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KH250 Oil Pump
Posted: Wed Jun 21, 2017 6:54 pm
by KHev
Hello, I bought a restored KH250 a few years ago and only just got around to riding it. It is smoking heavier than Dave Allan and after taking a look I noticed that the pump cam was not returning to the punch marks. I managed to get a replacement return spring but there seems to be some resistance on the shaft. I'm too much of a coward to take off the pump without knowing what I'm going to face. Any suggestions? I've thought about disconnecting the cable and putting a 50:1 petroil mix in the tank. Again any suggestions? Mineral or Semi Synthetic? Kev
Re: KH250 Oil Pump
Posted: Wed Jun 21, 2017 8:32 pm
by oldman
make sure spring is not trapped under cable cam
Re: KH250 Oil Pump
Posted: Wed Jun 21, 2017 9:27 pm
by Wolfie
You should look into that resistance to it turning, the pump isn't as frightening as you may think, especially now you have the full might of the members to bring to bear on the problem.
And, if it does break the 250 ones are still fairly easy to find.
It may have been left dry at some time and started to rust/fust internally.
Others have used premix but you can't beat a proper feed, I'd stick with it.
Re: KH250 Oil Pump
Posted: Fri Jun 23, 2017 5:14 pm
by KHev
Thanks, the spring is seated correctly. If I took the pump off I could have a look for any gumming up or corrosion on the shaft. My concern is that it's internal and will have trouble getting it back together. Are there any special tools? Does it need to be calibrated? Kev
Re: KH250 Oil Pump
Posted: Fri Jun 23, 2017 8:25 pm
by Wolfie
Nope and nope. Internally, it's a rotating shaft with a spring at the top end pushing it downwards, there's a ramped castellation at the bottom which rides on the cross shaft cam that the cable quadrant turns. The turning of the cam allows the rotating shaft to rise and fall over a greater distance so moving a greater amount of oil.
Channels and cavities around the upper shaft push the oil out of the outlets and the NRVs on the lines prevent it coming back..
Around the shaft and end covers some 'O' rings provide a seal. It's a very long time since i opened one so their exact location defeats me.
Here are some dismantled pumps from MrAxl and the CanadianTriples Site..
http://3cyl.com/mraxl/tunerwisdom/oil_pump_mod.htm
http://kawasakitriples.myfastforum.org/ ... asc-10.php
MrAxl is THE place to go for just about any Triple information, Dale has put together a fantastic site over many years.. Bookmark it!
Re: KH250 Oil Pump
Posted: Sat Jun 24, 2017 11:38 am
by KHev
Thanks, I've had a quick look at the link and read about oil bypassing the o rings on the pump. Can they be easily sourced? Btw which brand / grade 2t oil do you recommend? Cheers Kev
Re: KH250 Oil Pump
Posted: Sun Jun 25, 2017 6:25 am
by scouse
Try slacking off the nut on top of the cam slightly, if this allows it to return then you can remove the nut get a small amount of loctite on the thread and semi tighten the nut in place
Hope this helps
Gary T
Re: KH250 Oil Pump
Posted: Sun Jun 25, 2017 8:16 pm
by KHev
Thanks Gary, It's resistance on the shaft even when the not on the cam is not tightened. What's your opinion on brand and type of 2t oil?
Re: KH250 Oil Pump
Posted: Sun Jun 25, 2017 10:11 pm
by scouse
Back in the 60's when the 1st triple was manufactured oil was of poor quality compared to even the cheapest oil available today, you bike will run perfectly fine on Tesco 2 stroke ( other supermarket brands are available) , some people will run semi synthetic others will insist on fully synthetic, me? I just run on second hand 2 stroke out of the scooters they break
I think twice in the last 20 yrs have I been caught out and had to buy some oil
Gary T