It stops there. This can be problemmatic in traffic, btw : )

I ride by using a lot of throttle equalization when downshifting to control speed as opposed to straight braking, but I can assure you that I am not taxing the clutch. I use the friction zone, but no more than anyone else, and no more or less than recommended. Now that I'm thinking about it, I've noticed that it's been getting lodged a bit in neutral from time to time on down / up shifts from 1 - 2 or 2 - 1...say in the past two weeks (I don't ride THAT much). So maybe this isn't something that has just APPEARED OUT OF THIN AIR and more something that's been coming on slowly?

Based on the interwebs, and I'm probably asking the wrong question (which can make troubleshooting difficult), I can only find that it's either "the way the bike shifts" or perhaps its a hydraulic fluid or "air in the fluid" issue. I think we can rule out the former. I wonder if the work that was done on the bike introduced air bubbles into the clutch hydraulic system that are just now causing the issue? But wouldn't that affect more than just 1 - N - 2? This is where I'm lost -- seems like there is more torque and friction at those gears, so maybe a loss of fluid pressure is more substantial at those gear positions?

Anyway, has anyone experienced anything like this? Today I tried multiple taps, harder taps (not too hard so as to damage the shifting lever mechanism), shifting up a few gears and back down to no further than neutral, double clutching, no clutch...only twice on the entire ride home could I get it to go into first, and it was early in the 25 minute ride. It was mega hot today, and the thermometer was rising on the engine (already compromised a bit because of a leaky head gasket). I made it home fine, but I am no mechanic and I don't know where to start with the clutch other than with bleeding the line (if it's not too complicated), if the clutch is even the issue.

Any advice or help is appreciated.

Jason
 

·
Member Map
Joined
·
23,911 Posts
Air in the clutch line would tend to cause the clutch plates to not fully separate, meaning that the motorcycle would still try to pull forward when the lever was fully squeezed.

My guess is that there is internal damage to the transmission, which is going to be a big job.
 

·
Premium Member
Joined
·
5,274 Posts
If it is not air stuck in the line, usually at the banjo fitting on the MC, there are other things to look at. It may not be transmission damage, but wear in the assembly that turns the shift drum. Often, this is accessible by just removing the engine side cover; sometimes the clutch basket has to be removed to work on it, but seldom does a problem with the mechanism require opening the transmission case (depends on the parts that need fixing). You need a good service manual to see how it all works to diagnose.

But, I'd start by getting the last bubbles out. If they are trapped in that banjo fitting, you can usually get them out by getting the MC tilted so that the fitting is lower than the rest, then use the slow-pull quick-release method to pull the bubbles back into the MC and into the reservoir.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #5
I watched a video today on how all of this works together, i.e. the shifting lever turning the notched shifting plate on the exterior (beneath the clutch assembly in this particular demo - Suzuki of some sort) which translates to the shifting drum on the inside rotating and allowing the gear alignment arms to slide into the appropriate positions. Pretty cool stuff really.

So I did some more testing on trying to get it into first gear, and the transmission will in fact clank into first gear, as long as I have the revs high enough. This is slightly counter intuitive to me, but I did read several posts today on how some bikes like to lock into first while the gears are spinning faster as opposed to slower...this doesn't really jive with my experience in the last 600 - 800 miles, but it may lend a clue to what has changed inside the transmission case.

The engine oil appears to also lubricate the transmission. My oil is a slight bit on the low side, so topping this off will at least rule that out. It seems logical to me that that air in the clutch line should impact all of the gears, more or less the whole shifting system, not just first gear. Seeing how neutral was arranged on that Suzuki video makes me think that wear on the lever-side is more the issue -- with the up shift motion hooking around and pulling the shift drum there might be more force than with the down shift motion pushing the shift drum -- the tip of the lever could be worn down for all I know...will have to see about taking it apart. Trouble is if I screw up : ) Won't learn if I don't try I guess. We'll see.
 

·
Premium Member
Joined
·
5,274 Posts
Oil that needs changing, the wrong type of oil, too little oil, and yes, in some engines, too much oil can interfere with shifting. Also, a small amount of clutch drag can affect the lower gears more than the higher gears.
 
1 - 8 of 8 Posts
Top