Pocket bike idles, but doesn't rev under load

**Junkers** · 18th June 2008, 14:02

OK.. Just been out there and took the regulator off the carb. Plenty of gas coming through, took the jet off and blasted it with CRC.. no clogs there. Then I took the exhaust off and found a decent amount of fuel/black stuff hanging round the exhaust port. I stood the bike up and a small pool of black oil/fuel came out the rear of the bike, like pitch black crude oil. Is this the result of running "fat"? (Do you mean rich?) What could be doing this?

Well I tried starting it with the exhaust off, didn't work. Not sure if they work with the exhausts off though, they rely on back pressure don't they?

Before I took everything apart I managed to get it going again, but it only lived for a minute before it died, then I would wait a minute to start it again and it would idle for about 5 - 10 seconds before stalling.

**CookMySock** · 24th June 2008, 19:34

how are you getting on with this ?

What oil and sparkplug are you using ? What fuel/oil ratio are you running ?

Try heating the tip of the plug up using a propane torch or similar. You can get it pretty much red hot, so give it rings. Allow to cool a little and refit it as hot as you can. Choke, start, choke off, now get on it and RIDE IT HARRRRD. How does it go ? Don't doof around on it at all - just give it death, and certainly don't try to idle it around.

DB

**Junkers** · 27th June 2008, 14:00

Been playing around with it some more and have put it down to the carb. My new Dellorto style PHBG arrived today but they gave me a watercooled adapter

. I'm using castrol full synth @ 25:1 ratio.

I managed to start the bike the other day, and found out a interesting quirk. You can idle the bike with the choke on, take the choke off and give it a short blast. It will begin to roll happily and then suddenly surge and try to stall but the funny thing is.. if your quick enough and put the choke back on it won't stall. So I guess a lack of vacuum is not drawing the petrol out possibly?

I am going to try and make this watercooled adapter fit as I do not want to have to wait another 2 weeks. Let you know how I go.

**CookMySock** · 27th June 2008, 16:35

Originally Posted by Junkers

You can idle the bike with the choke on, take the choke off and give it a short blast. It will begin to roll happily and then suddenly surge and try to stall but the funny thing is.. if your quick enough and put the choke back on it won't stall.

Keep doing this and see how long you can keep it going for. Don't softcock it - give it heaps!! get the choke off as much as you can so it's running nice and clean. Get on it and ride it if you can, but give it some work to do and see if it begins to clear. Maybe once it has warmed up it will go now.

Also make sure your plug is nice and clean. Consider going up to 50:1 mix just until it cleans up.

HTH,
DB

**Junkers** · 27th June 2008, 23:13

It's fixed! the bastard goes...

After a bit of mucking around with the adapter plate and trying to make the float needle seal properly, we got it going. Goes very well now.. until we lost the idle screw and the kill switch wire broke off.

I am pretty surprised though.. the carb it came with was shot, the replacement was shot and the dellorto wasn't working properly either, got there in the end though so I'm happy, cheers for everyones help!

**CookMySock** · 28th June 2008, 07:57

yay for cheap chinese junk !! (we got two of them)

DB

**BigAl** · 28th June 2008, 21:44

Good stuff Junkers, perseverance eh!

**Junkers** · 29th June 2008, 21:15

Originally Posted by BigAl

Good stuff Junkers, perseverance eh!

Spoke to soon

The float needle on the new carb won't seal and shes pouring gas everywhere.. my bike must be cursed.

So my next question is, can genuine dellorto parts fit a replica carb?

**Gadgit** · 29th June 2008, 21:50

Yip they fit no prob...
You've had a bad run with carbs aye I got 3 19 rep carbs but they never had any issues like that... but using the genuine internals will give you a better power...if tuned right the genuine emulision tube is a better design

**Junkers** · 3rd July 2008, 18:46

Well I fixed the carb up and had it running for a day. Came in the next day and tried to start it.. what do you know. So I've caved and bought a new engine. If this doesn't work then I'm going to have to fly up to Auckland and throw the bike at bargains direct and hold them hostage until I get a new bike.

**racefactory** · 3rd July 2008, 22:57

hey mate glad you got somewhere.

yeah that oil in the header plays havoc if it builds up like that... good thing emptying it. was there tons??

hang on a sec... your using a 19mm rep carb on an air cooled cag?? thats way too much for those bikes i thought.

the air cooled guys come to the conclusion that the C1/B1 rep 39cc water cooeld 14/14 mm carb/ dellorto 14/14 is the best for the air cooled cags. try and find one of those if you can. a 19mm is overkill youll get crap all bottom end response on a air cooled cag- thats what ''they'' say.what was it like?

btw have you had a look at the plug again? maybe its running so rich/fat your starting to foul it again? check that mate. since you had it running for a while then it doesnt work again i have a feeling that MAY WELL BE the problem. scenario could be your running so fat (as indicated by your fuel and oil in header) plug is starting to foul again after a days use. since you using the 19mm dell rep carb yeah this sounds pretty likely to me...

damn man... hope you get it sorted.

ps... to solve the fuel leaking from unsealed needle problem.... get a hammer or something and give the carb a good tap with it... you can usually get it to seat again, at least on mine you can. i found that out when i crashed my bike one time.

**Gadgit** · 4th July 2008, 12:27

Theres a few mod daytona's running round with 19mm rep carbs one is winning prody mod class and the other I put the 19mm on and it made a Huge difference... it runs 7-60 gearing and pulls my 95kg ass no problem. Also runs a 0.100 jetting and loves all the fuel you can throw at it lol

**racefactory** · 4th July 2008, 17:47

cool man, good to know.

**Gadgit** · 4th July 2008, 18:51

Yea well I was a sceptic of the 19mm till I seen Bretts bike haul ass... the standed B1 responds well to a 17mm upgrade too just a bit of usless info throwen in there