My 2001 Honda Dio Build

[robokirby]

Hello! This is my 2001 Honda Dio build! I've recently been having some issues so I'll touch on those shortly - I'm going to try to be as descriptive as I can here, Maybe that will help someone some day in similar shoes, Here the details;



Locale/Elevation: Toronto, ON / 76m above sea level
Average operating temp: 25-30° C / 77-86° F

Engine
AF18E
Cylinder/Piston: Naraku Aluminium 48mm 75cc
Cylinder Head: Naraku 48mm
Spark Plug: BP8HS
Crank: Not stock – not sure what make though, previous owner install
PSI: Not sure of the exact psi however it feels really high, better than my Contessa ever was. Likely 130+

Exhaust
Giannelli Limited Series 70cc (similar to the Arrow)

Intake
Air filter: mini cart air box
Intake manifold: OKO 26mm reed block intake
Reeds: vforce 8 petal reed block
Carburetor: 21mm OKO PWK blk
Pilot Jet: 40
Needle / clip position: 3G9 (stock) #2/5 clip position (#1 being leanest)
Main Jet: 88
Air Screw: 1 turn out
Idle screw: .25 turn out, Idles at 1500-1750 RPM

CVT
Variator: Kitaco High Speed Pulley
Weights: 5g rollers - 30g total
Shims: 0
Drive Boss: SYM DD50
Belt: BANDO 669-18-30
Torque Driver: DIO ZX Driver – Over range 118mm vs stock 108mm
Clutch: KOSO Performance Clutch
Clutch Springs: 2000rpm red
Contra Spring: 1000rpm blue /w Motorforce twist control bearing spring seat
Clutch Bell: TWH light weight

Other additions
Kitaco 120km/h speedometer
Runleader RL-HM035LT Tach/Hour/Cylinder head temp sensor
Full SUPER DIO body kit - Pearl white paint
Front Disc brake conversion





The carb / CVT tune now feels great overall, Quick on launch with the mid range at about 8k rpm and WOT getting just under 10k. Haven't ran WOT for more than a minute or so since the cylinder is still new, After taking it easy for 100km or so I'll have to see what the top speed I could get would be.

[robokirby]

So the cylinder is new, as well as the carb/intake. I think I'm kicking myself for swapping these out at the same time, but it's just when all the parts arrived. I was previously running a pod filter and different jets in the stock carb and a Contessa 70cc kit but had seized. I could re-hone the cylinder, but for the price of a new piston/rings/gaskets and the honing I just got the whole Naraku kit – Plus I was interested in trying the aluminum, as well as getting the stock airbox working properly.

So the biggest issue I'm having is I cannot seem to get this bar tuned for the life of me. With the above jetting I can ALMOST get it to idle.. I have to have the throttle open the slightest bit. The midrange and response feels decent, and it is slightly boggy in WOT until the RMP's get past 7k or so. However I am not really going full speed WOT since it's a new cylinder so I'm mainly just trying to get the idle to ¾ feeling good now.

I have every pilot / main jet imaginable at my disposal, Also noticed my stock needle may work in this 19mm and it has a slightly different profile. I'm going to take off the carb today and really dive into it- I'm curious if something in the pilot circuit might be clogged since I am struggling so hard to get it to Idle though I figure this really shouldn't be the case since it's a new carb.

I've worked my way down from a 45 pilot and 105 main jet. I know the current 92 main still feels a little boggy, however I am hesitant to go any lower since I have yet to get it to idle properly. Plus my math seems to indicate I should be running closer to a 98 main so I am worried.

Stock 19mm carb 88 main jet + 5-10% (exhaust) + ??% (airbox modification)

The 19mm Carb also came with a 38 Pilot, however I just dont feel like that is enough from everything I've read. I just don't want another seize.

[Meatball]

You have alot of time/money wrapped up in your scooter. You want it to run and run well. Youve got it covered from stem to stern with hand chosen components that have been proven to be top notch many times over....my question for you is...

Why on Earth would you put a POS $13 carburetor on it and think it would be ok? Its like topping off filet mignon with a turd and thinking it will still taste good.
https://www.bamboonline.xyz/carburetors ... -10483.htm

Sounds like sweet ride otherwise tho. Welcome to the forum

[robokirby]

dang I got ripped off I paid $13.50 for mine. ebay link

I'm just really cheap haha.

Surprisingly it's actually quite nice - I understand me starting by saying I'm having tuning issues and a cheapo carb doesn't jive well. But trust me the quality of this one is helluva lot nicer than my 16mm.

[Meatball]

I agree with you whole heartedly that paying $13.50 for that carburetor is....indeed....a ripoff. Good luck with tuning and be sure to let us know how that goes.

[robokirby]

I am smacking my head trying to get this carb to idle. Everything is functioning properly, no jams in the pilot circuit. Tried larger / smaller pilots and 40 is the sweet spot. It will almost idle.. I have to have the slightly throttle Input.

I've been trying to read through people using a similar set up as me and almost everyone I see is using a larger carb with the arrow exhaust / 70-80cc cylinder.

Does anyone here have experience with the arrow exhaust?

[Meatball]

Plenty of members own Arrow exhausts. I had one for awhile before I swiss cheesed it. You have the Gianelli which is (supposedly) identical to an Arrow but I disagree. I have a Gianelli as well and the Arrow pulled harder and was able to revv higher. The G-pipe looks cool but Id trade it for an Arrow in a heartbeat.

[robokirby]

I mean I'm really just looking for Input if the 19mm carb is too small. This is the pipe I have so it's what I'll work with. Like I said I generally see set up with larger carbs.

Maybe some constructive feedback there?

[Meatball]

Your post had many statements and one question...which I provided input on my experience with the Arrow pipe.

A 19mm carb is fine for a 70-80cc bore. Its on the small side of the acceptable range for that size bore. Pipe used has nothing to do with choosing the size of carb, displacement does. As you change pipes, you WILL need to re-jet the carb to accommodate the different flow characteristics but not change carb sizes.

When you choose a carb size within the acceptable range of your bore, youre making a decision on how youd like your motor to operate...how you mostly ride. Choosing on the small size (in this case 19mm) it will be snappy on take-offs and acceleration since air speed at the venturi will be increased. However, it will platau on top end rpm’s because of the small-ish 19mm.

If you choose on the large side (say 26-28mm) your top end and max rpm’s will increase, you’ll use larger jets and mid to upper rpm torque will be improved. Assuming the pipe used can flow that well...your Gianelli pipe CAN. This will all be at the price of acceleration from 0-30.

This is why a 24mm carb is a popular choice for 72cc builds. Its a good “middle of the road” size with minimal top/bottom compromise.

Ditch the cheapo carb and get yourself a 24mm Polini PWK and save yourself the frustration.

[robokirby]

Awesome thank you!

I definitely have some shopping to do. Likely new intake manifold, 24mm Carb, & Air filter. Looks like I'll need new jets as well. Intake is the only part of the engine I haven't sunk much money into so I guess sit makes sense. Will likely go with OKO, Treatland has some good options.

I think that will only leave cheap-ish reeds in my intake set up - However I'm sure those will last the rest of the season and I'll likely upgrade those over the winter. Either that or I could always try swapping in the carbon reed from my old Contessa kit. But swapping out a 2 petal reed block for a 1 petal seems odd.

[robokirby]

So I've redone the intake and now I'm still pulling my hair out trying to get the carb set.

So I have an OKO intake / OKO 21mm / and this little cart airbox (https://scooterswapshop.com/products/ra ... 676b&_ss=r)

I managed to find a similar build thread (http://www.scootling.co.nz/bb/viewtopic.php?t=1311) with someone using an airbox. Seems to be hard to find build treads where people are not using pod filters.

In that thread they end up running a #45 pilot, #88 Main, stock needle at the mid #3 clip.

So with my set up I would rather be safe so I started tuning with a #45 pilot and #102 main.

I couldn't get the #45 pilot to feel right so I've gone down to a #42 and it idles fine and is feeling crisp to 1/2 throttle. I haven't touched the idle screw and the air screw is 1.0 turn out.

I've worked my way down from the #102 main to a #92. Now My issue is that at full throttle it will rev up, cut out, and repeat. If I back the air screw out to 2.0 turns it seems a lot better at full throttle - still cutting out but a lot less. But with the air screw 2 turns out the low end feels terrible again.

This is all just driveway testing too since it's not really moving anywhere. So I guess if I am seeing improvements backing out out the air screw that would be leaning out the mixture right? So I'm guessing the #92 is still too rich. I'm just having a hard time identifying a lean / rich condition. I figure once I get it moving I can do a plug chop but this is all just center stand testing.

I guess I can keep dropping the main jet I'm just getting worried at this point.

[Meatball]

Pressure test your motor and look for leaks. The oko is known to leak out of the box but are good once sealed up. Install a CHT if you dont have one, pretty tough to tune without one and are risking seizure. Ive never had the Taiwan bore you have but Im thinking 40/110-120 would be ballpark since the oko carbs like higher main jets than others. Be 100% sure theres no leaks before carb tune or youre wasting your time.

[robokirby]

Yeah thanks! I was actually just reading and saw someone realized their OKO was leaking through the choke pull assembly. I will sort out how to pressure test the carb and get that taken care of. I realized the carb boots hose clamps screw tracks are getting pretty beat up and I'm not able to tighten it down as much so I'm going to replace those with some aircraft quality hose clamps (https://www.aircraftspruce.ca/catalog/a ... kkey=29443)
I'm also waiting on some better quality exhaust gaskets so that should ensure there's no leaks that side.

I did install a CHT / tach combo, it's been super handy.

Thanks for the jet suggestion! - I will try moving the Pilot down to the 40, I did feel like the 42 was a bit too much. As for the main it's funny, Initially I had a foam pod filter on there and it could rev right up high with a #118, But I'd really prefer to get this thing set up with this airbox as the bike sits in the rain a lot, and this airbox as multiple attachment points so it shouldn't ever come off. So after adding the airbox I've been downjetting like crazy, but like I said I'm now down to a #92 and getting worried. I know for sure the 110-120 range was too high as everything was soaked in that range, spark plug covered and exhaust sputtering gas.

[Meatball]

I mustve missed where you said the stock airbox was used. Certainly need lower jet than with a pod. Also the intakes have been known to leak out of the box. Imperfect mating surfaces cause this. Some opt to try and correct this with high grit sandpaper on a piece of glass. I would just use a standard paper gasket with goop on both sides.

[robokirby]

Wow okay so here's some real progress now. Blocked all openings on the carb checked for leaks with my shotty little hand pump and seems solid, Still need to check the rest of the intake block / engine - That's on the to-do list when the hose clamps and exhaust gaskets arrive.

Kept moving the Main jet down and bam, it's feeling great now, Just need to sort out a few more kinks.

So what I've done is;
Main jet down to 88
Pilot down to 40
Needle clip moved up / leaned one position to the mid #3 slot
Air screw is 1 turn out
Idle is 1/4 turn in from stock - idle's at 1600 RPM

So once it's going it feels great, top end is responsive and strong. Everything is fine once your moving and it's over 3000 RPM. However from take of I can either hold 1/8 throttle until it revs up and go, or hold 1/2 throttle until it goes. On launch it's really sputtering from 1/4 to 1/3 throttle with minor improvements once you get going. The link below has a great chart that seems to show that 1/4 - 1/2 throttle is when the Needle clip / Needle taper matter the most. Seems like I could try to move the clip up / lean one more to the #2 position and that might solve that sputtering. Hopefully anyways because I do not want to get involved with changing out needles, That seems like a whole bigger headache.

https://www.millennium-tech.net/pdf/Jet ... trokes.pdf

This is just going around my block a few times, I have one or two more fresh spark plug so I'm going to really try to get this feeling best before I do some plug chops.