MOPED ARMY

^ def agree with moving the needle clip. in addition to that, have you played around with the air mixture screw at all? start with a 20 idle and 180 main, and do a half turn out and see if there's any improvement. if there is, that may be your culprit, and you can dial it from there using quarter turns. if not, i'm guessing air leak of some kind, (though probably not the bottom end) or your carb internals (float or slide) are stuck somewhere.

Sounds like a lean bog. Try going richer on the needle.

hey Russell,

I tried that and it gets worse if I put it in a richer needle clip setting

Remove topend and check for ring, piston and or cylinder seize damage, get rid of that pipe for it’s a 8k to12k rpm pipe so you need to jet it for that RPM and you can’t even get it to that RPM, I’d pitch restrictive air filter too,

I’m sure if you didn’t install the treats kids it’s not prepped, spaced, matched, squish nothing is probably done right on it to begin with either but If no cylinder seize damage and all looks OK then run a estroil or circuit type pipe, being a noob I’d run an easier to tune 14 mm bing carburetor probably first,

You will find the beginning set up of an easier tune carburetor and metal mesh filter and a low end pipe will give you if you great satisfaction of being able to use your bike instead of messing it constantly with a race pipe and carb and never being able to get it dialed in correctly

Simo is a great pipe, big old ripper, like the biggest badest pipe out there. Ive had it on 50 and 74cc set ups and works great, its just a bit hard to tune in. It hits late so low gearing is a must to get to the pipe faster. I think your problems are ignition related, try cleaning up the points and setting them at .45mm or .017". Usually if a bike is 4 stroking (no matter what jet you put in it) under heavy load its a case leak. Also most piston port set ups are much more forgiving to tune in with out an air filter.

Its really not that hard, dont be daunted. All said and done it takes about a 6 pack of beer and a couple special tools; the pullers, a strap wrench and maybe an impact to make your life easier. Tons of videos on the interwebs.

Gotra pull a bearing to replace the tranny side seal, you might damage the bearing getting it off. I would grab a new 6203 nr just to be on the safe side.

updating anyone who cares lol. I ordered an estoril pipe yesterday and gonna see if that jives better with my kstar kit. hoping the 4 stroking goes away....if not then ill order some new seals and see if its a case leak thats the culprit. I really am hoping the pipe fixes this issue though.

Only guessing going on is you guessing I haven't read the manual, which I have. lol.

ignition also addressed earlier in the thread. I'm sure someone reading this thread one day will appreciate the link to the mikuni site tho.

I haven't been able to run it WOT to do a plug chop but I was going thru plugs fairly quickly. I also went through a ton if jet sizes but the four stroking persists.

On the tuning spreadsheet I saw a bunch of people running PHBG 21mm carbs so I figured that the mikuni was a solid carb.

lastly, I value everyones input. feeling like I am getting some good learning points based on the symptoms that I presented. Definitely has helped me figure out a game plan vs being frustrated.

Alright here is an update. Made some crazy good progress so I'm excited AF.

installed the estoril pipe (Thanks Ken). was trying to get it dialed in. started with a 185 main and 22.5 idle.....worked my way down to 130 main and 17.5 idle ... was still super rich and boggy,

Took off the air filter and tried to start it but it wouldn't start till I pulled the choke lever. took it for a ride with the choke pulled and no air filter and that thing RIPPED HARD. blasted me to 37 mph with amazing acceleration till I eased off the gas.

so it seems that the air filter was choking off all the air. I put my mouth up to it and it was pretty hard to blow air through it.

So my next question is- can I just use panty hose for an air filter ? has anyone tried this? I know its ghetto but as far as function is there anything that will be detrimental ?

rather not wait or spend money on a new filter if the panty hose will work fine. please let me know what you guys think.

I will go back up on my jetting and rejet the idle and main jet with a panty hose filter just because I want to make sure I am not running lean since the bike only ran on choke.

thanks very much! Very excited...would tune more tonight but its past midnight and my neighbors will hate me.

I've used velocity stacks and fine metal mesh filters a few times. Expect to inspect & clean more frequently, but the performance is killer (though maybe not the best for longevity...).

As a generalized, non-scientific observation - I find that tuning issues like these crop up more frequently on bikes heavy on bolt-on upgrades. It's like half the bike is set to blast hard, the other half thinks it's stock, and finding a jet that spans the range is impossible. But glad you're making progress; you'll get it. Great looking bike.

Get the timing set to 18 and that you dont have sparks coming from the points...

then i would get a different pipe just about anything will be better on that kit with your weight

then start jetting

115 mains and 17.5 for idle needle in the middle