Author Topic: Broken piston jets  (Read 1261 times)

Offline MadMaxUK

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Broken piston jets
« on: Saturday, May 12, 2012. 03:49:53 PM. »
A friend got a 2005 Dyna in his shop to fit a 95 kit - did so with the 22851-99 pistons & SE jugs & the owner rode the bike away. Owner complained of a lack of power & took the bike to another shop to diagnose the problem. The other shop pulled the top end & discovered scuffed bores & both piston oiling jets broken off. The second shop brought the bike back to my buddy's place for a full tear down. I went & had a look - jug spigots are the length they should be ... pistons are the right part number .. we're scratching heads now?? Split the cases & the oil pump is trashed & some grinding going on in the big end bearings. Checked the numbers stamped into the flywheels & it's 23940-99. My thoughts were that it was a 4.375 stroke crank in the motor & then fitted with the 95 pistons & the skirts took out the oilers but it was a stock 05 bottom end before the 95 upgrade .. Any ideas????

Offline koko3052

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Re: Broken piston jets
« Reply #1 on: Saturday, May 12, 2012. 04:18:27 PM. »
 :emoGroan:
 Should have taken it back to the shop that did the work!!!
 Now it will be a fight of "who did what"! Not a good deal.

maybe the first shop got a little sloppy with whatever tool they were using to hold the rods...stuffed a bunch of rags in cyl. hole a little too aggressively?? :nix:

Let us all know what you find out please & thanx. :scoot:

Offline MadMaxUK

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Re: Broken piston jets
« Reply #2 on: Saturday, May 12, 2012. 04:40:42 PM. »
stuffed a bunch of rags in cyl. hole a little too aggressively??

Similar thoughts crossed my mind but more along the lines of any mishaps when fitting the wrist pin clips with the pistons held in the jugs. But for both jets to break off?? The guy is an experienced ex Dealership tech so I doubt it.  But really ... what else?? He's fitted dozens of big bore kits & has been around a long time .. not like him to mess up ..

Offline 02FYRFTR

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Re: Broken piston jets
« Reply #3 on: Saturday, May 12, 2012. 05:10:25 PM. »
1.  Verify the correct compression heigth of the pistons.
2.  Verify that the cylinders a 4.937" from head gasket surface to the motor case surface.
3.  Are the piston cooling jet bolts broken, missing or wrong length.
4.  Were the flywheels replaced during the build.
5.  Look for groove in the cylinder bore perpindicular to the motr centerline fron to rear.
6.  Are both piston wristpin circlips in place.
7.  Noise is associated with missing circlip like a very loud colapsed lifter or spark knock.
« Last Edit: Saturday, May 12, 2012. 05:13:03 PM. by 02FYRFTR »

Offline Roadhawg

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Re: Broken piston jets
« Reply #4 on: Saturday, May 12, 2012. 07:55:36 PM. »
Did the motor get turned over with the pistons still on the rods? If the piston skirt hangs up on the counterbore the other side of the piston skirt can hit the oiler.

Online Max Headflow

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Re: Broken piston jets
« Reply #5 on: Saturday, May 12, 2012. 09:19:09 PM. »
My bet would be either a rag combined with some improper movement snapped em off or something else found it's way into the lower end. It's possible that the left main roller blew out a side or an inner cam bearing let go to the inside. Look at all the little pieces and play some CSI..

Max
« Last Edit: Saturday, May 12, 2012. 09:25:08 PM. by Max Headflow »
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Offline Redrubicon2004

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Re: Broken piston jets
« Reply #6 on: Sunday, May 13, 2012. 04:22:12 AM. »
Checked the numbers stamped into the flywheels & it's 23940-99. My thoughts were that it was a 4.375 stroke crank in the motor & then fitted with the 95 pistons & the skirts took out the oilers but it was a stock 05 bottom end before the 95 upgrade .. Any ideas????

Pretty sure you would have piston/head contact if that were the case.

Offline Tattoo

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Re: Broken piston jets
« Reply #7 on: Sunday, May 13, 2012. 06:13:30 AM. »
Did the motor get turned over with the pistons still on the rods? If the piston skirt hangs up on the counterbore the other side of the piston skirt can hit the oiler.

I have seen that before..
"You can have anything you want
But you better not take it from me"

Offline RK103

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Re: Broken piston jets
« Reply #8 on: Sunday, May 13, 2012. 08:41:16 AM. »
Whats the deck hight on the pistons? Its possible they were miss boxed and are stroker pistons wich would pull down farther (hit oilers)  and not make much compression (lack of power).

Offline MadMaxUK

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Re: Broken piston jets
« Reply #9 on: Sunday, May 13, 2012. 02:09:44 PM. »
Some good points here -
Rubicon you're right so that rules that one out.
Frank .. I've noted all your points & will go through them when I see the guy tomorrow. The cooling jets were both broken, pretty close to the mounting side & the flywheels were not replaced although they will be as there is some grinding evident when pivoting the rods.
Hawg - that sounds like a very likely scenario - I'll check tomorrow and get back ..
As always, great help here .. Thanks!

Offline TA63

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Re: Broken piston jets
« Reply #10 on: Sunday, May 13, 2012. 07:08:55 PM. »
Any way to reliably tell if an oiler is broken without taking the top end off?

Offline Clayster

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Re: Broken piston jets
« Reply #11 on: Sunday, May 13, 2012. 08:01:21 PM. »
Broken oilers = sumping = loss of power

Offline TA63

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Re: Broken piston jets
« Reply #12 on: Monday, May 14, 2012. 11:09:53 PM. »
Are these oilers really that prone to damage?  Can they be R&R'ed without taking the entire top end apart?

Online Max Headflow

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Re: Broken piston jets
« Reply #13 on: Tuesday, May 15, 2012. 06:09:34 AM. »
Are these oilers really that prone to damage?  Can they be R&R'ed without taking the entire top end apart?

Nope. Yep.

but if you find then damaged, it's lower end time.

Max
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