Duromax 16hp in Yamaha g14

thefanman

Hi I"am Sam have a few questions. If you can help me with a few answers I would sure appreciate it. Have a Yamaha G14, Going to install a
16hp Duro Max engine.Useing stock, Yamaha gas tank,clutch, muffler,starter.Have some questions about modifying new engine.Plan too remove govenor, install 18lb valve springs. Should I change fly wheel key to advance timeing? How much should I advance timeing? Will parts from a gx390 work ok in this engine? Golf Cart has 6 inch lift kit and 22 inch tires,does 23 mph at 4000rpm.How long would it be safe to keep new engine at that speed? Or higher.
Thanks for your help.

BGW

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sho305

I've been told you can't do too much because the flywheel, if you get one then you can mod them to 30hp if you want. Above 6K the magnet flies out. After talking to some people I'm planning on taking a 16hp and cutting the head .60, you can go more if you use premium. Then a 4 degree timing key and you can port the head a little there are cutter marks from the valves you can get rid of. Then you can get a bored carb or a different carb, I found one I like but in my G9 I really need to find an angled intake and no luck so far. The rear shock is right there. Search in yamaha gas and I made a thread on a G9 install called 'clone specs for yamaha...or something like that. There are photos, doing another one in a little bit here. AGK has parts for them, GX390 honda most parts will work. You may need a cam to get over 5K rpm I hope above mods will get me 5500. If you get the flywheel that is like 250 (Arc makes them) then a rod, then you can run a cam and valvetrain parts it will really fly. I'm trying the mild mods right now this car is half utility not really wanting wild engine. Also you might as well get a new clutch if you do because its hard to mod the stock clutch to run more rpm a mod engine will need. Stock engine the yami clutch works great as does the starter/gen, just use the CPP adapter. I used all stock belts. I don't like the carb lawn carbs are not so good at part throttle. Note a lot of parts are for gokarts that run WOT high rpm, not on a CVT at 3.5K like stock carts, but AGK does have a torque cam. Precision cams also has some. Everyone seems to say with a cam you need rod, flywheel, valvetrain parts, without you don't. I did read you can shim the springs a little. The 13hp seems to rev a little more than the 16, which is actually just a stoked 13 that only makes 15hp anyway. But the torque of the 16 is nice I love it. It climbs hills spinning, night/day to stock tired engine. It just lays down on top though will not rev more than stock both with no governors. I would recommend you get some hours on it before you beat it and rev hard some have stuck rods. Ran this one most of summer and then I could feel it loosen up. It gets up to speed a lot faster, lot more power. Was told those mild mods should get 18hp out of a stock engine providing you have a header and free flowing intake/airbox/exhuast and of course you will have to rejet it. The one I did I put car airbox and car muffler on it, had to jet way larger, no governor but all stock 16hp carolstream engine otherwise. I even put the electric start engine in with a recoil and it all fit, barely.

thefanman

sho305

Hard to see but nice burnout.

thefanman

top speed 35mph at 5500rpm

sho305

The one I did is stuck at 5K or so, but I never went that far on a road with it. I have a long drive I run and that is what I base it on its maybe 800ft. I can top out my stock cart there and the clone gets up to speed much faster, so not sure why it would take so long to wind out. And most of the summer we were breaking it in and I was afraid to do a lot of rpm.

thefanman

i took more time to get up to speed, didn"t want to upset and disturb the neighbors. gets up to 5000rpm fast But the last 500rpm did take a bit longer to get up to

sho305

This next one I am going to advance the timing and cut the head, will see if that helps. Maybe it will hit 6K and blow a flywheel like some say, but I only top it out for seconds I never hold it there. Flywheel is $250 ouch, but this will be stock other than possibly a different carb if I can make a new intake.