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#81
Turning Wrenches / Re: Most used gear oil and 2st...
Last post by JKV45 - February 13, 2026, 04:09:12 PMQuote from: m in sc on February 13, 2026, 04:04:01 PMvery true.. but only really'flat tappet' cams issue mostly. really not a big issue on the Japanese stuff, tbh. at least ive never ever seen an issue on a dohc shim and bucket setup.ive seen a few v8 cams get wiped out tho.
As I understand it, you want the higher levels of ZDDP on any non-roller cam valvetrain.
#82
Turning Wrenches / Re: Most used gear oil and 2st...
Last post by m in sc - February 13, 2026, 04:04:01 PMvery true.. but only really'flat tappet' cams issue mostly. really not a big issue on the Japanese stuff, tbh. at least ive never ever seen an issue on a dohc shim and bucket setup.ive seen a few v8 cams get wiped out tho.
#83
Turning Wrenches / Re: Most used gear oil and 2st...
Last post by JKV45 - February 13, 2026, 03:04:52 PMOne change that has occurred to oil is the reduction of additives like ZDDP (Zinc and Phosphorus) that protect high pressure valvetrain parts like cams/lifters/rockers from damage in certain conditions.
Back in the day, regular auto oils were fine for cycle engines. Currently, regular auto oils are no longer safe. Diesel oils don't have the same restrictions, so they still have adequate levels of ZDDP.
That's why a lot of people run a diesel oil like Rotella.
Anything a conventional oil can do - a synthetic oil can do better. Synthetics flow better in cold weather and won't breakdown with extreme heat like conventional oils do. Their closed molecular structure makes them stronger and more resistant to oxidation.
EDIT: For 2-stroke trans oil, I don't believe ZDDP levels will matter, as it's mainly protection for high pressure contact surfaces found in the valvetrain. Friction Modifiers aren't an issue for the most part, as they are only used in oils under 40-grade,
Back in the day, regular auto oils were fine for cycle engines. Currently, regular auto oils are no longer safe. Diesel oils don't have the same restrictions, so they still have adequate levels of ZDDP.
That's why a lot of people run a diesel oil like Rotella.
Anything a conventional oil can do - a synthetic oil can do better. Synthetics flow better in cold weather and won't breakdown with extreme heat like conventional oils do. Their closed molecular structure makes them stronger and more resistant to oxidation.
EDIT: For 2-stroke trans oil, I don't believe ZDDP levels will matter, as it's mainly protection for high pressure contact surfaces found in the valvetrain. Friction Modifiers aren't an issue for the most part, as they are only used in oils under 40-grade,
#84
eBay/FB Marketplace/Craigslist watch / Re: RZ350 or a rusty 350
Last post by RDnuTZ - February 13, 2026, 03:01:12 PMlol
#85
eBay/FB Marketplace/Craigslist watch / Re: RZ350 or a rusty 350
Last post by m in sc - February 13, 2026, 01:30:06 PMthat bike partied a bit too hard. its the tawny kitaen of rzs. the 90s weren't kind to it. 
#86
Turning Wrenches / Re: Most used gear oil and 2st...
Last post by m in sc - February 13, 2026, 12:48:59 PMclutches are clutches (wet). no one's running full fiber discs these days, and the 4t motorcycle oil is made for wet clutches. so doesn't apply. maybe if you were running automotive mobile 1 or something w friction modifiers.. sure. but thats not the case
#87
Haus of Projects / Re: Yamaha Refurbishment Proje...
Last post by Rizingson - February 13, 2026, 12:12:32 PMTime for another update on the rare Yamaha 125 YAS1C Scrambler. Last update was full dismantling of the rear half of the bike. Assembly has now gotten underway, but many more small details to be worked on later.
Cleanup on frame has been completed here and the swing arm back in place
Rear fender installed after polish and inner side corrosion abatement.
Taillight assembly back together installed and wiring tested.
Rear shocks cleaned up and installed. Drive chain will be updated to a 428H from the standard 428 since clearance wasn't an issue with the wider heavy duty chain.
Attention to detail as every nut and bolt gets cleaned and/or polished.
Drive chain fitted and adjusted. Chain guard and foot pegs installed.
Now it was time to get the carburetors ready to clean. Carburetors were in pretty decent shape. Float valves were stuck and one idle jet plugged but overall they were easy to clean. Picture shows as they were opened.
Cleanup on frame has been completed here and the swing arm back in place
Rear fender installed after polish and inner side corrosion abatement.
Taillight assembly back together installed and wiring tested.
Rear shocks cleaned up and installed. Drive chain will be updated to a 428H from the standard 428 since clearance wasn't an issue with the wider heavy duty chain.
Attention to detail as every nut and bolt gets cleaned and/or polished.
Drive chain fitted and adjusted. Chain guard and foot pegs installed.
Now it was time to get the carburetors ready to clean. Carburetors were in pretty decent shape. Float valves were stuck and one idle jet plugged but overall they were easy to clean. Picture shows as they were opened.
#88
Turning Wrenches / Re: Most used gear oil and 2st...
Last post by RDnuTZ - February 13, 2026, 11:54:09 AMI've seen it claimed in more than 1 place that full synthetic is "too slippery" for our old clutches. Same used to be said for ATF which was really popular in dirt bikes back in the 1970s. Some oils specifically are recommended for "high mileage" engines. Ford has recommended semi synth for decades. Anybody have any test articles confirming a clear winner between old dinosaur oil vs newer tech synthetics?
#89
eBay/FB Marketplace/Craigslist watch / Re: RZ350 or a rusty 350
Last post by RDnuTZ - February 13, 2026, 11:45:08 AMyou gotta fight for your right to paaaarty!
#90