Reprofiled camshaft

[DomP]

5 degrees of overlap and 10 degrees of duration is the recommended settings to give to Newmans. They have confirmed they can do this.

I'll detail the timing issue later

There's a timing issue?

[Oddjob]

Here's the details of the timing.

Advance the timing 2 degrees static, but cut off one turn from the springs on the advancer and reshape the end of the next coil so the springs will fit back onto the advancer mounts. This slows the advance curve about 5%-8%, depending on the year of your bike.

Not my idea, got that off the web on a well known expert on these engines.

It's done to address the mid range flat spot.
He also added this.

Raise the jet needle in the carb slides one notch. Install a 10-size smaller main jet at the same time (5 size smaller on last-year CB550). Switch from the standard D7E (NGK) or X22E (ND) sparkplugs to the D8E (X24E) at this same time. Check the color of your plugs to make sure it does not get too lean, which can happen if you’ve installed individual air filters and/or headers that actually work (most did not), or longer, megaphone-type mufflers.

[DomP]

Does the timing have to be altered with the suggested cam profile Ken or is that just to eek a bit more out of it?  I'd rather leave my carbs as stock as possible if I can having spent quite some time sorting them. 

What I have noticed is that my advanced springs have been cut and reshaped already, I can see the sharp snipped ends and reshaped loops on the ends.

[Oddjob]

No you can leave the timing at stock, although if the springs have already been cut that will have altered the timing somewhat but nothing to worry you. Carbs can be left standard as well. Only do what you feel comfortable doing, if you want stock advance springs I’ll swap you for yours, try counting the coils though to confirm they are shorter than stock

[Bryanj]

I vaugly remember fitting a fast street yoshimura cam to a 500 and it neede more advance (38deg ithink) and a bigger rear sprocket to run right as it had more power at high revs but less low down

[Oddjob]

What we are advocating isn't so radical as the Yoshi cams Bryan, just the same sort of profile as the 650 but without the problems of the 650.

[Bryanj]

That was the only one i ever did Ken so just throwing in memory, i have a webcam 58a to go with a stage 2 head and 605 conversion when i find my square tuit

[DomP]

I'll get a photo up tonight Ken.

Hopefully posting the barrels tomorrow Bryan

[DomP]

No you can leave the timing at stock, although if the springs have already been cut that will have altered the timing somewhat but nothing to worry you. Carbs can be left standard as well. Only do what you feel comfortable doing, if you want stock advance springs I’ll swap you for yours, try counting the coils though to confirm they are shorter than stock

I suppose there is a chance the cam could have already been done

[Oddjob]

Doubtful Dom, not many go to the trouble, which is a shame as it's a decent mod.

[DomP]

Doubtful Dom, not many go to the trouble, which is a shame as it's a decent mod.

Here you go Ken, photos of springs

[Oddjob]

8 coils on one and only 7 on the other, odd.

[DomP]

8 coils on one and only 7 on the other, odd.

Nothing surprises me with this bike Ken.  How many coils should they have and are you still interested in a swap?

[Oddjob]

I'd need to see if I can find the spare springs Dom, as with most things you put them away and then can't recall where you thought a safe place was.

[Oddjob]

Looks like 9 coils as standard Dom, just found this picture of my restored advance/retard mechanism.