Specific oil pump question

[mellemeistel]

Hi everyone,
This is my very first post. My name is Melle and i am having a CPI GTR 50 LC.
I drove the scooter for 7 years now and slowly but for sure it loses performance/compression, so i am planning to rebuild the whole thing with a racing crank, 70cc stage6 sport pro mk2, Leovince gp handmade (for a bit stealthyness so not everyone instantly sees it is a fast machine), variable CDI and 28mm carb (for as much performance as possible, i dont care much about fuel economy).
People who driven and tuned the gtr told me that this setup was the way to go.
But... There is one thing in my mind that is not completely clear before starting the project: Keeping the oil pump or not (i know, a cliche on this forum). It is just that i hear from some people (and a known cpi gtr tuner) that i should not risk it. But i read on the other hand that some people say it is just doable and pretty reliable with a setup like this and an (cable adjustable) oil pump like there is on this gtr.
I want to have the luxury when tanking to not premix but i want to drive my gtr for years so i am asking this question with better safe than sorry in my mind before i start my project.
I saw things about an adjustable oil pump for minarelli horizontal, but it was from tnt and i dont know if it is reliable and an option for this project.
My question to you guys: Is it possible in some way for me to keep using the oil pump with my upcoming setup (like adjusting the existing cable one, replace it/the nylon gear with it, or take the tnt because people maybe tried it before me out and it works well) without much more risk of seizing the engine because of to little lubrication than the Standard Oil pump has with 50cc? I hope some of you have experience with this dilemma to help me out.
For your knowing: i am driving safely with the Standard Oil pump for 7 years (40000km), with every 10000km replacing the nylon gear and cruising at 70km/h and 8500rpm while the new setup will probably get to 11000rpm with 100+ ish km/h.

I really hope you guys can help me out with this specific question because then i know what to do

Yours sincerely,
Melle

[sinfull]

11k + rpm, personally I would not trust a nylon gear. Premix it and know it has oil. My vote is premix over nylon gear

[mellemeistel]

Jul 30, 2024 0:49:30 GMT -5 sinfull said:

11k + rpm, personally I would not trust a nylon gear. Premix it and know it has oil. My vote is premix over nylon gear

Got it! One vote for premix over nylon gear. Does anyone else have some experience with minarelli horizontal engines and using the oil pump on big bore kit?

[aeroxbud]

Stage6 recommend that if you are using the original autolube system you additionally mix up the fuel at 60:1
If you are simply pre-mixing and have done away with the original oil pump then mix at 33:1.
So either way you are mixing fuel. Might as well get rid of the pump.
The Leo Vince GP is not a very good match with the sport pro cylinder. It only revs to about 9,000rpm. That's when the sport pro isn't even getting into the power band.
I would buy a sports kit like the Polini, Malossi and use the gp pipe. Then run the oil pump. Or ditch the pump and buy a better exhaust to match the sport pro.

[mellemeistel]

Jul 30, 2024 5:42:50 GMT -5 aeroxbud said:

Stage6 recommend that if you are using the original autolube system you additionally mix up the fuel at 60:1
If you are simply pre-mixing and have done away with the original oil pump then mix at 33:1.
So either way you are mixing fuel. Might as well get rid of the pump.
The Leo Vince GP is not a very good match with the sport pro cylinder. It only revs to about 9,000rpm. That's when the sport pro isn't even getting into the power band.
I would buy a sports kit like the Polini, Malossi and use the gp pipe. Then run the oil pump. Or ditch the pump and buy a better exhaust to match the sport pro.

Allright that is a nice advice. Now i know the setup is just to sketchy for the oil pump and not ideal for the thealthy ish exhaust.
I think i will make it a mid race setup then, with the leovince, a doppler s1r crank, keeping the oil pump, a bit ported dr70 (i like the price/durability in comparison with polini/malossi). Two additional questions when thinking about the carburator/oil intake: Which (size) carb with oil insertion would you guys recommend with this setup? And do i have to adjust the oil pump with the cable or is that not necessary/nonsense on Mina hori replica engines?
Thank you so much in advance already with helping me out

[aeroxbud]

I would just go with a Dellorto 17.5mm carb. It will fit a standard air box.
I've never used the adjustable oil pump. But Brent says in the big bore tutorial. To turn the nut 3-4 turns out.

[mellemeistel]

Aug 1, 2024 5:50:28 GMT -5 aeroxbud said:

I would just go with a Dellorto 17.5mm carb. It will fit a standard air box.
I've never used the adjustable oil pump. But Brent says in the big bore tutorial. To turn the nut 3-4 turns out.

Allright, got it. Thank you so much for helping me out! Thread can be closed.