Dreaming up Ideas

[Coyote]

I had an idea and was wondering if anyone else might find it a good idea.
Lots of these old forks use a rubber cap. Under that cap is a snap ring and a plug to retain the spring. Works well and has for a long time. These forks however have one major drawback. If you want to change the fork oil, you have to disassemble them to get new oil in. So here's my idea.
Next time you have the forks apart, drill and tap the retention plugs for like a 1/4" pipe plpe plug. Get the type of pipe plug that uses an allen wrench so it sits in kind of flush. Now to add oil is no big deal. Just pump the old oil out through the drains, remove the rubber cap and the pipe plug and dump the new stuff in. No removing the snap ring and the sometimes hard to get back in spring plug! You like?

[tz375]

I like.

It's way easier than swapping out fork legs for early ones with screw in caps.......

[pearljam724]

I think it's a fantastic idea. Or, how about this. Comparable to other models that use air filled shocks / forks. GS models, Yamaha RZ, etc. Have a grease fitting drilled and tapped into the top. Pump fork oil into the forks once it's drained. I don't think a grease gun will pump motor oil, ATF fluid or fork oil effectively though. But, I'm sure something out there does. Just not sure what. The big issue with either idea would be verifying exactly how much oil you have inserted. But, shouldn't be that complicated as long as an oil doesn't seep past the tool you would use to fill it. You could fill a tool with measurements from a cooking measuring bowl, cup, etc.

[Coyote]

Don't think 1.4 inch when speaking in pipe threads. The hole size for 1/4 pipe is 7/16 before tapping. That's way big enough to just pour the pre measured oil in. No special tools needed.

[pearljam724]

Don't think 1.4 inch when speaking in pipe threads. The hole size for 1/4 pipe is 7/16 before tapping. That's way big enough to just pour the pre measured oil in. No special tools needed.

I see what you're saying and agree. Not sure if an ordinary grease fitting will not allow compression of oil to be pushed back out the hole. But a speed bleeder would definitely work. That's exactly what they are designed to prevent. Being you are at the point of currently messing with your forks. I personally, would like to see you come up with something along these lines that maybe we can all follow if it works out for you.

[tz375]

And for an interesting twist, I stripped a pair of late model forks recently and the top caps refused to out past burrs around the circlip slot.

I tried all the usual trick and ended up drilling and tapping a thread in the top to pull them out. Take that one step further with your filler plug idea and that thread is also available to insert a longer bolt to help remove the top cap.

It gets better by the minute

[Coyote]

Nifty idea to remove the spring plug. What needs to be invented is an easy way to put them back in. Generally I don't have much trouble getting the plugs out Putting the back is another story. Seems like no matter what, I'm in my own way. Using a socket extension I just have to keep pushing the plug in over and over. At some point the plug will cock slightly and bind. When that happens I work the snap ring in the hole, then using a large socket, push both pieces together till the snap ring snaps in to it's groove. Seems like there ought to be a easier way, but I haven't found it. And those few moments between where the plug binds and you are fiddling with the snap ring, I can't help but worry that the plug may fly out and rearrange my nose.
If you want to install plugs to pre-load the springs, then the job gets tougher exponentially.

[yeadon_m]

I'm in the drill / tap / bolt in the thread to make it easy to extract school. Got fed up with hassle getting them out so all 3 GTs have drilled / tapped threads, with an allen bolt that screws down flush enough to put the cap on, but out far enough to grip as needed.

Getting them in, not so hard for me anyway (so far). Push it in, then below the circlip groove with a big screwdriver, then use circlip pliers and a small 'driver to positively see / hear it click into the groove.

In both cases, please people, front wheel off the ground. I nearly rearranged my face the first time I ever got these out and, once the circlip is out, they can fly out rather well with weight on 'em!

Regarding playing with oil grade / volume, if I don't know what works (if I've not set that bike up for me before) I deliberately start on the low viscosity end (I'm reasonably light) and, if I need to, let out a metered quantify and add that volume back with much higher viscosity. I pulled a mixing chart off the web somewhere a while back. Then write down what I've presumably made as target viscosity and buy that for the future. I'm on 10W for the GT750, 7.5W for the 550 and 5W for the 380. Stock volumes.

Cheers,
Mike

[Suzukidave]

On one of the list posts i saw a cleaver idea he came up with , i piece of steel plate bolted to the handle bar clamp . Then he threaded a hole on the end just above the fork tube and ran a bolt down to hold the cap in place while he put in the clip .. simple to make and easy to use