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Old 10-08-2012, 07:48 AM   #1
wfopete OP
Suffer Fools; Gladly!
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Joined: Aug 2004
Location: Somewhere North of Dover, AR
Oddometer: 498
Debut, year one with a YZ465G

When last we left our hero he was lamenting the performance, or lack thereof of his bike (click here for story). The motor pinged; the front suspension was too soft on a MX course but one of the biggest problems was that the motor leaked tranny (ATF) fluid out the top of the clutch case. So I:

  • Set the timing to specs
  • Checked for air leaks
  • Installed a set of Race Tech Emulators Valves
  • Richened up the pilot jet 48 to 50
  • Installed new clutch cover gasket
The jetting and timing adjustments helped the starting…a little. Although I didn’t perform a leak down test, I couldn’t find any evidence of an air leaks by applying flammable stuff near typical vacuum leak sources. The bike will now start usually within ten kicks…hot or cold. Strangely enough it starts best dead cold with the choke off and the throttle open. Hmmm…what is it trying to tell me? Without heavier front springs the Race Tech valves did little to stiffen up the front end, that’s OK in the woods but not so OK on a MX track. I raced the bike at an AHRMA Regional MX in Portland, Michigan. I got the holeshot in the 2nd moto but the front suspension had me backing off so much I faded to the back of the pack pretty quick. The motor leaking oil was another issue to fix. I checked the case surfaces and made sure the vent hose was venting but after two new gaskets it still pushed out fluid through a small area on top where the two cases bolted together. I pretty much know I have a problem clutch case cover now. After continuing to leak oil and a race coming up, out of frustration I cleaned the effected area with carburetor cleaner, wiped it dry and smeared a thick layer on silicone sealant over the seam. Problem solved.

Sometimes the biggest problems are the simplest to fix.

I found this unseen casualty from my first race in Texas at Diamond Don’s. It was a mud fest. Probably not a show stopper…probably.

Rock-1 Sprocket-0

There was an AHRMA ISDT 2-day Qualifier race coming up nearby. I’ve raced a bunch of these AHRMA events before so I knew what to expect. I was told that the course would have some fairly tight sections & bark busters would be a smart idea, so I dug around & mounted a pair. I also threw on a crusty Preston Petty headlight, zip-tied an old license plate to the rear fender and crossed my fingers that I would not need a skid plate. The tires were fresh but I didn’t know how good the tubes were and since this was an Arkansas woods race I knew there would be rocks so I went to the high side for tire pressure (15 PSI!) and figured, if needed, I could adjust it while on the trail. In an effort to keep the exhaust noise down, I took a FMF Q silencer off my KTM 300 and fitted it to the YZ. The Q also had a spark arrestor in case the Forest Service was checking. My goal was to finish without breaking the bike or body. I gave myself a 1 in 3 chance.

Zoom Zoom

Basically these ISDT 2-day Qualifier events are based on the old ISDT format (surprise). When you get to the event, you get your race number (I was on the 13th minute), a scorecard for each day, go through tech then impound the bike overnight. The next morning when your minute comes up you have 60 seconds to get a stone cold motor started and move 60 feet. If you don’t, you get penalized. Then you ride a route maintaining a EZ speed average until you get to a special test section where you need to haul $$$ for anywhere between 5 and 20 minutes depending on your skill and the length of the test section. At the end of Day 1 you get one lap on a grass track for time. Same deal on day two but now the grass track is a five-lapper where you start with a gate full of riders using a rubber-band start. At the end of the day if you keep up with the faster times you get a gold medal. If you don’t stay within a certain percentage on speed/time you drop to silver, then bronze rankings. If you really have a bad day you “Hour Out” and pack it in.

Day 1 went like this (I told you it was an EZ speed average):

Typically, these big YZs were not known for razor sharp handling so I wondered how would it work it the woods. My only trip into the woodlands before this race was a wet, muddy, rutted, slick XC race so I really couldn’t past judgment on how the bike would do in drier conditions. Well at this race I found out: This bike is fun (in kind of a scary way) in the woods! In the test sections most of the time I could stay in third gear (stock gearing) and use the torque to get though. A slip of the clutch and things started to blur fast . Occasionally I needed to drop into second gear but I had to use care as second gear let the motor rev too quickly causing a wide-eye condition. It was also a good reminder that I was riding a YZ and not an IT465. Third gear was a blast though; you could just dial the amount of boost you desired to get down the trail. With the torque this motor makes, gearing was not an issue. Even first gear is good enough to get through the few real slow speed sections. The mushy front suspension sucked up the trail junk just fine while in the back, the monoshock, while stiff did OK; not as well as the front but not bad.

The first terrain test section was a rocky and right away I could feel the 15 PSI TP working against me so I couldn’t push too hard. At this point I’d rather give up a bit of handling than having to deal with a flat tire. Still, I kept up a decent speed until I let the motor stall in a tight section. Dang. If you’ve ever started one of these big YZ’s you know what I was up against. Fortunately the rest of the test sections were not nearly as rocky. Unfortunately, I stalled the bike once in each of the three test sections, which cost me at least 30-45 seconds each time to get the motor restarted. Grrrrrrrr. Arkansas Dirt Riders Club had it figured out with lunch stop on the trail, well, near the trail. Nothing like cruzing down a paved road on an open class MX bike and having a nice BBQ meal waiting for you.

Lunch Day One.

Other than a little fuel and chain adjustment the big YZ needs nutin’.

I didn’t know how much fuel the YZ would use so unless I was in a test section I stayed in a high gear & was fairly gentle on the throttle. Strangely enough this bike is very good on fuel consumption. If fact, sometimes I thought it was making fuel. The second test section was great: Not too rocky or tight… just right. The third test section on Saturday was the tightest, several riders got through it without bark busters; albeit very carefully. Saturday you get one lap on the grass track for time. Second gear starts seemed ideal and let the bike launched straight and true. Great, if I can start this well on Sunday’s 5 lap grass track race the holeshot could be mine, after that I felt I would have to deal with little 200cc bikes running circles around me as I’m not much of a grass track rider. At the end of day one I was on gold, but last in my class (+50 Intermediate). If you factored out 30 seconds for each of the three times I stalled the bike I would be right in the hunt for a top placing in my class.

Day 2

Sunday’s Schedule:

Like I said earlier; starting this bike is still an issue but it will start. There is nothing like trying to start a big bore bike on a cool morning to warm you up. It might take four kicks or ten or...

Sunday morning 9:13a.m.
Trying to light a fire in the YZ motor:

For Day 2 I made a couple of changes before the Terrain Test; I dropped the TP down to 12 PSI and I bumped up the idle to help keep from stalling the motor. Sunday’s only Terrain Test was the same as the #2 TT on Saturday but run in reverse. Things worked out pretty good, as I didn’t stall the engine! The bad news was that I caught and got stuck behind two other slower riders who were in front of me. One of the riders on an IT200 couldn’t find a spot to move over on the tight trail so I made a pass through the woods. It was ugly as I plowed through the trees and over a couple of logs but I still made decent time on the test.

Grass Tracks have always challenged me. To make good time you need to consistently use correct technique; I’m just not sure what that technique is yet. For sure it’s a thinking man’s race. I figured if I brought a big gun to the gunfight I might have a chance of posting a decent lap times.

I may have had the biggest gun but unfortunately, I have terrible control and I blew the holeshot on Sunday. Not only did I get a bad gate pick but when the rubber band was released I wheelied out of the gate. Crap. I clutched the motor to get the front end down and then promptly shot off into another wheelie when I released the clutch again. I guess that tire pressure drop gave me a bit more traction from Saturday’s ride. A feller has got to know his limitations, eh?

I managed to save face by still beating several riders to the first corner and passing a few during the five-lap race. I didn’t quite have enough time to run drown an XR500 Honda that was next in my sights but he wasn’t in my class either.

Wrap Up

Jetting or timing or both are still issues as the motor rattled too much for my taste. This ride I ran Shell 93 premium with some octane booster. The motor runs crisp so I’ll play with the jetting (starting with raising the needle) and if needed, back off the timing a bit in an effort to minimize the rattle. Over the winter I plan to get the cylinder head worked on too. I don’t know if it is the tires (Pirelli M16 rear & Pirelli Scorpion MX454 front), terrain or me but after one harescramble, two MX races and a two-day qualifier the YZ has yet to chunk a knob off either tire.

A common YZ465 problem. The pipe mount died late on Day 2

All in all I had a blast! The trails, facilities and people were great and the bike and body came through to finish on gold for both days. Next stop is in October at the Zink Ranch near Tulsa, OK for the ISDT Reunion Ride!

THE END (for now)

Suffer Fools; Gladly!....


ARA - Adventure Riders of Arkansas

wfopete screwed with this post 10-10-2012 at 09:20 AM
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