Quannon Sprockets and Mods

[Troy80]

So I found a company in the UK that, so far as I can tell, ships to the USA.  They sell +1 and +2 front sprockets for the Quannon 125.  So that's 16t and 17t front sprockets.  As far as I can tell, and according to everything I've read, they use the same sprocket sets.  So I ordered both a 16t and 17t in case there is clearance issues with the 17t. (calculators say 68mph instead of 60mph at same RPM)  Not expensive.  You have to search for "Quannon 125 sprockets" though.  I also bought a Carb Jet kit off Amazon, they asked for exact model, year, any mods and my altitude so they could send me the right Jets.  I'm gonna give it a shot, I'd like a little more top end out of this thing and make highway riding a little more comfortable.  I'm also planning on cracking open the airbox later this week and checking clearances, maybe I can fit a cone filter.  I've seen one exhaust kit out there but its wholesale, so I'd need to find some dealer to order it for me and I'm not ready to shell out the 300$. Anyone try any mods yet?  I'm starting to look for high compression pistons, but I'm thinking I'm gonna really have to get into the specs for that.  Another option is milling the heads, haven't checked on the cost for this yet so if anyone has experience with it I'd love to hear about it.  Neither will probably happen anytime soon as I'm still under warranty.  (I can make a quick sprocket or airbox swap and still get warranty service at the dealer)  Piston or Head swap, not so much.

[ophelia]

You mention looking at engine mods. Are you planning to turn yours into a race or track bike eventually?

I used to have a CBR125R, and looked into big bore kits and aggressive camshafts. It really wasn't cost effective and I didn't want to have an unreliable daily driver while I slowly got things dialed in. I bought a bigger bike instead.

Kymco has some pretty smart engineers that make their engines start easily and run really well and last a long time and pass emissions. I don't have that know-how nor the time. It's worth a consideration leaving the engine stock unless you're very familiar with building and tuning engines, or have access to a really good shop.

I would like to have a second smaller bike like the Quannon 150 again, so I've been watching threads about aftermarket sprockets with interest. But that's as far with mods as I think I'd personally go. Cheers.

[grantourismo]

  hello from australia

can u please post the website for the sprocket , i m thinking of getting a 16t front on mine too,

secondly what is the exhaust website ?

thanks heaps mate ~

[Vivo]

Are sprockets of Honda and Kymco similar?

[defated]

125 is the same with 150 except for their engine and cdi (from my researched)
okay first of all, i searched all over for any quannon mods and it is hard to find and get in my country. so i made my own mods. you can checked youtube 'quannon 125 to 150 mod'....
mods are:- side mirrors, signal light, exhaust, paints, foot peg, battery case(to fit new battery), new sprocket 16-38.
interior mods:- bigger piston n bore(125 to 150) but not yet port the intake n outtake so power is still at minimum, mushroom air filter.

 what is the top speed for stock quannon 150? my top speed is 143-145 km/h.

okay, for your question. the front sprocket is the same with honda cbr 125 but rear sprocket are still unknown ( well actually similar with venox 250 but you also have to change front sprocket and  chain). my solution is to mod rear sprocket by machine shop

hope this would help all

[Troy80]

So here's the update.  the website is www.wemoto.com for the 16t and 17t front sprockets.  So I installed the 17t sprocket, clearance was not an issue, perfect fit, easy install.  New top speed is 70mph at 8100rpm.  On flats I can reach 75mph, but this is not really sustainable and I don't like running those revs.  The power band is now more effective for my driving (rural highways and around town).  I can now get on freeways and keep pace with traffic.  I got my carburetor kit but it is not yet installed.  The main reason for this is that I run very lean at high revs this usually due to limitations of the Carb, exhaust, and filter.  The filter box is extremely restricitve on this bike so I'm going to pull it out and replace it with a cone filter. The Carb appears to be the limiting factor though. A few thoughts on this... This could be due to in adequate float height, meaning that there is not enough fuel in the float bowl to sustain consumption at high revs, thereby limiting power production and detonation due to lean mixture.  Secondly inadequate main jet size, again limiting fuel supply to the engine at high revs causing detonation.  According to my own research and experience the remedy would be to increase the main jet size, shim or bend the floats, most likely both along with a couple other jet replacements.  Also considering running a cooler plug that will draw more heat out of the combustion chamber thereby decreasing detonation.  With an increased fuel supply, I'll then open up the filter and modify the spark arrestor in the exhaust to allow a little more flow.  This would be useless without modifying the carburetor becasue the fuel supply is inadequate now.  I confirmed this by pulling the filter completely and doing a quick full throttle run down the road, The bike simply ran more lean, no increase in power except a little at low revs, top end remained the same.  The limiting factor is definitely the fuel supply.  I'll only do stepwise modifications I'm not into chasing issues.  So... Step 1 carb kit, Step 2 Filter, Step 3 Spark arrestor aperture.  If the detonation doesn't cease then I will go to a cooler spark plug.  If all these mods go well, then I will consider milling the head.  @thesurgeonistherobot  - I'm not planning on racing this bike at all, my goal is to increase its useability.  70mph(~120kph) is not achieved easily on this bike and that is the speed limit on the local freeways, on steep inclines I can't maintain 50 mph.  Moreover, I'm only conducting cost effective modifications, the carb kit cost 39$ the sprocket 13$ and a new filter is around 7-15$,  exhaust mod is a drill bit that I already own, milling the head is about 1 hr of shop time (I'd pull the head myself)   @ defated  I don't know how youre getting 143kph out of a quannon 150,  with 17t front and stock rear sprocket, I'm rpm limited to about 125 kph(~10,500rpm),  I have not confirmed this with gps yet, but I will very soon.  143kph sounds like a gross exaggeration to me.  I've seen this a couple times, some guy on this forum claimed that the stock quannon did 80mph and that some other owners bike was obviously not running well.  There's no way this is true unless there are different stock gearing setups for this bike, of which I've seen no evidence at all. 

[badjoke]

Cool mods so far... simple and effective.  Keep us informed of your progress, most definitely interesting stuff.

When I got my bike I was all ready to pump some cash into making it faster...then did absolutely nothing because I figured it wasn't worth it.  I don't know enough about carbs to be fiddling around with that stuff, it would mean I would be bikeless for who knows until I got it working again.

You've chosen unbelievably cost effective things that will really make a difference for your bike... totally awesome.  Again...would love to know how it turns out.

Question for you : what does machining the piston heads accomplish?

You also mentioned the float, in what I researched apparently the float is set too low (not enough fuel to sustain high rpm's).  I also know from experience having the bike sputter out on the freeways....with traffic...all around...lol... good times!  I was told that it would have to be bent/shimmed to get some more capacity...I have no clue what that means for what it's worth lol.

Also in total agreement with the "140km"...  even downhill with a wind behind me I could barely squeak out 130....so you must have been holding on to a faster car, or the bike was in a trailer and the car was doing 140.

One more question... how much of a difference is the launch off a stop with the 17t? 

[defated]

will take the vid as soon i can get a cam on my bike. as i said it can be done by 1.front sprocket 14T and rear sprocket 38T. 2. bore the engine(more power) 3. air filter changed.

[defated]

sorry 16T-38T

[Troy80]

@defated 143 still sounds a little high for the sprocket set you have but I'll take your word for it. 

@bad joke  I don't know if I wrote milling the piston heads.  I thought i said just milling the heads, might have been a typo.  Milling the heads is when you take block head off the top of the engine, you take that to the machine shop and they mill/cut a very thin cross section off the base of the heads.  This brings the top of the combustion chamber closer to the top of the piston when reinstalled.  Although this constitutes a very small reduction in overall displacement, it also constitutes an increase in compression ratio which provides more torque.  Same amount of fuel and air but more compression.  Horsepower is a measure of work which is energy and distance.  The energy comes from the fuel, so same amount of fuel = same amount of horsepower generally speaking.  Torque is an analog of force which translates into acceleration as Force = Mass x Acceleration.  So more force, same mass = more acceleration.
The primary risks associated with this modification are three fold.  1) too much metal is removed resulting in collision between valves and piston head  2) Too much heat generated by the extra compression results in early detonation of the fuel (thus cooler spark plug).  This phenomenon is observed in diesel engines that only use a "glow plug" to start and then ignite fuel by compression alone.  3)  Improper surface roughness can cause the head gasket to seal poorly and you lose your extra compression and leak fuel and oil.

So its not without risk but it is relatively inexpensive and almost all but high output engines usually have enough clearance to take off a few thousandths.  The same procedure can be done on the base of the jugs/block and occasionally a thinner head gasket can be utilized to accomplish the same thing, with the added benefit of being capable of returning to stock with a simple gasket.  One more option is to purchase a domed piston which increases compression by simply adding more material to the top of the piston ( these tend to be expensive and they can take a lot of research find the right one for your bore and stroke)

As for the Carburetor mods, these sound more complicated than they are, The shims are often just little washers that adjust anchoring points, Jets are unscrewed and new jets are screwed in.  So long as you really pay attention and follow provided instructions you probably be just fine.