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RPM crusing 18 May 2023 02:27 #884828

  • willemZ900
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I have à 19 front wheel and à 16 rear wheel. Sprockets are 15/32 tooths

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RPM crusing 18 May 2023 11:07 #884851

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Todays trip, 100/110 km @ 4000 rpm. 120/125km @ 5000 rpm

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RPM crusing 18 May 2023 14:43 #884867

  • Injected
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It was Norwegian national day here yesterday, so sorry for the delay :)

Front wheel - 100/90 - 19
Rear wheel - 130/90 - 16
Front sprocket - 16 tooth
Rear sprocket - 42 tooth

Haven`t checked these up against the webpage yet.

 
Scirocco did all the leg work for you and posted the results :

Stock gearing in red, +1 front sprocket in yellow, +1 front and - 4 rear in green - Only the rear wheel size matters.



 

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RPM crusing 18 May 2023 23:50 #884892

  • gordone
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Thank you all.

I`m some confuse but I belived I had largest sprocket I could have in front already.. I remember I got advise some years ago to go big as possible to reduce wear on the sprocket,
but what you saying there is space for 17th also ?

From looking at the table I think my RPM reader show approx. 1000RPM to much, I can also realte to these when it comes to idle for I`m idling at 2000RPM and not around 1000RPM.

So today:
4250 RPM - 88.9km/h

Going up to 17th in front:
4250 RPM - 94,6km/h

Going up to 17th front and down to 38th rear:
4250 RPM - 104.4km/h

What do you think ?








 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
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Last edit: by gordone.

RPM crusing 19 May 2023 00:52 #884895

  • Wookie58
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As advised by "Injected" 17/38 looks good for road use

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RPM crusing 19 May 2023 01:33 #884896

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So, you are not afraid I will change the ratio too much? Power peak curve on the engine etc... Normally when cruising in +7- 80 km/h it should be enough to go down to 4th and give throttle to pass cars, don`t need to go 2 gear suddenly ?

If I should to the middle step... ?

Today I always feel I`m missing the 6 gear so... so I think it will be good to do these change next time I change sprockets, properly smart to change all 3 parts when I do it.



 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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Last edit: by gordone.

RPM crusing 19 May 2023 02:33 #884898

  • Wookie58
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I think with your 810 kit this will be fine and you will then have 210Kmh at 8500rpm
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RPM crusing 19 May 2023 02:55 #884899

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I understand, guess the Mikuni VM24 will help here also, since they give me more power on low rev and less on high rev?
Since these carbs is orginal ment for 650cc... ?

 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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RPM crusing 19 May 2023 05:35 #884901

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So, you are not afraid I will change the ratio too much? Power peak curve on the engine etc... Normally when cruising in +7- 80 km/h it should be enough to go down to 4th and give throttle to pass cars, don`t need to go 2 gear suddenly ?

If I should to the middle step... ?

Today I always feel I`m missing the 6 gear so... so I think it will be good to do these change next time I change sprockets, properly smart to change all 3 parts when I do it.




 
I have no issue passing with my 17/38 gearing on the highway from 5th gear, no downshifting required. My engine is a bit more modified than yours, but I don't think you are that much off.

 

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RPM crusing 19 May 2023 05:49 #884902

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I understand, guess the gass consumption will go down when I`m cursing in 80-90 km/h also ?
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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RPM crusing 19 May 2023 08:05 #884906

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From looking at the table I think my RPM reader show approx. 1000RPM to much, I can also realte to these when it comes to idle for I`m idling at 2000RPM and not around 1000RPM.

 
Have you checked rpm with a known accurate tachometer to be sure that the tachometer on the bike is close to accurate?
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

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RPM crusing 19 May 2023 09:53 #884916

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No, planning to ugrade whole eletrical cabling and replace speedo and rpm with modern type in the winter so was not planning to use to much time on it.

why are you asking? Gesrbox ratio and wheel size + sprocket size should give the answear anyway?
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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