derbi senda metrakit sp 70cc big bore kit

[benjy bwoii]

hello i was thinking about buying a metrakit sp 70cc big bore kit and i was wondering are they reliable kit and what sort of bhp could i reach my set up at the moment is leo vince v6 race pipe mallosi 21mm carb.thanks everyone.

[Hutchysrs50]

the bikes are somthing like 2.3bhp standard.

no they are not reliable, but mostly comes down to how you ride them, your going to be riding it in the red if your putting a bigbore kit on, so your crank or brearings are going to be under alot more stress, also without the correct setup, they usualy seize befor anything els...

top speed will go up by about 4mph too
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Gilera SC 125 - Current

[ms51ves3]

[Hutchysrs50]

"If he's riding in the red, can he not change gear"
not sure what you mean by that?

"It'll only seize if he runs it without any oil or runs it super lean"
even tho the oil pump only puts out enough to run 50cc not 70cc?

"Also, his top speed won't go up at all unless he changes his final gear ratio"
it will go up as it will rev higher, with the 50cc head on they are ment to rev to 12k but with the big bore kits they rev to 15k

so more rpm = higher top speed?
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Gilera SC 125 - Current

[stevo as b4]

The MetraKit SP isn't a race kit, just a fast road 70cc kit, so i don't expect it to be ported much different to std, or rev past 12K or whatever the current limit is. The Cdi might well have an electronic limiter anyway. As said the only way for top speed to increase is to install new sprockets. If you get it right you should get a few mph more and better acceleration.

The Oil pump should supply enough oil for a 70cc top end, as none of the manufacturers normally state that a new pump is needed. It might be worth adjusting it slightly to provide more oil before full throttle is reached though. The rad is a decent size for the bike IMO so the cooling system should cope ok too.

TBH i wouldn't buy a big bore kit unless you can have these issues confirmed for certain by the manufacturer, as any reputable tuning company would make sure everything works and is up to the job before they start selling kits.

Reliability should be ok, but more cc will cause more wear on the bottom end, and so re-builds should be carried out more frequently than the std bike, and in line with what the aftermarket tuners reccomend.

Think the Derbi is about 8bhp std, so a well set up 70cc kit with the bigger carb and performance pipe you have should be getting close to 12bhp id say.

[Hutchysrs50]

[benjy bwoii]

cheerz people im reaching about 65 now soo what top end will ill be seeign with the right sprocket set up.cheerz.

[benjy bwoii]

and also is it true you can get top speed pipes e.g ginelli and tecknogas is this true as i have been told a leo vince is a bottom end/mid rang race pipe.cheerz.

[ms51ves3]

[Hutchysrs50]

[Finglonga]

May rev slightly higher but the crank won't last long.
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Andy Sez....
F.Y.Y.F.F.

[ms51ves3]

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[Hutchysrs50]

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[Hutchysrs50]

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[ms51ves3]

[benjy bwoii]

hello people why does my bike sort of start shutting down at like 8 and a half thousand revs and wont rev in to the red bit and all of my m8s derbi senda do it.cheerz.

[chillpill]

upjet

[chillpill]

[benjy bwoii]

cheerz people and i have a leo vince v6 pipe and a malossi 21mm carb and im thinking bout a metrakit sp 70cc kit could i reach 15 bhp if set up properlyy.chherz and what top speed would i be looking at if geared properlyy.cheerz.