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Post by arrow on May 19, 2020 18:59:37 GMT 1
Guy's, I'm after some help with oil pump info for the YSR 50 and the YSR 80. Story is, some time ago a guy in the USA sent me a 50 pump and the drive for it which I sent back, in a restored condition. Happy days so far. Now, it turns out he wants to use this set up for an 80cc bike. From what we have both found to the best of our ability is;
The pump for the 50/80 has the same part number. Ditto, wormshaft. Ditto, 28 tooth white plastic gear that drives the wormshaft. Ditto, crank pinion.
Now, if this is the case all should be well, but I'm struggling with this. My question is; if all these parts ARE indeed the same, then where is the extra oil coming from for the 80cc engine?
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Post by badger1 on May 19, 2020 20:29:39 GMT 1
Not sure if this is any help Rd80lc (5r2 shape) Rz50 Same engine different bore Just looked at both bikes parts numbers comparing the 80 to the 50 and they both have the same part numbers for all the parts you ask about with the ysr You did two pumps for my 80’s last year I would imagine the pumps could be similar? So is it just a case of setting it different from the 50 to the 80 or is it more involved than that. I couldn’t find the settings for the rz50 pump but I do have the settings for the Rd80lc pump.
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nat666
Weekend rider
Posts: 60
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Post by nat666 on May 19, 2020 20:39:58 GMT 1
Not sure if this is any help Rd80lc (5r2 shape) Rz50 Same engine different bore Just looked at both bikes parts numbers comparing the 80 to the 50 and they both have the same part numbers for all the parts you ask about with the ysr You did two pumps for my 80’s last year I would imagine the pumps could be similar? So is it just a case of setting it different from the 50 to the 80 or is it more involved than that. I couldn’t find the settings for the rz50 pump but I do have the settings for the Rd80lc pump. I was just about to post the same thoughts on settings for the 50 & 80 may be set to different marks .
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Post by arrow on May 19, 2020 20:49:41 GMT 1
Thanks for the info. Based on the bigger bikes and their pumps, the 50 would need a 60% increase to oil the 80 motor. Shims could not do this. Pulley marks just alter where the oiling is in relation to the carb movements. Total amount of oil can not be increased in this way. Still perplexed!
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Post by hoist1 on May 19, 2020 22:46:46 GMT 1
What’s the revs comparison? Not sure I want to post anymore now I’m on 350.
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Post by hoist1 on May 19, 2020 22:55:54 GMT 1
Actually 351 don’t sound bad. Sorry. Back to reality. Be interested to know if your percentage thing is less relevant with low cc . It must be ok unless 80 engines don’t last. Montesa made a 25cc bike I think? Perhaps the starting point is 80 and the 50s are overoiled .
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Post by hoist1 on May 20, 2020 0:45:37 GMT 1
Max horsepower at the same revs for the 2 from what I could tell, as they dont seem to have a rev counter.
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Post by hoist1 on May 20, 2020 0:48:36 GMT 1
Would it oil more with a shorter cable?
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Post by arrow on May 20, 2020 1:10:23 GMT 1
Would it oil more with a shorter cable? No. (And pulley alignment marks would become irrelevant). Thats like saying, would the bike go over normal top speed with a shorter carb. cable, No.
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Post by badger1 on May 20, 2020 15:34:46 GMT 1
Gary could it be the pump std is really to much for the 50cc but runs and has to put up with it, can be set ok for the 80cc and adjusted for say a 125cc. Being as these bikes and pumps were mass produced and parts interchangeable with different models. Just a idea
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Post by hoist1 on May 20, 2020 16:03:18 GMT 1
Gary could it be the pump std is really to much for the 50cc but runs and has to put up with it, can be set ok for the 80cc and adjusted for say a 125cc. Being as these bikes and pumps were mass produced and parts interchangeable with different models. Just a idea That’s what I was inferring above, the bit that says 50s are overoiled
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Post by hoist1 on May 21, 2020 9:30:04 GMT 1
It’s the only thing I can think of that makes sense 😊
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Post by tony2stroke on May 21, 2020 10:18:53 GMT 1
Gary! Your the oil pump man, if you can't tell us the answer then its guess work only, they all have to abide by strict rules on emissions, I can't see the 50cc over oiling because of this, they all use the same seals, from 50cc up, so must be same size pumps, the only difference can be worm cog and worm drive or bore and stroke of piston plunger, but again the bore must be the same as they use the same plunger seal, so can't be plunger bore, and as they are same dimension body I can't see the stroke being different either, the only logic being the worm drive and cog is different, but if same part numbers its not that either.
So does the 50 pump use all the pulley cam part or not, or even a different pulley, and is that where the extra comes from on a 80, ie 80 pulley goes round more and uses more of the cam part, only things I can think of.
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Post by arrow on May 21, 2020 10:47:14 GMT 1
I hear what your saying Tony, but we still have a common part number for the two bikes, so they are sold as the same item.
Also, and not related to this here, due to above same part number, there are four different piston sizes that I've seen over the years. So they don't all use the same seal. They are; 3.5mm, 4mm, 4.5mm and 5.5mm.
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Post by hoist1 on May 21, 2020 11:00:40 GMT 1
I know an 80 is a small engine but a 50 is going to be ragged everywhere, not good for emissions perhaps only on part throttle. Forgetting about competition bikes isn’t the only road 2 stroke still sold a 50cc scooter, there must be something in that. Perhaps 50 is small enough not to matter, don’t know what other countries do but regardless of legislation, we don’t yet include an emissions test for a bike mot.
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Post by tony2stroke on May 21, 2020 11:08:41 GMT 1
I hear what your saying Tony, but we still have a common part number for the two bikes, so they are sold as the same item. Also, and not related to this here, due to above same part number, there are four different piston sizes that I've seen over the years. So they don't all use the same seal. They are; 3.5mm, 4mm, 4.5mm and 5.5mm. Very interesting, as you know I am curious gezzer, after lots of searching I couldn't find any reference to different plungers, I then assumed, always told never to assume anything, and this is why. Look forward to hearing the answer to this one, when you do find out that is.
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Post by hoist1 on May 21, 2020 16:01:03 GMT 1
I hear what your saying Tony, but we still have a common part number for the two bikes, so they are sold as the same item. Also, and not related to this here, due to above same part number, there are four different piston sizes that I've seen over the years. So they don't all use the same seal. They are; 3.5mm, 4mm, 4.5mm and 5.5mm. Very interesting, as you know I am curious gezzer, after lots of searching I couldn't find any reference to different plungers, I then assumed, always told never to assume anything, and this is why. Look forward to hearing the answer to this one, when you do find out that is. Strange it jumps and there is no 5mm
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Post by tony2stroke on May 21, 2020 17:46:51 GMT 1
Very interesting, as you know I am curious gezzer, after lots of searching I couldn't find any reference to different plungers, I then assumed, always told never to assume anything, and this is why. Look forward to hearing the answer to this one, when you do find out that is. Strange it jumps and there is no 5mm Yes I was thinking that too, as 4.5 to 5.5 is a big difference, but you have to take into account the different cogs too, the course cog going round faster and pumping more oil than the finer cogs, its looking like a minefield this, you think you know something and find out "you don't" if anyone can bottom this out it will be Gary.
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Post by arrow on May 21, 2020 17:59:22 GMT 1
The 3.5mm piston is on the 50cc and 80cc engines. The vast majority of pistons are 4mm. The 4.5mm item came in an unknown job lot, and the 5.5mm piston came in a pump from an early DT400.
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Post by hoist1 on May 21, 2020 18:05:10 GMT 1
Looks like Gary does have some normal ( whatever that is ) dna , and not a super being 😊. Not really, the truth will out. Perhaps the 80 is underoiled, and yam had a rare boo boo. Trouble is with a common bike it’s possible to get an idea how long they last, I mean with gentle use any wear rates can be way off the average. Test rode an fj1200 years ago that was owned by an elderly rider, it had what I was sure was the original front tyre on with well over 20000 miles on! Can remember doing a rear in a 1000 miles and that’s with reasonably considerate use.
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Post by hoist1 on May 21, 2020 18:10:26 GMT 1
As in if the 50 is oiling correctly, the 80 must be under, and if the 80 is correct, the 50 must be over. Surely, or not. Occam’s razor ?
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Post by arrow on May 21, 2020 18:13:58 GMT 1
As in if the 50 is oiling correctly, the 80 must be under, and if the 80 is correct, the 50 must be over. Surely, or not. Occam’s razor ? Exactly my thoughts.
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Post by hoist1 on May 21, 2020 18:22:33 GMT 1
Hope that’s the answer, though is the only solution to add a dash of oil to the petrol?
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Post by hoist1 on May 21, 2020 18:23:48 GMT 1
Thought this thread may run forever 😊
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Post by arrow on May 21, 2020 18:37:32 GMT 1
I could build a pump for the 80cc motor. It would have the same type of modifications as the 125cc~180cc pump. These are totally different mods. to the ones on the 421cc uprated pump. Problem is I don't have the justification for doing that, based on the two pumps having same part number.
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