Q: steps replacing fuel pump (YBR 125)

[w_leeds]

Hi guys,

I had intermittent issue with fuel not priming on my ybr 125 (known issue for a lot ybr's) while it is parked on direct sunlight, so I decided to replace the fuel pump (just the small pump itself, not full plastic assembly).

I took the tank off, opened the plastic fuel pump assembly and switched the old fuel pump with the new one.

The pump would prime but the bike still would not start.

If I tested right with the pressure tester, it shows 0 psi

If I remove fuel line hose, it just squirts a little bit of fuel on the prime cycle, and that's it (doubt it is anything near 40psi)

So the way I understand is that the new fuel pump primes but does not deliver enough pressure.

Took out "new" fuel pump and put the genuine old one in the plastic fuel pump assembly - same issue - fuel pump primes but no start (in addition, would not prime on direct sunlight)

After reading it up online, I have found that such issue is caused by the small rubber valve O rings which have to be placed inside plastic assembly on top of the fuel pump (pic below). I have found one rubber ring, but I heard that there should be "couple of them". The image below is just from the web to show what kind of O rings I am talking about

https://s227.photobucket.com/user/deatschwerks/media/IMG_2665.jpg.html

Can anyone please give me a direction to troubleshoot the problem and may know how many rubber O rings should be inside the fuel pump plastic assembly?

Thanks!


Just quoting what I read in this forum ".... Further investigation showed that the new fuel pump was not seated quite correctly in the plastic housing and pressurised fuel was escaping back into the fuel tank. There are a couple of rubber O-rings that fit over the output nozzle of the pump - make sure you fit these correctly otherwise you will have the same problem as me !....."