Author Topic: 120 runing rough  (Read 807 times)

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Offline MakoHD

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120 runing rough
« on: April 14, 2019, 04:42:50 PM »
M8
120ci cp pistons
Compression 11:1 front cylinder 190psi rear cylinder 200
Ported heads, 1mm over size valves, high lift springs
62mm HPI
D&d exhaust
Few months back the bike sumped due to that it had the stock oil pump.
I put feuling pump and cam plate. But whent it sumped it got really really hot and my old man didnít pull over ridding 2 up. When he got home the bike was sizzling hot. I let it cool down and when cranked it up she had  a small knock, sound like piston slap coming from the front cylinder, we decided to keep  ridding the bike because it was running great but it just had that noise that came and left. Well he was ridding on the high and the bike started to make noises and it shut off. It would only crank up when you give throttle...
what Iíve tried
New spark plugs
New cables
I have spark in every cylinder
No rocker arms broke
Put new intake seals
Changed MAF sensor
The bike idles bad and runs bad, itís not drivable. Iím about to pull it apart and go to a 124 because of the piston slap but Iím afraid that when I put it back itíll still have the same issue.  What can cause this? The compression test readings are as of today.

Offline BVHOG

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Re: 120 runing rough
« Reply #1 on: April 15, 2019, 07:00:30 AM »
Broken cylinder spigot would be my first thought on the noise. As for the rough running an intake leak could be the culprit. Do a leak down test to make sure the valve seal is where it needs to be.
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Offline happyman

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Re: 120 runing rough
« Reply #2 on: April 15, 2019, 07:17:49 AM »
if it was sumping for many miles and boiling hot, would think the complete motor is toast.  does it have a nasty odor when you remove the dip stick by chance. if so you can bet its serious.

Offline BVHOG

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Re: 120 runing rough
« Reply #3 on: April 15, 2019, 09:03:44 AM »
Also that piston slap noise could be a head gasket leak
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Offline rbabos

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Re: 120 runing rough
« Reply #4 on: April 15, 2019, 09:30:08 AM »
if it was sumping for many miles and boiling hot, would think the complete motor is toast.  does it have a nasty odor when you remove the dip stick by chance. if so you can bet its serious.
I agree. Time to start over.
Ron

Offline MakoHD

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Re: 120 runing rough
« Reply #5 on: April 15, 2019, 10:32:54 AM »
Itís been runing with the piston slap for 2000 miles. Iíve had motors cook up because of sumping and 10000 miles later still kicking it. bike turns on idles rough, like if it were runing on one cylinder. Iím going to do a fuel pressure test this afternoon and Iím going to make sure that both injectors are workingt. This is when a good scanner would help big time. I would love to see live readings on everything. I know  the motor is not 100% but it shouldnít be running like this with the compression that it has. Has anyone every heard of this motors jump timing? Canít see how, but you never know... for the intake leak I put a new intake seals, 4 new plugs and 4 new wires, maybe the coil has an intermittent problem. Could be anything Iíll let you guys know when I figure it out. Thanks for the input.

Offline 86fxwg

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Re: 120 runing rough
« Reply #6 on: April 15, 2019, 05:38:36 PM »
If its missing or completely dead on 1 cylinder, hit the pipes with a temp gun, the one that's dead will be much cooler. At least u will have a idea what cylinder is the culprit.

Killing a cylinder will or should help u find what cylinder is knocking to. It works in the auto industry.

Check ALL electrical connections, chances of ignition part failure is pretty slim as the bike is almost new other than ur fingers being in it!


86
« Last Edit: April 15, 2019, 05:45:14 PM by 86fxwg »
86fxwg 06flhx 10flhx

Offline VDeuce

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Re: 120 runing rough
« Reply #7 on: April 15, 2019, 06:02:07 PM »
I'd do a leak down test. Got a camera to peek in the cylinders?

Lots of reports of stuck rods when they sump real hot like that.

Offline happyman

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Re: 120 runing rough
« Reply #8 on: April 15, 2019, 06:27:46 PM »
Most certainly. Also if the motor was boiling  hot, you will not are hand the diode stick. Also chances are you will not be able to turn it out by hand.  When you get it out a d your inside it has an oder you cannot believe.  Al's when you look at the wheels they will be of a yellow  to gold color I would call it. It will be the oil level line on the wheels . It's a smell and a sight to behold.

Offline MakoHD

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Re: 120 runing rough
« Reply #9 on: April 15, 2019, 06:36:27 PM »
This thing has 60 psi of fuel. Iím
About to put a match to it....
changed throttle body
Changed crank sensor
Changed AF sensor
Iím about to change the bike and start fresh lol

Offline GMR-PERFORMANCE

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Re: 120 runing rough
« Reply #10 on: April 16, 2019, 07:04:01 AM »
 Pull your Crank position sensor and take a look at it . I have seen where they sump and get so hot it is melted . at that point the crank is hurt . Just went through that here Used GRC with the larger pin they make Stanley has been doing cranks for a very long time .
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Offline MakoHD

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Re: 120 runing rough
« Reply #11 on: April 16, 2019, 02:59:01 PM »
Pull your Crank position sensor and take a look at it . I have seen where they sump and get so hot it is melted . at that point the crank is hurt . Just went through that here Used GRC with the larger pin they make Stanley has been doing cranks for a very long time .

yeah i tried that too. i think the tune might of gotten corrupted, have you seen that before? 

Offline MakoHD

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Re: 120 runing rough
« Reply #12 on: April 18, 2019, 07:46:22 PM »
When I said I removed the rocker box cover I never removed the rocker arm and it kept some tension on the spring, not making it seem broken. I should looked closely. Lesson learned!!! Shame on me...

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« Last Edit: April 18, 2019, 07:53:25 PM by FSG »

Offline No Cents

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Re: 120 runing rough
« Reply #13 on: April 19, 2019, 05:04:08 AM »
  what spring manufacturer made that spring?
Do you know what lift they were suppose to handle...and what cam was you running?
Did the valve touch the piston?
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

Offline VDeuce

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Re: 120 runing rough
« Reply #14 on: April 19, 2019, 07:11:06 AM »
Yes, what spring? Concerning...

Offline kd

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Re: 120 runing rough
« Reply #15 on: April 19, 2019, 07:31:09 AM »
The silver lining here is that it was a double spring set.  One spring was maintaining the keepers in the collar and that likely saved the valve, head pistons and even the engine as a whole.   :up:
KD

Offline No Cents

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Re: 120 runing rough
« Reply #16 on: April 19, 2019, 07:34:30 AM »
 yep...he might have just got lucky with the other spring not allowing that valve to fall that had the broken spring.
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

Offline MakoHD

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Re: 120 runing rough
« Reply #17 on: April 19, 2019, 04:06:54 PM »
Iím not 100 % sure what brand spring is it but yes they were designed to hold high lift. I use a 544 lift cam. No the valve never dropped. Iím replacing them all to different spring.

Offline No Cents

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Re: 120 runing rough
« Reply #18 on: April 19, 2019, 06:06:42 PM »
  was your bike dyno tuned?
The piston showing looks awfully black...but that broken spring could of contributed some of it if it was ran that way for awhile.
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

Offline MakoHD

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Re: 120 runing rough
« Reply #19 on: April 20, 2019, 10:23:13 AM »
yes it was but you can imagine how rich it was running with the valve spring broken. the piston are also coated on the side.