2013 Supermoto Mini-pit track hack!

[binge]

I've not ridden my Mini-pit since the Pit bike club weekender at the start of the year, when this happened. :icon_lol:

(Hard to see in the picture, but it's bellowing smoke out)

https://sphotos-e.ak.fbcdn.net/hphotos-ak-ash3/577302_10150865983695606_303904741_n.jpg


It would literally run for 3/4 of a session, before nipping up tight. Then when I pushed it off the pit lane back to my car, it would take 600ml of oil (Literally a full engines worth).

The cause was a scored barrel and some damn sh*gged piston rings.

I spent a while rebuilding the 140 engine, before pulling it all apart again to start tuning it.

In the meantime, The Z155 I had originally planned to put in the Chaly, was replaced with a Lifan 150 (Better suited for the Chaly road bike), so it left me with the Zonga to play with.

It had a few issues. One being a shattered input shaft bearing, The other being knackered kick start gears.

After a complete strip down over 12 months ago now, I finally started putting it back together today. Which wasn't fun considering the engine had been in individual pieces, on a shelf in my garage, for a year. I'd been nicking bits and pieces from it for other engines. I'd also merged other engine bits in with the Z155 pile of bits, making it a bit of a pig to sort everything out. Not to mention It's been like a year since I built a pit engine, so memory is very vague.


Anyway, At 15:00, today, I started with this:

A pair of cleaned, and checked engine cases, fitted with new gearbox bearings;
https://sphotos-e.ak.fbcdn.net/hphotos-ak-snc7/418659_10151312794190606_2129794650_n.jpg


I then fitted the gearbox and selector drum into place, using different thickness shims to eliminate all lateral play in the gear hubs. The 155z is common for jumping into gear from neutral when tilted over because of this.
https://sphotos-a.ak.fbcdn.net/hphotos-ak-prn1/734090_10151312821700606_2097497313_n.jpg


Final checks before I closed it up.

• Note my Oil spinner mod. The 155, is the same as the early YX160/150, and all early YX140s. The spinner can be removed, and replaced with a specially made tube.
  

https://sphotos-a.ak.fbcdn.net/hphotos-ak-ash3/577863_10151312826705606_913390731_n.jpg




Okay, so among this lot, is the components for a 6 plate clutch.
https://sphotos-h.ak.fbcdn.net/hphotos-ak-snc6/249869_10151312855055606_1432955873_n.jpg




Found it!
https://sphotos-c.ak.fbcdn.net/hphotos-ak-prn1/13753_10151312863305606_249763915_n.jpg




At this stage, I was questioning myself, weather I should close the engine up now, and finish it. Or do the De-comp mod on the head.
I really wanted to give it to Gaz, to have it milled flat, and then drilled/tapped in a pillar drill or milling machine to get it perfect.
But I got inpatient, and went at it with a grinder and a die-grinder;
https://sphotos-h.ak.fbcdn.net/hphotos-ak-ash3/533855_10151312894615606_1637999595_n.jpg



All fitted:
https://sphotos-a.ak.fbcdn.net/hphotos-ak-prn1/536073_10151312963700606_579462790_n.jpg




I counter sunk the whole thing into the head about 4mm using a 15mm drill bit. Did this for two reasons. One, to give me a little more clearance around the exhaust and spark plug. The other, is it now has a completely true surface for the copper washer to sit into/on, rather than on a badly ground alloy surface. :icon_lol:
https://sphotos-g.ak.fbcdn.net/hphotos-ak-ash3/528627_10151313133340606_1237221182_n.jpg




All boxed up with the Mikuni VM26 carb fitted, Forward facing TBr manifold (Gas flowed), and the TBr M6 exhaust system (IIRC).


https://sphotos-a.ak.fbcdn.net/hphotos-ak-ash3/181394_10151313159070606_1839464991_n.jpg




https://sphotos-f.ak.fbcdn.net/hphotos-ak-ash4/307669_10151313070145606_1096774778_n.jpg


https://sphotos-e.ak.fbcdn.net/hphotos-ak-prn1/154417_10151313126585606_724231905_n.jpg


https://sphotos-b.ak.fbcdn.net/hphotos-ak-ash4/400045_10151313128945606_77940441_n.jpg







Next up is the bike being built back together.

So far, it looks like this, but with no wheels:


https://sphotos-a.ak.fbcdn.net/hphotos-ak-ash4/303477_10150911343290606_1578448727_n.jpg


Potentially going to be fitting +1 CRF50 forks with vertical steering damper retro-fitted, and a +2/3 TBR Swing arm or similar

[CarlosCBR]

Getting in early for "best thread 2013"? Going to be epic!
____________________
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[binge]

Aha! This sort of build isnt a patch one some of the full on custom stuff like Chris' turbo and charged up bikes.
Still a good fun toy though.

Spent today building up the Hybrid engine. It's been sat in a box in bits since I bought the Lifan 150 for the Chaly. It was the one which was dramatically burning oil in my race bike.

This engine will be my spare, which I will just take to track days with me. If the 155 should go bang, I've got the 140 to throw in to keep me going through the rest of the weekend.
I can change an engine with the help of a mate for the lifting and holding tasks, in about 10 minutes tops.

Eventually I will build up a second bike (all I really need is frame, swinger, and forks, I have the rest!), and run my wets on it permanently. That way, I will have a slightly less powerful bike, which I can set the suspension and brakes up a lot softer/weaker to behave better on a wet track. And if it stats to rain, I have a second bike to jump on.


The engine is quite an interesting one, and gets people really scratching their heads at tracks as they cant work out what it is, or why it's so fast.

It's made up of a Road legal Masai DB125H bottom end. This is a Kick in gear unit (not the cheaper Primary Clutch set ups). So it shares the same style crank and gearbox as the 140/150/160 bikes, but it's on a much shorter gear ratio as it's for a 125cc top end.
It also has the 125cc selector barrel too, which is 1N234, as apposed to N1234.

The cases only have a hole in them big enough to cater for the skirt of a 125 barrel.
Pete. from this forum kindly turned down a barrel for me a few years ago when I decided to build this Frankenstein of an engine, and since then, My mate Gaz has done the same to a second barrel now, as the first one died after 2 full seasons of hard track riding.

The barrels I've had turned down are YX140 barrels, which are 56mm bore, rather than 52.5mm on the 125.
The skirt needs turning down by 1.5mm on the out side, so it will fit into the cases, leaving a wall thickness of little over 1mm, but it works!

I really wanted to fit the 145cc bore kit from OORacing, which is nikasil plated, and I think runs a slipper piston.
But taking the bore size out further will leave the wall thickness less than .5mm, which I think will get a bit hot and weak.


But either way, the 140cc barrel paired up with a high compression piston does what I need it to.


It's then all topped off with a Skimmed & Gasflowed, Lifan 150 cylinder head, and an NBR cam from OORacing, the cam is made for a YX140 head, so the bearings had to be pressed off the stock Lifan cam, and onto the NBR cam so it would fit into the 150 head.
The lift is higher, and gives the engine a f*ck load more grunt.

Complete, the engine will pull away from YX140's, and I don't think it would be too far behind my Zongshen 155.


It's fitted with a full billet SFB Racing cover kit, and head breather.

The carb is another Genuine Mikuni VM26, bolted to a gas-flowed inlet manfiold.

I have also done the Oil Spinner Mod on the 125 bottom end, and fitted an Outer Rotor Kit like the Daytona one, but it runs on a standard Pit bike CDI/Ignition rather than the mappable one.

Lightens up the crank a treat.

Z155 on the Left - 125 Hybrid on the right:

https://sphotos-a.ak.fbcdn.net/hphotos-ak-prn1/154537_10151316513855606_1695581083_n.jpg

https://sphotos-h.ak.fbcdn.net/hphotos-ak-ash3/582486_10151316514095606_1818248946_n.jpg



And then the bike currently;

Still a lot to do. Full strip down, powder coat the frame white I Think, lower it, shorten the forks, new seat (TBr One), Higher bars, and a rear brake needs making up.

https://sphotos-c.ak.fbcdn.net/hphotos-ak-ash4/295166_10151316535135606_1205343610_n.jpg

[binge]

I will be starting work on the roller tomorrow.
My new tyres are 1/2 fitted to the rims, I just need a couple of narrower tubes and then they can be completed.

They're pretty awesome looking rubber actually. Made by Schawlbe. Model is 'Paceman'. Considered a very good racing tyre in the scooter scene.

I went for the 3.00x10 size because the 3.50x10's are available, but not without parting with nearly £60 per tyre. That sort of money could buy me a set of PMT-R tyres. So I went with the slightly narrower option. Hopefully they'll be okay. I cant see why not, and to be honest, I'm on quite narrow rims anyway.

https://sphotos-f.ak.fbcdn.net/hphotos-ak-ash3/16544_10151314259610606_506259064_n.jpg

[Noxious89123]

Must say, this looks like a stupid amount of fun
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[binge]

They're fantastic mate!

Sooo many upgrades and tuning parts are readily available. There are a fair few tracks who promote the sport. Track days are awesome, a much friendlier vibe than you get at big bike track days etc. Nobody gives a fuck how much money you have, or how good your bike is. Or even how fast or slow you are.

If you are out on track, your bike breaks etc, you have people coming over to your gazebo/tent offering to help fix it, lend/donate parts etc.

Everyone pulls in, and has a bloody good time.


Some of the lads ride CRF150's, on 12 or 14" wheels. They're not that much smaller than a full size supermoto!
Then you have other lads on bikes like mine, and smaller.

Rich Cooper comes out with us from the British Superstocks. He's a demon! Here is he battling it out with Barry Burrell. I'm over on the outside of the track, casually letting them both past, otherwise they'll just force their way through! Fucking animals!

https://sphotos-c.ak.fbcdn.net/hphotos-ak-ash4/403841_2586298934004_1456132433_n.jpg

[Noxious89123]

[binge]

They are, and they fall under the specification to enter the adults open class in the FAB championships.

Those who can, will.

And those who cant, be hating!


They fucking own everything on the straights. Absolute power houses!

[binge]

Then there is this demon.

It was built by a friend called Dan. He built it for his old man.
Fortunately (or un-fortunately, depending on which side of the fence you're on), it doesnt fall under any racing groups.
But it's okay for open track days.

It's a Stomp KZR frame (Same as my old mid-size bike, one in my avatar), with a Honda CRF250 engine fitted.


Nothing... I mean nothing, out on that track can touch it. It's another league...


https://i1184.photobucket.com/albums/z331/chace033/C5D2C4FE-8627-4EAD-B68E-0C2CF656269E-1963-0000018DC8D4D322.jpg

[sulphur]

Obviously this won't be in the same league, but I had a Thumpstar 125 a few years back and it was batshit mental. Proper good fun, but I was always shitting myself on corners 'cos it was so small.

I'd love one with slicks on for fannying about on track though, would be a ball ache for me to transport though.

Yours looks a right little weapon, although that black stomp kzr looks awesome!

[binge]

Mine is based around a MonsterMoto Mk1, but with shortened forks, and a custom made shorter Shock. So it's about the same sort of size as an early Thumpstar 110, or an original Mk1 FYM Xsport. Very small.


With the 140 hybrid in, mine was pretty fooking fast. With the 155z in, it should be a bit of a weapon. I've not ridden for a good 8 months though so It'll take some getting used to.




Ben

[sulphur]

Could this basically be taken up using ( for example) a Thumpstar 125 with track tyres and crash bobbins? Is that all it'd take, bike wise?

[shahidsaif]

[sulphur]

[Noxious89123]

All his posts are garbage, he's just here to promote his website.
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[sulphur]

Hah, my bad.

[speedy]

soo jelous looks like way to much fun, are these things money pits? only reason i ask is i used to play with 2 stroke mopeds and had a few feild bikes a few years ago and i know everytime something died on those it was expencive to replace/upgrade parts.
im seriously considering buying one and building it and taking it on a few track days
also that 250 bad boy is very enticing lol how much of a struggle was it to squeeze in?

[binge]

[speedy]

just bought a demon x 140

[sulphur]

Regarding the tyres, I really appreciate the offer. Mucho coolio of you, but my questions ATM are more of curiosity for now. My cash I all spoken for getting my licence and buying a road bike.

When I had my Thumpstar, I was dying for something likenthisnto be available, but anywhere near me didn't cater for pits at the time. Plus I'd have to find a way of transporting it to and from.

It's definitely something I will be looking into though in the future, looks too much 'cheap' fun to ignore.

I'll be watching this thread though

[binge]

A lot of the Kart tracks have been running pit bike days for years and years. But it's not really been a big sport up until a few years ago.

I started about 5 years back now. Did my first track day at Kinsham Raceway. Chaz Davies and Casey Stoner show there faces there quite regular, on both supermotos, and Karts.


It's 100% one of the best sports I've ever been into.
Whilton Mill hold bike only track days every bank holiday, and you get all the minimoto lot turning up too.

[evoboy]

https://sphotos-h.ak.fbcdn.net/hphotos-ak-ash4/304023_190343494373079_1179307062_n.jpg
https://sphotos-c.ak.fbcdn.net/hphotos-ak-ash4/302579_190343337706428_387743687_n.jpg

Mucho fun. Even when you crash. Which you will .
____________________
Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[sulphur]

[h00dwink]

Well tempted for something like this when I'm done with the sr125 rebuild. Looks like proper cheap fun n quite a few tracks around compared to normal track day stuff. And the added bonus of just being able to chuck it in the boot of the car
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[chris-red]

I'd probably love this, if I wasn't 6'5
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