'26F maintenance



9 replies to this topic
  • MikeOK

Posted August 05, 2000 - 05:58 AM

#1

Well I've had my 426 about 2 months now, 2 races under my belt and several trail rides with my son. I was wondering how you other owners do your maintenance... The manual is very specific and I have been following it for the most part... changing oil after every race or maybe an hour or so of trail riding, I checked my valves and they were good, I haven't changed my fork oil yet. No problems yet at all and I found that if I start at the gate in second I can send all the little 2 stroke 250's to their momma's hehe. This is a great bike, especially for hammer-dog riding. It's not my first pick for just casual riding because it's so hard to ride it easy, it seems to beg to be ridden hard. I still feel when I sit on it that I'm trying to ride a big mean horse that I can't quite handle, this thing is capable of doing way more than I am. I've watched others at the tracks who can make them really fly, almost art... I'm getting ready to take it out tonight and race again, 100 degrees and sun yuck we'll both be overheating!

Mike

  • ruiner911

Posted August 06, 2000 - 05:03 PM

#2

After every HOUR of trail riding?!???! Doesnt that seem a little excessive?? Once every few or maybe dozen rides but wow

  • Hick

Posted August 07, 2000 - 09:05 PM

#3

ruiner911: Yes, changing after every ride does seem overboard and I doubt many folks go to that extreme. When the bike is new its a good idea. I remember my KX500 manual called for new rings and cylinder de-carboning right after initial break-in period. Yeah right.

MikeOK: I know exactly how you feel! 426 handles better the harder you hit it. For me this bike has been very confidence inspiring. Some things you may consider:

Grease the bearings. These bikes don't have much grease from factory, so watch steering head and swingarm bearings, especially if you ride in wet stuff. You may want to grease them now regardless.

Front tire. Most guys hate it. Dunlop D756 is popular replacement for stocker, sticks better in corners.

Watch your clutch. Some bikes have faulty clutches. If yours is grabby or noisy have it checked. Some clutch baskets are not made properly, some bikes don't get enough oil to plates and others' have basket rivets that don't clear case. Also a few bikes have had nut holding main gear to crankshaft come loose (like mine); this is kind of noisy.

Arm Guard. Also called a chain slider this is the piece of rubber that protects forward portion of swing arm from chain. It doesn't last very long. You can grind/smooth off the weld on the arm underneath it to prolong its life or buy a new slider from Terrycable. Not cheap but 400% more durable than stocker.

Oil Screen. At the bottom of the oil reservoir is a removeable fitting. Can't remember if this is mentioned in the manual but you need to clean it as metal flakes from newer bikes collect here after initial break in. I had to use an impact wrench to get mine off (24mm deep socket is needed).

Accelerator Pump. You no doubt are now familiar w/ how easy it is to flood your 426. In addition to being able to render you bike unstartable, pump also has propensity to collect grunge. You may want to consider an in-line fuel filter, although w/ stock tank there isn't much room to install one. At some point you will probably need to clean the accelerator pump.

Jetting. Lots of folks have mitigated/cured what is usually described as hiccup or flat spot off of idle w/ some combination of richer pilot, going 1/4 to 1/2 turn out (richer) on idle screw, clip a notch or two lower (richer) on needle. 426 is pretty widely acknowledged to have a lean spot at initial throttle openings, especially at lower altitudes.

Oil. This is a point of contention and much debate but you can save money on oil changes w/ Mobil 1 synthetic vs. expensive Yamalube. But beware those friction modifiers!! Read this good tech article on oil for strokers:
http://www.eric-gorr...h_june_1999.htm

And of course I wholeheartedly recommend regular checkups at thumpertalk! The WR forum here is much more popular and questions that apply to both bikes (YZ/WR) are answered more quickly and robustly on the WR side.

Hope this is helpful!

[This message has been edited by Hick (edited 08-07-2000).]

  • MikeOK

Posted August 09, 2000 - 09:56 PM

#4

Thanks for the info, HICK. I probably don't change my oil every hour, but I do after every race. And I may go a week of trail riding on and off and always change the oil once a week if I've ridden much at all. I have cleaned the frame screen and I change or at least clean the filter every other oil change. I think if a person pays 5,000+ for a toy an oil change is a small price to pay for longevity, but I also like to tinker... I ride at about 800' alt and I have noticed the dead spot right at the bottom as I've heard decribed here but mine hasn't been bad enough to try and correct (yet). It took me a bit of riding to get the suspension dialed in but I've found a good overall setting now. I'm short and heavy (210) so I raised the forks as high as they will go in the clamps and that was the best improvement I've done so far. The tire rubs the fender just a bit on bottoming but the handling improvement was great. Mine has become second nature to start, usually first kick, but it took me a long time to get used to it. Mine doesn't behave like what I have read on most posts on starting, in fact I have found it best to NEVER use the hot start button except for immediately after a stall. On a warm engine I hold in the comp release, kick twice, then start normally and almost always fires first kick. My pipe turns cherry red at the gate if I let it idle for more than a minute or so, so I drilled myself on the starting until I found what works. Stalling was a problem when the bike was new but since I read the manual and set the idle at 1800 RPM I rarely stall anymore....

Mike
Pryor, OK

  • fershy

Posted August 09, 2000 - 10:22 AM

#5

You haven't changed your fork oil yet? What are you waiting for? I'll bet those aluminum slider are just choke full of filings. Check the manual, it says to change the fork oil almost immediately. Good advise too.
fershy

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MikeOK

Posted August 09, 2000 - 01:08 PM

#6

fershy- since you brought it up, I have a question about changing the fork oil. I've never done this myself, always took it to a shop. I'm doing all my own maintenance now and I've read the manual and other articles on changing fork oil and I'm wondering why it seems so difficult? If you've never had a leak why can't you just measure how much you drain and replace it with the same amount? Looks like it would be so much simpler than completely taking them apart and doing all that fancy measuring stuff. And if you do disassemble, why can't you just measure the level with a stick or something to get the level right? I did have a concern over the maintenance on these forks since they have aluminum internals but I've posted the question about how often to change oil on the RMD and everyone says they don't change their fork oil so often. I'll prolly tear into them next week anyway just for peace of mind...

Thanks,
Mike

  • Hick

Posted August 09, 2000 - 01:45 PM

#7

Glad I could be of some small help MikeOK.

My 426 ALWAYS needed the hot start when I first got it. But I ride at 4,000 ft. alt. minimum and my bike was actually a bit rich on idle and pilot circuit.

So I guess I kinda went against the grain in this area what with everybody else going to richer pilots and maybe a clip richer on needle. But in the summer in the high desert I swear it runs better with the leaner pilot (in the winter I may end up back at stock setting) and about 1.5 turns out on idle mix.

Anyway, with this jetting my 426 only needs hot start if you drop it or otherwise flood it. This makes sense, especially w/ respect to idle mix.

Fershy makes a good point on the forks. Mine were noticeably better after first servicing, there was tons of crap in the oil. I consider myself to be very mechanically inclined but I admit that forks scare the hell out of me. Luckily I found a guy in El Paso who does great suspension work. Too bad he doesn't do any motor work.

But now my forks are due for another trip to El Paso and someone told me I should have the mid valve replaced. Something about stock mid valve being a weak spot in Yam forks.

Anybody heard this? Who makes a replacement mid valve (Race Tech, PC?), what's wrong with stocker and should I replace it?

Maybe I'll start a new topic and pose this question...

  • STLmxracer

Posted August 09, 2000 - 04:35 PM

#8

Originally posted by Hick:
Glad I could be of some small help MikeOK.

My 426 ALWAYS needed the hot start when I first got it. But I ride at 4,000 ft. alt. minimum and my bike was actually a bit rich on idle and pilot circuit.

So I guess I kinda went against the grain in this area what with everybody else going to richer pilots and maybe a clip richer on needle. But in the summer in the high desert I swear it runs better with the leaner pilot (in the winter I may end up back at stock setting) and about 1.5 turns out on idle mix.

Anyway, with this jetting my 426 only needs hot start if you drop it or otherwise flood it. This makes sense, especially w/ respect to idle mix.

Fershy makes a good point on the forks. Mine were noticeably better after first servicing, there was tons of crap in the oil. I consider myself to be very mechanically inclined but I admit that forks scare the hell out of me. Luckily I found a guy in El Paso who does great suspension work. Too bad he doesn't do any motor work.

But now my forks are due for another trip to El Paso and someone told me I should have the mid valve replaced. Something about stock mid valve being a weak spot in Yam forks.

Anybody heard this? Who makes a replacement mid valve (Race Tech, PC?), what's wrong with stocker and should I replace it?

Maybe I'll start a new topic and pose this question...


Try contacting "Nick Costello at Pro Valve" in Costa Mesa, Ca. He is a member of the "Over the Hill Gang" + 30 Racing club. He has allot experience working with YZ forks. The mid valve problem is a design flaw & Yamaha will try soak you for $$$. Nick has devised an alternate replacement part in conjunction with Southern Calif. racing / Tech teams. It worked great on my 98 YZ250. You should be able to find him through the Gang web sight @ www.overthehillgang.org , look under links section. Good Luck

  • Guest_Guest_*

Posted August 10, 2000 - 03:37 AM

#9

Race Tech valves are the way to go. With the video they really weren't terribly hard to install.

Nick

  • JBM

Posted August 10, 2000 - 05:34 AM

#10

Mike, the midvalve is a weak point on the YZs. It bends after a certain amount stress and causes inconsistent or bad action. I sent my forks to MX-Tech for service and they automatically fixed the problem. Guess what the cost was....$8. It is a permanent fix. They do good work for reasonable prices. If you're interested, their site is www.mx-tech.com. I highly recommend them. They just won a suspension "shootout" in MXA against all the big players.





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