Topic: Electric Tach

[chrisf]

I've never dealt with a points and condensor system, so I have to ask: Can I run an electric tach? My thought is that I could hop off one of the coil leads, but I'm a bit fuzzy on this.

Also, the bike is a '69 CL350. The redline on the tach is 12k RPMs. What is the useable reve range on the se old 350s?

--Thanks, Chris

[crazypj]

If you get tach off late model bike it will not read correct rpm.
Just about all tachs I've looked at are crank triggered but the CL is triggered off cam so runs at half speed.
you can use it to 11,500 rpm, but not really recommended to go that high unless you know exactly what parts are in the crankcase ( modified/expensive )
PJ

[chrisf]

But can't I wire the tach off both coils to correct this?

--Chris

[chrisf]

Actually, will the tach off a CB500 work with the CB/CL350 motor? I like those much better because they are a much lower profile.

--Chris

[dusterdude]

you can get an electric tach to work,i think it needs to be for a 2 cylinder bike since our engines fire 2 cylinders at a time,i could be wrong tho.

[crazypj]

you can get an electric tach to work,i think it needs to be for a 2 cylinder bike since our engines fire 2 cylinders at a time,i could be wrong tho.

I think you are,they still fire from the crank and not cam.
CL350 only has two cylinders.
If you have two sets of points and you wire to both, neither will work as your always grounding one set. If you fit diodes into leads to only allow current one direction it will work.
PJ

[chrisf]

I think you are,they still fire from the crank and not cam.
CL350 only has two cylinders.
If you have two sets of points and you wire to both, neither will work as your always grounding one set. If you fit diodes into leads to only allow current one direction it will work.

That's just as well, and I now see what you're talking about. So has anyone used the lower profile CB500 gauges? Do they spin at the same ratio as the CB350?

-_Chris

[kslrr]

Hey dusterdude you are so correct.  That is how I made that old Sun Tach work on my CB350F.  I changed out some resisters inside so that it is setup for a 2 cyl. engine.  Does the CL350 have 1 or 2 point blocks?  I can't remember from the days of my CL175.

[crazypj]

CL175 had single points and dual lobe cam so it fired every revolution therefore it would be correct crank rpm
Twin points set up running off one coil triggered from cam will read half of actual rpm
PJ