Ultima Engine Bummer
Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
Likes: 419
From: Vermont
Pistons are .020 but stock compression out of the box, calculator put it at 130" with the overbore. Sachs took some off the first set of heads when he ported them, like a said, like the way it starts now.
Had to drill 2 holes down thru the boxed section of frame to take the rocker bolts out, altered 2 allen wrenches to get the 4 lower rocker cover box bolts out. Had to bend a extension magnet in a 90 degrees to put the lower rocker cover bolts back in and one little turn at a time 4 bolts
If this engine lets go it will go for 32 cents a pound and the baby Briggs 89" comes off the shelf.
Had to drill 2 holes down thru the boxed section of frame to take the rocker bolts out, altered 2 allen wrenches to get the 4 lower rocker cover box bolts out. Had to bend a extension magnet in a 90 degrees to put the lower rocker cover bolts back in and one little turn at a time 4 bolts
If this engine lets go it will go for 32 cents a pound and the baby Briggs 89" comes off the shelf.
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Joined: Nov 2006
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From: la la land jerzey
a motor that big we would set it a at least .0035 and would not be surprised to see .005 become the number - my super gas cars engine lasted the longest at .0075 but its a small BBC at 468
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Seasoned HDF Member
Joined: Aug 2008
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From: Ohio
Pistons are at .003 clearance by a local boring shop, Sachs has ran them at .001 in some of his posts on other sites.
If you want to pioneer, Tman Performance sells pistons for TC's that are 4 1/2 stroke with a larger than 127' bore for a 131", Tman says they won't work but I can get you in contact with someone that currently runs that piston in the 127" The pistons are around $400 tho, that is why I have the $175 Ultima Pistons.
Same guy also squeezed a 4 5/8 S&S flywheel in a Ultima case with the Tman pistons for a 135" he told me the jugs will be bored to the same thickness as a 88" TC to a 95" liner in a TC big bore kit
Ran the 127" today and noticed the power moved up in the RPM's about 500 rpm's with the slight compression loss but still impressive. Installed a 640 S&S cam with the higher ratio Ultima rockers over last winter and the compression really played well into that cam, starting to advance the timing some because it was pulled back before, may get some of the earlier power back but not going to push the timing to the edge of detonation
If you want to pioneer, Tman Performance sells pistons for TC's that are 4 1/2 stroke with a larger than 127' bore for a 131", Tman says they won't work but I can get you in contact with someone that currently runs that piston in the 127" The pistons are around $400 tho, that is why I have the $175 Ultima Pistons.
Same guy also squeezed a 4 5/8 S&S flywheel in a Ultima case with the Tman pistons for a 135" he told me the jugs will be bored to the same thickness as a 88" TC to a 95" liner in a TC big bore kit
Ran the 127" today and noticed the power moved up in the RPM's about 500 rpm's with the slight compression loss but still impressive. Installed a 640 S&S cam with the higher ratio Ultima rockers over last winter and the compression really played well into that cam, starting to advance the timing some because it was pulled back before, may get some of the earlier power back but not going to push the timing to the edge of detonation
Last edited by 1997bagger; Aug 20, 2015 at 08:39 PM.
Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
Likes: 419
From: Vermont
Pistons are at .003 clearance by a local boring shop, Sachs has ran them at .001 in some of his posts on other sites.
If you want to pioneer, Tman Performance sells pistons for TC's that are 4 1/2 stroke with a larger than 127' bore for a 131", Tman says they won't work but I can get you in contact with someone that currently runs that piston in the 127" The pistons are around $400 tho, that is why I have the $175 Ultima Pistons.
Same guy also squeezed a 4 5/8 S&S flywheel in a Ultima case with the Tman pistons for a 135" he told me the jugs will be bored to the same thickness as a 88" TC to a 95" liner in a TC big bore kit
Ran the 127" today and noticed the power moved up in the RPM's about 500 rpm's with the slight compression loss but still impressive. Installed a 640 S&S cam with the higher ratio Ultima rockers over last winter and the compression really played well into that cam, starting to advance the timing some because it was pulled back before, may get some of the earlier power back but not going to push the timing to the edge of detonation
If you want to pioneer, Tman Performance sells pistons for TC's that are 4 1/2 stroke with a larger than 127' bore for a 131", Tman says they won't work but I can get you in contact with someone that currently runs that piston in the 127" The pistons are around $400 tho, that is why I have the $175 Ultima Pistons.
Same guy also squeezed a 4 5/8 S&S flywheel in a Ultima case with the Tman pistons for a 135" he told me the jugs will be bored to the same thickness as a 88" TC to a 95" liner in a TC big bore kit
Ran the 127" today and noticed the power moved up in the RPM's about 500 rpm's with the slight compression loss but still impressive. Installed a 640 S&S cam with the higher ratio Ultima rockers over last winter and the compression really played well into that cam, starting to advance the timing some because it was pulled back before, may get some of the earlier power back but not going to push the timing to the edge of detonation
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Seasoned HDF Member
Joined: Aug 2008
Posts: 5,081
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From: Ohio
like u this bike will get ridden pretty much all the time other than big trips..001 might be a bit tighter than I am comfortable with air cooled. The piston price doesn't scare me. Anything u would do better on the ultima piston? I still have ultima rockers. Getting ready to jump on TC and head out to Nova Scotia. If it's ok like to pick your brain When I get back Going to start getting stuff ordered sept 1 or so. Crank think I will keep fir now. Thanks a bunch for your knowledge and testing. Lol
Ultima camshaft works good that specs 640 with the Ultima rockers, the S&S specs 640 with stock rockers so some more lift with the Ultima's. Believe it or not the S&S cam idles kinda smooth and a sleeper but pulls real hard when in giddy up, The Ultima cam has some lope at idle and serious lope at 1100-1400 rpms but the power seems kinda peeky depending on rpm range, the S&S doesn't care where it is.
Check that #1 rod lateral movement when it is at top dead center, it has a tendecy to wear and gain clearance.
Have fun on the ride, pull a plug wire on the TC if you miss the vibrations
Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
Likes: 419
From: Vermont
The Ultima pistons are now made by Mahle, coated and good looking pistons, just bore and install, put the rod clearance cutouts the right direction. If you want more compression you will need to mill the heads but a good starter, battery and cables are a must, it will still kick back at times. That is why I'm liking the stock compression right now, very rarely will it kick back.
Ultima camshaft works good that specs 640 with the Ultima rockers, the S&S specs 640 with stock rockers so some more lift with the Ultima's. Believe it or not the S&S cam idles kinda smooth and a sleeper but pulls real hard when in giddy up, The Ultima cam has some lope at idle and serious lope at 1100-1400 rpms but the power seems kinda peeky depending on rpm range, the S&S doesn't care where it is.
Check that #1 rod lateral movement when it is at top dead center, it has a tendecy to wear and gain clearance.
Have fun on the ride, pull a plug wire on the TC if you miss the vibrations
Ultima camshaft works good that specs 640 with the Ultima rockers, the S&S specs 640 with stock rockers so some more lift with the Ultima's. Believe it or not the S&S cam idles kinda smooth and a sleeper but pulls real hard when in giddy up, The Ultima cam has some lope at idle and serious lope at 1100-1400 rpms but the power seems kinda peeky depending on rpm range, the S&S doesn't care where it is.
Check that #1 rod lateral movement when it is at top dead center, it has a tendecy to wear and gain clearance.
Have fun on the ride, pull a plug wire on the TC if you miss the vibrations
Thanks a bunch
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Seasoned HDF Member
Joined: Aug 2008
Posts: 5,081
Likes: 2,159
From: Ohio
Thanks for all the info. Mahle pistons I trust. Have used them in our 355 flat top 2 ring motors . Think I will learn from you. Going to keep compression down. Maybe just a cut to clean heads up. Maybe run the ultima cam for now as this motor never did see 2000 miles . Checked the rod and crank pin. No slop. Built a starter already for the ole EVO and made all new heavy cables. Changed ground around and got it off starter. Moved bike hot wire direct to batt from circuit breaker so it's away from hot starter. If u have a phone number to order Pistons let me know. Gaskets came in while I was in trip. Nice 2000 mile ride on the twink. Did u run a comp or a direct sprocket? Thinking Barnett clutches?
Thanks a bunch
Thanks a bunch
Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
Likes: 419
From: Vermont
Thank for your help
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Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
Likes: 419
From: Vermont
Thanks in advance
