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This little beaut just arrived yesterday (2-5-07) in the
-11 degree weather of northeast Wisconsin. No riding today, we're talking
months. Soon to come will be a complete test report on rideability, power,
handling, and very important, durability. Remember, I'm not a 14 year old (that
was 30 years ago, do the math) so this bike will be adult (at least) ridden and
the impression will be accordingly. Click
Polini to check out their
website and their specifications on this bike. This bike was purchased at
Rock River Powersports in
Jefferson WI
****Riding impression from Fall of '07.
****
Best features of this bike are the brakes,
and the ergos. Top notch. Hydraulic Disc brakes have good feel and bring the
bike down nicely. Good thing because you can get around a track at a pretty
decent clip on this bike. After I slow down for a corner, I can plant myself on
the bike nicely and get around it real well, get on the gas good and give it a
little clutch help if I need it, and it often does because the power is a little
soft.
Suspension is good, but could be so much
better. There's plenty of travel, and it doesn't bottom out on the track that I
ride, but the action is "springy". You move through the travel quickly, and if
it had adjustments I would slow down the compression and rebound, but there are
not any adjustments. After riding a little while though, you get used to it and
then it's real nice. No harshness at all, but it moves quick and soaks up quite
a bit.
Now for some bad news, my bike is a puffer.
I blows smoke after it warms up, and blows it quite a bit. Not like a blown up
motor, but way more than it should and it's noticeable. Everybody that has
watched me ride has commented on it, and yesterday I looked and it was not a
cloud or anything, but a definite noticeable puff every time I cracked the
throttle. I tore the top end off today and don't see anything obvious. Its
Sunday, so I have everything packed up to bring to the bike shop tomorrow and
see if its valves, or excessive piston and/or ring clearance. I have a call into
the shop I bought it from to see if they will do anything for me.
Durability is still good. I've got about 5
good hard rides on it and everything has held up.
*** Riding impression from spring of '07.***
This little guy is the bomb. Power is pleasant, but don't take that bad, it does
not mean slow. Here's the scoop, it has linear power with a good low end, and
smooth progression all the way up to a good over rev. I'm not talking knock your
socks off power, but very decent, pleasant (I know, twice now) power. The 4
speed tranny has perfect ratios for the power this bike has. Huge bonus over
KLX110's is this is a 1 down, 3 up, 4 speed tranny. Your KLX (DRZ) has 3up, just
like a fiddy, and first is super low. First gear on the Polini is pretty low
also, but not super low. Second and third are the main gears, and if you click
into fourth your going along pretty good. It's not fifth gear tapped on your
450, but it's moving right along.
I can't stress the gearbox/power
combination, along with a perfect working manual clutch enough. This bike could
be a great woods warrior. You can lay it into soft corners, throttle up and if
you need just a touch more pull, give the clutch a little tug and it's there. On
Fugs tight little track we had to cut out a sloppy corner and slice through some
tight trees, and that's where this bike shined. Not that is sucks on the open
track, it just didn't have anything more than the KLX110's on the open range,
but the fine mesh of smooth working accompaniments made this bike very fun to
ride in all situations.
Suspension is pretty darn decent also. Fugs
track only has one big launch we call the "Holy Schmidt" in honor of our
favorite midwest lost soldier. This bike gave me the confidence to clear about a
15' jump off a pretty peaky/rutty launch. The bike tracked straight, jumped with
confidence, and soaked up the landing very well. I'm a buck fiddy in
weight, and I had the rear shock on the soft setting and I think I could have
used the stiffer mounting hole. We'll try that next time, but set up the way it
was it worked just fine. Fugs track is not a suspension torture test, it's more
of a corning and accelerating track where smoothness will gain you tenths of a
second, and you'll need all of them when the pack comes rolling around.
Durability-wise, the first day had no
issues. The bike puffed a little smoke that we all noticed, and the smell was
tranny oil. It ran great, but we can tell it's getting a little oil up past the
piston rings. I'm going to keep riding it, and if and when I get energetic this
summer I'll pull off the cylinder and check things out. This is not that out of
the ordinary, I've had this happen with many of my mini 4 strokes. I rev them
out a little and don't give them much of a break, and these little 4 poppers are
maybe not meant for hard riding for long periods of time. The air cooled bike
didn't seem to overheat, and never lost power over the duration of our motos,
and we put in a few 20 minute-ers. Clutch play never changed, and the tranny
kept shifting nice and smooth. I don't ride the heck out the clutch, I just tug
it when I need it out of almost every corner.
Brakes are another big bragging point.
Hydraulic discs front and rear. Your KLX (DRZ) has drums unless you've upgraded.
You might this it's overkill on a mini bike, but the added stopping power comes
in handy. Here's the deal, discs give you more stopping power than you really
need, so you can pull (or push) lightly on the levers to get what you need
instead of grabbing a handful. When you can operate with a light touch, you can
finess instead of bull dogging. My fiddies all have drums and I have absolutely
no issues with them, but I tell you, hydraulic discs are very nice.
So, final words are that I like this bike
very much. I have an XR80 that I stiffened up the suspension on hoping that,
with the larger wheel size, would be the answer for mini mayhem. It's not,
because of the slack head angle and soft (stock but rebuilt motor) power just
doesn't get you around the track good enough. The Polini has a perfect head
angle, aggressive riding position with all the controls right where they should
be. Lever play was perfect, nothing loose or sloppy, and everything worked the
way you'd hope it would. Equal power to a KLX110, but better gears and a manual
clutch. A stock KLX wouldn't hold a candle to this bike, but the bikes I ride
with have high end suspension fitted up, and we were all pretty much dead even
around the track.
To bring a KLX (DRZ) up to the standards of
this bike you need beefed up suspension front and rear, a manual clutch, and
disc brakes front and rear, and you still have your 3 up tranny. But on the
other hand, you have proven durability. The Polini is still under scrutiny for
that.
Let me know what you think of all this at
info@50ccracing.com
        
When I was looking into buying this, I couldn't really find
any good pictures, so here's a bunch. This thing is stone stock, and will stay
that way for a while. Not a scratch on 'er yet. Just wait.
We've got lots to compare it to,
Fug has a KLX 110 that
he's building up the suspension and motor on, Matt has a KLX110 with a 143 kit, but stock suspension. That's a
treat to ride, brings you back to reality on why you don't put an XR650 motor in
your mini bike. And we have a stable on hopped up TTR 90's (110's) and XR/CRF50
(88's).
XR/CRF 50's are great fun, and I love riding a clean
running, sweet handling fiddy, but peer pressure and curiosity has brought me to
this purchase. No deals were cut, so I won't hesitate to slam this thing into
next week if it sucks.
HOP UPS???!!??
be careful!! This engine similar to a
Honda 50, but it has differences. You can't just buy a Honda 50 cam and put it
in this bike. The cam chain sprocket has a different size guide hole, and it has
a 3 bolt attachment where a fiddy is 2. Cam bearings are different also. The
cylinder stud pattern is the same, and perhaps you could exchange a complete
cylinder/head/piston combo, but the cam chain length would have to be the same.
It probably is. Not sure of the stroke length on this, and how it compares to a
fiddy. All things that would need to be considered. For sure a Honda exhaust
pipe will not work because of the way you would need to snake through the frame.
Maybe this engine is a closer copy of a Honda 70.
Stock power is pretty good, but not jaw dropping. Nice and
torquey 107cc power plant that has a good spread of power from idle all the way
up to a decent rev out. No hard hit, no flat spot, no burbling, just nice decent
power. First gear is real low, but second picks up nice, and third and fourth
and real good and spaced well. It lights right up on the first or second kick,
and idles right along forever. Appears to have very good carburation.
www.polini.com is the European (Italian) website, and
on that site is an English description of a Polini manufactured high performance
XP4.
http://uk.polini.www.portal.tradenet.it/pages_268.html Don't know about it's
availability, or if it's the best choice for high performance. Anybody out
there? Let me know at info@50ccracing.com
this is from the PoliniUSA message board, and talks about
the Polini brand hop-ups and more.
http://www.poliniusa.com/forum/viewtopic.php?t=376 and
http://www.poliniusa.com/forum/viewtopic.php?t=264 and
http://www.poliniusa.com/forum/viewtopic.php?t=23
This thread talks about using a Paioli shock from an X3 and
your XP4 spring. That shock is adjustable.
http://www.poliniusa.com/forum/viewtopic.php?p=1739&highlight=#1739
Specification worth noting: 107cc 4-stroke, two valve
engine. 22mm Mikuni Carb. 4 speed manual clutch, 1 down, 3 up pattern. 138 lbs,
30.5" seat height. It's bigger than a KLX110, but smaller than a KX85.
Points that I've noticed just by looking at it closely:
1. The steering head/frame junction looks well built and
sturdy. It appears they have some good triangulation built into the head, and
rear motor mount design. Looks like all you can get out of an open cradle frame
concept. Frame is steel, it's just painted aluminum color.
  
2. Brakes are front and rear
hydraulic disc setup. Feel and power are fantastic. No complaints.
 
3. Front forks look beefy, and have a good feel just from
pushing down in my kitchen. Rear shock is a non linkage design. I don't see any
adjusters for dampening or rebound on the front or back. Looks like you can
adjust the spring in the rear, and change the oil viscosity and level in the
front. Polini offers aftermarket products if you have a boat load of cash. I'll
tweak the stockers first.
   
Also, the rear shock has two different mounts on the
swingarm. I connected the shock to both, and the upper hole delivers a
noticeably stiffer rear feel. No riding impressions yet, but you get a choice it
looks like. Seat height is identical with both, except the stiffer setup sits
higher.
   
4. Ergonomics feel very nice, the skin stayed
on my tailbone now so I can give it a break from the hunched up fiddy.
 
5. I see radiator shrouds, but no radiators. This is an air
cooled engine based off of the Honda 50/70 motor. I've heard you can bolt up
your XR/CRF motor in the motor mounts. You'd loose the manual clutch though,
unless you have that.
6. Bike has a manual clutch and 4 speeds. No problem
getting it into neutral, and with a firm pull on the shifter you get a positive
shift. Not a buttery smooth tranny, but works well.
7. Bike also has a very nice looking folding shift lever,
and it has enough room to fit an adult boot in there.
8. Bike also has an unusually cheesy looking stamped rear brake pedal connected to a very trick looking rear hydraulic disc.
Spring return works great on the pedal, but brings it back up to hit the engine.
WHAT???? Yes, the rear brake pedal upper stop is
the engine kick starter boss. Their lowest paid engineer came up with this one.
I'm going to wrap the pedal lever with some rubber, or at least grind it so the
pedal isn't sharp to try to keep it from damaging the engine.
  
9. Air filter looks very good. The element has plenty of surface area, and looks
like it will come out of the box without dropping dirt in the boot.
  
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