Learn from my pain, you never want to over-tighten your motorcycle’s oil drain plug.
What started as a routine oil change on my CRF250L Rally soon turned into a potentially incredibly expensive repair caused by a moment’s inattention. But before we get into what happened let’s rewind a bit.
With the shocker of a year 2020 has been, the CRF-Rally has spent much of the year in storage unused.
Without being able to perform an oil change before the bike sat idle for 6 months, performing an oil change and some basic maintenance was high on the priority list once it was back in the garage.
Having purchased all the necessary parts through local Honda Motorcycles distributor Blue Wing Honda, I was thoroughly looking forward to getting my hands dirty and even purchased a new 1/4 inch torque wrench to ensure everything was tightened up to the spec dictated by the owners manual.
Sadly that is where it all went pear shaped...
After draining the filthy oil I then proceeded to do up the drain bolt to the specified 24nm - which interestingly is 8nm tighter than the CBR250 manual states for the same engine.
Whether through distraction, inattention or simple unfamiliarity with the new torque wrench, I went well past the specified torque and stripped the thread. The result was the drain bolt wouldn’t fully seal or tighten beyond a certain point, with oil slowly seeping from the drain hole.
This is where things got tricky. The local Honda dealer technicians weren’t prepared to work on the bike to remedy my blunder, as re-tapping the drain hole and fitting a Heli-Coil style fix has its potential problems and they, quite understandably, didn’t want to be liable if the repair failed. After sending the bike into the city for another dealership to look at, the verdict came through that they were also not willing to perform a repair and instead favoured replacing the damaged engine case. The cost was estimated at $2400 while due to COVID-19, getting the parts in from Thailand could be some time.
Having neither the time or that sort of money lying around I needed another option, which thankfully was arranged by the publisher of Kiwi Rider Magazine - who we work closely with to produce the kind of content Kiwi Motorcyclists need at their fingertips. With over 30 years in the industry, if someone knew somebody who could help me, it was Mr McPhee.
Within a week he had collected the CRF-Rally from the dealer and transported it up to Auckland to Bruin Engineering, a firm run by a former MXGP and MotoGP engineer Tjebbe Bruin.
Renowned as one of the cleverest guys to ever spin a spanner on a motorcycle, if anyone could fix the Rally, it was Mr Bruin.
At this point in the tale three weeks of back and forth conversations with dealers and insurance company personnel have passed since the original act of stupidity, and to my amazement, within FOUR HOURS of being in the hands of Bruin Engineering the Rally was fixed and holding oil like a champion.
From what I can tell, the stripped thread was drilled out and a new bolt inserted into the case to act as a new fitting. This was then drilled and tapped for another, smaller bolt, to be screwed in to to act as the new oil drain. Ensuring the new bolt wont go anywhere is taken care of by lock wire which threads through the head of the new drain bolt and is secured into the engine case.
While I won’t go into how much the cost was as it was a bit of a “mates rates” deal to my understanding, it was significantly cheaper than replacing the engine case.
Sure, the resale value of the bike will be impacted (not that I plan to sell this bike) but the only potential real-world issue is that the new drain fitting now sits lower than factory. If I succeed in the long term plan of setting up the CRF250L Rally for serious adventure riding I’ll have to ensure I fit a sturdy bash plate to prevent it getting hung up on anything.
After a test ride along the Kawhia-Raglan coastline, the fix is holding well with no signs it won’t hold on for a long time yet.
Other than that, it has been one hell of a learning experience. Sure, you can follow the rule book but it might not always pay off.
Perhaps the biggest takeaway is this: Never torque your oil drain plug. A simple hand tightening and quick nip with a wrench will suffice for any engine.