V Raptor 250 problems

[TastyRabbit]

Hi,

I own a Skyteam V-Raptor 250. I added a new exhaust, and I think the mix is a little lean.

I contacted ooracing to get some jets off them and a tuned CDI. The guy asked me to take photos of the jets and send them to him. I took apart the carb, taking the entire thing out... which took a while. Here's a photo of the jets -



Anyway, I think I may have done something stupid, because I was left with a spring........

Here's a photo of the carb...



I took the spring and pushed it into the first hole (on left) and screwed the jet (?) needle thing in (the one on the right in the first pic), as it seemed to fit it.

I put everything back together on the bike and hit start. Nothing happened, so I opened the choke and it ran at massive RPM so I shut it off straight away. I'm guessing the small jet thing (its not the primary or secondary jet I'm sure) controls the idle speed? Do I have to take it apart again?

I don't really know what I'm doing, but someone told me it was easy and I guess you have to start somewhere!

[Weldangrind]

Welcome! I'm trying to guess at the Tasty Rabbit reference; are you a Python fan?

These carbs really are easy, and the fix for the crazy RPM will only take a moment. What likely happened is that the carb slide is in backwards. If you unscrew the top cap again and pull the slide out, you'll notice that there is a groove on one side and a small ramp (at the bottom) of the opposite side. The groove lines up with a pin in the bore, which is on the left side of the bore from the rider's perspective.

The jets in your pic from left to right are main jet, slow jet and pilot mixture screw. You were correct in placing the spring in the pilot mixture screw hole. Did you happen to count the number of turns it took to remove it? If not, just GENTLY tighten the screw until it stops, and then back it out 1.5 turns. That should be close enough.

If you remove the carb again, don't bother removing the pilot mixture screw. There are no gains to be had by replacing it.

The slow jet and the main jet are mounted in emulsion tubes, as in your pic. The jet actually unscrews from the emulsion tube, and each jet will have a number stamped in it. If you tell us what number is on the jets now, we can guide you towards a better number.

[TastyRabbit]

Thanks very much for the help. I've got to take the carb apart again today to get the numbers off them... I forgot to write them down. I'm sure its placing the accelerator screw in backwards.

[TastyRabbit]

I've tried switching everything around again but it still idles really fast. I've tried swapping the top cap around, and screwing the pivot screw to 1.5 - 2.5 and 3.5 turns, all start but rev at full, and require full choke to start.

It takes me for ever to take the carb apart on the raptor.

[Weldangrind]

What I mean is, unscrew the top cap and withdraw the slide. The slide is a cylinder that fits into the upper carb body. Can you confirm that the slide groove is lined up with the pins in the bore?

[TastyRabbit]

Ok I'll check later, I can't face taking it apart again...

[SpudRider]

Welcome; we are glad you joined us.

As usual, Weldangrind is giving you superb advice.

[TastyRabbit]

Thanks for the help.


I feel like an idiot.... I pushed the slide down with a metal stick and everything's working again.

The guy from OOracing recommends a 42 pilot 110 main. Its currently 38 102. It runs a little lean at the moment with the new exhaust.


Does anyone know the diameter of the air intake on the Carb, to fit an aftermarket air filter, and how to get the stock air filter out? Also, the stock air filter has two tubes running to it, I noticed the after market filters don't have any tube inputs. I guess one is just the mess out tube (don't know the technical name) and the second I have no idea, but it goes to the engine.

Thinking of getting these sets of jets -

http://www.ebay.co.uk/itm/151324720866

http://www.ebay.co.uk/itm/stage6-Kei...item5d4f2e44f9

They look the same as mine, I guess they'll work.

[Weldangrind]

Until you actually unscrew the jets from the emulsion tubes, you won't know if the jets are the same as the eBay links. I've had trouble finding replacement slow jets for Keihin carbs like yours, but you might have an easier time in the UK.

The carb intake OD is likely to be 42mm. This is the filter I've used on a few different bikes: http://www.ebay.com/itm/42mm-SPONGE-...957d39&vxp=mtr

I can't answer your stock airbox questions without pics. Perhaps other V-Raptor owners will know.

[TastyRabbit]

Hi again,

The jets arrived and I've been trying my hand at fitting them. I've been having a lot of trouble though...

I've now modded the following -

EGR gone - made a ali cover for it.
Pod filter
Exhaust

The jets on the bike say 38 - 102

I think they are different from the jets I have....

When I changed them the bike splutters when I turn the throttle. I put in a 42 and a 110. If I put in a 38 - 102 of the new ones I get the same issue.

I really don't get how to tune the carb at all. I ordered some other jets to try, I think the jet size printed on the stock jets is wrong, the number seems meaningless I tested it with some micro drill bits, and the sizes aren't in mm.

Anyone got any idea what jet sizes you would use on a 223cc engine.... I think its the same engine as the ACE.



Also I'm going to respray it British Racing green, I'll put a photo up when I'm finished.

[Weldangrind]

At least the main jets should be Metric. A 110 jet should be 1.1mm, or 0.043". Really, you should be in the ballpark with a 110 main jets on a 223 with a pod filter.

Please show us pics of what you modified, the cover you made for it, the exhaust header and the new muffler. We can make recommendations from there.

There isn't really much tuning to be done on these carbs. You need to install the right jets to suit the intake / exhaust, set the jet needle to the right height, set the pilot mixture screw and adjust the idle. That sounds like a lot, but it really isn't.

[Weldangrind]

Looking forward to before and after pics of the respray!