Vintage Dirt Bike Q & A

Hi,

I can't find much info on these pumps and would like to see a complete diagram including the internal mechanism of the pump. Not Clymer or Haynes, they don't have enough detail regarding the internal components. On the oil line there is a loop for a bolt on both ends, so I assumed that meant I could remove the bolt on both ends to replace a broken line with a new one. However, the bolt on the pump broke off when I tried to remove it the line looks fine and I should be able to use it again. I assumed one of two possibilities regarding why that bolt broke and I still can't get it out with a jack hammer. It was glued in with some kind of super adhesive or it is permanent on the pump side which would make no sense. Clymer and Haynes did not help, nor did the internet. Can someone please advise me on this?

Thanks!

Its just a banjo bolt its hollow with a hole towards the top of the bolt so oil can flow thru the middle and out thru the top of the bolt into the oil line and into the manifold. I assume your talking about an mt and I have a shop manual for an mt250 as well as a spare pump and line and a lot of other parts let me know if you want me to scan thier diagram and email it to you.

Thanks very much! I feel better knowing it was a bolt meant to come out at some point for oil line replacement. Now I need to remove what's left of it and find another oil line. Then I need to take everything apart and clean to make sure metal pieces don't get pumped into my motor in case they don't come out when I manually pump something through it.

Have you heard about any gauges or devices people have used to monitor and ensure oil flow?

I know I can look at the inpection hole showing I have oil, but that is useless when your pump stops working.

Honda would have been wise to have included a simple warning light or buzzer to alert operators that the pump is not functioning. Especially when they put extra non critical lights on the bike like high beam and neutral. Those lights don't come close in priority.

Mercury and Evenrude old 70's and 80's outboard motors with oil injection had this feature so I know it was not rocket science.

I'm not trying to offend anyone, I'm just pointing out an obvious screw up by Honda and am hoping to receive input so I can buy this cheap insurance or build it myself. It should be fairly simple except I don't want it to be permanent in case I ever sell to a collector.

If I do build something I'll make a few kits with directions and I'd be glad to send them for the price of parts and shipping only.

Thanks again!

I'd suggest using an Easy-Out bolt extractor on the oil line bolt, along with plenty of heat to soften any adhesive and expand the tapped threads (assuming the bolt is threaded into aluminum). An impact driver would be ideal, but if you don't have one you can try using lots of short, sharp rotations of the socket wrench instead. Make sure the Easy-Out is fully engaged before you start, obviously.

This guy may have the 15542-358-000 'one-way' oil line bolt:

http://www.cmsnl.com/products/boltone_15542358000/

If you're worried about the pump not working, just run pre-mix in the beginning, and seal the intake manifold bolt hole for testing. You should see oil flow out the motor end of the oil line. I ran pre-mix in my friend's MT until I was sure the pump was OK, with no problems.

Apparently these pumps are extremely reliable, but if it doesn't work there's always the pre-mix option. This oil injection system is not like Suzuki's CCI, where the oil was injected directly to the bearings in addition to the intake; all the MT250 pump does is squirt oil into the intake. Pre-mix should work just as well (you may have to re-jet the carb).

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric