[Jack Straw]

As I was changing the fork oil yesterday I fondly recalled the days when, rather than remove wheel, fender, caliper, ABS doo-dads, maybe the headlight brackets, and Gawd knows what else to enable us to pour the fork oil out the top we merely removed a drain plug from each slider, grabbed the brake lever and pumped the stuff out the bottom.   

A fork oil swap used to be a 20 to 30 minute job if you were taking your time.

Is there some reason, other than saving 97 cents per bike that the plugs have gone away?   

I know from threads here that some use a siphon pump to pull out the old fluid but they seem to get scolded for such an infraction. 

How did I drain my forks?  I'm not telling.

[9fingers]

3 of my old Honda trails bikes have them, but they are 70s and 80s bikes. Maybe you took off your gas tank and turned your bike upside down over a drain pan...........would work!
9fingers

[wachuko]

I miss those too... very easy to replace the fluid.

[ceekay]

I recall those, kickstarts too.

[Jack Straw]

9fingers suggestion to turn the scooter upside down is good but that's why I have  sky hook.

[NVDucati]

seem to get scolded [/b]for such an infraction. 

Chances are that those doing the scolding don't change their fork oil as often as people who use suction. They claim one can't get all the old oil out, which is true.
But if after you get as much as possible out ... add some fresh oil to the residue and suck again.
If an internet scolding hurts ... Just don't tell anyone how you do it

[RalphG]

Yes, I certainly remember fork drain plugs, with only fond memories.  Bikes from the 50s and 60s frequently had them, although my 1948 Velocette 350 had girder forks and used no oil at all!  It has an exposed spring and friction washers to afford damping.  The rider actually could reach down and forward to adjust them on the fly. 

At least fork oil does not need to be changed no more more than about once a year. 

Ralph

[zimmemr]

When I was still working in the MC industry, I was seated with several Yamaha engineers at dinner when this very topic came up. Their reply was that rather than simply drain and replace the fork oil, which essentially left 90% of the dirt and grit in the fork tube to be re-distributed by the fresh oil, leaving the drain bolt out forced the mechanic to strip the fork, clean and inspect everything and then refill it. It's sound reasoning, but presumes that the majority of owners would have the job done properly by a qualified dealership. Emphasis on qualified.

 They also had the attitude that as delivered the fork oil  level and viscosity was perfect, and that the average owner wasn't qualified to make any changes. Anyone that's followed GP racing know how intractable some of those guys could be. Even Kenny Roberts had to fight with them to make suspension changes. 

Once the big four got away with it, I think other manufactures adopted the practice because it probably saves two or three bucks a bike, which multiplied over a thousands of bikes production run saves real money.

As a side comment I have a shop owner friend that served a formal 4 year apprenticeship in Germany to become a licensed motorcycle mechanic. Over there when they changed the fork oil they inspected and cleaned everything the way the Yamaha engineers had envisioned. When he came to the US he was appalled at how lax the standards were in most dealerships, and at how many corners were cut by owners and mechanics alike.

[Jack Straw]

Ah, engineers, ya gotta love 'em.

In the early seventies when BMW automobiles were getting a solid foothold in the US a German engineer was asked why they didn't install oil pressure gauges in their cars.  His reply was "a properly maintained engine will never lose oil pressure under any circumstances." 

At the time I was driving a BMW 2002 sedan.   On my way home from Hollywood Honda one afternoon I heard a loud pop and a fizzing sound, pulled over, had a look.  The oil filter had blown off the side of the motor.  A visit to the BMW dealer revealed a service bulletin about oil pressure relief valve failures leading to sudden loss of oil pressure.  It wasn't all bad as my car expired within a few yards of Barneys' Beanery, the chili Mecca of West Hollywood.

I really admire engineers but I've known more than a few who had totally rigid, fossilized thought processes.
Following the logic of those Yamaha engineers makes me wonder if they would advocate a full engine teardown rather than a simple oil and filter change.

[dcolak]

As I was changing the fork oil yesterday I fondly recalled the days when, rather than remove wheel, fender, caliper, ABS doo-dads, maybe the headlight brackets, and Gawd knows what else to enable us to pour the fork oil out the top we merely removed a drain plug from each slider, grabbed the brake lever and pumped the stuff out the bottom.   

A fork oil swap used to be a 20 to 30 minute job if you were taking your time.

Is there some reason, other than saving 97 cents per bike that the plugs have gone away?   

I know from threads here that some use a siphon pump to pull out the old fluid but they seem to get scolded for such an infraction. 

How did I drain my forks?  I'm not telling.

I use vacuum pump to drain my forks, without having to do anything more than just unscrewing the caps on top.

Like many others here, I notced I had 310ml in each fork, from factory.

[zimmemr]

Ah, engineers, ya gotta love 'em.

In the early seventies when BMW automobiles were getting a solid foothold in the US a German engineer was asked why they didn't install oil pressure gauges in their cars.  His reply was "a properly maintained engine will never lose oil pressure under any circumstances." 

At the time I was driving a BMW 2002 sedan.   On my way home from Hollywood Honda one afternoon I heard a loud pop and a fizzing sound, pulled over, had a look.  The oil filter had blown off the side of the motor.  A visit to the BMW dealer revealed a service bulletin about oil pressure relief valve failures leading to sudden loss of oil pressure.  It wasn't all bad as my car expired within a few yards of Barneys' Beanery, the chili Mecca of West Hollywood.

I really admire engineers but I've known more than a few who had totally rigid, fossilized thought processes.
Following the logic of those Yamaha engineers makes me wonder if they would advocate a full engine teardown rather than a simple oil and filter change.

Totally agree here. Some of the ones I've worked with had brains like steel traps: Nothing got out. I've had many "discussions" with guys that went to all the right schools and could give you a hell of a technical discussion, but didn't know shit in a practical sense. Half of them couldn't fix a sandwich, let alone a piece of machinery. Good ones are a pleasure to work with, but they're few and far between. Many of them can't even explain a simple concept without resorting to complex, technical and confusing jargon.

[Adrian II]

I don't know if the internal construction of the new RE twin forks will even permit the following, or if anyone would dare try this out, but the B5 and C5 forks on the UCE/EFI singles brought this madness to the export market after it appeared on later home market 350 AVL Thunderbirds.

On my pre-ABS C5 and B5 forks bought for some very non-EFI REs, I drilled, tapped and plugged the fork top plugs to allow filling and also drilled and tapped the bottoms of the fork sliders for a 2BA drain screw on each side, M5 would do. File a flat for a washer to sit over the top of the threaded hole, a good smear of sealant on the screw threads and boom, job done. Any use for you guys,at all? It would be worth investigating casting thickness and the cost of replacement fork parts if you get it wrong! All modifications are entirely at your own risk.

A.

[Keef Sparrow]

His reply was "a properly maintained engine will never lose oil pressure under any circumstances."

He's obviously never owned a Jaguar with the XK 6 cylinder or the V12 engine!

[Starpeve]

He's obviously never owned a Jaguar with the XK 6 cylinder or the V12 engine!

Indeed a very stupid statement, eh? So many ways an engine can lose oil.
For the better part, I find it amazing that any engine can keep it all in!

[gizzo]

For the better part, I find it amazing that any engine can keep it all in!

Plus 1 😅. Especially having grown up with air cooled vw, Holden 6 and Detroit diesel. Oil leaks for days...