Piston problems

tile · Sep 16, 2004

2002 FE501E Upon inspection at teardown, appears piston is contacting driving shaft counter balancer gear.
New piston installed and have contact at same place between piston and gear on end of shaft. All bearings checked for play and appear in good order. Anyone have any experience with this problem? Do not want to assemble engine without solving problem.

LINEAWEAVER · Sep 16, 2004

Hi Tile,
If contact is between the piston wrist pin boss and auxiliary drive gear your trouble is most likely the result of an auxiliary drive with excessive axial float. Insure that the retaining ring is in place and that the drive nut is properly torqued. Often on early models shims must be placed between the drive nut and the shaft shoulder.

Hope this helps.
Kind Regards,
Dale

Taffy · Sep 17, 2004

Dale

have you ever thought of doing a haynes or clymes workshop manual?

Taffy

tile · Sep 17, 2004

Contact is at bottom of piston under oil ring. The driving shaft counter balance is cutting a slot in the shape of a woodruff key in the piston skirt. It appears the piston is coming down far enough for the gear on the shaft to mill out a groove. My parts book lists two shafts and I was wondering if there was a difference in the diameter of the gear from one to the other. I cannot find any slack in the shaft side to side or up and down, new bearing on shaft.
Thanks,
Tile

LINEAWEAVER · Sep 17, 2004

Hi Tile,
If possible please send a digital photo of the following scenario and I shall see what I can do to assist.

Install the crankshaft / piston assembly minus the liner into the left case. Rotate crankshaft until contact is once again made.

The piston should be of slipper design with no skirt on the pin axis. Is it by chance a full skirt piston?

Regards,
Dale
[email protected]
www.D-Lineaweaver.com

Ps
Please send a photo of the piston damage as well.

mkall32 · Sep 17, 2004

Piston problem

Tile/Dale,

I found the same problem when I rebuilt my 2001 501. When the piston was at the bottom of it's stroke it would hit the counter balancer drive gear and looked just like a woodruff key or slot. I couldn't find what was causing the problem, so I took a dremel tool and made the groove larger so it would clear the counter balance gear. It was amazing! no more ticking sounds and no more tiny aluminum flakes in the oil??
I wish I took a photo but it sounds just the same problem.
Maybe a replacement/aftermarket piston??
mkall32
2001 FE 501E
Mesa, Az

LINEAWEAVER · Sep 17, 2004

Hi Mkall32,
Thank you for that as I have yet to assemble a post 2000 501 lower end. The 501 / 550 are near identical with exception of the bore size. Perhaps an engineering oversight has allowed a slightly different 501 piston configuration to come in contact with the balance gear. What is the post 2000 501 pistons dimensions taken from pin bore center?

Dan / MotoXotica do you have an OEM you would be willing to snap a photo of and / or measure?

Anyone else with a post 2000 501 had a similar experience?

Best Regards,
Dale

tile · Sep 17, 2004

Dale,
I have emailed a message to you with the photos and explanation.
Any help or advice you can offer will be appreciated.
Thanks,
tile

LINEAWEAVER · Sep 18, 2004

Hi Tile,

Damage is indeed the result of a production oversight.

Two connecting rod lengths are available (123mm and 124mm) depending upon year. In addition and regarding the 95mm bore of the 501, several piston manufacturers have been used. The pictured Piston (believed to be a Wossner) has a thicker lower ring land than say an Omega.

Improper matching of various OEM components is the root of your trouble. Please do not fret as such is not uncommon regarding OEM Husaberg.

Note:
In Later models even block height was altered.

Rotate the piston to TDC and record the deck height.
Measure the total ring belt (land) thickness.
Measure the center to center rod length.
Measure from the top of the pin bore to the top of the piston.

From said measurements I can identify your hardware and supply you with more suitable options.

Kind Regards,
Dale

Ps
For those of you owning a 501 this may account for the mysterious Aluminum flakes.

tile · Oct 14, 2004

Sorry for delay in answering, other things to take care of first. Back to piston problem; assembled engine and ran a total of 18 minutes when much smoke out tailpipe. Disassembled engine and found wrist pin had come out of piston to gouge cylinder wall. Upon closer inspection found wrist pin to be too long, causing wrist pin retainer to jump out of groove, thus allowing wrist pin to slide over to cylinder wall. This is OEM piston from Motoxotica with correct part number. I have ordered and received another piston and cylinder from Motoxotica and it has the same problem of too long wrist pin. I called Motoxtica and talked to Dan who refered me to Bill Slipp at BMG. Both have promised to get back to me after they have investgated problem. So far I have a ruined piston, cylinder, wrist pin bushing, and head gasket. I strongly suggest anyone replacing parts in thier engine check all replacement parts very close. All parts I have are OEM and in correct packaging. Orginal and both replacement pistons are Wossner . tile

LINEAWEAVER · Oct 15, 2004

Hi Tile,
With all due respect was it not evident that the retaining clip had failed to seat as a result of the incorrect wrist pin?

Sincerely,
Dale

tile · Oct 15, 2004

Retaining clip appears to be seated to the bare eye, but with magnifing glass can see that it is not quite fully seated in groove. When both clips and pin installed can bump pin gently with tool and second clip jumps out. tile

LINEAWEAVER · Oct 15, 2004

tile said:
Retaining clip appears to be seated to the bare eye, but with magnifing glass can see that it is not quite fully seated in groove. When both clips and pin installed can bump pin gently with tool and second clip jumps out. tile

Hi Tile,
Thank you for clearing that up.
Dale

Grok · Oct 16, 2004

Scary stuff tile!

Anyway, it sounds like the chamfer on the wrist pin could be a touch bigger. Or perhaps they forgot it altogether?

I used to make Teflon buttons for my bikes and binned the clips altogether.

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