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Post by bigbol63 on Sept 16, 2013 16:59:22 GMT 1
Hi all, new here and so howdo to you all.
I have clear oil feed pipes to the carbs on my 250LC. After a few days I've noticed that the oil is running back towards the pump, in other words I have air bubbles at the carb end of the pipes.
Thoughts please gents.
Bol
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Post by Roofmonster on Sept 16, 2013 17:09:03 GMT 1
Welcome to the forum
If you get in touch with arrow on the forum - he will sort your pump out.
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Post by arrow on Sept 16, 2013 17:13:50 GMT 1
Hi Bol, welcome in. If you take the pipes off at the carb end and blow hard, are there any leaks around these pipes at the oil pump end?
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Post by carioca656 on Sept 16, 2013 17:26:10 GMT 1
sounds like a leak at the pump to me
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Post by Denzil on Sept 17, 2013 6:46:15 GMT 1
Arrow is your man for anything to do with the pump. In my opinion just send him the pump he will work his magic for a small fee and the pump will be like new when it comes back. Superb service and one thing that you know you can tick off as sorted.
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Post by turbopresh on Sept 17, 2013 8:00:26 GMT 1
Agree with everything said about arrow here.. top bloke!
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Post by bigbol63 on Sept 17, 2013 12:35:50 GMT 1
Hi Bol, welcome in. If you take the pipes off at the carb end and blow hard, are there any leaks around these pipes at the oil pump end? Hello Arrow, seems you're the man to talk oil pumps. Excellent. As I like to tinker shall I just get a service kit for the pump? Or shall I post to you/ Cheers dude. |
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Post by daveo on Sept 17, 2013 13:21:37 GMT 1
Sounds like the seals in the pump are duff. I got mine from the Two Stroke Shop but there must be somewhere closer to home?
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Post by arrow on Sept 17, 2013 13:31:55 GMT 1
You are most welcome to get a 'service kit' but there is much more to my full re-furb service than that. Here;
I made some tools for pushing the seals in. Its important especially with the tiny seal to use a tool just a couple of thou smaller than it. If this seal is fitted with the wrong tool it is very easily dished, this causes it to be too tight a fit on the piston causing rapid wear. The front seal is fitted after the plunger assembly is fitted, this way the side pin is not pushed through the new seal. Sometimes the main casting is scored in the bore, this reduces oil flow. I have had to tell a few people that the main casting is scrap and replace it with another one. Yamaha modified the camshaft on later pumps to prevent this from happening and I incorporate this mod on all the pumps I re-furb. Some time ago a developed a check to measure the cams for wear limit, at this time I don't know of anyone else that does this. Some camshafts are worn out of spec and others are hardly worn at all. I always de-burr the cams with a diamond tipped needle file. If the cam is worn then the pump cannot deliver the correct amount of oil at the 3/4~full throttle setting. The cams do not run in the 2T oil and therefore should be packed in grease, there is not much grease left in a 30 year old pump! Lots of pulley springs have wear on the coils (they rub together in use) if the wear is light and not concentrated in one spot then the spring is ok to use, if not I will replace it. Same with the plunger spring. The piston is resurfaced, but I only need to take off about 0.0002" (2 tenths of a thou) to do this. If the pump has been running a zero stroke for long enough the piston sometimes has a score mark and needs to be replaced. Some times the thrust washers are worn out and sometimes they are like new. The underside of the big washer normally has a heavy wear mark where it contacts the heel on the pulley, this upsets oiling at the lower rev range, I always remove the wear by lapping it off. The check valves always have some debris in them and many are passing. The steel balls can be discoloured and marked affecting the seal. I used to inspect the balls but this is not easy and takes time. I replace both balls in all the pumps as a matter of course, as well as scrubbing the hard rubber seats with a purpose made brush. All the work is done by hand, without the use of power tools. Although some stubbon screws are removed after cutting a slot in the heads with a dremel.
Your issue is most likely with the clear pipes them selves. Do you have the correct retainers fitted? If the valves were passing then the flow goes the other way due to positive pressure in the header tank.
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Post by bigbol63 on Sept 17, 2013 13:51:21 GMT 1
Sounds like the seals in the pump are duff. I got mine from the Two Stroke Shop but there must be somewhere closer to home? I think Yambits sell as a kit. |
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Post by arrow on Sept 17, 2013 13:53:55 GMT 1
The genuine parts are still available, and much cheaper.
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Post by bigbol63 on Sept 17, 2013 14:06:52 GMT 1
You are most welcome to get a 'service kit' but there is much more to my full re-furb service than that. Here; I made some tools for pushing the seals in. Its important especially with the tiny seal to use a tool just a couple of thou smaller than it. If this seal is fitted with the wrong tool it is very easily dished, this causes it to be too tight a fit on the piston causing rapid wear. The front seal is fitted after the plunger assembly is fitted, this way the side pin is not pushed through the new seal. Sometimes the main casting is scored in the bore, this reduces oil flow. I have had to tell a few people that the main casting is scrap and replace it with another one. Yamaha modified the camshaft on later pumps to prevent this from happening and I incorporate this mod on all the pumps I re-furb. Some time ago a developed a check to measure the cams for wear limit, at this time I don't know of anyone else that does this. Some camshafts are worn out of spec and others are hardly worn at all. I always de-burr the cams with a diamond tipped needle file. If the cam is worn then the pump cannot deliver the correct amount of oil at the 3/4~full throttle setting. The cams do not run in the 2T oil and therefore should be packed in grease, there is not much grease left in a 30 year old pump! Lots of pulley springs have wear on the coils (they rub together in use) if the wear is light and not concentrated in one spot then the spring is ok to use, if not I will replace it. Same with the plunger spring. The piston is resurfaced, but I only need to take off about 0.0002" (2 tenths of a thou) to do this. If the pump has been running a zero stroke for long enough the piston sometimes has a score mark and needs to be replaced. Some times the thrust washers are worn out and sometimes they are like new. The underside of the big washer normally has a heavy wear mark where it contacts the heel on the pulley, this upsets oiling at the lower rev range, I always remove the wear by lapping it off. The check valves always have some debris in them and many are passing. The steel balls can be discoloured and marked affecting the seal. I used to inspect the balls but this is not easy and takes time. I replace both balls in all the pumps as a matter of course, as well as scrubbing the hard rubber seats with a purpose made brush. All the work is done by hand, without the use of power tools. Although some stubbon screws are removed after cutting a slot in the heads with a dremel. Your issue is most likely with the clear pipes them selves. Do you have the correct retainers fitted? If the valves were passing then the flow goes the other way due to positive pressure in the header tank. Cheers for that Arrow. Clear pipes and retainers bought from Nobo so will presume they are correct. Not sure what you mean by 'If the valves were passing then the flow goes the way....' Bigbol. |
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Post by arrow on Sept 17, 2013 14:10:30 GMT 1
If the valves are passing the issue is oil going into the crankcase and not running back from the carbs as you have. Did you do the check I mentioned?
If they are not passing then the oil cannot flow back through the pump itself.
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Post by daveo on Sept 17, 2013 14:51:58 GMT 1
Arrow - now I want you to give my pump the once-over please! I recently went back to using it as I was fed-up with the pre-mix hassle and found that my pump was a zero-stroker due to wrong shimming but you are obviously an expert so how do I access your services?
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Post by arrow on Sept 17, 2013 14:54:46 GMT 1
Arrow - now I want you to give my pump the once-over please! I recently went back to using it as I was fed-up with the pre-mix hassle and found that my pump was a zero-stroker due to wrong shimming but you are obviously an expert so how do I access your services? You have pm Sir. |
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Post by bigbol63 on Sept 17, 2013 17:46:51 GMT 1
If the valves are passing the issue is oil going into the crankcase and not running back from the carbs as you have. Did you do the check I mentioned? If they are not passing then the oil cannot flow back through the pump itself. thanks Arrow, I've not had chance to check just yet. |
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Post by bigbol63 on Sept 19, 2013 13:38:12 GMT 1
So after not being near the LC in a few days I decide to check what Arrow suggested and there's no air in the pipes! Murphy at it again.
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Post by 47x on Sept 19, 2013 18:24:13 GMT 1
just send your pump to arrow,it will be good as new,not worth messing about with the oil delivery chap....
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Post by arrow on Sept 19, 2013 19:38:51 GMT 1
So after not being near the LC in a few days I decide to check what Arrow suggested and there's no air in the pipes! Murphy at it again. Did you see any oil at all emerging from the pipe/outlet union joint? Or any movement of air going down towards the pump whilst blowing? |
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Post by bigbol63 on Sept 20, 2013 10:39:13 GMT 1
Hi Arrow, I've still not tested as you kindly suggested. I had a quick nosey last night and there's no air in the pipes currently and it's been stood almost a week.
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Post by arrow on Sept 20, 2013 18:44:44 GMT 1
Ok, another thought. Has the pump been off the bike? If so then it takes a while to bleed (completely). The air you see may be a combination of tiny bubbles that collect together when the bike is standing.
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moggy
Weekend rider
Posts: 60
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Post by moggy on Sept 20, 2013 20:07:33 GMT 1
I recommend anyone reading this to send your pump to arrow for a refurb, top service, top job, top bloke, sent mine Tuesday morning and its back today(fri) looking like a new un, my only gripe is my bike will need polishing more now cos the pump shows it up !! :-)
Thanks again Gary
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