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Hi guys,

I have a 2016 Grom I am looking at putting an older 2-stroke engine in and there are a couple of immediate issues that I forsee holding me up.

1. The engine has a mechanical output in the gearbox cover to drive the speedo mechanically. Is anyone aware of an adapter that can be used to convert that cable rotation into a voltage that the Grom dash can use, as I would like to keep the original instrument cluster if possible.

2. The new engine is carburetted so the fuel pump is now surplus to requirements. Did people weld a threaded fitting onto the bottom of the tank to retro-fit the fuel tap, or is there a way to plumb the pump into a reservoir, which is tapped at the bottom for the carb with some sort of large return line back to the tank to lower the fuel pressure.

Would love to hear from the guys who have covered these issues with their groms or other bikes.

Thanks,
 

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As for the speedo, kitaco make a kit intended to be used when there 5 speed box is installed that simply gains the speedometer pickup from the bolts on the front disc brake. I think it's about $100 or less.

as for carby setup, there is no reason why you can't plum from the tank to carb directly.

timing and ignition will need to be taken from the donor motor. May have to replace the throttle assembly on the handlebar depending on the carb layout.

are you planning to squash in a 2 cylinder 250 2 banger? We all thought of it, just couldn't be bothered! Yes we are all lazy.
 

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i'm curious as to what motor you are using as well. (see my signature and you'll understand why). as juls said they make an adapter. however, the check engine light will still be on. might be good to use an aftermarket cluster with external pickup as they are all over ebay for super cheap and look like the grom gauge. id go that route, just my .02
 

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Most importantly, if for street use, be sure the motor you chose has a lighting coil / stator, or a after-market stator w/ a lighting coil can be adapted. Otherwise, you'll need to run a total loss system (rechargeable battery) ;)

as for a speedo / dash, there are alternatives aside from OEM; i.e. Vapor
 

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If you do want a different cheap china dash (that looks exactly like stock), ive got one that ill probably never use. I forget what I paid for it, but id prolly let you have it for ~30$
 

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Unable to edit post... <_<
Also, I think the dash includes a speed pickup. you'd need to make a bracket and stuff, but that's minor compared to a motor swap.
 

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oh, thats cool. very cool!!!i assume you are in the uk?
 

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Some top quality info there chaps. Thanks to each of you!

I was going to keep it on the down-low but the donor is an NSR150. Should have somewhere in the vicinity of 35hp of 2-smoking goodness. I will make a build thread shortly.

Cheers,
Ohmagerd!
 
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