2 stroke , pit bikes???

[Peter1230]

You very hectic sean01 :l

 

[Cam_47]

ok, thanks sean01, a bit off track but still good info. Typicly, how often should a 2 stroke race bike be rebuild, new pisten rings, ect? Would you reccomend the pp 160cc xr. For a first bike? I need something faster than a honda crf 100

 

[thump*140]

as far as maintenance goes, after initial set up, a 2stroke 85cc mxer will *probably* need more maintenance than a bike such as the PP160XR.... generally you should account for a new set of rings in a 2 stroke every 15-20hrs ride time, reeds about the same, oil changes every couple of hours, and consumables such as 2 stroke oil, chains, sprockets, tyres and spark plugs will generally need replacing more often on a 2 stroke, as opposed to a 4 stroke... Mind you, before all the warriors start tapping away, all the above is the factory RECOMMENDED maintenance schedule... very few owners actually do that amount of work on their bikes, that often...
as for the arguments above, a two stroke will actually run a little cooler than a thumper in *most* situations... dont believe, put your hand on the barrel or pipe of a two stroke after a few hot laps.. it's pretty hot isnt it... now put your hand on the barrel or header pipe of a thumper after a few fast laps.. oh look, your hand has stuck to the pipe, and you have 2nd degree burns... however, fourstrokes have the inherit ability to cope with higher running temperatures, mostly due to their air cooled nature (pitbikes i'm referring to, and some jap thumper trailbikes) and bigger oil capacities...
as for which revs higher... once upon a time, *traditionally* 2 strokes revved higher.. now the new generation thumpers YZF's, CRF's etc etc, rev just as high, if not higher than their equivalent two stroke stable mates... 450's happily wind up to around 10500-11000rpm, and 250's well over 13000rpm... which i'd say is pretty high revving... quirky info, but at 10000rpm, in any engine, the piston is going up and down 166 times a second.. yes, one hundred and sixty six, not sixteen point six...
Not starting any arguments here, but hopefully settling some.
oh, and there are plenty of 65cc and 50cc MINIbikes out there... italjets, huskyboys, LEM's, TM's KX65 kwakas, KTM 65SX's...
and throwing my hat into the ring as for the MINIbike Vs PITbike, traditionally a minibike has been a 50, 65 or 85 competition based or trail based bike for young children.
Pitbikes are traditionally recognised as modified bikes such as CRF50's, growing into the midsized 140's, 150's and 160's we see today... my opinion is that CRF or KLX based bikes running horizontal fourstroke engines are Pitbikes...
The jap 2 and fourstroke bikes such as kx's sx's, LEM's husky boys etc, yz85's and bikes like that are generally considered minibikes...

And yes, that do fly in the face of this forum being called MINIriders... ha ha ha
Just my 15c worth.

 

[pbk]

thankyou thump 140

 

[Cam_47]

Thunks thump, great info.

 

[PIMP50]

seen a fair few on planetminis using kx and rm65's and ktm65's they would be great fun

 

[Th3D3v1Ly]

how about this, modifiying a pit to take a kawa kx250 engine. I think that would be nice. Im looking for a new bike, dont know whether to stick with a 4 or go for a smoker.

 

[DvDRip]

how about this, modifiying a pit to take a kawa kx250 engine. I think that would be nice. Im looking for a new bike, dont know whether to stick with a 4 or go for a smoker.

hahah we were just talking about that in chatbox last night, but it was putting a loncin 250 in a pitbike, turns out there are midsize atomiks out there running 12"/14" & a loncin 250, now a kx250 engine that would be pure insanity let me know when you start selling these modified bikes

If this guy can do it with a tt500 engine then it's definatly possible to do a kx250 pitty

 

[thump*140]

^^^that is THE Most Awesome Pitbike I've ever seen.
Would be truly epic to ride if you could get the bastard started...

 

[Cam_47]

What a beast! Truly a one off.

 

[wogtaz ryder]

Basically 65's are not classed as a pitbike .. or popular with adults is because ... 99% of minibike racing the rules STATE.

Open cradle frames only.

With this picture you can see there not

but for you everyday freeride minibike , a 65 would be frigging sweeeeeeet .. change springs front and rear and your ready to go!! with the awesome 2-stroke power , suspension 10x better then your average pitpro it would be Ultimate! and there getting pretty cheap these days.

 

[Cam_47]

Ok, It ooks ike they have a bit of go. Can I just ask , why dose it matter what frame a bike has, in racing tearms I mean??

 

[wogtaz ryder]

Thats just the way the rules where made a long long time ago . they have to set rules or else there would be all soughts of things turning up to the races lol

And the other rule , Air cooled engines only.

Basically if there wasnt that rule , there would be Crf150r's with 12" wheels or even 250f's LOL

Like this 150r

 

[Cam_47]

Ok, good point. Do you race? If so i might be starting next year, could you reccomend a decent bike for under 3000 or one that i could find second hand for under that? also you picture didn't work

 

[wogtaz ryder]

Oh the picture is working for me?

yer i have done a few races with the HRI round that just went , and a few at Fort lytton mini track

For 3g i would be looking at a Pitster pro Lxr like i got . cant go wrong! the suspension is great , you can pick between a few engines , and they all rip pretty hard!


Have you owned a minibike before?

 

[sean01]

lol this thread still going....

i see the odd person fitting kx65 rear swingarm and front forks to pit bikes over on planet minis...
if the prices werent so high on the prices of secondhand kx gear, id give it a go myself..

 

[Cam_47]

Never, But I am really keen to get one. But chosing very wiesly as I don't want a shit heap that will fall apart with in a week. I was looking at the pp 160-type r, the only reson being is that I have seen and sat on the bike and seems to be a good pick. Also, seems to be around entry to mid level for racing. As it would be a first bike , I wouldn't want a top end bike.

 

[Cactus Jack]

You can build a two stroke pit bike ... Just fit a PW50 or PW80 Yamaha engine into an open cradle pitbike frame then work it over ... no cheating with watercooled vertical 2 stroke engines or expansion chambers ...

Here's a Thumpertalk 2 stroke vs 4 stroke thread ...

140cc pit bike vs 65cc 2 stroke - ThumperTalk

140cc pit bike vs 65cc 2 stroke - Page 2 - ThumperTalk

And the Japs DID make 2 stroke minibikes ... they just weren't as good as the 4 strokes so they failed to take off ... Even the Yamaha GTMX80's couldn't compete with XR75's ... so the Japs started cheating with the YZ's ...

 

[wogtaz ryder]

Few pictures of a 12" crf150r to druel over.

 

[Cactus Jack]

Basically ... one of those debored or detstroked to 130 cc is what you'd compare to a KX65 ....