Home Depot Lifan 420 (15HP) Mods

jerryggable

Just wanted to let anyone thinking about buying a Home Depot Lifan 420 know that the one I just purchased included the Honda style rev-limiter coil and flywheel. After I installed a billet connecting rod, torque cam, pushrods, guideplate, intake, muffler, and 35lb springs it still would not rev beyond 3700 rpms even though I had removed the governor. I was not aware when I purchased it that Home Depot Lifan's had the Honda style rev-limiter built into the engine but I could tell it was hitting a rev-limiter. I then purchased a standard coil from Vegas Carts but then the engine would not run. I could tell it was firing at the wrong time. Turns out that the rev-limiter coil and flywheel are a matched set. You have to change both for it to work. So I then purchased an OEM flywheel from Vegas Carts and it now revs over 5000 rpms. Have only made one quick run (started raining) with it so I don't know the max rpm, but I hope the torque cam limits rpms to around 5500 because I did not install dual valve springs, just the 35 lb ones. Bottom line is it runs great but I could have purchased their 460s for less than I have in the engine and upgrade parts. (But I wanted to buy and engine and do the upgrades myself just because I thought it would be fun). Make sure that you get the 4.450" billet rod if you have the Lifan 420, not the shorter one for the GX390. The 4.450" rod is slightly longer than the stock rod so it will raise the compression ratio slightly, but not a significant amount. If you install the shorter rod you will lower your compression ratio. I did have to do minor clearancing of the block for the rod bolts and minor clearancing of the balance shaft for the rod itself. The Lifan castings are really clean inside and the machining looks really good though. This engine is installed in an off-road gokart that probably weighs about 350 lbs.

BGW

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Brian Boyer

YOUCH!,..

My Lifan just arrived last night,.. And its apparently the latest and greatest/ has the charcoal canister (i guess?) under the carb etc for emmissions.

******!, did not know this/ rev limiter deal.

I only bought the Lifan for the rep as best clone w/ HD warranty to boot,.. And wanted charging capabilities.

Have not fired the motor yet,.. Guess i better decide what to do.

Brian Boyer

I wanted to mild build mine/ just enough extra ooomph to NOT require forged rod swap.. Now sounds like its pointless.

Return the mota' ?

Brian Boyer

Yyyyyeellloow??


(Kidding)


Well should i put the tach on it, add oil and fuel and push the throttle WOT for a sec and watch the tach?,.. If this thing cant be worked i dont want it, i'll send her back and run to Harbor Freight

jerryggable

The Vegas Carts Hi-Torque cam did provide some extra oomph even with the governor and rev-limiter still installed. (I installed a Vegas Carts adjustable carb and their Walker muffler at the same time so I don't know how the cam alone would do.) Still a bummer.

sho305

Thanks for the new info, everyone going to those coils. They put the magnet in a different spot due to timing advance of the coil, that is why the flywheel is different. That kind of sucks for us. You can buy a coil at NR racing without the limiter for a Honda gx390 (the new style) for $80, but I don't know if it works on lifans.

Brian Boyer

Well i'm definately watching this thread, as i need to decide to keep or return the Lifan and go to Predator.

Mine says "Electronic Ignition" 190F-BDQ-CA Lifan 15.0 on the recoil cover.

Jerry is this model # close to the description your Lifan uses?

Kustrud

Well shoot, maybe this explains my issue! For the life of me can't figure out why I can't rev past 4000 RPM. I have the 35 lb valve springs installed and it has PLENTY left, but at that RPM it just hits a wall and skips/misses then backfires. That exact RPM, every time. This sound like that's what my problem is?
Sho, if that coil fits, would that solve my problem??

Here's the coil for anyone interested

http://www.nrracing.com/mobile/Produ...=UT2COIL-WOREV

sho305

The honda coil should work, but I can't say it will since some of the clones have detail changes now. They have not copied the new model honda far as I know, but I don't know how different the new honda is. Maybe NR knows they are big into clones and can be helpful, someone needs to ask them. The only good thing is the timing advance electronic coils are supposed to run slightly better, I don't know if you use the same timing key with them.

Brian Boyer

I'm leaning back towards "i dont care i bought it for the better Lifan quality and three year warranty",.. Use it under warranty stock with gov restrictor screw opened up as much as possible (hopefully 4,000 RPM capable) and abuse it for a bit with no worries,.. Meanwhile hopefully Geoff or another 420 Guru can get answers for us in a few months.

The reprts of a better running engine are appealing to me if theres anything to that anyway.