200cc consumes absurd amounts of gas

[Wild Dog]

Originally Posted by OneLeggedRider

Why is fuel consumption so important to you? 55mpg is quite acceptable for these bikes. I have a big bore 400 2-smoke that has a huge fuel tank that might last you 3 hours at most. I also have a big Chevy truck that gets 8mpg on the highway on a good day. Even my daily driver, a Toyota 4x4 only gets 12mpg. Gotta pay to play.

There are a lot of reasons why, that can range from economy to environmental.
My Toyota Hilux 4x4 diesel gets about 30 to 33 mpg, i can haul all i need, i can do about 900 km with a tank. So why settle for less mpg?

Same goes here if other motorcycle with the same engine are doing 70 mpg why settle with 55 mpg. It's just a waste o money and resources.

[OneLeggedRider]

Originally Posted by Wild Dog

There are a lot of reasons why, that can range from economy to environmental.
My Toyota Hilux 4x4 diesel gets about 30 to 33 mpg, i can haul all i need, i can do about 900 km with a tank. So why settle for less mpg?

Same goes here if other motorcycle with the same engine are doing 70 mpg why settle with 55 mpg. It's just a waste o money and resources.

Diesel..

All the reasons you stated are valid, but to me 55mpg is good gas mileage. And anything that is designed to go offroad usually isn't fuel efficient.

[Wild Dog]

Originally Posted by OneLeggedRider

Diesel..

All the reasons you stated are valid, but to me 55mpg is good gas mileage. And anything that is designed to go offroad usually isn't fuel efficient.

Since he uses liter pero kilometer, i think he is either from South America or mostly from Europe.
In the old continent and South America we have a lot of old stone paved roads that can be pain to ride with a street motorcycle and for those roads, the on/off motorcycle are a great choice.


About the 55 mpg i don't think is that bad either. Like in said in an early post i used to have the same millage when i was running a bit rich. The only reason that i tuned the carb was because the engine was randonly stalling at idle and the petrol smell was too strong.
But if his motorcycle runs fine i wouldn't worry that much either.

[Rozkrwawiacz]

And anything that is designed to go offroad usually isn't fuel efficient.

Are you aware that Chinese street and dirt motorcycles gets the same engines? Things that is more or less off-road oriented are wheels and frame. So apart from aerodynamics there is no reason for it to consume significantly more fuel, unless actually used off-road. Mind you I'm not complaining about high usage in the dirt, that is obvious.

All the reasons you stated are valid, but to me 55mpg is good gas mileage

It is avg. mileage for bikes about 450cc. Why should I settle for worse of both worlds: high consumption and struggling to get to 65mph at the same time?

Like in said in an early post i used to have the same millage when i was running a bit rich.

It would be great if I was running rich, but unfortunately that's clearly not the case.

Since we got through discussion if it is important for bike to be fuel efficient or not, can we focus on reasons for increased fuel consumption apart from carb tuning?

[bogieboy]

Originally Posted by Rozkrwawiacz

Are you aware that Chinese street and dirt motorcycles gets the same engines? Things that is more or less off-road oriented are wheels and frame. So apart from aerodynamics there is no reason for it to consume significantly more fuel, unless actually used off-road. Mind you I'm not complaining about high usage in the dirt, that is obvious.



It is avg. mileage for bikes about 450cc. Why should I settle for worse of both worlds: high consumption and struggling to get to 65mph at the same time?





It would be great if I was running rich, but unfortunately that's clearly not the case.

Since we got through discussion if it is important for bike to be fuel efficient or not, can we focus on reasons for increased fuel consumption apart from carb tuning?

on the mileage comparison with road bikes, tires and aerodynamics play a BIG role when you are talking a 15HP engine... i noticed a huge difference i acceleration and rolling resistance/throttle percent to hold a certain speed when i swapped the knobbies for supermoto wheels/road tires.... however, the top speed and fuel consumption stayed about the same, since the main jet in the carb is what its running off of when its whacked full throttle for the 55+mph cruising around here.... just am able to get there quicker....LOL

bottom line is asking a 200cc to push 65mph and be efficient just isnt going to happen, not on a carb'd overhead valve engine (or stock ohc for that matter)

[Wild Dog]

Originally Posted by Rozkrwawiacz

It would be great if I was running rich, but unfortunately that's clearly not the case.

can we focus on reasons for increased fuel consumption apart from carb tuning?

So far you have done this

-You worked on chinese bike before
-You checked the spark plug, cables
-You replaced the piston rings
-You changed the carb for a pz30.

Which means you have done almost everything to have the bike running properly

BUT

This is the problem when it comes to troubleshooting over the internet and i'm saying this without trying to be rude or offensive.
We have to assume that all of those step were done without mistakes, that you checked the CID, that you checked that the cylinder and piston clearance is within specs, that the carb is jetted correctly and tuned right.

[duck9191]

It's fairly simple, either the carb is rich, the engine is inefficient to your standards, the bike has a defect or your riding style is wasting gas. Have you checked for dragging brakes or a tight wheel? Do you use the throttle as an on/off switch or ride WOT constantly? Have you had someone knowledgeable with carbureted engines check your tuning work? The carb is the only way gas gets into the engine which is why most are pointing you to it being jetter rich. Riding style would be the next guess, yeah its only 50cc bigger but its a completely different engine, if you beat the hell out of it it's going to consume a lot more fuel.

[Wild Dog]

Originally Posted by duck9191

It's fairly simple, either the carb is rich, the engine is inefficient to your standards, the bike has a defect or your riding style is wasting gas. Have you checked for dragging brakes or a tight wheel? Do you use the throttle as an on/off switch or ride WOT constantly? Have you had someone knowledgeable with carbureted engines check your tuning work? The carb is the only way gas gets into the engine which is why most are pointing you to it being jetter rich. Riding style would be the next guess, yeah its only 50cc bigger but its a completely different engine, if you beat the hell out of it it's going to consume a lot more fuel.

Not even 50cc, just 29cc bigger

[franque]

I would double check compression and leakdown. What are your valves set at? This is assuming that you've covered the basics like not having too restrictive of an exhaust (like undue restrictions from bad welds from flange to header, or the pipe being plugged up/fouled by the burning oil), a clean air filter, nothing binding in the driveline (like from the wheel spacers being put on the wrong side), or also like bad bearings or dragging breaks, and no air leaks on any side. You could also play with spark plug heat range. Also, is the crankcase vent plugged? That can reduce efficiency, too. You probably won't reach peak efficiency until the engine is properly broken in, too.

I had a Chinese bike where the intake manifold had a gasket (if its the Honda copy, the intake should normally have an o-ring, which if the o-ring isn't bad is sufficient to seal it) that was cutting of 1/8 of the intake port. Speaking of ports, you could also clean up the ports, because the more efficiently the bike makes power, the more easily air can be pumped by the engine, and the more efficiently it will burn fuel.

After that, I would consider gearing. What is the speed that you are hoping to cruise at, and do you know roughly where the max torque is produced? I would gear accordingly, so that you can run (if it has enough power) roughly 3/4 load at the torque peak RPM (where the engine is running the most efficiently) at cruising speed. You could also adjust cruising speed accordingly.

After that, you could look at fuel injection, that might eke out a little more economy.

[Rozkrwawiacz]

@bogieboy

on the mileage comparison with road bikes, tires and aerodynamics play a BIG role when you are talking a 15HP engine..(...)however, the top speed and fuel consumption stayed about the same, since the main jet in the carb is what its running off of when its whacked full throttle for the 55+mph cruising around here.... just am able to get there 8quicker....LOL

Yeah, so it doesn't matter for fuel consumption, is what you're saying, supporting my point that street and dual-sport bike with exactly same engine shouldn't vary all that much when it comes to economy.

bottom line is asking a 200cc to push 65mph and be efficient just isnt going to happen, not on a carb'd overhead valve engine (or stock ohc for that matter)

That's not what I'm asking for. I said that I don't wanna settle for 55mpg on bike that doesn't easily gets to 65mph, since that's what about 450cc's burn at average whilst not having problem to get to such speed. Another words: if my bike have to burn so much I expect it to be faster, and if it won't get so fast I want it to burn less fuel.


@Wild Dog

You changed the carb for a pz30.

In fact I replaced it. It was pz30 before (shengwey to be exact) but it got bend due to clamping on broken gasket.

This is the problem when it comes to troubleshooting over the internet and i'm saying this without trying to be rude or offensive

I perfectly understand. I'm active on my local forum and often have the same dilemma.
On this note, because it started to bother me, are there some tuning templates for this setup (like jet sizes and needle position)?


@duck9191

It's fairly simple, either the carb is rich, the engine is inefficient to your standards, the bike has a defect (...)

And I am looking precisely for that defect.

Have you checked for dragging brakes or a tight wheel?

Multiple times. I even had case of break caliper (not even pads) grinding against disc, but I filed it down.

Do you use the throttle as an on/off switch or ride WOT constantly?

I would say that I am not the most "grandma-like" rider but I am not racing from every traffic light either. In fact I rarely turn throttle all the way to WOT even commuting between towns.

yeah its only 50cc bigger but its a completely different engine, if you beat the hell out of it it's going to consume a lot more fuel.

Actually my bike has 196.9, or something like that, not that it really matters. I just don't believe that semi-properly tuned Chinese 200cc (so either 163fml ohv or ohc) should burn that much unless there is something wrong in another department. That leads me to seeking help in locating this problem.


@franque

This is assuming that you've covered the basics like not having too restrictive of an exhaust (like undue restrictions from bad welds from flange to header, or the pipe being plugged up/fouled by the burning oil)

This is interesting, since this engine was actually burning oil for some time. I will definitely get to it (is there some smart way of going about it, or do I just stick some cloth/brush down the pipe?).

a clean air filter,

I got new foam this year. Did not have chance to get dirty before I noticed problem. Also checked it several times later.

Also, is the crankcase vent plugged?

On the contrary, it breathes air rhythmically and spit small amounts of oil systematically. Oil level is within specs so I think that maybe it's not thick enough?

You probably won't reach peak efficiency until the engine is properly broken in, too.

This bike was produced in 2006. I think that it's breaking-in days are long gone. I bought it used last December and now I'm getting it to serve me as good as possible.

[JerryHawk250]

One main factor is not mentioned here. What sprockets are you running? If you are running a low geared set of sprockets you will be turning higher rpms at 55 mph which means you will be burning more fuel to do the same speeds if you were geared higher. Good example is my set up. Saturday I took a long ride running 55-60 mph with 17/40 sprockets. At 55mph I'm turning about 5200 rpms and got 70mpg on the trip. I usually get 65-70mpg depending on speed. At one time I was running 15/40 sprockets. At 55 mph I was turning about 5900 rpms and would only get 58-63 mpg. 700 rpms affected the fuel mileage a good bit as you can see. I never really checked it with the stock 15/50 sprockets because they were to low geared so did do much street riding to check the fuel mileage. At 55mph it would be turning about 7400 rpms. But I'm sure it was much less the what you are getting now.

[franque]

Originally Posted by Rozkrwawiacz

On the contrary, it breathes air rhythmically and spit small amounts of oil systematically. Oil level is within specs so I think that maybe it's not thick enough?

This bike was produced in 2006. I think that it's breaking-in days are long gone. I bought it used last December and now I'm getting it to serve me as good as possible.

I can't say about viscosity, but it could be that you have excessive blowby (like the rings aren't sealing properly), as ideally it wouldn't be puking oil. Most motorcycle engines have breather tubes for the crankcase, but I've rarely seen ones fill up on a healthy engine.

Break-in primarily refers to the relationship between the rings and the bore; you put new rings in, it has to be re-broken in, and it is a matter of hours/revolutions the engine has turned with the components inside of the engine, not the age of said engine (especially as ideally the piston is never in contact with the bore, just the piston rings). It is possible that the bore is glazed, too, and if so, it would need to be re-honed so that the rings could properly seat, or you could replace the cylinder, as they're a dime a dozen. Like I said, I'd do a compression and leakdown test.

[bogieboy]

so, lets pull some empirical evidence... 2008 wr250r, averages from Fuely.com, so real world numbers that people have recorded: http://www.fuelly.com/motorcycle/yamaha/wr250r/2008

Based on data from 28 vehicles, 757 fuel-ups and 81,950 miles of driving, the 2008 Yamaha WR250R gets a combined Avg MPG of 57.94 with a 0.65 MPG margin of error.

and since you brought up 450s, how about a 2008 wr450... http://www.fuelly.com/motorcycle/yamaha/wr450f/2008

Based on data from 2 vehicles, 154 fuel-ups and 10,572 miles of driving, the 2008 Yamaha WR450F gets a combined Avg MPG of 42.67 with a 1.00 MPG margin of error.

2013 Honda xr250: http://www.fuelly.com/motorcycle/hon...0_tornado/2013

Based on data from 5 vehicles, 90 fuel-ups and 11,915 miles of driving, the 2013 Honda XR250 Tornado gets a combined Avg MPG of 57.19 with a 2.65 MPG margin of error

honda xr400r http://www.fuelly.com/motorcycle/honda/xr400r/2004

Based on data from 3 vehicles, 27 fuel-ups and 2,232 miles of driving, the 2004 Honda XR400R gets a combined Avg MPG of 47.28 with a 4.40 MPG margin of error.

and for fun... 2008 kawasaki ninja 250... http://www.fuelly.com/motorcycle/kaw...inja_250r/2008

Based on data from 71 vehicles, 2,065 fuel-ups and 350,754 miles of driving, the 2008 Kawasaki EX250F Ninja 250R gets a combined Avg MPG of 53.02 with a 0.45 MPG margin of error.

so in the end, it would seem that 55-60 mpg is acceptable for a 200-250cc engine mainstream, but not really for a 400-450...

may i ask what dual sport 450s with carburetors average 60 mpg?

[Rozkrwawiacz]

@boogieboy
May I ask why you bring fuel consumption of Japanese bikes while we are talking about Chinese bikes that, as was clearly stated before, doesn't have specific dual-sport engines?
Also why asking of specifically dual-sport 450cc bike, when it was you who allegorical evidence that actually supported point that style of frame and wheels doesn't matter much in fuel economy department?

If you wanna talk empirical evidence show me averages of engines from Chinese line. It would be 163fml for 200cc and 167fmm for 250cc.


By the way, Fuelly.com is not popular with chinese motorcycles owners, it seems. Found one owner of LF200GY-6 though (it's a 200 dual-sport with ohv version of engine as mine).
http://www.fuelly.com/motorcycle/lifan/lf200gy-6

[Wild Dog]

All those chinese engines are not chinese but clones or licensed copies of Japanese engines