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D50b0 stock cylinder tunning

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Jaxx
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D50b0 stock cylinder tunning

Post by Jaxx » Wed Jun 19, 2019 2:36 am

Hi,
sorry it isn't really GPR/RS, but it has D50B0 engine (bike is Aprilia RX 50 2016, more or less 'rebranded' Derbi Senda DRD R). Current setup is like this...
- engine D50b0 with stock 50cc cylinder,
- pipe Turbo Kit RQImage
- stock carb PHVA 17,5 (upjeted with removed baffle plate)
- stock air filter
- front sprockets 11 to 13...

I have few questions, since this pipe is quite hi revving, up to 12.000...
- should stock crank be ok (that's at least my concern, just checkin)?
- Are stock reeds ok? I've got mixed opinions on this, some say they are fine, some that they should only be changed with BBK, some say that they only good on completely stock bike?
- Stock CDI Ignition isn't limited, I guess it's safe to 12.000 rpm?
I should add that I never trash it over 10.000 for longer periods...
Thanks...
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toratora
Posts: 3161
Joined: Wed Oct 11, 2017 1:05 am
Location: San Francisco
Replica: Derbi GPR
Cagiva Mito
Cobra CX65
Aprilia RS50
x 1768
x 1977
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Where’s My Senda!!

Post by toratora » Wed Jun 19, 2019 7:39 am

Hey Jaxx,

It’s cool to post about Senda related bikes here. They all employ basically the same engine/technology. There are a number of members here that also have Sendas, and there’s even a thread in the Marketplace section for these bikes.

My experience with the stock bottom end of the Derbi has been quite good. It is a robust engine. For years I ran a Metrakit ProRace top end on a stock Euro2 bottom end, and never had any issues whatsoever. It is a good idea to upgrade the bottom end if you are going to be running an aggressive top end, and doing aggressive riding.

Image
Failed Malossi Reed
The stock Derbi reeds again are quite good. Yes there are advantages to going to the performance reeds, but that doesn’t mean that the stock units are bad.

In the early days people use to use the stock reed cage and fit them with carbon fiber reeds. I have that setup in my ProRace bike. It use to have a nice Malossi reed cage, but it failed, so I replaced it with a stock unit fitted with the fibaa.

The thing to remember is what you are trying to achieve. That should be your guiding path on upgrades—way more so than what people say you should get. The project threads are a great source of information to find out what works, and what doesn’t. :paw_prints:
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Jaxx
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Re: D50b0 stock cylinder tunning

Post by Jaxx » Sun Jun 30, 2019 9:31 am

Thanks Tora.. What do you think about stock oil pump, is it really that bad and unreliable, since many folks remove it and use fuel premix?
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toratora
Posts: 3161
Joined: Wed Oct 11, 2017 1:05 am
Location: San Francisco
Replica: Derbi GPR
Cagiva Mito
Cobra CX65
Aprilia RS50
x 1768
x 1977
Contact:

D50b0 stock cylinder tuning: Introducing the Oil

Post by toratora » Sun Jun 30, 2019 6:23 pm

The stock oil pump is very reliable on a stock bike. But once you start tuning the bike it becomes compromised. It can’t keep up with the needs of the modified engine. That’s why people with performance engines remove the oil pump, and go premix. So it’s not that the pumps are bad or anything, they just weren’t designed for a performance oriented engine. :paw_prints:
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