Yes...he means the crank seals...oil seepage is usually an indication they have poped out...


The reeds are in the reed cage between the carb & motor...unless it's a piston port...then it will not have reeds...If it has reeds you want to inspect for cracking...they control the pulse of fuel/air created by negative crankcase pressure...

 

OK - sorry to be out of the loop for so long... in the time lag since my last post I've replaced the one-way starter clutch with a used one, replaced the variator with a used one, disassembled/cleaned/reassembled the centrifugal clutch and replaced the belt. Oh, and put a kick starter back on - after completely disassembling/cleaning/reassembling the mechanism inside the case... Also replaced the transmission input shaft seal, which was leaking into the CVT space and had created a thick layer of 'mouse fur' made of dust/belt debris + trans oil all over the inside of the CVT case.

Put new front/rear brakes, front bushings/seals, rear seals on her as well - my son got her for free, which was about what she was worth!

Turns out the biggest issue I was having with idle-to-WOT and back was a seriously dragging throttle cable!

Now it'll start and, once warm, idle pretty smoothly - and go to WOT and back very smoothly - but WOT doesn't seem to be very high RPM-wise...

I've read these little quads are limited at the high end, and wonder what my options are for opening her up a bit more? The throttle limiting screw is wound all the way out, so it's not doing anything. Aside from re-jetting the main jet (and I'm not even sure that would do it) I've heard the best way to get more top end is a CDI built to allow more RPM?

any help appreciated, and to all you dads/granddads out there, "Happy Father's Day!"

 

I'd make sure that WOT at the throttle equals WOT at the carb...meaning I'd hold the throttle open and ensure the carb slide is all the way up (you can validate visually or I sometimes stick a finger in there).


If all that is good there may be "other" restrictors on the machine limiting WOT performance. I know LT's come with a clutch washer that keeps the primary from shifting out completely and thus limiting top speed...there is also an exhaust restrictor...I'd ensure anything like that is taken care of first...


If all that is good, then the rest depends on your budget. Shaved head/exhaust/performance reeds/high flow air filter/jetting are just a few of the more common bolt-off/bolt-on mods. 2 strokes take well to such mods as they produce power on every other stroke. Major point is to ensure clutching is matched to whatever RPM/HP gains you increase the motor by. Sometimes you'll see "kits"...they may be worth the extra $$$ as they often come with clutch mods to match the motor mods...

 

DirtDevil101, I've verified WOT = WOT @ both ends... didn't see any restrictors on exhaust, other than the smallish pipe outlet. I'd read others talking about spark arrestors and such, and don't see anything like that.
What's done beyond this is up to his Dad - I've sunk over $250 into it, and the brakes, carburetor, kick starter, variator, clutch and belt are all new. It runs decently well, pulls my 195 lbs around the yard and up the only hill I could find pretty well, so I'm pretty much done w/it.

What about aftermarket CDI for higher top end? I've read about these, but not enough to know what I'm talking about... and that seems to me to be the cheapest entry into modding - not to mention the easiest mod to do!

Thanks for EVERYONEs help in getting this far - certainly couldn't have done it w/o you all!!

 

I see a couple on ebay ($18 & $40 - I'd carefully look at the plugs and ensure a direct fit), but they don't specifically say anything about the rev limiter...


Did a bit of reading and if the CDI will fit both the 50 & 90cc then it will not have a rev limiter as the 90s did not have limiters stock...


At least that's what I'm reading...

 

DirtDevil101, I found a parts location that shows a new number for the DS50 CDI - with "(5900 RPM)" beside it - but I'm not sure whether what's in the bike now is limited at that 5900 RPM... how do I best determine the high-end rpm on one'a these bikes?

my grandson cane home from his last day of elementary school to find his rebuilt DS50 in the driveway w/a "Congrats, Grad!" balloon tied to the handlebar!! Made his day... and mine!

 

Was reading folks get 7000-9000 with porting...so maybe 5900 is right for a stocker...However, I don't think you want it limited at 5900 either...as mentioned above, just get one for the DS90 as I believe that had no built-in limiter...


LT80 would know for sure...