Missing at constant speed?
- Thread starter Bodeen
- Start date
J
Jack Klarich
Guest
Are you sure the cams are timed right? Fuel does not help, spark does not help, have you run a compression test yet? No need for a leak down test yet IMO Does this bike have a VOE switch and is it working right?
BUBBIE
Well-Known Member
Page 5 post #41:
Bodeen says:
Checked compression on front and rear cylinders. 155psi and 165psi respectively.
Have or will you try this?
IF you apply the brake Just enough make the engine Labor Just a Bit off the easy cruise and apply some fuel to keep the speed up......Then does it still Miss?
Meaning under a little power.... holding brake some.... OR Is it only when Low throttle and soft cruise...???
Hope that makes sense...???
signed....BUBBIE
Bodeen says:
Checked compression on front and rear cylinders. 155psi and 165psi respectively.
Have or will you try this?
IF you apply the brake Just enough make the engine Labor Just a Bit off the easy cruise and apply some fuel to keep the speed up......Then does it still Miss?
Meaning under a little power.... holding brake some.... OR Is it only when Low throttle and soft cruise...???
Hope that makes sense...???
signed....BUBBIE
Timing is right because it runs really good under acceleration, compression test done, no VOE
It definitely sounds different, but I am pretty certain this is a miss under light throttle.
Haven't tried that Bubbie but I would bet that it runs good under a fairly good throttle load. Soft cruise, steady throttle like through a school zone or through the neighborhood. When hammered it goes like nobodies business. I cant really notice a miss or difference at idle either but the new cam has a difference about it too....
dolt
Well-Known Member
Didn't think plugs were the problem but you have eliminated plugs and wires now as potential sources and, IMHO, that plug is well suited for your motor configuration; better than the stock plugs.
2003 Road King, new 21 mouse cams, new S.E. plate and pump, S.E adj. push rods, Street port heads, new valves, springs etc. Rinehart TD'S, CV carb with sporty needle, 46 slow 190 main.
Reading this from your OP, there is no mention of an ignition module which means your ignition timing has not been modified; still the OEM ignition map. This is a bit of a long shot but after market ignition modules like the DTT TC88 are installed with cams, heads, more compression, etc. so that timing can be adjusted.
I am not suggesting that you cough up the $300 for an aftermarket ignition module but units like the DTT TC88 do include a "multi spark" mode for quick starts and smooth cruise. Normally for Stage I upgrades the OEM ignition map works fine; however, when you include cams, ported heads and more compression, the OEM ignition map is often found lacking.
I am also going back to the compression of 155/165. While I don't see the compression as being the source of the missing, I do think it is a bit low for the motor configuration you have built. A good target for your configuration would be 185psi. The bike is carbureted so in order to get an accurate CCP reading, one would have to physically hold the slide up to allow full air flow into the cylinders. I remove the carb completely from the boot when checking compression on a carbed motor. The carb is vacuum operated so holding the throttle open does open the butterfly but the slide doesn't move. If you did not hold the slide up or remove the carb from the boot, run another compression test. If you don't have north of 180, IMHO, you are not getting full value from the money you spent to build the motor.:nosad
BUBBIE
Well-Known Member
I MAY have a couple of ignition do-dickies that have Low time on them. I used to Play like I had a million$ when i was younger... Tried many of them...
I'll look and PM you at what I find in my X-tra box....
Careful Bodeen,,,,, I Can Hear You...:newsmile100:
""OH NO,,,, Not BUBBIE again...":nosad
signed....BUBBIE
I'll look and PM you at what I find in my X-tra box....
Careful Bodeen,,,,, I Can Hear You...:newsmile100:
""OH NO,,,, Not BUBBIE again...":nosad
signed....BUBBIE
Your just full of surprises! The carb is fine, and always has been. Some would love to see what is in your "X-tra box"! Or maybe not......
Re-checked compression with slide up and not a lot of difference than the last readings. Not sure if I indicated that this is still stock bore, piston and rings. When I pulled the plugs to check comp. the front plug is burning very lean compared to the rear. So I got something going on there and not sure which cylinder it is but I'm leaning (no pun intended) toward the front since it is making the noise.....