Stock Air Box Reinstalled! Time to set mixture...

[tango]

Hey gang!

As I stated in a post some time ago I was in the process of obtaining a stock air box. And so it is, I have it installed and ready to go. She now runs so quiet that I realy wonder if it'smy scoot I'm rising! Lovely stuff! Anyway, I'm now in the process of tuning the carb. I never touched the jetting of the carb when I had the cone filter because I used a restrictor plate to limit airflow. I've tried my hand at setting the ilde/mixture but I just want to make sure I did it correctly. This is how it went:

1. Located mixture screw (recessed Phillips screw, close to the air box) and turned it all the way in, then turned it out 1.5 turns.
2. Started engine.
3. Located idle screw (raised flat head screw closer to the oil inlet tube) and turned it in to a fairly fast idle.
4. Adjusted mixture screw in then out until highest idle speed is found. I achieved this perhaps 2 or 3 turns out from the 1.5 turn start point.
5. Adjusted idle screw out for normal idle.

Is that correct?

I'm smoking a bit more than I did yesterday (with cone filter) but I suspect that not as much oil was actually getting into the mixture as there is now. Another possibility is the fact that I'm actually running TCW-3 in there. I can hear the respective blood pressure starting to boil! LOL! I had NO idea that I was doing her an injustice at the time. I'm in the process of draining that and getting some 2T instead so bear with me. Please, chime in guys. Thanks in advance!

[90GTVert]

Sounds like you got the idle right. I wouldn't worry about a little more smoke if it's running well. It's just a richer (oil) mixture with the airbox and it's normal to smoke, especially without synthetic/smokeless oils.

[mccanic]

the smokes a good thing this time! lol

[tango]

Thanks guys!
I have been itching to give her a true morning cold start. It's pretty humid here in Jamaica at times so mornings come with dew and the temperature drop. I also live a few hundred feet above sea level so that's another tuning challenge that I wasn't initially taking into consideration, though I'm not sure just how much issue that will cause to tuning. I started her this morning and she stumbled on the first atempt. The second attempt she started but was barely idling. I shut her down and went for the flat head screwdriver to bring the idle up a bit. She start on the thrid attempt, but stalled a few moments later. I staretd her a 4th time and then brought the idle up (turned the idle screw in) by 1/8 turn. The idle came up nicely and then settled. We'll see how it goes, but I'm prepared for more tuning down the line.

[tango]

Okay...update time. I started her to head out to work and she fussed a little but managed to idle okay once I had given her a little gas. At this point I'm pretty convinced that my auto choke is busted. I'm gonna just get myself a new carb when I get the chance. I know I can get the choke by itself, but I think I owe it to myself to get a new carb along with a new intake manifold (which is cracking quite badly, but I don't suspect any leaks...yet).

Anyway, I get her idling and head off to work. At first, she doesn't want to go above 60km/h on level ground which disturbs me because she normally does over 80. I pay it no mind because I am feeling very good throttle response right through the rev range, meaning that my jetting is pretty much fine. After a few minutes she starts creeping up slowly towards 80km/h when pushed. She eventually gets there. I suppose she was just getting warmed up. On my way home, however she goes up to 80, albeit slower than normal.

Now...what can I report? Excellent sound and the engine has actually smoothed out at mid to high rpm. The throttle repsonse is lightning quick and buttery smooth. She also doesn't smoke as much as she did last night. That may have been humidity or just carbon being burnt off the internals after running with a poor mixture for so many years. Any thoughts?

Now for the down side. Firstly, startup is not as good. I'm going to spend the next few days adding a little fuel to the idle mixture, making it a bit richer than ideal. That should aid cold starting. Also, she doesn't rev as quickly and takes longer to get to terminal speed. The filter setup I had before obviously had its benefits.

But would I ever go back to a cone filter? Absolutely not. Stock box for life!


Tangent: I just hit 100 posts folks! I'm now a Senior Member! Woo hoo...okay...so who do I talk to about my lapel pin, my shoulder patch, my certificate, my tassle, and my stole?

[bigjeff]

wow - I need to post more so I can get my stuff.

[mccanic]

i have a carb you can have if you pay shipping

[tango]

Aug 4, 2011 22:30:08 GMT -5 mccanic said:

i have a carb you can have if you pay shipping

Thanks, brother! Would that include the intake manifold as well? New/used? I'd be willing to pay for shipping for sure. Remember that I'm in Jamaica so I would opt to ship to a FL address. What would the best route be to accomplish that?

[1quikvento]

Congrats on the success of your airbox install AND the senior status member. Im getting awfully close. I plan to stay till this bike is running tip top and i move on to a second project.

[mccanic]

ya ill throw that in, you have a Minarelli right? and its used but in working condition, is your carb have 2 cables or one going to it?
idk about the shipping??

[tango]

Yeah, she's a 82cc 1PE50QMF Minarelli. I have a single throttle cable to the carb and one oil control cable to the pump. The stock air box is side mounted and the transmission is a short case. From what I can tell everything is externally identical to the 49cc's. But not to worry, I'm in no rush so we have time to figure out a process for paying for shipment. The guy a bought the air box from still has his carb and is willing to sell it to me, I just don't have the money for it yet.

Update: I adjusted the mixture richer by 1/8 turn with no noticeable change in ease of start. She's still running smoothly and is getting to regular top speed, but still not as quickly as with the cone filter. I just give a slight twist of the throttle when starting and that helps.

Quick question though. My snorkel is pointed to the right, towards the engine. Would there be any advantage to rotating it 180 degrees to point towards the left side? I'm thinking that pulling in air from over the engine would have me taking in hot air, which means less power. What say you guys?

[90GTVert]

I dunno that it makes much difference, but I used to rotate the snorkel to face the most fresh air. Now I just remove the snorkel and rejet/readjust the carb.

[tango]

I just turned the snorkel towards the left and it made absolutely no difference at all. I guess I just answered my own question. But as a side note, I took the liberty earlier of getting to the bottom of the rattling I was hearing in the transmission. It turned out that two of the three needle rollers in the starter clutch had fallen out of place! I put it back together and then took it for a ride with the snorkel adjustment. When I tried to start the damn motor just kept spinning! I kick started her and rode her back home and disassembled. Turns out that the recesses that the needle rollers sit in were clogged with dirt and grease and had caused the needle rollers to get stuck in their inner most positions. That prevented the ratcheting function from occuring. I sprayed some carb cleaner in there, cleaned all the crud out and eventually loosened the retaining springs and now the needle rollers sit snugly in place. Put everything back together and now she's running like a charm. I'm learning so much here. Dayum!

[mccanic]

ill way the carb and see about shipping. im glad your learning!!

[tango]

I see where UPS has a service where the receiver pays the fee and the sender just drops off the package at a store. I hear that both FedEx and DHL have that option as well. Now...if the very capable (and affordable) USPS has a similar setup we'd be good to go, right?