Two strokes for dummies

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
thirdgenlxi
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Two strokes for dummies

Post by thirdgenlxi »

I guess I'll throw my $0.02 in as well on the oil..... in the 2 years I've had my bike I've had some great luck with both the Spectro Platinum SX-2 that I ran for awhile, and now currently Motul 710 that I've been running for awhile now. Both mixed at 40:1. I like the low flashpoint of the 710, helps keep the power valve from gunking up. I bought the bike used in March 2015 (2000 200) with unknown hours.... the previous owner rode it for 2 years before I bought it and he didn't do anything do it as far as rebuilds. It was super clean though and ran great so I didn't bother tearing into it. I've since put on 620 completely trouble free hours, and a little over 11,000 miles..... dirt, dual sport, supermoto, and even a track weekend. Also did my first race here recently at the Big Buck GNCC with 611 hours. I've had zero engine issues whatsoever, and still haven't had to do a thing to it. Still runs as good as the day I bought it, still starts first kick hot or cold, has 155 psi compression, and leakdown test only dropped 0.5 psi over 10 minutes (which was probably more my super ghetto method for plugging off the exhaust and intake ports, lol), plenty of power and smooth as butter. Power valve has never needed cleaning, it's still clean and opens/closes perfectly smooth running it manually. Piston and cylinder are also both clean and smooth. Now I'm not saying this is the best oil out there to use, I'm just giving my experience with it, on a bike that, in comparison to many, sees A LOT of use, lol. The previous owner ran Amsoil, which I'm sure is a great oil too. The only thing that turned me off to the Amsoil was reading too many different stories about crank bearings rusting and making an orange paste around everything in the bottom end. Whether it's actually true or not.... I don't know. But I did read enough different stories about it that I decided I didn't want to take the chance with my own

For tranny oil.... regular old ATF has never let me down either. Still on the same clutch for as long as I've had the bike...... and trails are very steep, rough, and technical here where I ride at all the time... it still grips great
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Re: Two strokes for dummies

Post by TeamExileRacing »

80wt oil? I know amsoil makes an sae 80, specifically for two strokes. Should I look into that?

So the build is coming along great but slow which is fine, I wouldn't have time to ride it anyway lol. I ended up buying a 2000 kdx220 roller and Frankensteined the two together, it looks amazing. Just need a rear fender.

Soooo I dropped my piston and cylinder of at my engine guys shop a couple weeks ago. Asked him to check clearances and do what's needed, clean kips, and clean the 7 years of barn storage buildup off it. Well stopped by yesterday to drop off a cylinder for another build and he had it all cleaned up and ready to put Kip's back in. Looked awesome! Anyway on the side of the cylinder it had "the works" etched into it. Anyone have input on that etching? Is it a ylinder works job?
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Re: Two strokes for dummies

Post by david »

I would not run 80wt gear oil in the transmission, that's waaay to thick and will cause clutch drag and possibly difficult shifting. The factory calls for 10w30 motor oil, I and many others use ATF.
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Re: Two strokes for dummies

Post by KDXGarage »

80 weight gear oil is equivalent to 10w-40. I was thinking 10w-40 was what the manual said.

Anyway, 75 weight is like 10w-30.
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Re: Two strokes for dummies

Post by david »

Guess I've never compared them then. I use 85w140 in my Jeep and I know that is a lot thicker than 10w40 motor oil.

The inside of our transmission is not that different than the inside of an automotive automatic (spur gears, needle & roller bearings, wet clutches). ATF can be found anywhere, is relatively inexpensive and allows for easy shifting in all temps.

Edit: Well, it wasn't a wasted day. I learned something.
http://www.doolittleoil.com/faq/viscosi ... so-or-agma
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Re: Two strokes for dummies

Post by KDXGarage »

Interesting chart. I got my info from an old Bel-ray article they had on their site a decade ago.

I have been using Bel-ray Gear Saver 80 wt and Maxima MTL-R?? 80 wt for many years.
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Two strokes for dummies

Post by Motnednah »

Need help with clutch!!! New to 2 strokes (and forums). Bought a 2002 KDX200. Decent condition, but not great. Ran well on test ride, but I noticed the clutch would not disengage with a hard left turn. Bought it and replaced cable and re-positioned lever so the cable wouldn't bind on a hard turn. Did some maintenance (cleaned carb, changed plug, etc.) It sat for several months then I finally put it back together and fired it up. Still runs good, but as soon as I started it the clutch cable let go (best way for me to describe it). It was in neutral and I grabbed the clutch to put it in gear and take it for a spin, but there was suddenly no tension on the clutch what-so-ever. I reached down to the clutch cover and checked the clutch release lever and the only tension on it is from the clutch release lever spring. I removed the clutch cover and added an additional shim to the clutch pusher, but there is still no tension on the release lever. It had some old looking trans oil in it and I was starting it so I could warm it up and drain it and replace. I went ahead and drained it (and it looked pretty bad) and replaced with fresh oil, but that made no difference. Clutch seems to stuck. I'm guessing the next step is to remove the clutch, but I'm not sure what I'll be looking for when I do. I appreciate any helpful suggestions.
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Two strokes for dummies

Post by TeamExileRacing »

Any input on what company etched "the works" into my cylinder?
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Re: Two strokes for dummies

Post by TeamExileRacing »

Alright I'm about done just lack the exhaust and case saver being on and she's ready. What's the break-in process for these bad boys?
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Two strokes for dummies

Post by SS109 »

My break in procedure...

Warm it up to full temp, shut off, let completely cool, then check for leaks, all fluid levels, and check the torque of the cylinder to case nuts. Then fully warm up again, take off riding, get in 2nd gear, rev it up pretty good (up in the powerband even) and chop the throttle and let it engine brake down to where you can rev it back up quickly and repeat about 5-10 times to help the rings seat quickly, then ride it like you stole it! I followed this exact procedure yesterday on my complete rebuild of my 220. Doing the rev-then-engine-brake-then-repeat procedure is actually overkill but I like to know the rings are seated good for long ring life.
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Re: Two strokes for dummies

Post by TeamExileRacing »

^^^^sweet, thanks for the input, that's about exactly how I break in four stroke engines.
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Re: Two strokes for dummies

Post by VTMTcowboy »

SS109,

Just wanted to say that both your KDX builds are sweet! The 1990 is beautiful and I bet a blast to rip around town as well. If/ when I move away from California I might be asking you a few questions in regards to making a KDX street legal (blinker, horn, brake light, etc.).
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Re: Two strokes for dummies

Post by bultaco4ever »

Here's what I've learned from many engine experts. Jetting sizes control lean vs rich mixtures. Too lean and it runs too hot. Too rich and it runs too cool and may foul plugs. The gas air mixture has a lot to due with the temperature that the engine runs at. The oil does not affect the temperature except that if there is more oil molecules in your mixture because you run a heavy rich ratio....then there is less space (volume) for gas and air molecules. More gas molecules richens the mixture and cools the burn temperature.

A 32:1 mixture allows for less gas molecules than a 50:1 ratio. Gas molecules will cool the tempature down. Too few of gas molecules creates a lean mixture that runs hotter.

Whatever ratio that you run....do diligent plug readings to ensure you have the correct jet sizes in. Personally, I run modern synthetic oil (Golden Spectro or Amsoil) at 50:1. In my old Bultaco Astro racing days...the factory mechanics would run regular bean oil at close to 100:1 in order to get more horsepower out of the engine by allowing more gas molecules per the volume of the cylinder. They jetted accordingly to keep the temperature cool enough to prevent seizing the piston. They skirted to boundary of the proper ratio for more horsepower. But the bikes did run on 100:1 ratio's without seizing.
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