Arreche 19mm carb tuning

[Shaka]

Does anybody have any experience tuning an Arreche 19mm carb?  I just got one for my zx50.  Along with a Technigas pipe and Airsal 70cc big bore kit.  I got it running and idling.  I just cant get the main jet tuned right.  When I give it more than about 3/4 throttle there isn't really anymore acceleration.  The motor seems to make a clicking noise.  I can't really tell if it's internal, or just something rattling.  I'm running an 85 jet right now.  I had the 90 in it, but seemed to do the same, however I have it running better overall since I had the 90 in it.  The needle is in the middle clip position.  I'm about to do some plug chops, but it seems that it may be quite a bit off.  Just wanted to get some opinions before I throw a bunch of plugs at it. 
Thanks, Shaka

[zombie]

try raising the needle 2 notches. this will give you a direction to go w/ jetting. Also check your burn pattern on the plug. dark is bad, white is worse. I also run 1 0z. of synthetic 2 stroke in every tank to help w/ the larger cylinder, and higher temp. If raising the needle makes it worse go down on the jet, and visa versa. By raising first you are at least not leaning out the mix , and taking a chance of burning the piston.

[Shaka]

Zombie- Thanks.  I will first start with raising the needle.  I only have one notch to raise or lower it too.  I'm also running premix, so the oil should be good.  Unfortunately, yesterday the auto choke wires fell down onto my exhaust and melted together, which fried it!  I need to wait for a new choke to get it going again.  Hopefully that is the only reason it died!  It really sucked too, I had to push it home a mile!  I'm hoping to get it going again this weekend.  I will keep you posted.

[zombie]

Yeah man Iv'e pushed a few myself! good thing they are light. your posts will help all who are in the same spot. seems most posts have to do w/ carb/ fuel trouble.

[Shaka]

I got the choke replaced. She's running again! I'm going to in grab some spark plugs and mess with it tomorrow. Will post results/questions.

[Shaka]

I've done a few plug chops now. It looks like my 90 jet is too small, even with the needle raised all the way. I'm off to try and find some jets locally. I read that the mikuni jets will fit. Guess i'll find out shortly.

[zombie]

To fit jets in a mako 490 i once owned I bought a set of pin drills. They are rated in thousandths. I kept going up till I locked in what I needed.

[Shaka]

My local dealer didn't have the right jets. I ended ordering some. I know i could have drilled them out. At this point i have been messing with this thing so long that i want to eliminate any other variables or errors on my part.

[zombie]

I hear that!!!

[Shaka]

I got the new jets in and did a couple more plug chops.  The largest one I got is a 110 and I think it is still too small!  The knocking sound at WOT is still there, but has gotten much better, and the plugs are still white on the tip, but maybe a little more tannish colored further down.  For the most part they all look about the same from 85 - 110.  The only thing that has really changed is the very loud knocking  has quieted down.  I'm gonna have to order more jets, they make them up to a 140 so hopefully that will be big enough!  I am curious what size jets others are running on their 70cc's.  Any imput would be greatly appreciated!

[zombie]

I have an italian carb (forgot the name) their jets are metric , but a 95 thousandths bit fits perfect. my needle is the stock one from the carb ,and i raised that 2 notches I have a malossi 70cc jug w/ technigas pipe. i also went down 1 step on the plug (colder) Every add on on your scoot will have an effect on jet size right down to tire preasure. it sounds like your on the right track though. The sound you are getting could also be your pipe. try removing the glass packing  ,and see if that stops it. tan is good!  I also loosley wraped bi/weave fiberglass cloth in my silencer. It let me use the colder plug w/out fouling

[Shaka]

Thanks Zombie!  That gives me some comparison.  I don't know why I'm having to jet so much larger than your?  I guess it's just a little different setup.  I have gone to a cooler plug I'm running a B9HS.  The needle height shouldn't affect the WOT.  From my research it should be fully lifted out of the jet at that point.  It is supposed to control between 1/4 and 3/4 throttle.  I did move it for a few test runs and it didn't make a difference.  It just ran much richer at about 1/2" throttle, so I moved it back to the middle position.  As for the knocking, I'm almost positive it is detonation at WOT, not good!  I'll look into the exhaust as a possible culprit though.

[zombie]

Dude it might sound silly, but are you running Premium gas. It makes a HUGE difference. I didn't post ,Opening your silencer will make for a LEANER mix, thus increasing your problem. You know I Use whatever works NO-MATTER what the book says.If you are up to 140 jet MAYBE your carb is too large! 2 much cfm?

[Shaka]

I am running premium gas, premixed with full synthetic oil.  I got a good ride on it today, it definately seems to be running lean.  The noise sounds very bad at WOT, and definately seems to be coming from the engine!  Correction, they only do jets to 130.  I'm going to order the rest of them to finish off my set!   It seems to be running pretty good, maybe a little rich up to 3/4 throttle.  Not being able to fully open her is frustrating though!  She seems to want more fuel badly!  If anything if the 130 is still too small, it seems as though I would need a bigger carb, maybe 21mm.  Am I wrong?

[Shaka]

I got the 130 installed and it definately seems to run better. However, it is not running as fast as it was.  It seems like it hits about 42-44mph and it just doesn't have anymore.  The plugs chops at WOT are looking pretty good.  It seemed it was bogging at 1/2 - 3/4 throttle so I dropped the needle all the way down.  Seems to be smooter through the throttle, but still lacking in top speed. And the bad sound I was hearing before at WOT was the piston slightly hitting the head at the top of the stroke.  I put in another, total 2, head gaskets.  I was already 2 gaskets between the the cylinder and the crankcase.  Seems to have taken care of the clearance issue.