Picked up a 2003 Bigdog with a 107", 6,000 miles on it. Sent the heads to Larry that he got back to me a week or 2 ago.
Pulled the nose cone to ensure it had the S&S .600 cam. The breather gear was off a tooth, if I remember right it was advanced.
Was 2 months ago. Should of took a picture to remember.
Doubt the cover has ever been off.
I don't know if Bigdog was assembling these or S&S back then.
So I'm of the belief these cases and the gear itself have optimized windows for the "application" so to speak.
So anyone see any reason someone would of optimized even further the breather timing by advancing the gear or just a mistake by the assembler?
I wouldn't guess at it. The only way to know is use the Delkron Space N Time Tool or a degree wheel and know what the timing degree events you want to use are.
I can't say with any experience or authority, but sounds to me like......mistake! They put timing marks on those for a reason. I think.
-JW
Instead of relying on internet hearsay, have you considered simply asking S&S if they built the engine?
Time it to the marks on the cam, breather & crank. All done. The Big Dog motors aren't different. It's the Indian motors that would give you problems. When they started assembling the motors themselves a lot of them looked like they were assembled with whatever parts were laying on the bench at the time.
If it hasn't caused you problems before now leave it alone. It seems I've heard of big stroke motors liking early venting
When we were building strokers (1/2" and above) in the early 70's, one of the things we did was remove the screen and dremel the port timing in the breather longer. It opened up the timing cycle to compensate for the increased pressure pulse caused by the longer and faster stroke.
Its not uncommon to have to set the S&S breather gears of by one tooth when checking the breather timing. Just ask S&S.
Quote from: turboprop on June 18, 2020, 07:41:58 PM
Instead of relying on internet hearsay, have you considered simply asking S&S if they built the engine?
:up: I'm calling them today with the serial # and get their take. Was my plan all along.
I just wanted to throw it on here and sift through some hearsay. :SM:
When I put a 93" stroker in a '78 FXS, I bought 2 protractors and taped them to get 360 degrees.
I then verified the openning according to the SnS instructions. I was one tooth off from the specs sent in the assembu sheet.
I installed the breather one tooth off and did not have any issues with breathing.y
Well, was shipped unassembled to Bigdog in 2003.
Tech said the kit was shipped with the .520 emissions cam.
So lucked out with it having the .600 in it.
I know original owner, I'm the 2nd, doubtful he got into it.
So guess Bigdog was throwing whatever in them.
He instructed me to time it straight up with the marks.
They put timing marks on those for a reason. I think.
:hyst:
-JW
Quote from: kd on June 19, 2020, 05:10:49 AM
When we were building strokers (1/2" and above) in the early 70's, one of the things we did was remove the screen and dremel the port timing in the breather longer. It opened up the timing cycle to compensate for the increased pressure pulse caused by the longer and faster stroke.
KD hit the nail on the head. :up:
John
I would still check it with a degree wheel just to make sure. Like I said it wouldn't be the first that didn't line up marks or not.