part/full throttle bog, fuel diaphram & carbon cleaning

[viking427]

New here, but not to motors;
1) 1985 Spree starts up fine warm or cold but won't pull any weight above 1/2 throttle & bogs then dies if extended to full throttle. Clean air filter and lid are in place, A/F screw adjusted 1.875 turns out. I cleaned lower half of carb (bowl, float, needle/seat) by sloshing around in a cup of gas and checking float/needle action before finding this forum (I'll follow up with proper carb cleaning R&R as described).
2) Can a 2 stroke motor be "steam" cleaned of carbon deposts by carefully spraying small amounts of water into the air stream ahead of combustion like water injection ? Automotive (any 4 stroke) motor pistons/chamber/valves have been cleaned spotless this way since the dawn of time, but I hesitate on 2 strokers since the crank/rod/bearings are exposed to the A/F mixture - that would now contain water vapor.
3) I'm aware of the fine-tuned state of 2 strokers (intake and exhaust components work together as a system) - precluding any modification to either one, but I have a ? on compression (haven't checked it yet). I saw some mention here that excessive compression (over 115#) can cause problems also - how ? I have access to a bridgeport mill and can flycut .060" off the head to restore/add compression if required, but would like to know the danger of bumping the compression a bit (other than needing higher octane gas) - someone mentioned it'll lower your upper rpm limit - how ?
4) My fuel valve lets fuel flow from the tank freely ..no vacuum source needed. I suspect dirt holding the diaphram open and I'll fix this, but how could this cause a too rich condition since the bowl float and needle jet are what regulate fuel flow out the bowl and into the airstream (not sure about the idle cicuit) ?
-TIA

[Tippmann98]

If you want to take some carbon out or clean the block / head just take it off and do so. If you use water, just be sure to wipe it down and get it dry. I personally use carb. cleaner and a file carefully. Plus, water doesnt burn well and it would probably not help any within the muffler. (that is if any was left after combustion). Your petcock valve does sound amiss, i would try soaking it in carb. cleaner or some sort of solvent for a while and then see what it does. If no luck, i think there is one currently on e-bay.

[Jerry]

If the fuel shutoff is allowing fuel to run constantly, then it's obviously dirty (not closing properly) and could also be allowing fuel to seep into the intake port of the engine giving a rich mixture. (What should be vacuum).
As for water intake to clean carbon deposits....ABSOLUTELY NOT. Water would not compress and it will pop the rings in a heartbeat. Probably the piston too if cooled so rapidly. Don't even attempt it. I've heard of others with the same questions and also heard of blown pistons after they attempted it.
As for the fuel valve - contact drichardson@core.com he should be able to help you out. (Cheap and dependable).
Excess compression (over 120) robs power believe it or not. Insufficient fuel flow, air flow and exhaust. Mix goes haywire usually hotter and burns the piston. The rings don't last either.

[Tippmann98]

Oh, my post was kind of mis leading. I meant using water as in with the parts OFF the engine. As a final rinse down or something. But before putting the block back on. Dip your finger in 2-cycle and swave the inside of the block. It makes the process easier.

[noiseguy]

You can't cut .06" off the head without smacking the head into the piston. Insufficient clearance. I pulled .015" off the head on mine, bumping compression up to around 130 PSI. Helped starting, but didn't make it any faster. Pulley mod will make it a little faster.

You can't bump compression up enough on these engines to require special gas. That said I alway burn premium anyway.

Excessive compression usually indicates carbon fouling; thus carbon fouling is the problem, not excessive compression.

Try removing the fuel valve and soaking it in clean gas for a few days. Worked for me.

[spree-geek]

I just got my spree from my neighbor and mine does the same thing. At about 3/4 throttle it bogs out and will die if you keep it pinned. We used to own it and my dad cleaned the carb, we gave it to our neighbor and he cleaned the carb, and now I have it and I cleaned the carb. I dont think that its the carb. I dont know much about the sprees and when you take the gas line off the carb., the gas doesnt run out of the gas line. Is that normal? I also took off the thing right below the tank that is attached to the gas lines. I blasted carb cleaner through it, that didnt work. Could it be the air filter? I dont know help me out!

[ferchja]

Obviously a noob to Sprees but not engines. My $0.02 if the manufacturer (who believe it or not spends 10's of millions on R&D on trying to get the most, both performance balanced with longevity out of an engine) and aftermarket companies (who spend 100's of thousands on R&D) do not offer any performance mods to an engine product, it may be that the product has reached nearly a 100% of its potential. Think about it.

The engine, transmission and rear wheel assembly are as small as a $10 toolbox and they can propel an average human being to a sustained 30+ MPH all while getting between 80-100 mpg. The whole scooter is light enough to pick up and move into the basement or store above the refrigerator.

I agree with most on this forum I am not sure I want to go any faster than 40mph on this. It's an early version of a Razor scooter. If you are willing to spend $400 on performance mods to get the thing from the mid 30's to let's say 50mph, then buy a 1984-1987 250+cc motorcycle. I just picked up a Yamaha 1982 400cc Seca for $55, and it will do 100+mph.

Not saying there is anything wrong with performance mods, I do them all the time on my other vehicles, but its usually based on results by companies that have million invested and getting proven performance boosts. I personally think the Sprees and other Honda scooters are very respectible, just the Spree is priced to live life as a unmoded transportation device.

Jeremy

[vette76]

they cant be that concerned about performence with that big restriction in the intake. removing that was proven to give 4-5mph increase.

[noiseguy]

Obviously a noob to Sprees but not engines. My $0.02 if the manufacturer (who believe it or not spends 10's of millions on R&D on trying to get the most, both performance balanced with longevity out of an engine) and aftermarket companies (who spend 100's of thousands on R&D) do not offer any performance mods to an engine product, it may be that the product has reached nearly a 100% of its potential. Think about it.

Jeremy

You are correct, to a point. Keep in mind that scooters have legally mandated performance levels. 2.5 or 2 hp (for Iowa model), 49cc max, and exhaust noise maximum levels below 78 dBA. Even if the manufacturer wanted to make it faster, it would not be legal to sell in the US.

So if one derestricts the intake and exhaust, one can bump the Spree above 2.5 hp and increase noise levels to above those legal (but still below "ticketable.") Now the Spree would be illegal to sell new, but not interesting enough for most officers to ticket. Harley's are a great example of this phenomenon; that's why everyone swaps pipes.

As for the price/displacement, I agree, there are cheaper ways to go faster. But you can do a lot with a Spree and not spend much money. That's what we're aiming for here.

[vette76]

it really * me off that a spree cant be a little louder but a harley can have straight pipes. what the * is the difference?

[darat]

well a harley has a 4 stroke and a spree has a 2. 2 need back pressure. i got a dump on my spree with the muffler so i can have it going through the pipe or right off the moter. with the cap off that thing is so loud it sounds really cool. my dump fell off when i was comeing home from my house and at the light there was a harley next to me and it was louder then the harley when i took off. the guy just looked at me like *. it was so funny.

[vette76]

i was thinking of doing that. what was the increase of speed?

[vette76]

20min. later...

well, i did it. all i need now is to get the parts back that are being machined. i used part of a threaded scooter fork. a quarter fit in the hole in the nut perfect and the nut stops so it wont fall out. cant wait to * off my neighbors,lol. well see what that * up the street with the harley likes it.i need to break in my parts first tho before i put it on the kickstand and race it in front of his house.