GB600R oil feed problem - ideas please

hi all,

over the last few months i have been tinkering in the garage neatly every night putting an XR600R motor into a GB400 frame. the motor had a blown big end, so had to strip the whole thing down and do a full rebuild. Got the motor in the frame, and have been fiddling with electrics - till i finally got it running tonight.

i wanted to make sure oil was feeding thru ok, so i undid the banjo bolt on the oil feed to the head... and waited.. and waited... and waited... and no oil pressure. so i thought maybe the oil pump is sucking in a whole lotta air, so i opened one of the caps on the rocker cover, and poured in a bunch of oil thinking it will lubricate the cam and submerge the oil pump to prime it. so i ran it for about another minute, and still no oil pressure to the head.

the oil tank was half full before i got it running. after the two runs it was all full. my guess is that the oil pipes to and from the oil reservoir are reversed, so oil is running the wrong way thru the system. then again i would have thought that the pumps on the gb400 and xr600 are similar.

i have read thru all the threads on priming these pumps, but with the oil tank filling up, i somehow suspect the issue is elsewhere.

any ideas would be appreciated.

regards,

Nik

There are two pumps, so it is plausible the scavenger pump is primed and the pressure pump is not.

Some have put a little air pressure into the tank to get it to prime.

Dave

What Dave said... When I rebuilt mine, I stuck an airchuck in the oil tank and pressurized it. Spark plug out, (air blowing into the oil tank) hit the starter and let it spin. After a few revolutions, it was oiling fine.

If this doesn't do it, I would be suspicious of oil pump problems...

ok thanks... so i've tried a few things, with still no luck.

i suspect the oil pump may be the issue. i bought the motor with a blown big end, and i guess this is how it failed.

next question is - can i use the oil pump from the gb400 motor, on the xr600? they look the same, but have different part numbers. the first part of the numbers is the same though - 15100-xxx-xxx.

gutted i'll be taking clutch and all off yet again :smirk:

n

So, i should have listened to what i was told... but hey that would be too easy.

i got a compressor and pressurized the oil tank... gave it a few kicks, and got an oil feed.

checked it about 5 million times as it was sitting there idling, just to be sure, and all good.

Took it for a thrash up and down the road (no lights, tacho, or any electrics yet), and boy does she get up and go. Totally different bike to the 400.

Cheers Again!

Nick

*Sometimes* we accumulate and share wisdom here (as opposed to concentrating and distilling foolishness over in town square, heh)

Dave

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