Bill Hoddinott - VA
Post Posted: Sun Aug 05, 2007 8:07 pm
 Subject: 118,172 Miles on '88 250 Ninja - Maintenance Time

Most readers are aware of my 100K mile road test report that is on the Wall of Shame in this forum. Some may recall my experiment with the replacement '01 engine to use 5w-30 non-synthetic car oil and run it until mis-firing or other symptoms of distress appeared. The '01 engine had 1700 miles when I bought it, and I checked the tappets at that time. It was installed in the bike March 25, 2004 with fresh oil and filter, and the oil has been changed twice a year since then, as has been my practice. Most use is highway riding, 65-75 mph which gives 70+ mpg on 87 gas.

A few days ago at 118, 172 miles, after several miles in traffic flowing at 75, I pulled up to a gas station to fill up. On re-starting, aha, it didn't want to fire up immediately as it always has, hot or cold. When it did fire, it mis-fired a little under load. That was all the clue I needed to know it was maintenance time. I believe what causes this symptom is that the spark plug gaps gradually increase, until they reach a critical dimension. The bike may run fine at 75 mph, with the system voltage around 14 giving a good spark that can jump the widened gap. BUT, when you crank the engine on the starter, the system voltage drops right down to 10 volts or so from the heavy load of the starter, AND, the sparks may not be hot enough to jump the wide gap.

Okay, now the engine has 32,902 miles since new and the plugs have never been touched. No reason to.

Back home, next day put the bike up on the (invaluable) air lift in the shop. Took off fairings, seat and tank and put in a safe place, tank propped up securely so it couldn't flop over and slop gas out. It is better and easier to take the tank off with minimum gas in it, but this time it was full.

Drain coolant, catching it carefully because it 'pees' so hard when you pull the plug. Pull the top cover and the coolant return fitting, remove RH coil and extract top cover out the right side carefully.

Removed oem NGK CR8HSA plugs and sure enough, the original .025" gaps were both right at .040" due to the sparking erosion to both the central electrode and the ground electrode. This was almost certainly the cause of the mis-firing. I could have carried on with the same plugs by just regapping them to .025", but I had a fresh set of NGK C8HSA plugs (these were new in box but may be obsolete now, albeit perfectly good) still left in the previous owners stash of tools and parts he gave me so put these in (after checking the gap was .025" - it was) with a light coat of anti-seize on the threads (available at NAPA and other autoparts stores). It is imperative to use anti-seize on replacement plugs otherwise you are gambling that they won't be permanently stuck/seized the next time you want to remove them.

BTW, the "color" of the old plugs was perfect, the central porcelain nice and clean and dry, but not dead white which might mean running too hot. There was just a slight build-up of deposits on the top of the ground electrode, a good sign which means it too is not running too hot. Evidently the plugs Kaw called out for their engine were running exactly right in the service I was giving it. I seem to recall a horror story on this forum a couple months ago where someone holed their piston at 80 mph, possibly through running non-approved plugs, which again possibly overheated and caused a typical pre-ignition failure classically displayed as a hole through the center of the piston crown. Detonation is another matter that results in piston damage at the edge of the crown, likely trapping the rings and killing the compression, or seizing the piston.

Using the Kaw tool (it might be tough to get anything else in there under the frame and all) I tightened the plugs carefully by hand at first to avoid cross threading and then used a box end wrench carefully on the Kaw tool as they tightened too much for fingers (some carbon and corrosion inevitably gets in the threads in service, and I see no practical way to get it out - I wouldn't want to put a 10mm plug tap down in there even if I could, since it would rain some debris down into the cylinder, maybe even metal chips. This is not necessary) . Tightening the plug down carefully until I felt the plug washer contact the head, when it starts to tighten for real. I found that it took about 3/4 of a turn after this point to get the plug washer fully flattened and sealed, when my calibrated hand told me the plug was fully tightened. So stop.

All right, you may say, what did the tappet clearances look like after 31,202 miles without inspection and running the 5w-30 non-synthetic car oil? Good question and I was waiting to see, myself. Having no metric feeler gauges, I did some higher math and determined that Kaw approves clearance of .003-.005" for intakes and .004-.007 for exhausts. One intake tappet was found to be .002" and the others were .004-.005". I corrected the tight one to .004", but at .002" it certainly was not tight enough to do any harm.

One exhaust tappet was found at .003" and one at .004" so I opened these both to .007". The other two were .005" so I left them.

I found everything immaculately clean and copiously oiled under the top cover, no sludge anywhere. The timing chain was nice and tight on the cam sprockets and there was no perceptible wear in the cam bearings when attempting to move the camshafts up and down. The original '88 engine did have some play in the camshafts at removal with 86, 970 miles, besides the dangerously slack camchain.

I did notice just the slightest witness of wear on the very nosetips of all the cams, but not enough to feel with the fingernail. I assume this is normal and not detrimental. We'll see how it looks next time.

I used Kaw's tappet adjusting tools, they ease what must be a very meticulous job and after disturbing the adjusters, you need to check the tightness of the locknuts two or three times. I check the clearance by turning the nut on the crankshaft end with a 9/16" socket wrench the normal running direction (counterclockwise on the left side) until the nosetip of the camlobe of interest is 180 degrees from the camfollower underneath.

Put everything back together, refilled with fresh 50/50 antifreeze coolant. Engine fired immediately and I continued to top up the coolant as it purged its air, until it was totally purged and full. Rode bike around the block, and all seems well. We'll see how it works on a normal duty cycle of 65 miles on the highway.

Whenever I do this kind of work I am reminded that every piece, part and fastener is important, and every operation has to be done with the greatest care, to get a good result. I spent about six hours on this project, with nearly 60 years wrenching experience, since model airplane days, because I want the utmost reliability, and I don't want to damage anything by hurrying too much. The socket head screws that secure the fairing to the tank, for just one example. You have to be extremely careful to get them started straight and not cross-thread them. After just short of 20 years and over 118K miles, these are still okay.

Novices can learn to do any of this work well if they want to, but even white-haired mechanics like your scribe have to be very meticulous to avoid making mistakes that can lead to trouble. Good luck and have fun.
Post Posted: Sun Aug 05, 2007 9:04 pm
 Subject: Re: 118,172 Miles on '88 250 Ninja - Maintenance Time


Thanks for the update. The details of your reports are very helpful.

If I have this right, after the valve adjustment at 1700 miles, it went another 31,200 and only needed slight adjustment. It looks like KHI has very good quality materials in the valve train.

I found a similar situation as motor went from 4,261 miles to 20,534 miles between valve adjustments and I only found one exhaust valve slightly tight. The spark plug gap had widened to .030, somewhat proportional to what you encountered. Impressive motors indeed.

I do have a question. I have never run across a spark plug seized into the threads. Is this more common than I've come to expect?

Thanks again for sharing your experience and experiences with us.
Post Posted: Sun Aug 05, 2007 9:13 pm
 Subject: Re: 118,172 Miles on '88 250 Ninja - Maintenance Time

Awesome write up. Really interesting to see how long you could go without doing any maintenance. Experiment for you, common practice for some maybe Very Happy

Goes to show how sturdy this engine is. Thanks for sharing your experience!
Post Posted: Sun Aug 05, 2007 9:43 pm
 Subject: Excellent write-up, mate. :thumbup:

Thankyou bill, you give me the faith I need to keep my old girl on the road... Well done, and, I hope you continue having the great success you've experienced so far, stay safe...

Bill Hoddinott - VA
Post Posted: Mon Aug 06, 2007 12:41 am
 Subject: Re: 118,172 Miles on '88 250 Ninja - Maintenance Time

The whole bike is top quality. At 118K I have never had to touch any part of the electrical equipment except replace a few headlight and other bulbs, and the flasher relay thingie with a 12v universal from the autoparts store. Since I started out with the old Brit bikes in the '50s, an electrical system that functions for years with no problems is a minor miracle to me. But my bike does stay in the shop, never left outside. Bikes that stay outside inevitably get corrosion in the electrical connectors and fittings that leads to circuit problems.

It is not common to have seized spark plugs, but it is not unknown. It would be the sort of thing you would get with bikes left out in the weather for a while unused, and no anti-seize had been used on the threads. No doubt in my mind that the best practice is to use some anti-seize when replacing spark plugs. Then you have one less thing to worry about.
Post Posted: Mon Aug 06, 2007 1:56 am
 Subject: amazing, please update every few months-thanks for your time

Bill Hoddinott - VA
Post Posted: Mon Aug 06, 2007 1:27 pm
 Subject: Re: amazing, please update every few months-thanks for your time

Glad you like that. Full road test this morning, everything running normally. Nothing dripping so far.
Post Posted: Mon Feb 06, 2012 10:43 am
 Subject: clutch slippage with car oil?

with 5w30 did you experience clutch slippage? i know that an engine can run pretty much any oil for lubrication and still work well (within limits and depending what oil you use) but the oil is shared with the tranny. i thought the reason motorcyles use 10w-40 was because it has to interact with a clutch and i thought car oil is more slippery than motorcycle oil.

VERY good write up/report. This just proves my point that you if you take care of any vehicle it can last you a long time, no difference if its an (ie) cavalier (shitty) or civic (awesome).

when i get my 250 again i will keep it till it breaks!
racer X
Post Posted: Sat Apr 25, 2015 3:56 am
 Subject: Bills bike

Just an update
I still have bills bike. It has 138000miles on the clock. I restored the bike using a salvage 2001 and it is running great.

I sold the original body to someone in California and that is leading a new life. The bike is being converted to a cafe racer and will eventually race at Bonneville in 2017 (I hope).

I will have the bike on the road after this season. Besides the blue collar bobber kit I am going to add fuel injection from the Etron setup. And I have a turbo engine already sitting on the bench ready to go.
This old bike has been around

As for Bill ?? He put 30000 miles on a 2010. Then upgraded to a 300 ninja. He is still riding every day.
Post Posted: Fri Jan 22, 2016 7:51 pm
 Subject: All good to hear!

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