Help Daytona 150FDX 4v Keihin PE 28mm jetting

[Shawn5236]

I just bought my first pit bike and want to set up supermoto style for my local track a high speed kart track. Bike is a Pirahna Daytona 150 4v (N-1-2-3-4 shifting).

I bought the bike from sea level and I live in Colorado at 5280 feet elevation. The thing really comes off weak on the power from the bottom. I tried moving the idle air screw out a bit (helped the idle slightly). Then I took out the needle and moved the clip to the top position thinking that it would help lean it out.

No luck it still sucks. It seems okay on full power though but for our track getting midrange hit is pretty important (that's why I bought a four stroke). Want to get this thing ripping so any help is appreciated.

I am turning 40 years old in a week and this is my present to myself. Want to get back into racing... and used to race mx.

Also what are some good things to put on it to be quick. Right now the only thing I have is 2.5 inch wheels front and rear with Sava racing tires.

Thanks
Shawn
Colorado USA

 

[my67xr]

Welcome to Miniriders,
So are you running the standard jetting in the carby, 125 Main and 40 Pilot ?
And you tried tuning it too, i'm guessing the idle mixture screw is set somewhere past 3 full turns out?

I'd get a 35, 36, and a 38 Pilot jet and see how that set's it up
Your Main jetting will have to wait till you get the Pilot dialed in, but i'm guessing that the 125 is way too big.
But get some smaller Main jet's too, starting at 108 - 122

I have my Daytona 190 running sweet (at sea level) with a PWK28 ,45 Pilot and 110 Main jets.

 

[ringo]

Yeah I ran a pwk 28 with 116 main and 45 pilot at sea level.

Check what ignition map it's set on, these maps make a huge difference, if it's set on the top map disconnect all of the wires so it's on map 1 and see how it goes then off the bottom.

 

[Shawn5236]

Okay guys thanks so much for the help.

I pulled out the jets and the main is a 110 and the pilot/slow is a 38.

So it's funny because without checking myself I assumed they were stock and ordered a yep... 110 man and 38 slow... ****.

I will go to my local shop today and see if they have any smaller slow jets but I think the main is good it seems to rip at WOT but I haven't gone crazy on it since I live in a family neighborhood and I don't want to piss off my neighbors.

I wanted to post a pic of the ignition wire harness (at least I think that is what I disconnected)...
please help me verify that yes this is what I should disconnect. Also what is the setting that it is at now in this pic prior to me unplugging it.

The previous owner was a Pirahna sponsored rider who was a top mini guy in the state of Ohio USA. I think he was like 13-15 yrs old. That is sea level altitude btw.

This thing also smells like it has race gas in it possibly. Can I run normal 91 octane pump gas? Also just to verify that one wire that is not connected to the harness was like that already when I got it. When I gave it a quick visual inspection upon delivery that was one of the things I noticed.... "like what the hell does that wire do?"

 

[my67xr]

That plug connect's the stator to main harness.
The green w/red stripe wire is for a neutral only start switch (not used)

The wire's that Ringo mentioned are a second lot that come out of the cdi unit, under the front of the seat close to the tank
CDI is bottom centre in the pic below

The list of Timing Setting's / Rev Limiter setting's is here on page 18/37
http://mypitbike.ru/downloads/DaytonaAnima150.pdf


How many turn's out is your mixture screw now ?
And how does it rev when you blip the throttle? Any hesitation / stumble's ?

 

[Shawn5236]

2 turns out but no matter how far I turn out it will not stumble which lead me to believe that it needs a smaller pilot jet (????)

I just wanted to verify I unplugged the right thing now please. This is to retard the ignition to give low end grunt and limit the top end and limit the revs??? correct?

I just want my bike to rip I really don't want to compromise... is that possible?

 

[my67xr]

No, that is where the main harness wire's meet the CDI.
On the opposite end of the cdi, there will be 2x bunches of wires coming out, see my pic above

Try a 36 or 37 pilot in it.

Have you checked for any vacuum leaks?
Start the bike and let it idle, spray some degreaser/wd40 over all the joins on the carby to manifold, manifold to head etc.
If the idle changes in any way, then there is a leak.

 

[Shawn5236]

Put in a 35 pilot which was the only one they had at my local shop. Stuck with the 110 main.

Seems to be working really good so far. I will test at the track this weekend I hope. Only other thing I am struggling with is that I went to put on my 12" Pirahna supermoto front wheel and it needs bigger spacers. Hoping to find some locally. Wish they told me that I would need those on the phone when I ordered the wheels PITA I just wanna ride already.

Thanks for the help on the jetting. Just gonna leave the ignition alone for now until I get it on the track and test it. Need to learn to ride such a small bike, hope the learning curve isn't too hard.

 

[Shawn5236]

Fabbed up a spacer and I am ready... just need to put on the Sava race tires on the supermoto wheels which came with a set of Kenda's that I read aren't very good for the track.

I had previously mounted the Sava rear on the stock rim so I might just leave that on the bike for now since mounting the tire was such a chore. I will post a pic of the bike when tire is on the front though.

 

[Shawn5236]

Took the bike to the track today and started getting used to it.

The good:
Shifts good
Good stick from tires and feedback from the rear wheel
Good and loud four stroke
Smells like a proper race bike
Unique here in Colorado the only Chinese bike out there

The bad:
I want more power and quicker rev up... and more torque
Pegs are too low and scraping them upsets the bike quite a bit
Seat is too soft and narrow
did I say too slow... well yes too damn slow I need more power and speed
Rear brake is hard to reach with my foot it's really far into the inside and takes a lot of down movement to engage
Front brake is weak
The whole thing just feels cheap compared to a Japanese bike
Worried while riding that something is going to break but starting to trust it after about 30 laps
front end feel is lacking and trail braking is hard to do with confidence

Overall fairly disappointed with the ride but at the end of two session (1st short, and the 2nd really long) I am about 2 seconds off my pace on my big bike so that's not terrible I suppose figuring there is a pretty long straight where I feel like I am just sitting there wishing I was going faster. I really need to learn how to carry more corner speed to get a good lap time.

Also, there was some moisture on my left boot after both sessions which concerned me. Not sure if it was gas or possibly oil from the air filter. I will be going out again tomorrow with some other mini riders and I hope to learn how to ride it better. I took some GoPro video so I'll try to post that up later. Cheers!

 

[my67xr]

Sound's like you need some more cc's.


I have seen a couple of rebuild's that use a bigger bore/piston kit 70mm instead of the stock 62mm, this will take it out to 190cc or very close on it.
The other thing you could do is fit a 190cc crank and rod to take it out to a 190cc

The first mod above will give it huge torque, but the cost is a bit high,
the second mod will make it into a standard Daytona 190 62mm bore x 62mm stroke

There are also quite a few after market part's available for them too
http://www.miniriders.com/chinese-mini-s/40857-daytona-190-performance-parts-new-releases-etc.html

 

[gottagetacheaperhobby]

What forks are you running? Front end feel could be as simple as changing your fork oil, or if you have the money zocchies feel brilliant on dirt, imagine they would be easy to adapt for motarding. The front brakes could be improved with a larger disc and good twin piston caliper with copper cintered brake pads, my front brake is touchy as on the dirt, and thats just a 210mm disc and china twin pot caliper with quality fluid. Rear brake could be improved with fresh fluid, and if you want it to engage earlier you can play with were the pedal connects to the brake system, winding it up or down on the thread to lift or lower the pedal depending where you want it. Simple bit of brute force will position the tip of the brake pedal where you want it, or look for a larger tipped brake lever.
All in all if your 2 secs off your big bike pace on a 150cc china, with plenty of room for upgrades, I would be pretty happy

 

[china911]

Braking.....You can install a soft pad in the front to help braking .

peg clearance.... buy some road bike rear sets , grab a peg mount get someone to weld it up. l did this on a yz490 . motard

china quality .. overall not that bad , many dudes cutting laps on these things week in week out. My euro bikes give me more problems.

 

[my67xr]

As mentioned in the posts above use the sintered copper disc pads, you'll have to suss out what shape your bike uses before ordering them
De-glaze your disc's before fitting them too.

You could alway's upgrade the disc's and fit larger ones, 220mm or 240mm front (if they'll fit), and fit a 210mm rear.
Caliper's there are some nice one's available, including Radial mounted 4 piston caliper's, to suit floating disc's etc

http://nuovafaor.it/en/detail-parti...5/disco-freno-motard-flottante-diam-240mm.htm
http://nuovafaor.it/en/sez-parti-moto/2/impianto-freno-doppio-disco.htm
http://nuovafaor.it/en/sez-parti-moto/5/prodotti-pit-bike.htm

 

[my67xr]

As mentioned in the posts above use the sintered copper disc pads, you'll have to suss out what shape your bike uses before ordering them
De-glaze your disc's before fitting them too.
Search Results - Advanced Search - TBolt USA, LLC

You could alway's upgrade the disc's and fit larger ones, 220mm or 240mm front (if they'll fit), and fit a 210mm rear.
Caliper's there are some nice one's available, including Radial mounted 4 piston caliper's, to suit floating disc's etc

Nuova Faor Italia - Dettaglio - FRONT FLOATING MOTARD DISK diam. 240mm.
Nuova Faor Italia - Catalogo - Twin disk brake system Motorcycle parts, Supermotard, Brake Discs, forks, anodized details
Nuova Faor Italia - Catalogo - Pit Bike Products Motorcycle parts, Supermotard, Brake Discs, forks, anodized details

 

[Shawn5236]

Went out again to the track today... and I am starting to gel with the bike and actually had a lot of fun on it. I stiffened up the front forks and changed the needle jet position out on the clip which leaned out the mid range a bit helping somewhat. Also I changed the position of the rear brake pedal and that really helped with my braking.

I still want more power but starting to appreciate the fun of wringing this things neck WFO on many parts of the track.

I will probably spring for the 190 kit sometime in the near future but not until I feel like I can ride it to the absolute limit. I still think there is a long way to go on this bike before power alone is the limiting factor.

Another problem that I need some help with:

The front wheel is bouncing around (not all the time but sometimes really bad) I did not balance the wheels when I put on the new tires so maybe this is the problem. I was thinking it might have been a flat spot on the front tire originally from them maybe sitting around with the seller and thought maybe it would work out after some riding. 4 sessions on the tires and it doesn't seem to be improving.

Here is the 190 kit from Wholesale Cycle. Anyone every installed one of these? How challenging is it? I have done some top ends before but have never split cases and worked on a crank/rod in the bottom end.

 

[my67xr]

Rotn50 has that stroker kit for his 150 4v, not sure if it's in yet though?

I have swapped a couple of crank's over before one in a GPX140, another in a 150 Lifan, and i have a Daytona 150 2v here to do next.
They aren't that hard to do, taking it easy doing it while taking reference picture's as you go, first time i reckon you could do it in 2.5 hour's all up.

Here's a copy of the engine parts diagram- http://mypitbike.ru/downloads/DaytonaAnima190.pdf

 

[Shawn5236]

I played around with the ignition firing and rev limiter settings finally.

It was set at position #2 for both the ignition and rev limiter.

First I moved the ignition setting down to #1 which is everything unplugged and it retards the ignition. This made it bog even worse.

Then I went to position #3 which advances the ignition and HELL YES what a difference.
I then test position #4 and it wasn't as good as position #3 so I put it back there.

I then moved the rev limiter setting up to position #4 taking the rev limit from 12,200 up to 13,600. Haven't test that because I don't want to get the police coming after me in my neighborhood so it will have to wait for another track day I suppose.

This programmable ignition in a little pit bike is AWESOME! Thanks for the help y'all.

 

[ringo]

Another problem that I need some help with:

The front wheel is bouncing around (not all the time but sometimes really bad) I did not balance the wheels when I put on the new tires so maybe this is the problem. I was thinking it might have been a flat spot on the front tire originally from them maybe sitting around with the seller and thought maybe it would work out after some riding. 4 sessions on the tires and it doesn't seem to be improving.

Mate don't worry too much about it, I've never had a 12" tyre that is truely "round". Tried heaps of brands (CST, Dunlop, PMT, Sava) on different wheels and they all bounce!!!!!

 

[Shawn5236]

Took the bike to the track for a couple of hours today (I can load and be on the track in 30 minutes so it's very nice). Today was my birthday so what better way to celebrate.

The ignition changes helped liven up the bike and the higher rev limiter helped a bit too but I was still bouncing off it on the straights looks for more. I need to try a different clip in the throttle slide on the carburetor. I called Wholesale Cycle which sells the Pirahana bike that I own and they had it available in stock. I will order it tomorrow. I am also tempted to pull the trigger on the 190 kit... but but don't know still undecided. Anyone her ever ridden both motors and can give me feedback on the differences? Strengths and weaknesses.

For me the strengths so far in the Daytona 150 4v engine.
Seems reliable (I've been hammering it for very long track sessions)
Sounds great
Doesn't spin the rear tire with full throttle delivery even mid corner
Starts easy and hasn't kicked back (no decompression cam either that I am aware of installed)
I am forced to focus on learning to carry corner speed and brake later or I will be going slow.
Not enough compression to upset the rear tire when downshifting.
Forced to keep revs up and in the meat of the power band ringing its neck which is kind of fun.
Again feels very reliable.

Weaknesses:
Slow on the straights
Revs up slow when trying to lay down power to the pavement
More torque would be useful if I blow a corner or on uphill sections.


I asked the tech at Wholesale Cycle how hard it was to change out the crank and piston and he said it's not too bad and that you don't even need a bearing press or have to remove any part of the transmission. I would like to learn how to do it and enjoy learning to wrench on new stuff.... just not as much as I like riding.