Topic: Front sprocket 1978 cb750k

[Dime]

Ok so I got the cover off and the front sprocket looks to be in good shape however I am not sure it is the right sprocket for the bike.

It is 17 tooth like I want but from what I can size up it has play in it due to not having a raised face like JT Steel Front Sprocket 17T (530) - JTF338.17 once the bolt and washer for the sprocket is in place.

I am guessing someone did a slap together job of converting to 530 chain. Which does not surprise me acording to all the other work done on the bike.

Maybe I am overthinking this as well and it is supposed to have play between the washer and sprocket but it doesn't make sense.

Anyone want to let me know if I am over thinking this?

[bryanj]

That is a sprocket for an earlier bike that locates with a fixing plate and two bolts into the threaded holes

[Dime]

That is a sprocket for an earlier bike that locates with a fixing plate and two bolts into the threaded holes

Ok I am going to have to count the rear sprocket teeth and see what I am into here. It was too much to.hope something was done right on this bike, LOL.

Thank you

[madmtnmotors]

Did you remove the transmission/shift cover to get the sprocket cover off, or had you planned to remove the trans/shift cover anyway? The sprocket cover can be removed without removal of the shifter cover as demonstrated in a short video I did here:

There is a link to the post in my sig below as well as one or more links to 630 to 530 conversion info.

[Dime]

Did you remove the transmission/shift cover to get the sprocket cover off, or had you planned to remove the trans/shift cover anyway? The sprocket cover can be removed without removal of the shifter cover as demonstrated in a short video I did here:

There is a link to the post in my sig below as well as one or more links to 630 to 530 conversion info.

I planned on removing it anyway. The stator was suspect. One of the yellow wires turned out to be burned. I cut off all the old ends going to the stator and tested and all the yellow wires tested 0.4 ohms as it should so at least the stator is good. Will be testing the rotor next.

[bryanj]

You mean field coil, the rotor is a lump of steel with a wavy groove in it

[Dime]

You mean field coil, the rotor is a lump of steel with a wavy groove in it

Field coil is on the list too but no I meant pulling the cover and testing the rotor.

[bryanj]

There is no test you can do on the rotor except is the crank bent

[Dime]

There is no test you can do on the rotor except is the crank bent

Maybe I am not using the right term but I am taking about doing an ohm test which should result in between 4-10 ohm between the rings

[bryanj]

That is for the field coil not the rotor, the generator consists of 3 parts
1 the field coil
2 the stator coils
3 the rotor

A Honda document of the 3 phase charging circuit is attached

[Dime]

That is for the field coil not the rotor, the generator consists of 3 parts
1 the field coil
2 the stator coils
3 the rotor

A Honda document of the 3 phase charging circuit is attached

Ok cool. Thanks for clearing that up for me. I was obviously confused

[bryanj]

No problem you aint the first and wont be the last, hope the document explains the charging sytem for you

[scottly]

Maybe I am not using the right term but I am taking about doing an ohm test which should result in between 4-10 ohm between the rings

That test is for a DOHC, which has a different alternator. The SOHC field is the white and green wires that are with the 3 yellow stator wires, and should read about 7 ohms.

[Dime]

Maybe I am not using the right . I am taking about doing an ohm test which should result in between 4-10 ohm between the rings

That test is for a DOHC, which has a different alternator. The SOHC field is the white and green wires that are with the 3 yellow stator wires, and should read about 7 ohms.

Thank you. I am used to dohc. This is all new to me.

I tested the wires as you said and got exactly 7 ohms.

So looks like the burnt wire at the connector for the yellow wire was the issue

[scottly]

Both the field and stator are attached to the inside of the alternator cover. The stator goes over the outside of the rotor, which is bolted to the end of the crankshaft, and the field coil goes inside the rotor. The field coil is an electromagnet: when current flows through it, it magnetizes the rotor, which in turn induces current in the stator. The regulator controls how much current flows through the field, which in turn controls the output from the stator.

[Dime]

Both the field and stator are attached to the inside of the alternator cover. The stator goes over the outside of the rotor, which is bolted to the end of the crankshaft, and the field coil goes inside the rotor. The field coil is an electromagnet: when current flows through it, it magnetizes the rotor, which in turn induces current in the stator. The regulator controls how much current flows through the field, which in turn controls the output from the stator.

Thank you for taking the time to.break this down for me. Electronics is not my.strong suit. I barely passed electrotec as part of my mechanic program but still managed to graduate top of my class. So ya I definitely struggle in this area and appreciate the time you guys are taking to help sort this out.

[Tracksnblades1]

Dime,

I think your looking for a 17 tooth later model genuine Honda 650 sohc single shoulder 530 sprocket that uses the single center retaining bolt… I believe this one spaces the sprocket away from the case like the OEM 630 sprocket did..

The earlier OEM Honda’s to76 (750s) had a shoulder on each side that used the two bolt spline lock retainer..

[Dime]

Dime,

I think your looking for a 17 tooth later model genuine Honda 650 sohc single shoulder 530 sprocket that uses the single center retaining bolt… I believe this one spaces the sprocket away from the case like the OEM 630 sprocket did..

The earlier OEM Honda’s to76 (750s) had a shoulder on each side that used the two bolt spline lock retainer..

Thank you. In another one of my posts a gentleman touched on this very thing about the shoulder on the sprocket and how it needs to.go inward. I had just forgotten

You guys are so helpful. It is much appreciated