I need help! Pamco timing!

[jgimar]

That could depend on your mods. You said you have 1.5" pipes. Straight pipes with no mufflers? They can be difficult to tune for. You also said pods. What kind? If they're the K&N pleated type, they can cause running issues, premature break-up requiring smaller than ideal jet sizes. The 30 pilots you put in now could also be contributing to the break-up, maybe they're too big.

The '76-'77 carb set had the largest needle jets (Z-8) put in any 650 carb set. These limit the jet sizes you can use, especially the mains. You can't go as big as on some of the other 650 carb sets or you make the already rich midrange too rich. The 3 circuits in your carb overlap the one next to them slightly. Larger mains or pilots also effect the upper and lower parts of the midrange .....

very enlightening! okay back to the board then. i have stuck torque cones in the pipes hoping that would help some. pilot jet, i'll move back to the 27.5, main jet, i'll order up some smaller sizes like the 132's you mention. any others you think i might have on hand? i haven't touched the needle jet, it's still a Z8. the needle, i'll leave at the 2nd from top notch for now. soon as i get that all rounded up, i,ll get back to ya, thanks for the diagram, big help. add anything else if you wish. thank you! oops, back to the pipes, without getting into the old man look, what would you suggest for a muffler if i have to resort to such? or would a baffle serve the same purpose?

 

[jgimar]

That could depend on your mods. You said you have 1.5" pipes. Straight pipes with no mufflers? They can be difficult to tune for. You also said pods. What kind? If they're the K&N pleated type, they can cause running issues, premature break-up requiring smaller than ideal jet sizes. The 30 pilots you put in now could also be contributing to the break-up, maybe they're too big.

The '76-'77 carb set had the largest needle jets (Z-8) put in any 650 carb set. These limit the jet sizes you can use, especially the mains. You can't go as big as on some of the other 650 carb sets or you make the already rich midrange too rich. The 3 circuits in your carb overlap the one next to them slightly. Larger mains or pilots also effect the upper and lower parts of the midrange .....

Hey 5twins, ??? You mention being straight pipes may make things difficult for me, short of mounting mufflers, would an adequate baffle benefit me any?11[-aaAqq as Qq qq

 

[5twins]

It might. I guess all you can do is try it. These run best with mufflers. They don't call short straight pipes "drag pipes" for nothing. They make their best and most power at high RPMs up near redline, lose power in the lower RPMs. That's fine for drag racing, not so much for street riding.

 

[jgimar]

It might. I guess all you can do is try it. These run best with mufflers. They don't call short straight pipes "drag pipes" for nothing. They make their best and most power at high RPMs up near redline, lose power in the lower RPMs. That's fine for drag racing, not so much for street riding.

Heard that same thing from a friend pf mine. So, muffler it is! But, can i make do with a “pleasingly esthetic” bullet style glass pack or do i have to get something big, bulky and ugly?

 

[gggGary]

These Borlas work awesome.

but I seldom use them cuz LOUD (but deep tone) LOL
Unfortunately NLA

 

[jgimar]

These Borlas work awesome.
View attachment 188487
but I seldom use them cuz LOUD (but deep tone) LOL
Unfortunately NLA

 

[jgimar]

Thank you!

 

[5twins]

Another option might be this 18" megaphone w/ mechanical baffle from YamahaXS650.com. They claim it has a nice tone and isn't super loud, but I've never heard one so can't say for sure .....

https://yamahaxs650.com/product/xs-performance-reverse-cone-megaphone-muffler-18-with-adjustable/

But in my experience, short mufflers are usually loud mufflers, lol.

 

[jgimar]

Another option might be this 18" megaphone w/ mechanical baffle from YamahaXS650.com. They claim it has a nice tone and isn't super loud, but I've never heard one so can't say for sure .....

https://yamahaxs650.com/product/xs-performance-reverse-cone-megaphone-muffler-18-with-adjustable/

But in my experience, short mufflers are usually loud mufflers, lol.

I don’t mind loud, just don’t like ugly! I am familiar with that business, and that style is acceptable, but as always the case, will have to see how the funds runs. Thanks for the input, soon as i progress further, i’ll let you know the outcome!

 

[jgimar]

Another option might be this 18" megaphone w/ mechanical baffle from YamahaXS650.com. They claim it has a nice tone and isn't super loud, but I've never heard one so can't say for sure .....

https://yamahaxs650.com/product/xs-performance-reverse-cone-megaphone-muffler-18-with-adjustable/

But in my experience, short mufflers are usually loud mufflers, lol.

Hey 5 twins, i am making headway with my project, but one thing leads to another. I am having trouble with the right carb sir mixture screw. We’ve made our jet adjustments and now i’m down to our mix screws working properly. The left one is performing proper, the right one has no response. We screw it all the way in and nothing. 1 1/2 turns or more out and nothing. Needle and spring are good, i know it’s not clogged. Any remedies or suggestions?

 

[5twins]

No response from the mix screw can be an indication that the float level is set wrong.

 

[jgimar]

No response from the mix screw can be an indication that the float level is set wrong.

Well heck of a deal. I’ll check it and get back to ya. Thanks

 

[5twins]

The spec for your '76-'77 carb set is 25 ± 1mm.

 

[jgimar]

The spec for your '76-'77 carb set is 25 ± 1mm.

Very good thank you!

 

[jgimar]

The spec for your '76-'77 carb set is 25 ± 1mm.

Well, tore ‘em down and checked both floats. Set ‘em both at right about 25mm. Slapped it back together and really no appreciable difference. So my next move? Short of any additional advice I think I’ll tear them down to scratch and blow out every orifice I can possibly force air through. If you have any further advice, keep it coming.