Topic: tachometer pretty static under load

[Bahumut]

I'm fed up with the other problem I'm having today so I figure I'll try and sort something else:

So, while in neutral, I can get the bike ('77 550K) to rev to the moon.  However, while the engine is under load, the bike never wants to climb beyond 3-4K RPMs.  Occasionally, if I stay in it, it'll shoot up to 6 and bounce. 

Any idears?

[Gordon]

Is this true for all gears?  As in you can't even get it past 4K rpm in 1st gear? 

[Bahumut]

Is this true for all gears?  As in you can't even get it past 4K rpm in 1st gear? 

Yeah, all gears.

[Gordon]

What modifications from stock have been made to the engine, intake and exhaust?  When was the last time a full tune-up was done? 

[Bahumut]

What modifications from stock have been made to the engine, intake and exhaust?  When was the last time a full tune-up was done? 

Well I had this bike at a shop and they supposedly did a "tune up" while it was there.. But also forgot to mention a fully leaking oil pan gasket, the non-idling issue and the fact that the bike wouldn't run. 

I've been slowly getting it going myself after that and in fact, up until this weekend, have been riding it two-weeks straight to work and back.  As far as mods, it has pod filters, some unknown 4into1 exhaust and I upjetted the mains to 120s.  I haven't touched the slides. 
.
The bike doesn't run right now, but that's another thread.  It's NEVER shown the RPMs higher than 4K in any gear while under load

[Gordon]

Start off by doing a full tune-up, since you have reason to believe it either wasn't done or wasn't done properly, and then put the stock air box and filter back on and go back to stock jetting.  You have too many unknowns in the current configuration to have a good base to start from. 

[Bahumut]

Yeah, that's not going to happen.  I got the bike for less than $100 because it came in two boxes, a bucket and a bunch of ziplock baggies.  I don't have a stock airbox or set of pipes and definitely don't plan on spending all that dosh just to get a baseline.  I can tell you that the gauge set isn't for this bike as the speedo only goes to 90 and the faces on both the speedo and tach are black, not green.

[CycleRanger]

Yeah, that's not going to happen.  I got the bike for less than $100 because it came in two boxes, a bucket and a bunch of ziplock baggies.  I don't have a stock airbox or set of pipes and definitely don't plan on spending all that dosh just to get a baseline.  I can tell you that the gauge set isn't for this bike as the speedo only goes to 90 and the faces on both the speedo and tach are black, not green.

Check the gear ratio on the tach. It should be stamped on the bottom. The tach should be 4:1.

[Bahumut]

Check the gear ratio on the tach. It should be stamped on the bottom. The tach should be 4:1.

As in if I pull the tach outta the housing it should be under there?  I'll take a look!

[CycleRanger]

As in if I pull the tach outta the housing it should be under there?  I'll take a look!

Yes, remove the chrome housing and the ratio will be stamped on the bottom.
If the ratio is correct and you're sure the cable is good then it's probably the tach is shot.

[Bahumut]

Okay, so I pulled the tach last night and here's what I got:





All the pictures I've seen show bikes of my year (77 CB550) with GREEN guages, not black, so I'm pretty sure my speedo and tach don't belong on my bike.  I couldn't find the ratio on the rear of the tach either.  PLUS, there's a light that references some rear air shock or something?  I don't know WTF that's about...

[CycleRanger]

Definitely not the correct tach. Probably from a newer bike. I think the later Goldwings have airshocks.

I had the same problem with one of my bikes.
Only my gauges looked correct but they were from another bike, I still don't which one, and the tach ratio was 3:1.

[Gordon]

Could be a tachometer from a 650.  It's possible the PO did the 650 cam swap, which requires a 650 tachometer in order to read correctly.  Or he just thought it was a direct replacement for a 550 tach, which it isn't.