Any Eastern Virginia people? (looking for some tuning help)

[Doug10]

Any of you folks around the coastal part of Virginia? I am looking for a shop or team that has some experience getting these little carbs on the 50 2-strokers to mind their manners. Tossed the stock airbox and switched to UNI filters and now the jetting is a little out of wack.

Doug

[selbygirl]

WHATS THE BIKE DOING DOES IT FEEL LIKE IT IS BOGGING THEN TRY A SMALLER JET GIVE A DESCRIPTION ON WHATS GOING ON AND IM SHORE SOME ONE ON HERE CAN HELP YOU SEEYA TOMMY

[Doug10]

Motor is stock with a custom exhaust, (1.25" OD head pipe to a blimp pipe, then to .9" section to a tiny muffler can from what looks like a cobra 50 dirtbike) i am not sure how much porting was done to the jug but i know it was ported some, i also know that the head is from the malossi MHR 50cc kit, pn# 31 8403. The cylinder/jug is still in the box but the oring head was put on there (hi comp) i am pretty sure of.

I pulled the carb off tonite and the needle was in the 2nd slot from the top with 3 more avail. slots below it to add more fuel, the needle is 3CR1.

The pilot is a 17.5 and the main isnt stamped but it has #66 scratched into it.

I had trouble setting the air screw tonite. all the way in the bikes idle would drop down and cut off and about 1/2 to 3/4 turn out it would rev up and from there out it didnt really change anymore from the initial rev up, that was with the tires on the ground and off. I noticed today running it with the uni installed, that the bike lugged a little bit getting up to speed out of the hole then flew up to WOT for a few seconds before it bogged down. If i lifted on the throttle and pinned it again it would pick back up and then bogg again. Im thinking it was running out of fuel.

The carb is whatever came stock on the 02 polaris scrambler. Its a mikuni and im guessing a 16mm.

I think the pilot may have been stopped up a little but not all the way. Its soaking tonite and im thinking i will put her back together and drop the needle clip 2 spots maybe to see if the top end is helped any. Not sure if the local shops are open to get bigger mains tomorrow and possibly a size or 2 bigger pilot.

I am not setting it up for my son to run wide open yet, its his first time on the quad and i was gonna limit the throttle to 1/4-1/2.

Im just worried about it being too lean. Before removing the airbox and going to the direct filter it was in my opinion a bit rich but then i was running klotz techniplate on 93 octane at 32:1. It was leaking oil out of the pipe sitting in the garage right bad and smoking pretty good too so i decided to switch to amsoil dominator 50:1 and also went to 50/50 110 race fuel and 93 octane (around 102). The previous owners daughter ran TT with the bike and said it liked to run on 110 but would run on pump gas.

Thanks all

Doug

[EthansDad]

some good info doug. first off, I think you are right to worry about it running lean. switching the pipe and air filter both can effect that.

here is what I'd like you to try first

-get it on a stand and run it 3/4 - full for a few seconds, and cut the motor. take the plug out and tell us what it looks like. my guess, very white or no color at all with those jets.

With that info, we can better help. here are my guesses what we'll get into -

- jets too small, also carb to small. that setup would run better on a 20 mm carb, or 21. on our 20mm, we run in the range of 50 pilot and 95 main - this is on a 50 mod.

-pipe -not knowing what you have is a bother. some pipes really take to different carb/jetting different than others. the cheapo koso chrome plated pipe works wonders on that malossi top end you have.

-fuel - you are on the right track. for the pipe oil leaks, well welcome to 2 strokes. just make sure those head pipe bolts are snug, they do back out. loctite is your friend there.


on limiting control for first time riders, yes again. I did that with my kid, will be doing it with my girl too. use the physical throttle stop screw. you might find you have to clutch it different such that it takes off at lower rpms, else they might not be able to get it to go at all with only 0-1/2 throttle available.

[Doug10]

thanks for the info, The malossi cylinder/jug is sitting in the garage not installed. I really need to pick up another exhaust system that is semi comparable to what others run, not so much for the performance because that really does not matter to me now, but to compare apples to apples. I also really need to see how much porting is done to the exhaust area on the stock jug thats on the engine now.

The pipe was allready on there when i purchased it also. i forgot to mention that earlier. Thanks again all.

Doug

[EthansDad]

oh, did not catch all that hop up stuff was not on yet. might want to keep it off for a first time rider. not that they can't handle it, but it does tend to make the bike "peaky" and harder to rider, especially if you plan on throttle limiting.

just my $.02 on first time riders, set it up such that the kid gets used to riding full throttle (on slower or throttle limited bike), then as they get better, bring the heat on the motor. if you start with a higher end setup, most kids will "blip" the throttle since its fast and that is how they learn.

[Doug10]

you hit the nail on the head, but...I dont have much of the stock stuff, like the pipe and whatnot. I only have mo bigger stuff like the malossi top end and a 70 kit lol. The airbox was just annoying so i wanted the simplicity of the uni filter, i didnt realize the can of worms i was opening. I have it running decent at 1/4 throttle for now. One thing i noted today was i took a stock scrambler plug and slapped it in there. BIG NO NO, one crank on the starter and that plug got crushed. Luckily i didnt damage the piston. As long as she is smoking on him at 1/4 throttle im not going to worry. I did move the needle clip down 2 spots today and ran her at 100% again and she is still revvin up nice on top end then just dies like the carb is runnin out of fuel but that cant be.

Doug



Doug

[selbygirl]

hows it run wen the clip is in the middle we had a bike ran great you go 50 yards and it would bog down for some reason ther was to much fuel line travel ran a line from tank to carb and cleared right up

[Doug10]

The tank does run slow to the carb. Im thinking about doing awway with the fuel selector switch and just running fuel line from reserve tank pickup to carb, thas pretty much a straight shot. I did blow back through the line into the tank and it was fine but im wondering if the selector is restricting it somehow.

Doug

[selbygirl]

when i noticed my problem with the fuel line i held it abought 1/2 or more above the carb were the fuel line goes in and the gas would stop i went to advanced auto and bought a fuel filter and a fuel shutoff and fuel line thet they use for lawn tractors i think the total was around 5 bucks thats what i run on all our bikes and zip tie all the conections get a zip tie tool makes them real tight sounds like your getting closer hope you get it take care tommy