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I may be getting older, but I refuse to grow up!
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Hello all!, i recently purchased a 2018 raptor 90 for my son to start racing with. it became clear very quickly there was no aftermarket support for this bike. HMF and big gun offer exhaust but that was about the extent of it. so i contacted a "well known" bike performance shop who said to bring it in and they will do a high compression piston and head porting. Well after 6 weeks of run around from this shop, i picked my engine back up and took it to a local builder who specializes in smaller 4 stroke atv, dirt/pit bikes. 15 min after dropping the engine off and him pulling the top end apart and taking a few measurements with a mic, while i was standing there he said the options are wide open. Apparently yamaha or whoever builds the new generation engines converted the stud pattern to a Honda stud pattern. He went through several options i had as far as piston sizes, **you can only bore stock sleeve 3mm before needing to bore cases if you wish to go any bigger than a 50mm piston and you will need a larger diameter sleeve as well obviously. but there are options to build this thing well over a 125. Next was head work, the stock heads flow terrible from his explanation and even porting them you were better off to look at other heads that dont cost much more than a quality port. We settled on a V2 race head with perfomance cam. This is just the beginning of options. i could have went with a larger roller rocker head which would have allowed for a domed piston bumping compression. so all said and done i settled for a 50mm piston (stock is 47mm and i didnt wanna tear into the cases at this time to go larger than 50mm), v2 race head with performance cam and larger valves and mikuni vm22(which i had already). After some jetting my son has a raptor that RIPS! the low-to mid range gains were impressive!. ***now dont go and buy these parts thinking your gonna slap a head on and go, there was some machine work that had to be done on the new piston to clear the larger valves as the 50mm piston is more of a flat top. Any questions feel free to ask, this is huge news in my opinion for this bike that has been pretty much considered a useless competiton bike. Not for older raptor 90's, 2016-18 and i would imagine the 19's as well
 

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I must be living in the worst part of country ,cause I can’t find nothing performance wise and nobody knows nothing here in SoCal so help us all out those that are in the know even engine swaps that y’all know will work are options
 

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The 90 doesn't have much of an aftermarket because it's not a performance machine.
Even though kids race them, there still isn't a big market.
Unless you happen to have a good running, larger cc engine sitting around, and the welding and fab skills to put it in the 90 frame yourself, you would otherwise being throwing money away.
Reason being, you'll never get your money back out of a project like that.
Most people would pay less than stock for it after a swap too.
Bike engine swaps are usually not as straight forward as car engine swaps either. Many cars can usually swap in a different engine of the same or similiar line or size with little to no modifications, aside from say motor mounts, or ecu swap for fuel injection.
Vs bikes that have one engine of a certain physical size and shape, usually with 3 or 4 mounting points.
Chain alignment must be correct too, so a bigger engine may need to be offset to one side to accomplish that, which can lead to other issues.
The best upgrade you can get for a Raptor 90 is to sell it(as they get outgrown fast anyway), and get a 125 or 250 Raptor, or any larger machine.
It will be much simpler, easier, and handle better as well.
 
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