5200rpms at 70mph, too high!! kz1000m2

bound wrote:

Thanks! I was thinking of going 18 in front and 44 in rear which would drop my rpm by 200 at 70mph. I don't want anything to crazy so I'm keeping the front sprocket the same diameter. Please let me know if there is anything to be wary of concerning the sprockets. 

Sounds about right (the calculator will confirm) I am running (when it's finished) 18 - 46 on my 82 Ltd but that has 17inch zx9r/Bandit 600 wheels

Wookie58 wrote:

bound wrote:

Thanks! I was thinking of going 18 in front and 44 in rear which would drop my rpm by 200 at 70mph. I don't want anything to crazy so I'm keeping the front sprocket the same diameter. Please let me know if there is anything to be wary of concerning the sprockets. 

Sounds about right (the calculator will confirm) I am running (when it's finished) 18 - 46 on my 82 Ltd but that has 17inch zx9r/Bandit 600 wheels

bound wrote:

Yeah the CSR was the only one that was cable driven that year... which works out well for me. I was thinking I would be able to swap the speedometer from a late kz1000p since they are also cable driven and those speedometer show up to 120mph while still looking stock. The only thing of concern is that the police bikes had a 18 inch front wheel compared to my 19 inch. I did a little research and the difference in speed reading was only like 3% or 2% which is pretty negligible.  Is the CSR uncommon or something?

I don't know about the US but here in the UK they are very rare

I'm curious, where does that put you at for rpms and acceleration? My concern in lowering my rpms is making it too hard to take off in first.

bound wrote:

I'm curious, where does that put you at for rpms and acceleration? My concern in lowering my rpms is making it too hard to take off in first.

Your are only dropping from 2.6:1 down to 2.44:1 so I can't see it being an issue

My set-up

Your set-up with 18-44

I should be able to dig into my tachometer on Tuesday so I'll post my results and what I did to (hopefully) fix the problem. I'll probably stick a drill on my tach and spin it and compare the reading to my 440 tach at the same drill speed. After that my plan is to fiddle with the needle to see if I can get it to read differently and if so, I'll adjust it until it reads the same as my 440. My suspicion is that spring may have gone weak and maybe isn't resisting the electrical force of the magnet like it used to. I hope the problem isn't the magnet itself or any of the other things... While I'm in there I'll try to lube everything that could cause friction.

I'll report back on Tuesday! 

Wookie58 wrote:

hardrockminer wrote:

If the tach doesn't solve your problem I would guess transmission as the next point to investigate.  KHI made a close ratio tranny that was long in first but short in the higher gears.  One way to check is if the bike is 1980 or older and has a plate over the kick start hole...it's probably a close ratio tranny.

HRM, the bike is an "M2" which makes it a "J" motored 82 CSR

The transmission will probably still fit.  But I think 1981 and newer bikes had no kickstart.  With a close ratio tranny you cannot use a kickstart.  Don't ask how I know.

I had a similar issue with my tach.
It would be accurate to 5000rpm then it would read high.
I always thought I was at redline when I wasn't even close.
I mounted a Autometer Monster tach(got it for $24) just to verify my rpm.
The stock tach reads high by at least 2000rpm.

Anyway, I bought a Uni-T non-contact laser tachometer(UT373--about $30). Put a small dot of included reflective tape on the timing advance bolt and checked the tach against it (take off the clear plastic on the reflective tape). 
The Autometer tach is good---old Kawa tach bad.

I have a feeling a lot of old bikes with cable driven tachs suffer the same problem---inaccurate as the engine spins faster.

ps... on the handlebar is a Sigma BC 5.12 bicycle computer($30).
I use this for checking my speedometer as well as having a clock.
It can measure up to 199.8 kmh/ 124.15mph.

meters.uni-trend.com/product/ut373/



 

That's pretty smart and something to consider...

Bound i do a lot of gauge work and those numbers you're reading are often times merely suggestive and not a true indicator of either engine or road speed. Looked up thru ebay what a CSR1000 gaugeset looks like. You should have the "green" plastic back and fuel gauge built-in. Have fun taking those apart, experiment if you will! I do although see one for 30ish USD on ebay that's not too shabby looking but it still has the chrome cover on the back so you can't see of the Green plastic is cracked and they DO crack!  

Thanks for the clarity Asphalt. I do understand that these mechanical speedos are never going to indicate a true speed or rpm and not just at the fault of age and wear. The ebay option might be a good option if I can't fix this. My main goal through this experiment is to better understand how these gauges work, which I already have a basic understanding of how magnets create electricity. I'll let you know how this goes tonight!

They are pretty simple units in theory but have to be precision enough in applied application. Example of a 1980 KZ750 with higher redline but same principle of what you will be seeing of course. Only problem you might encounter is having replacements bits available. Nothing in these gauges were available thru any Kawasaki catalog so you must have several spares to pull from. Also be gentle with that needle, it's plastic and probably weak so as will snap off in a blink! Have fun!