Sluggish acceleration.

[Banshee's Veil]

Hello, I took the project bike out for a little spin. As in one block and back. Acceleration is garbage. She bogs down hard. After I got back I synched the carbs performed and idle drop procedure, and re-launched the carbs. The idle was a lot better. However the riding experience was the same. Super boggy, slow acceleration. Granted I didn't go out of 2nd gear.

[jetmechmarty]

In 2nd gear you should be hanging on tight. Stock exhaust or aftermarket? Stock airbox or pods? Stock coils or aftermarket? Does the vacuum advance operate? How about the mechanical advance? Is it hitting on all four? Did you service the carburetors? Could they be dirty?

[Bax]

First step, read the plugs. See if all or some cylinders are too rich or lean.

Bax

[Banshee's Veil]

In 2nd gear you should be hanging on tight. Stock exhaust or aftermarket? Stock airbox or pods? Stock coils or aftermarket? Does the vacuum advance operate? How about the mechanical advance? Is it hitting on all four? Did you service the carburetors? Could they be dirty?

Pods. Carbs so clean I would use them as an operating tool. Running 140s and 45s. Started with 1 3/4 turns out before idle drop. 4-1. I dont know about the coils. New plugs, plugs will no give an accurate color due to me coating the pistons with oil before first start.

How do I check the vaccuum and mechanical advance?

[Banshee's Veil]

First step, read the plugs. See if all or some cylinders are too rich or lean.

Bax

I would need new plugs, the ones I have have soot sue to me dumping a bit of oil on the pistons to hand crank the motor during valve adjustment and before I ever started her up.

[Bax]

The oil would be gone very quickly. If you have soot on the plugs it be running rich and respond to the throttle like you describe. Did you replace the needle when you did the carbs? K&L rebuild kits have notoriously included needles with too small diameter at off position. So as soon as the throttle plate opens the fuel wells from the main and bogs the engine down even with the CV slide still fully down.

[Bax]

Quick test of the vac advance unit. Take timing cover off and rotate the pickups by hand, they should move freely. Then apply advance and pinch the vac line or plug the port with your finger and the advance should slowly return. If this is the case then your probably okay and don't have to do the vac pump test........ since its running you could probably just watch it and see it respond.

---Bax

[Bax]

I totally agree with Marty, 2nd gear, throttle twist, HOLD ON!!! XS acceleration.

[Banshee's Veil]

The oil would be gone very quickly. If you have soot on the plugs it be running rich and respond to the throttle like you describe. Did you replace the needle when you did the carbs? K&L rebuild kits have notoriously included needles with too small diameter at off position. So as soon as the throttle plate opens the fuel wells from the main and bogs the engine down even with the CV slide still fully down.

I'm running the stock needles. I have new stock jets I can put in there. I did see some flash rust from tank cleaning did make it past the petcock filter . I got some inlines I'll slap in there as well.

[Bax]

The 45 pilot may be the most suspect. Stock 42.5 pilot was set with the pilot screw at 1-1/4 (really close to 14.5:1 mix) Carb setup thumb rule would be re-jet to the next larger size when pilot screw needs >4 turns. Unless you've done big bore with hot cam 42.5 pilot would be sufficient for lower end mixture with room to richen for power with remaining 2-3/4 turns on pilot screw.

-Bax

[tarzan]

Just curious, what year and model are you working on?

[Bax]

Tarzan, Banshee's been wrenching on a SH.

[tarzan]

Then you should be running 110 to 120 Main jets. Not the 140’s. That’s your bog unless someone put older carbs on it. It’s been a few years since I rebuilt a set, but I I think 110 across all four, or 110’s on the outer carbs and 115’s on the inner carbs was stock on some.

[Bax]

Then you should be running 110 to 120 Main jets. Not the 140’s. That’s your bog unless someone put older carbs on it. It’s been a few years since I rebuilt a set, but I I think 110 across all four, or 110’s on the outer carbs and 115’s on the inner carbs was stock on some.

Probably not to the main jet yet as Banshee indicated he's only gone a block or two in 2nd. I wouldn't expect the slide to raise quickly if bogging off idle.

here is the jetting chart

[Bax]