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Hello from Ed209-Superbyke RMR200 owner
Well, I've posted a few questions so I suppose I should introduce myself! I'm in the UK and been riding for about 12 years. Bikes are my main form of transport so I commute every day. My main bike has been a Honda VFR800 for the past 2 years, but rising fuel and servicing costs got me thinkng about gettting a second , more economical commuter, saving my VFR for Fridays and weekend fun...!
I wanted something cheap to run, but reliable and fun, that didn't look like a learner bike.......after a lot of research I became aware of the Superbyke brand (QuinQi rebadged) and the 200 supermoto caught my eye. I didn't want to buy new, as I felt that inititial deptreciation would be horendous, so I kept my eye open on e-bay. It didn't take long to find a 300km, year old minter going for £1000 Buy It Now, and only 56 miles away. Being impulsive, I didn't bother bidding and secured it for the B-I-N price! I picked it up 4 weeks ago and immediatley noticed three things:
1-1st gear was ridiculously low
2-It is very light ,nimble and fun!
3-It has great modding potential....!
The first thing I did was get the exhaust off and see what makes it so quiet and restrictive.......Mmmm, it is very heavy, contains a lot of baffles, and has a catalytic converter material just sort of 'stuffed' in the base of the exhaust!
So out came the angle grinder, and after an hour and 3 grinding discs, I managed to remove about 5 inches off the end, which got rid of 2 baffles. I then drilled 5 holes around the ramaining baffle, and repeatedly hammered a very long drill bit down it to try to create some kind of straight path for the exhaust gases.This was semi-successful - I could see a tiny prick of daylight if I held it at the rght angle. So I bolted it back on and fired her up. That's more like it - much more fruity and felt a bit peppier too.
Next up I swapped the 48 tooth rear sprocket for a 44 tooth - I ordered the satndard sprocket for a Suzuki TS125, whic bolted stright on. This really improved things, 1st gear become useful, and weirdly improved acceleration - I think because I now don't have to change up to 2nd about 1 milisecond after pulling away! It's also made high speed riding les buzzy, but didn't really add much top end - I have got 75mph out of her, but in normal conditions she races up to 60, and anything extra is very much dependent on gradients, headwinds etc..
I still wasn't happy with the exhaust's restictiveness though, and trawled this and other forums forslip on options - none seemd avialble in this country. Then I struck gold on e-bay, Xian Racing do a 'P&P' pipe for £65 which they claimed should fit most chines 125-200cc bikes. but might require a bit of inginuity. I though 'what the heck', and ordered one on Thursday. It came the next day , and I have just fitted it today - wow. Firstly, it is literally a slip on, it fits the header pipe exactly and tightly.It dopesn't have slits or a jubilee type clip on it, but to be honest it doesn't need one.I fitted it with some exhaust repair gum ( Sets to a solid, heat proof seal), and bolted it to the bike with the supplied strap, which lines up with the first mounting (nearest the front of the bike).The end rests against the rearmost mount, and when bolted up, it feels very solid.There are no leaks at the join (which is more than I can say for the original), and it sound awesome. A quick test ride has confirmed a definite power increase, acceleration is much improved. Haven't had a chance to test out if any top speed has been gained yet though.Am very happy though, it looks WAY better than the original, and must have saved at least 2 kg in weight!
Other minor mods I have done are:
-Removed pillion pegs ( they look ugly, and I won't be using the bike to carry a passenger)
-Removed the rear tool holder thingy
-Fitted a tailpack, which bungies nicely to the grab rails.I have put the tool kit in there as well
-Fitted mirror extenders, so I can now see more than my elbows!
-Put an '08' race number on the front, because its my favourite number! I have an 8 tattoo on my arm and I have called the bike 'Lucky Eight'!
Overall I am ver happy, i've put another 750Km on the clock, and the only problem I've had has been an ongoing battle to adjust the valve clearances myself (which some other members will now about!).I thought I'd check/adjust them at 1000Km, but now they are worse than when I started, After 5 goes, I've just introduced a rattly noise......probably gonna just take it to a pro and stump up the 1hr labour cost for peace of mind.
Anyway, here are some pics, the first one was taken after my initial standard exhaust mod, and I took the other two today showing the new exhaust.
Qingqi QM200GY-BA / Superbyke RMR200 mods.
Great write-up ed209. Agree with all the points raised. Have been looking for an alternative exhaust and it seems I've found it.
As luck would have it a poster on a British forum, Gareth Truscott, who uses the nick "Shy:", runs that Chinese bike tuning shop in Newport (Wales, UK) and has that exhaust on his e-bay shop. I'll contact him to get one for mine.
You've probably already trawled this forum for items about your bike. There are lots if you search for "Qingqi", including a tutorial on setting the tappets.
Motorcycle Natural Resonant Frequency
Good ol' Herman VonHelmholtz. I did a science project in High School building band-pass sub-woofers using the Helmholtz Equation to try and calculate optimal port length. That was some crazy stuff!
I had read an article on Natural Resonant Frequency (NRF) as it pertains to motorcycles sometime in the past but can't remember the details. I found a great link from California Sciences that discusses the application and importance of NRF to motorcycle air-boxes in particular. Its got more equations than you can shake a stick at!
If you have 10 minutes, it's quite short and really worth reading.
http://motorcycleinfo.calsci.com/Airboxes.html
Some quotes:
"...In the '70s, the US government started making noise regulations tighter. At some point, the manufacturers realized that the noise from the air intake was part of their problem. They started to look for ways to muffle not only the exhaust, but the intake roar too. Sound waves are pressure pulses in the air. Pistons pull in air on their intake stroke, creating a low pressure pulse in the air box. Then on the compression, power, and exhaust strokes the intake valve is closed and the air box is free to return to atmospheric pressure. These alternating low pressure and normal pressure pulses are sound waves. The manufacturers needed some way to dampen them out."
"... So at resonance, air flows through a tuned air box almost without resistance. This is as close as we can get to a superconductor of air. "
"The idea that the snorkel makes for a significant impediment to air flow into the engine is questionable at best. Drilling holes to let in more air is exactly equivalent to drilling holes in your speaker cabinets to let out more sound. Removing the snorkel from your air box is the exact same thing as removing the port in your speakers, the tube that's carefully engineered to have just the right diameter and length to reinforce the bass on your speakers at low frequencies. By altering your air box in any significant fashion, you're most likely going to cost yourself three to five hp in the mid range, and gain nothing measurable at high rpms. "
Paz,
CC