Getting prepared to rebuild my forks.
Any hints or tips? The Clymer manual says to use 10W30. Still a good thing to do 46 years later?
What size is the hex bolt at the bottom of the forks?
Thanks guys
John
You might be happier with 15 weight.
Canuck,
IIRC, the bolt is a fine pitch M10, possibly M12. In any case, I am 99% sure the required allen socket is 8 mm. A 5/16" can be used in a bind, but is about 0.06 mm undersize, so a sloppy fit.
ok thanks again... Ive order an extra long hex socket set and a Universal Socket in case I need it.
Quote from: 85RZwade on February 22, 2020, 09:07:44 PM
You might be happier with 15 weight.
I think ill start with that... although they are prolly stock springs (as the rest of the bike seems to be stock) and im 245lbs naked.
If I am bottoming too easily I'll just drain the forks and go to 10W30. Thankfully its easy to do so on these forks.
At 245 lbs, stock fork springs are way too soft. They may even be too soft for someone weighing 145 lbs....
According to Racetech, stock springs are 5 N/mm, while their recommendation for a rider of 245 lbs is 8 N/mm
Play with the numbers yourself here: https://racetech.com/ProductSearch/12/Yamaha/RD400/1976-78
I am around 220 lbs myself, and have 7 N/ mm springs in my significantly lighter than stock RD350.
(Super B 2600 battery, minimal battery box, no air filter box, LSL rearsets, alloy handlebar, bar end mirror, expansion chambers, no centre stand, Powerdynamo CDI, repop R5 seat from Yambits, fiberglass front fender, Brembo 13 mm MC, single brake line, H4 headlight with plastic lens. So at least 10 to 15 kg lighter than stock regarding sprung weight)
Thanks for the link!
Quote from: rd400canuck on February 24, 2020, 02:25:29 PM
Quote from: 85RZwade on February 22, 2020, 09:07:44 PM
You might be happier with 15 weight.
I think ill start with that... although they are prolly stock springs (as the rest of the bike seems to be stock) and im 245lbs naked.
If I am bottoming too easily I'll just drain the forks and go to 10W30. Thankfully its easy to do so on these forks.
I use .90kg's from Sonic Springs for your weight bracket, Set the sag no more than an inch.
15W or 20W fork oil.
I set the fork oil height at 6" inches from the top of the fork tube with no spring and fork collapsed all the way up.
Chuck
http://sonicsprings.com/catalog/index.php?cPath=27_179&osCsid=6eb8121eb3e091149e22ded3f5222a8a
And remember that a 10W30 is a 10 weight oil at what I'l Call room temperature. You're probably going to want to go thicker, like Chuck suggested.