Hi, here goes my first post so I hope you guys can assist and help me through a frustrating time with a Quad I bought for my son.

I purchased a Masai K50 which also goes by the name of Dinli Cobia and Goes 50XS basically a 50cc, 2 stroke kids Quad which currently has a WFZ Walbro carb. The Quad is around 5 years old and has hardly been used, a quick clean of the dirt and dust has revealed a sparkling new bike underneath!

When I picked it up I knew it wasn't a runner, but it appeared to be a carb issue through been stood. The battery is toast but it would turn over on the kickstart but immediately stall. So first job was to strip and clean the carb, air filter and fuel lines, dump old fuel and first kick it roared into life and stopped a few seconds later. This is all it seems to do and no amount of adjusting needles makes any difference it is exactly the same.

Today I tried it again and tried pumping the throttle and off it went, I rode it round for 20 minutes but at low revs was always pumping the throttle to get it to stay alive. Stop and it dies pretty quickly...

I have read the carb tuning set up guide on here, but I cannot even get it to idle to make adjustments and listen to the results, it starts immediately burbles and hiccups for a few seconds and stops, sometimes pumping the throttle picks it up, other times it will continue to die.

The only thing I have not done yet is change the battery, I am waiting for delivery of a new one and the plug I just cleaned and reused it. Can a bad battery cause this at low revs I don't think so, but thought I would ask?

Any help would be gratefully received, I get the impression it is not a settings issue with the carb but willing to try anything.

I have a reasonable knowledge and work on my own DS650 as long as I have a service manual I do my own work ;-)

Thanks and look forward to your valued responses....

KEVIN

BOMBARDIER DS650 - MASAI K50 - I WANNA SIDE-BY-SIDE!

 

if applicable, have you pulled the idle screw out and cleaned behind it? being careful not to lose any parts. did you clean the orifices on the jets, particularly the idle jet? they may have been clean but some solids may have let go somewhere and made their way back into the jets. if you have to feather the throttle to stay running, i would imagine that the idle circuit is slightly dirty. just my two cents.

 

Welcome to the forums.
I'd try a new spark plug..just cuz..

 

Thanks for your reply, I was thinking about stripping it all again and cleaning once more just in case

Tried it again today and now it wont start unless throttle is applied then it runs great but still needing to pump/feather throttle to stop it dying at slow speeds.

I have ordered a plug, fuel filter and battery just to rule these out, though I do not think it can be these but Quads have caught me out before and simple things have made them work!

Problem where I live is you cannot go out and buy anything from local shops, I spent all afternoon yesterday at motorbike shops trying to get a filter with no luck! So I have to resort to mail order, sometimes from the UK.

Can the reed valves cause any problems like this?

I do think it is something to do with the carb!

As a matter of interest can somebody please confirm what the 2 adjustments are on the WFZ carb so I am 100% sure! Its has a knurled screw that you can adjust with fingers I think that is the idle and the other is a flat head screw which I think is the mixture?

Tx

KEVIN

 

man, i understand 2 strokes and how they operate but i hate working on them, some of the parts i don't totally understand how they work, so i shy away from 2 strokes, but back to the subject, it sounds like your presumption is correct on the carb adjustments. i couldn't find any pics of the WFZ carb, but it sounds like you've identified it correctly. hopefully a 2 stroke expert will jump in here for you!

 

Thanks I hope an expert comes along as well

Tomorrow I should have new fuel filter and plug so I will report if a miracle happens. After that its strip the carb and clean again....

KEVIN

 

I also searched everywhere for some info on the Walbro WFZ, couldn't find a photo, manual or anything. Even the Walbro site doesn't seem to give info on older carbs................very strange
If anyone has a manual for the carb I would love a copy....

KEVIN

 

see if they have one hidden here....

Service Manuals

 

Tx tried that site without any luck, might email them you never know!

KEVIN

 

OK so far drained and refreshed fuel tank, new filter, new spark plug, new battery, cleaned and blasted carb again with cleaner...

Result...........same

Starts fine, won't idle pumping throttle gets it running and I can ride it doing this, but I can't put my kid on it as I am winding the throttle in to keep his speeds down!

If I get it going on the throttle I can turn the idle and mixture screws but nothing happens, good fuel flow seems to be coming through, I am a bit lost now

Can anyone tell me what the reed valves do that are located after the carb, can they cause any of this?

Thanks...

KEVIN