Honda Spree and Elite 50 Forums

I have an 04 Kymco zx50, which I understand uses the Honda dio engine.

If I had known this before I started the rebuild/modification I would have picked up some better components, but oh well, there's always potential for another scooter in my stable.

I've been a motorcycle rider for seven years, but have wanted a scooter since my mid teens. I finally got one for $20 with a siezed engine. I rebuilt it with some aftermarket and oem parts and absolutely love it so far.

Current Mods:
OEM Crank and bearings
Airsal Cylinder and Piston 70cc
Arreche Carb 19mm w/#80 main (this may be causing problems..)
Technigas expansion chamber exhaust
1500rpm Clutch springs
Stiffer torque spring
7g roller weights in stock variator

My only issue that I have with it (while it ran well) is that my top speed is limited to 37-38 mph. I'm using it for commuting mainly, and two of the roads I travel for a total of 4 miles, are 45mph speed limits. The remainder are 20-35 with the majority being 35mph.

The CDI is still restricted, I can derestrict it with a simple scotchlok connector, but for engine life I think I should leave it alone. I made another post, and was recommended a gear kit, so that's on the list of future mods.

I'm still on the original intake manifold (12.5mm w/ a 19mm carb) which I believe is causing issues. What parts should I look into for changing out the intake side? I'll be honest, I know nothing about scooters. I have alot of experience with 4 stroke carb'd and FI motorcycles, but nothing 2 stroke, and no scooters.

My oil mixture pump is shot. This is what caused engine failure for the previous owner. I don't know how much a replacement is, still waiting to hear back from the dealer. However, being that it's a standard dio engine I think I may just pick up a used one for much less. The question is, do I trust that pump? Or do I premix? This leads into the next question

My #80 main jet. This may be the source of what ails me currently. I tuned the engine through plug readings alone. Everything seemed to be fine, I had to move the needle down one clip, but other than that it was great. I started out on two tanks of 50:1 conventional 2 stroke oil. After a 45 mile trip I decided I could switch to 30:1 synthetic. I mixed 4fl oz of mobil 1 2 stroke racing synthetic oil to one gallon of 93 oct. After that it never ran right. I was having problems prior to that, but they increased after switching the fuel. My thinking is that it's possible after reading other's ideal setups, that my main is too small and by increasing the viscosity of the fuel, everything got messed up.

Before I knew the oil pump was shot, I decided to give it a try after having the above issues. I hooked it up, put oil in the lines, fresh fuel in the tank, cleaned the carb out and started it up. Engine fired right away no problems, revved beautifully, but when I pulled off the output line from the oil pump, there was no flow, even when I manually opened the oil pump valve. I immediately shut the engine off (less than a minute runtime w/o oil).

Basically where I'm at now is that I want to increase my top speed, and get her to run right either with a mixing pump or premix, doesn't matter to me. Premix would be cheaper without a doubt, but what it looks like to me is that premix is too heavy to be drawn through the carb and intake properly. If this is the case, would replacing the intake manifold/reed valves to match with my intake make up for this?

I can justify spending as much as the scooter will save me over the summer which I have calculated to be $1080. I'm $750 into it, so I don't want to spend more than another $350 to finish if at all possible, but that's not to say I'm not willing to spend more. Basically whatever it takes at this point, I'm too deep into it to put a small cap on.

So my main question is where do I go from here?

1.) Gear kit
2.) Intake manifold? Reed valve?
3.)???
4.)???
...

Sorry for the rambling post, hope it makes sense to somebody and you can give me a hand.

most of that stuff can be bought from any moped shop in hawaii . I seen intakes on ebay for real cheap. Sometimes way cheaper than shops
let me know i can get some good deals sometimes on what your looking for

im telling you dude.
Gears!

i have a bike with a weak bore kit, stock carb, stock pipe, and stock intake and i can hit 50-55

A moped is like a motorcycle stuck in first gear. No matter how strong /fast you make it, it will only go like 5mph faster then stock.
But if you gear it down some (stock is like 11:1. Gear it down to 8.44:1) its comparable to a motor cycle in 3rd gear. But since the motor is giving off more power the take off does not take a lose. And, since its geared out it will have much more top end.

The best bore kit you can get alone will only add 5mph if that. But that same motor with that same bore with a gear change will add 20-30mph more to the stock top speed.

What about my carb issues?

Is premixing the way to go or can I trust a new oil pump? What do the oil pumps mix at? The cyl manufacturer recommends 30:1, so I would like to stick with that, but running premix caused it to be finicky.

danmdevries wrote:What about my carb issues?

Is premixing the way to go or can I trust a new oil pump? What do the oil pumps mix at? The cyl manufacturer recommends 30:1, so I would like to stick with that, but running premix caused it to be finicky.

what do you mean 'Carb issues' ?
Jets only change if its rich or lean. Just do a plug chop and make sure your not running lean.

if the cylinder is 72ccS or less your good with going with the pump. Just wire tie it open.

if you need the ease of the pump, get a new one, you can trust it. you can either put it on and calibrate it, or hang it in the 'cable failed-full oil' position...

if you don't just premix.

32:1 is on the 'lots of oil' side of the ratio spectrum, with a good synthetic i'd be comfy at 40:1

Allright, I'll play with it some more.

I've got some running problems that I haven't tracked down completely, when I have time I'll get back out there to mess with it. They only started after I switched premix ratio and oil type.

I'm thinking I want to go back to using the oil pump for a few reasons.

One: when I switched from 50:1 to 30:1 I suddenly ran rough and fouled out plugs like crazy. I drained tanks and ran straight fuel and it ran great but I found my oil pump wasn't working. I connected a syringe and very slowly added oil to the port on the carb and it continued to run great while smoking from the oil, so I thought the fuel was not passing through the carb effectively. I attributed this to two things, one being that there's a huge restriction at the outlet of my carb and the decreased flow may be affecting the venturi effect that the carb should have and second, the fuel possibly became too thick at 30:1 to pass through properly. Call me out if I'm completely retarded in my thinking, again this is my first two stroker.

Two: I got about 55-60 miles on a gallon of fuel. There's going to be times I won't be able to stop at home to refuel with a proper premix, and I don't want to mix in the tank for fear that I would not mix thoroughly and end up with a clogged carb.

I'll order the gear kit once I get everything running properly again. I got a price quote from my local dealer on the OEM parts I need, can anyone tell me if these prices are reasonable or if/where I should look for them somewhere else?

Drive Belt: 39.99
Oil Pump: 62.99

To me it doesn't seem too out of line, except the drive belt that I wouldn't expect to be over $20, but I don't know...

you will know if the oil pump goes bad, in the morning when you start up the engine will smoke like *.

gears is one of the main restrictors in a stock motor..
if i was you, dont use the oil pump. just do a 40.1 mix which is about 3.5 oz to 1 gallon. Very important, Use good quality Synthetic pre mix oil, no wally world weed eater special ! LOL That stuff wil clog pipes...
aloha
D

tru72 wrote:gears is one of the main restrictors in a stock motor..
if i was you, dont use the oil pump. just do a 40.1 mix which is about 3.5 oz to 1 gallon. Very important, Use good quality Synthetic pre mix oil, no wally world weed eater special ! LOL That stuff wil clog pipes...
aloha
D

I am definitely ordering a set of gears once I sort out my running issues.

I explained why I would like the oil pump, I can not always make it home by the time I need a fill up, and I don't want to mix in the tank for fear the oil will not mix and clog the carb.

danmdevries wrote: I'm thinking I want to go back to using the oil pump for a few reasons.

One: when I switched from 50:1 to 30:1 I suddenly ran rough and fouled out plugs like crazy. I drained tanks and ran straight fuel and it ran great but I found my oil pump wasn't working. I connected a syringe and very slowly added oil to the port on the carb and it continued to run great while smoking from the oil, so I thought the fuel was not passing through the carb effectively. I attributed this to two things, one being that there's a huge restriction at the outlet of my carb and the decreased flow may be affecting the venturi effect that the carb should have and second, the fuel possibly became too thick at 30:1 to pass through properly. Call me out if I'm completely retarded in my thinking, again this is my first two stroker.

Two: I got about 55-60 miles on a gallon of fuel. There's going to be times I won't be able to stop at home to refuel with a proper premix, and I don't want to mix in the tank for fear that I would not mix thoroughly and end up with a clogged carb.

I'm running Mobil 1 full synthetic 2 cycle oil which I assume is good stuff

maddog wrote:you will know if the oil pump goes bad, in the morning when you start up the engine will smoke like *.

My oil pump did not pump oil at all.

Anyone have any recommendation on where to get the drivebelt cheaper than the dealer? Are Honda branded belts cheaper than the $40 the Kymco dealer wants?

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Anyone have any recommendation on where to get the drivebelt cheaper than the dealer? Are Honda branded belts cheaper than the $40 the Kymco dealer wants?[/quote]

I think they are like 30 bucks but am not completely sure..maybe $34

Okay I can not seem to eliminate this issue.

This is a recurrant problem: I have started it up, rode it for many miles (today 69), including shutting it off and restarting after a short rest. After it sits for 20-30 minutes after running beautifully, it will start fine, then rev up and immediately foul the plug and die. No amount of coaxing will get it to restart. Even if it sits after ripping around the neighborhood it doesn't seem to affect it, it's only after running at high speeds for long periods of time.

To get it to restart previously I have:

Cleaned the carb
Drained the tank and refilled fresh
Changed the plug
Cleaned the plug
Let it sit for a couple days

Nothing consistently fixes the problem. I was thinking it could be an issue with the electric choke, but the unit gets hot so I'm assuming it works?

Plug results: black at full throttle, dark brown at partial throttle

I emailed VT about ordering a gearset, intake and reed valves today, I'm not going to try for a spot-on tune until it's set up the way I want it.

Sounds like the plug is fouled by the time you stop; the only reason it's firing up after short stops is that the chamber is still hot.

Couple of things to try. I've never messed with these engines stock, let alone with mods, so take it for what it's worth:

1) Unless the engine is high compression (is it with this jug/head?), try running lower octane fuel. This is counter-intuitive; it caused the combustion chamber to run hotter and may help. Either way it's cheap to try.

2) 30:1 sounds high... don't most guys run 50:1? Why not go back to 50:1 of conventional oil/fuel like you were using?

3) Try running a hotter plug.

2-strokes are funny; they are more sensitive to tuning on the intake and exhaust than 4-stroke. Hopefully the expansion chamber you're running is a good combo for the rest of the setup. For the intake, you might try lengthening the run to the pod filter that I'm guessing that you're using. The engine is sensitive to the distance between the slide and the mouth of the filter.

On the oil pump; oil will dribble out of a stock pump at about 1 drop every 5-10 seconds at idle. Likely you didn't do any damage in 1 minute; the bearings hold oil a while.

I went back to a 40:1 premix. When I went 30:1 it wouldn't run right, it would run the way it does when I have this problem of fouling.

The plug I'm using, don't know the exact number off hand, it's an NGK BP9...? I can find out, it's the size that came with the cyl kit. It's a different number than the stockers.

My intake side consists of: stock intake manifold, stock reed valves, stock airbox with stock filter foam and a 19mm Arreche carb. That will change whenever I hear back from vtcycles, I will replace the intake with one that fits the carb and run a pod filter of some sort.

I heard back from VT cycles today. It appears that I am out of luck for increasing my top end any further as there are no gearkits that will work with my scooter. The engine falls flat on its face around 40mph. The Kymco uses 12" wheels, and if I gear up with any of the available elite kits, VT claims it will not be able to move it with the larger wheels.

According to them, stock gearing is somewhere around 15:1, so I'm wondering if it would be possible to put stock elite gearing in there.

And as far as an intake manifold, he wants me to buy an entire performance intake/carb kit with reed valves, intake manifold, carb and air filter. I just spent $160ish on just a carb through moped hospital racing, I would like to make that work, but it's a 19mm where the one VT wants me to put on is 28mm. The entire kit they're suggesting to me is the same price I paid for my carb alone...

I closed the gap on my plug a bit and it's been doing well so far. I've found it to be extremely finicky about fuel. I measure out the oil in a 30cc syringe (1oz) and if I'm not as precise as possible, the plug fouls. The last tank that I had problems with (I've thrown out 9 gallons of fuel now due to bad mixtures) I wasn't precise, I think I probably put 32mL in each syringe, which left me with about a half oz too rich on the oil end, and it wouldn't run.

I can't get on and ride when i first start it up, I have to leave it on the center stand and slowly get into the throttle to about a quarter throttle and let it cough spit, choke out for about 10 minutes and then it'll go, with intermittent misfiring for the first 5 miles or so, then it clears up and runs great.

I really think my running issues are a combination of running stock airbox and stock intake manifold, it's got signs of severe restriction, like falling flat on its face above 40mph. Once I hear from you guys or VT on whether it's worth it to go with their 28mm setup over my 19mm with a new intake mani we'll find out. I haven't inspected my reed valve either, what's the symptoms of a bad reed set?

A picture of it as it sits. I'm going to put the plastics back on, but cut them back to only cover the tank/electrical and hug the frame down to the floor, and trim down the fender, installing a tire-hugging fender instead and paint everything bbq black or chalkboard green, there's no saving the plastics and I'm not going to replace them.



Here's where I started, locked up engine, looks like it had never been oiled