Unpopular used foreign BMW! A little touring trip to the beach! Vol.18

A fellow motorcyclist invited me to go out to eat new buckwheat noodles! I nodded my head and went out for a short trip of about 140 km round trip. I have been tinkering and maintaining my big bike for the past few years, and it has been many years since I have been touring. With the exterior parts disassembled and all painted, there are various parts that need to be checked for running. After all, there are some things you can't understand unless you ride it.

Oil leak from the right side front fork

I just replaced the left and right front fork seals, but for some reason they have started leaking oil. The cause was found to be on the seal holder side of the outer tube (bottom case)!

I have practiced a little test drive of about 20 km around my home neighborhood many times. A few days after returning from the test drive, there is a leak under the right front fork.

While the left side is perfectly fine, the right side front fork leaks more oil than expected from the seal area. I just replaced the oil seal, so why is it leaking ......!

Failure during oil seal replacement is the cause of the oil leak?

The dust boot that was not delivered in time for the previous oil seal replacement (I diverted the one for the K100 series), so I inspected the oil seal again at the same time I replaced the boot.

It turned out that the oil leak was caused by a part of the oil seal holder on the bottom case that was "pushed from the outside and deformed". The fork was knocked over and traumatized during assembly!

Forced pressure compresses the front forks.

The end face of the holder into which the oil seal is hammered was slightly deformed, so it was pushed back in and visually checked to make it a perfect circle before restoring it. The front forks are being forcefully pushed in to check for oil leaks.

Both the BMW and the trampo (Subaru Sambar) are known for their sturdy engine design, so the Beemer's fellow bikers say that the mileage is still at the level of a completed narration. It will blow white smoke right after starting....

New buckwheat noodles are delicious! A little touring with two very rare bikes

My motorcycle friend's CB750K0 is a rare early production bike with a sand crankcase and a frame and engine number in the 1000s. I think my 3-engine BMW is also rare in a way.

We drove from Yorii via Kumagaya to Kodama -> Nagatoro via R254 and had tenzaru soba at a soba restaurant in front of Kami-Nagatoro Station. It has been a while since I had a little tour, but it was a lot of fun! When the weather gets warmer, I'll make my high-speed debut!

No oil leak to worry about, but the feeling is ......

After returning to the garage, no oil leaks from the front forks. However, the front area seemed strangely springy. I checked the tire air pressure and was surprised! It was unadjusted.

One day, after completing the approximate setup and repeating a little test driving, we received an invitation from a fellow motorcyclist to go touring to eat new buckwheat noodles. I would have said, "Great! In the past, I would have said, "Great! Let's go! I would have said yes with a simple "Yes, let's go! I am not in good physical condition yet, and I am too scared to go out on a solo touring trip. I promised to take it easy and go with him, and we set off on our little tour.

There was a reason why I wanted to ride a longer distance than the usual test run. It was to "check the oil leak" of the front fork. The bottom case was painted and the inside of the front fork was completely cleaned. All parts such as oil seals and O-rings were also completely replaced. However, after repeated test runs, there was an oil collar on the oil seal of the right fork. Eventually, oil leakage became noticeable, so a paper rag cut into thin strips was wrapped around the seal lip and secured with paper tape. When I returned from the test run in this state, the paper rag, which should have been white, was stained the color of fork oil. ...... It was a repetition.

At first, we thought it was an "assembly error" that had scratched the oil seal lip. So I disassembled the front fork again and replaced it with a new oil seal. However, during the test run after assembly, oil leakage occurred again. Moreover, the oil leak was coming from the same place ....... I thought there might be something wrong, so I took it apart again and visually inspected the area around the oil seal. At that time, I noticed that a part of the outer circumference of the seal holder part (the upper end of the bottom case), where the oil seal is set, was deformed. It is possible that the oil seal holder part may have been bumped with a knob while disassembling the bottom case and practicing painting. Or, I knocked over the front fork during assembly? I don't remember now, but I think I made a slight dent on the top edge of the bottom case.

In any case, it was an assembly error not to notice the dent. To repair it, we wrapped a hose band around the outer circumference of the seal holder with the oil seal still installed, and while curing it so as not to push it back too far, we lightly tapped the affected part of the oil seal holder from the inside to the outside with a knack, knack, knack to restore its shape. After correcting the concave portion in such a manner, I reassembled it and there was no oil leakage at the level where I went out for a test run. I wanted to check such a situation, so I went out for "Sinsoba Choo-Too".

During the touring, I was concerned about the kickback, or springiness, from the front forks. In fact, the problem seemed to be in the "tire air pressure adjustment" that we thought we had done before we left. The rear tires were adjusted to the specified values, but the front tires seemed to be caused by only injecting air and forgetting to adjust them. During the touring, the front tires had a whopping 3 kilos of air pressure, which seemed to be the honey of the problem. After that, I tried adjusting it from 2.0 kilos to 1.9 kilos, and now it is settled at 1.9 kilos. Still, the nose dive of the front forks feels hard, so now I am contemplating lowering the fork oil level.