low cold cranking

[-JC-1]

yesterday I put the compression gauge on my 124, and got 120 both holes, with the electric compression releases unplugged, and 90 with them plugged in.
This motor was at 200, with 11.2 comp with S&S 640 gear drive cams,
I pulled the cam chest apart to see if I screwed up on the cam install, but both inner and outer gears are indexed properly to each other, and I've got the inner front gear on the front cam, and the inner rear gear on the rear cam, so thats good-
I was convinced last night after I did the ccc test that i had screwed up the install someway, but so far I haven't found my mistake-
I'm wondering what my next step should be?
appreciate any suggestions
joe

[xzo124]

You sure you had the throttle WFO  ??...xzo

[06roadglide]

Make sure your battery has a good charge on it.  I usually put a charger on as I crank.  Are your lifters pumped up yet?  Pushrods adjusted properly.  Air filter off? 

[-JC-1]

yes it was wide open, and I thought maybe the guage was bad, so I put it on my softail and it got 210, right where it should be 

[Jeffd]

air cleaner off?  seems strange they would both be identical and low.  What symptoms did you have that made you check in the first place?  maybe the EAC's are not closing all the way.  I would warm it up good and then check again.

[-JC-1]

air cleaner was on, I forgot to take it off- no symptoms really, just double checking-
how much difference would the air cleaner on make?
I'm kind of wondering about the compression releases myself- it has been starting easier than it should- I thought it was because I switched to the mikuni, but maybe carbon build up in the release?

[Admiral Akbar]

Coupla squirts of oil in the cylinders and try again,, See whet you get..

Also try taking her out and run it up to the red line a couple times and check again warm..

Max

[BUBBIE]

-JC-1

How long has this Build been running (miles?) When did you first notice it was Starting EASY?


signed....BUBBIE

[rbabos]

Time for a leakdown test to find out the source.
Ron

[Barrett]

It seems like you would have noticed a loss of power with that big of a drop.

[Jeffd]

if there are no symptoms and it runs good be happy.

[-JC-1]

I've got 9,000 miles on this latest [and hopefully last] build on this motor
I noticed it starting easier after I swapped out the xxx carb for the mikuni- that was a couple of weeks ago
I haven't noticed a drop in power-
I'm thinking about re-installing the camplate and cams and checking it again, and maybe borrowing a leak down tester-
it doesn't use any oil, and the plugs look good, white with a fuel ring deep, and about 4 turns of color on the threads-

based on past experiences my default position is that I screwed something up- I'm a carpenter not a mech, but I'm trying to learn 
thanks to all

[BUBBIE]

I'm trying to follow you here.. You say 9000 miles on the build. If your compression WAS HIGHER like you stated 200 lbs. and you Only took off the carb and added the mikuni.
That Would NOT have anything to do with lower compression.... When  was the Last cc pressure taken? At 200#s...
IF you fiddled with the cams AFTER the 200 # reading, It may be what you say, a Screw-up,, BUT you say you took it apart to check and everything was fine...
Your LACK of compression is EVEN and I would SUSPECT the relief valves as BOTH cylds. are OFF  the same OR the cam timing is OFF on the Crank to Cam Marks NOT on the Cam to Cam. THIS IS possible.

If it was recient or even Long ago, I doubt 9000 mile would Have anything to do with the Drop in pressure.. Saying earlier you had it and now you don't and BOTH cyls even? I don't suspect head gasket as both are same

So check and get back with a Report.. Hopefully GOOD .

signed....BUBBIE

[rbabos]

I'd like to add that I'm surprised it will start and stay running at 90 psi. Sure that gauge is accurate? Have you tried it since testing it on the softail?
Ron

[BUBBIE]

rbabos,

He said that it was 120 and 90 with the reliefs on.. Still a LONG Way from 200lbs..

signed....BUBBIE

[rbabos]

rbabos,

He said that it was 120 and 90 with the reliefs on.. Still a LONG Way from 200lbs..

signed....BUBBIE

So, it's starting at 90 psi, right?
Ron

[BUBBIE]

YES,  rbabos,,,,, you are right.. My BAD.. 90# like you said....

signed....BUBBIE

[Hillside Motorcycle]

Sure the releases were inoperable, at the time of the check??
Scott

[ORork]

You say you noticed this symptom after installing the Mikuni. I would do as Max says and instill some oil through the spark plug holes and check the pressure again. If you find the pressure is back up to snuff, I would think the Mikuni is rich to the point of washing the oil from the rings and ring grooves. Get an accurate reading of the A/F ratio.

[-JC-1]

I hope to get it back together this evening, I've got the Mikuni jetted at 25 pilot, 2 turns out , 97 needle clipped in the middle, 185 main, and my afr guage shows a little rich on the front cylinder- the only one being read, and my plugs look good-
I don't know about the releases, it seems to me that if I get a 30 psi difference between them being plugged in and unplugged they are working?
in order to get them off, I'll have to pull the rockers,
after reading all of your responses, I think the readings I got have to be inaccurate- or operator error-
I'm going to try and get it back together this pm, and I'll test it again, If my results are the same, I'll try the oil in the spark plug hole and retest,
then I could pull the releases, which i don't want to do unless all else fails-
I don't mind pulling the cams and re-installing, it's been good practice learning how, but jeez!

thanks again, I appreciate the help!

joe

[-JC-1]

I had plugged in the battery tender yesterday am, and then last evening I reinstalled everything and it fired right up, so I checked the front cylinder and got 150 with the releases unplugged, and 120 plugged in-
the battery tender showed red, so I waited til the charger brought the battery to green, and just now  checked the rear, and got 120 both plugged and unplugged.
had the air cleaner off this time, and i made sure the throttle slide was wfo
Two things I know for sure: I need a new battery,and having the air cleaner off makes a difference
Beyond that, I trust these latest readings more than the first ones-
I'm thinking my next plan is to pull the rockers so I can get to the releases, and take them out and inspect them-

right course?

[1FSTRK]

You may want to try a leak down test first. You will be able to hear where the air is escaping before you go after the releases.

[86fxwg]

You may want to try a leak down test first. You will be able to hear where the air is escaping before you go after the releases.

K.I.S.S.

[-JC-1]

my goal this weekend is to find a leakdown tester

thanks-

[rbabos]

my goal this weekend is to find a leakdown tester

thanks-

I'm suspecting the releases themselves as in not sealing on cranking rpms. Extra pressure when running might close them. That, or there is an exposed hole in the threads that the releases thread into, caused from not going deep enough in the machining operation.
Leakdown test will show the problem, whatever it is.
Ron