Trx90 build

[velociraptor]

This shaft is throwing me a loop it had a piece of yellow plastic on it with N labeling it

 

[velociraptor]

It clicks into place as though an andjustmemt

 

[velociraptor]

Reading up on dratv.com while shopping i found they offer lifan e22 heads offered for trx90 all years and honda 70-90 certain bikes....i mean does a lifan e22 head honestly fit a trx90? If so bam i found one for 40$ us brand new

 

[velociraptor]

Might rebore to 110cc as well idk yet

 

[my67xr]

Yeah it'll fit, fit's the Honda's 50cc, 70cc, 90cc and 110cc
You can pick up cheap used china engine's every where, might be cheaper as you get everything you'll need plus some spare's ?


A china alloy 52.4mm bore will make it 107cc, and a cast iron china 54mm bore/piston will take it to 114cc
Then add a domed piston for more compression, a bit of a port de-dag and clean up and stronger inner valve spring and a Crower G2 camshaft and a 22mm carby


Crower Power G2 High Perfomance Cam for Imports - Crower Power - Pit Bike Parts


A new china complete 110 auto (single speed) engine start's at about $260
Amazon.com: Promax 110cc Dirt Bikes Engine Motor 110 CC Engines 4-stroke Zongshen Pit Bike Engine Pitbikes Dirtbike Motor with Semi Automatic Transmission Kick Start: Automotive
Or a 125cc 4 speed with clutch for about $250
Amazon.com: TMS® Lifan 125cc 1P52FMI-K Engine Dirt Bike Motor Carb Complete for Honda XR50 CRF50 XR CRF 50 70 ATC70 Z50 CT70 CL70 SL70 XL SDG Dirt Pit Bike Motorcycle: Automotive
Then you can get atv/quad version's with electric start and 3 speed semi auto with a reverse

 

[velociraptor]

Nice ideas xr ill check em out. She had trauma a while back and shes wobbly getting back into stuff so im ....really really restraining from going beyond mild lol. She loves the heck out of trxs had herself a 450 back when.but im kinda shaky on spending buku bux just yet so im shopping till December as per the woman in charges ruling lol and she told me she wants custom plastics ect...oh boy lol. Some of my builds i made for others strictly track racing has her worrying if i tweak it shell be in a tree so shes building it with me to assure i dont up the ante too much.

 

[velociraptor]

I bought a head a while back for my 74 ct70 when I went 88 cc it's still newish had larger valves and such installed but I know the cam is different and from what was said the trx90 head is only similar on 1980 ct70?

 

[velociraptor]

Well from what I found the bottom end is good and it being hers she wants the lowest priced fix first lol. The bore is good the valve head I have for it now I just need the starter and a few more parts including cdi and the motor can be built. The tires on the other hand I may have two off a John deer to fit for now but I'm gonna end up just slowly saving for all four

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[velociraptor]

Well so try to say this bike was near completion and I ended up catching Lyme disease among other things ended up selling but on a great note a friend gave her a 3 yo Yamaha grizzly that just needed a single gear so it was a bit of an upgrade at least

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