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Author Topic: New gauges on my CB550 but tach reads low  (Read 1392 times)

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Offline neurotoxin312

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New gauges on my CB550 but tach reads low
« on: April 18, 2018, 04:51:15 PM »
So I picked up a set of these sweet gauges aftermarket gauges made by Emgo. The problem is that it appears as though the Tach never goes above 4000 rpms. After purchasing I realized the ratio on the tach was 4:1 instead of the 20:3.

Two questions:

Is there a difference between the CB750 speedo and the CB550 speedo?

Will I need to return the tach since it isn't a 20:3 ratio? or Can I perhaps use a different tach drive/cable?
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Offline flatlander

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Re: New gauges on my CB550 but tach reads low
« Reply #1 on: April 18, 2018, 10:29:50 PM »
Quote from: neurotoxin312 on April 18, 2018, 04:51:15 PM
or Can I perhaps use a different tach drive/cable?

different tach drive won't fit on the camshaft, so no.
different cable won't do anything for the tach ration or reading.
as cal says: send 'em back.
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Offline PeWe

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Re: New gauges on my CB550 but tach reads low
« Reply #2 on: April 18, 2018, 11:35:30 PM »
It is the tacho that is not made for CB500/550. I was very surprised when Z1parts claim their tacho fits both CB500/550 and 750. is it the same gauge?
I have used a Honda CB500 tacho on my CB750 so I know what happen. It will show way too high rpm.
A CB750 tacho on a CB500/550 must be too low. It's strange how the seller can claim that same tacho fits CB750 and 500/550.

Quality issues made me to stay away from the good looking K3-K6 gauges and avoid problems claiming new or money back and impossible to return it. Shipping and customs discussions will cost a lot of energy. I preferred the much more expensive path, old Honda K2 gauges I'll repair.
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CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
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Offline Gordo

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Re: New gauges on my CB550 but tach reads low
« Reply #3 on: April 19, 2018, 12:22:58 AM »
Drop a 650 cam and tach drive in their. Tach will read correctly and gain a bit of pep on the way.
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Offline neurotoxin312

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Re: New gauges on my CB550 but tach reads low
« Reply #4 on: April 19, 2018, 10:12:40 AM »
What about the Speedo? Is that the same between CB550 and CB750?
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Offline Gordo

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Re: New gauges on my CB550 but tach reads low
« Reply #5 on: April 19, 2018, 03:06:29 PM »
Quote from: neurotoxin312 on April 19, 2018, 10:12:40 AM
What about the Speedo? Is that the same between CB550 and CB750?
Yep speedo is the same just tach has different ratio
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Offline neurotoxin312

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Re: New gauges on my CB550 but tach reads low
« Reply #6 on: April 20, 2018, 09:59:08 AM »
Anyone have good recommendations for a tach and speedo dial faces? I can't seems to find a lot of options for the CB550.
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Offline madmtnmotors

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Re: New gauges on my CB550 but tach reads low
« Reply #7 on: April 20, 2018, 10:07:15 AM »
Dang, if you had posted a week ago you could have swapped gauges with Pyroviking:

http://forums.sohc4.net/index.php/topic,171655.msg1997929.html#msg1997929

He already purchased a replacement. Maybe he'll make you a deal?
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