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Post by troutyboy2 on Apr 6, 2016 20:56:33 GMT 1
I have just fitted a 57v throttle cable to my rd 350 lc n model the timing marks are below the 9 o'clock mark on the oil pump does anybody know if this is putting more or less oil to the carbs not enough adjustment on the cable to bring it back to the correct position any suggestions.thanks
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Post by muttsnuts on Apr 6, 2016 21:22:06 GMT 1
so are you saying when you pull the throttle to the stop the mark goes beyond the timing mark?, if so it will be over oiling, not too bad a thing unless its too much in which case it can make it run weak
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Post by rigga on Apr 6, 2016 21:23:43 GMT 1
Got the cable under the spring on the pulley?
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Post by yazza54 on Apr 6, 2016 21:25:28 GMT 1
so are you saying when you pull the throttle to the stop the mark goes beyond the timing mark?, if so it will be over oiling, not too bad a thing unless its too much in which case it can make it run weak I understand how extra oil makes you run weak using premix as its a mixture going through the jet.... But I don't understand how excess oil from a pump could make it run weak?? Not saying I think you're wrong just hoping you can explain. |
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Post by troutyboy2 on Apr 6, 2016 21:52:24 GMT 1
Yes the cable is under the spring,when on tick over the mark is below the timing mark can't lengthen the cable enough to line the mark up to the 9 o'clock mark just hoping this is giving the bike more oil rather than less.
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Post by KevtheRev on Apr 7, 2016 9:44:44 GMT 1
so are you saying when you pull the throttle to the stop the mark goes beyond the timing mark?, if so it will be over oiling, not too bad a thing unless its too much in which case it can make it run weak I understand how extra oil makes you run weak using premix as its a mixture going through the jet.... But I don't understand how excess oil from a pump could make it run weak?? Not saying I think you're wrong just hoping you can explain. Mutts is correct. Think about it - More oil in the mix=less fuel and the same amount of air , so it will in effect weaken the mix . We're talking about the fuel/air ratio and not the fuel/oil ratio . Hope that helps . |
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Post by arrow on Apr 7, 2016 9:48:49 GMT 1
Extra oil from the pump does not weaken the mixture, the opposite in fact.
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Post by arrow on Apr 7, 2016 9:49:55 GMT 1
I have just fitted a 57v throttle cable to my rd 350 lc n model the timing marks are below the 9 o'clock mark on the oil pump does anybody know if this is putting more or less oil to the carbs not enough adjustment on the cable to bring it back to the correct position any suggestions.thanks A photo works wonders in these matters. |
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Post by yazza54 on Apr 7, 2016 10:31:40 GMT 1
Extra oil from the pump does not weaken the mixture, the opposite in fact. Explain pls  |
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Post by muddyfox on Apr 7, 2016 10:35:33 GMT 1
if you run premix you need to jet for the fuel to oil ratio, and yes to much makes you run lean!!
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Post by jackjabba on Apr 7, 2016 11:16:54 GMT 1
Did you get your cable from Yambits? I have found their cables are no good for setting up the oil pump adjustment, best getting one from Yamaha.
I get the idea of jetting up for Pre mix, but remember reading an article from Stan the Man saying that it really wasn't needed.
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Post by muddyfox on Apr 7, 2016 12:05:08 GMT 1
it would be if you run say 50/1 and your jetted for 32/1 youll have problems, thats why you always start with needle in the middle and work from there, your jets will need to be in the ball park to get it running right, ie no flat spots and burbles under 1/3 throttle
the pump cable needs to 13.2cm from nipple to sleeve, if you dont have the right lenth youll never get it setup right,
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Post by yazza54 on Apr 7, 2016 12:13:40 GMT 1
Yes yes jetting up for premix makes total sense but the pump delivering more oil making the engine run lean needs some further explaining. Arrow care to expand as others seem to think this is the case but I'm with you it doesn't sound right the mixture of air to fuel is still the same regardless of how much oil the pump has pumped in independantly??
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phil38
Thrash Merchant
Posts: 426
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Post by phil38 on Apr 7, 2016 12:30:49 GMT 1
The petrol from the tank is regulated by the carb in proportion to the amount of air. The carbs are set-up to maintain the correct air-fuel ratio (bit more complicated than that in practice but this is the principle). The autolube pump puts oil into the fuel air mixture coming into the engine after the carb - the air:fuel ratio is not affected (to any degree you could measure) by the presence of the drips of oil.
If the petrol in the tank is actually 90% petrol & 10% oil, the carb is now regulating the amount of petrol + oil in response to the amount of air coming in, hence you are running 10% less fuel for the same air flow, i.e., you are now running leaner
In actual fact a small proportion of the oil is lighter fractions, hence some of it is effectively acting as fuel in that it will burn during combustion. This means of you have 10% oil in the pre-mix it won't be quite 10% leaner. By the same token, injecting some oil into the inlet after the carb will richen the mixture a tiny bit, hence arrow's comment.
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Post by muddyfox on Apr 7, 2016 12:45:12 GMT 1
its always worth over jetting the pilot when running premix, this will stop the engine running dry when off the throttle
pumps are crude things, if you ride around with a bottle of 2smoke and make notes of how much fuel you put in and try to add the right amount of oil every time you fill up, youll defo run lean at some point lol
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Post by muttsnuts on Apr 7, 2016 12:46:13 GMT 1
having thought on this some more, I suspect Arrow is correct that it will run slightly richer, whereas with premix it does indeed make it run weaker due to the fuel regulating via the jet. The one problem I see with too much oil is fouling of the plug.
Either way, this is detracting from the problem to hand (my fault I know), as said by others, a picture says a thousand words and if it is a Yambits cable, just throw it away and buy a genuine one and your problems will be solved
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Post by muddyfox on Apr 7, 2016 12:48:20 GMT 1
i had to trim my yambits cable sleeve to get the pump to line up as it was setup perfect before my cable snapping!
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Post by arrow on Apr 7, 2016 13:03:06 GMT 1
The petrol from the tank is regulated by the carb in proportion to the amount of air. The carbs are set-up to maintain the correct air-fuel ratio (bit more complicated than that in practice but this is the principle). The autolube pump puts oil into the fuel air mixture coming into the engine after the carb - the air:fuel ratio is not affected (to any degree you could measure) by the presence of the drips of oil. If the petrol in the tank is actually 90% petrol & 10% oil, the carb is now regulating the amount of petrol + oil in response to the amount of air coming in, hence you are running 10% less fuel for the same air flow, i.e., you are now running leaner In actual fact a small proportion of the oil is lighter fractions, hence some of it is effectively acting as fuel in that it will burn during combustion. This means of you have 10% oil in the pre-mix it won't be quite 10% leaner. By the same token, injecting some oil into the inlet after the carb will richen the mixture a tiny bit, hence arrow's comment. Exactly Sir. The oil has some calorific value so adds to the fuel when pumped in via the pump. Extra oil in premix will of course weaken the mix as the oil has much less energy value than petrol does. |
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Post by Tone on Apr 7, 2016 18:17:49 GMT 1
Even mentions this in the good old Haynes in the last section of the engine rebuild chapter. "Do not on any account add oil to the petrol under the mistaken belief that a little extra oil will improve the engine lubrication. Apart from creating excess smoke, the addition of oil will make the mixture much weaker, with the consequent risk of overheating and engine seizure. The oil pump alone should provide full engine lubrication"
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Post by steelaway on Aug 13, 2016 17:51:49 GMT 1
I'm confused.
There seems to be far to much oil now being metered into my YPVS.
The pump settings are set as per the manual and even a little on the weak side.
Most modern oils are now fully synthetic and are quite capable of running safely at 40-1 mix.
1990 oils were designed to run at 25-1(?) and the oil pump settings are for this percentage mix.
How do you turn down the oil pump to supply a 40-1 + mix throughout the rev range?
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Post by arrow on Aug 13, 2016 18:31:19 GMT 1
That's not possible I'm afraid. The pump supplies between 90:1 and 20:1 through the rev range. I have a pump here from a forum member that is over oiling. It's the check valves that are passing, plus this is compounded by some later modifications from Yamaha.
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Post by arrow on Aug 13, 2016 18:33:22 GMT 1
Forgot to say, a correctly setup pump will deliver around 35:1 when looked at long term, against fuel usage.
I provide a full refurb service on the oil pumps, should you require that.
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Post by steelaway on Aug 13, 2016 21:23:16 GMT 1
Thanks for that - some one who knows what they are talking about.
I'm happy (at the moment) that the pump is working correctly, I would restrict the amount to suit modern synthetic oils and improve the burn and performance.
I used to use up to 50-1 pre mix in my race bikes (Castrol 747) that would keep the plugs at a very nice and clean light brown.
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Post by davey on Aug 14, 2016 8:15:38 GMT 1
Send your pump to arrow would be my advice .
Arrow has done hundreds of pumps for forum members , they come back as good if not better and more efficient than ever .
For peace of mind this would be my advice
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Post by paulsx on Aug 14, 2016 8:29:42 GMT 1
I'm confused. There seems to be far to much oil now being metered into my YPVS. The pump settings are set as per the manual and even a little on the weak side. Most modern oils are now fully synthetic and are quite capable of running safely at 40-1 mix. 1990 oils were designed to run at 25-1(?) and the oil pump settings are for this percentage mix. How do you turn down the oil pump to supply a 40-1 + mix throughout the rev range? |
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reggit
Drag-strip hero
Posts: 230 
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Post by reggit on Aug 14, 2016 10:25:27 GMT 1
Send your pump to arrow would be my advice . Arrow has done hundreds of pumps for forum members , they come back as good if not better and more efficient than ever . For peace of mind this would be my advice 100% agree, arrow turns them round quickly and they come back looking better than new. He also kept me informed of any issues the pump had and supplied spares at cost. |
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