400/21 vs 22 hp rating

munkeystew · Post by **munkeystew** » Thu Jul 24, 2008 11:28 pm

I was wondering horspower of both motors? I know porting is different, but is one better than the other? I'm thinking of free air with early liquifire recoil housing, dual carbs,and cdi ignition. Will it survive???? Is the cdi reliable enough, or should I stick with points? Beyond the pto seals spraying out, and lack of pistons, what else is there to look out for?

400brian · Post by **400brian** » Mon Jul 28, 2008 12:10 am

Most of us here lean more toward restoration than modification, that is partly why you have not seen a bunch of replies to your questions.

Originally, the CDI was considered more reliable ( at least less maintenence )
30 years down the road, I'm not so sure that the points are such a bad deal. Every winter we see several guys with failed CDI boxes. New aftermarket CDIs are available.

The /22 engine has more cooling fin area, and would be the better choice in my opinion.

Running the engine as a free air doesn't seem like a good idea to me.

good luck

Post by **Matt** » Mon Jul 28, 2008 7:35 am

I think the HP difference is something like 40/46, but that takes into account the CDI and pipe used in '75. I personally still think CDI is the way to go, especially if you buy a new Hewtech.

Free air? I don't know how that would work.

Post by **Matt** » Mon Jul 28, 2008 7:15 pm

Woops, my bad. I was talking about the 440.

JDFanPa · Post by **JDFanPa** » Mon Jul 28, 2008 10:11 pm

If you have a properly set up points system it will be reliable aswell but the cdi is nice to have. The 22 has noticable power over the 21 in my opinion due to the tuned pipe however both motors run really well for there era. If your gonna run it free air you best have pistons gaskets and cylinders on hand I would not do this. The 22 in my 75 x8 melted a piston last winter in the cold after a fan belt failure got so hot it melted the engine cover the plastic part and the plastic on the nearby cables.

HoosierDeereMan · Post by **HoosierDeereMan** » Tue Jul 29, 2008 9:30 am

The KEC 400/22 was used in the JDX6 machines. I think these engines were used in some raiders also.

It never used a tuned pipe. It used the same can style muffler system that the 400 and 600 used.

The Prestolite CDI units offer a hotter spark for more power than the points systems do. However it seems that the CDI has a higher failure rate than the points systems. The CDI units are pricey compared to points and condensers. The OEM replacement CDI's out there from aftermarket suppliers are not worth the $. If a CDI is what you want buy a nos one, rebuilt one with guarantee, or go the Hewtech route. If you are talking about building a engine from scratch you need to verify which ignition system you have buy pulling the flywheel and checking. The CDI uses a timing ring and pick up that is totally different from a points system.

I would not even try the free air. There are plenty of KEC engines still running fine today with the heat shroud and fan. It's proven and works! It also provides a nice source of heat on those really cold days. With new bearings, proper belt alignment and tension I don't think you will loose that much HP due to the fan drag.