1972 400

Deleted User · Post by **Deleted User** » Fri Oct 21, 2005 5:33 pm

Hello everybody i have managed to get my hands on a 1972 400 John deere sled and i am so pumped. i was looking for parts for it as i need to get new pistons for it and maybe have it bored out as there is some scratches running up and down the cylinder wall. i was just wondering if it is best to get it bored out or if the 500 series cylinder would fit onto the 400 crankcase as they have the same stroke?? or is there some other mods i can do to get more horse power as i want to get as much out of this sled as possible. mostly because nobody and imean nobody in my area has anything like this and i want to give a good showing

B) sorry for the novel but i just want you to know all the info

thanks for your replies and AWESOME SITE i am glad i stumbled upon it

400brian · Post by **400brian** » Sat Oct 22, 2005 1:03 am

DK has been listing some new jugs for early sleds on ebay. That's an option if you want to go that direction.

If it was me, I'd fix the engine, and enjoy the sled. As far as hopping it up?
When I hear high performance, and 2 stroke in the same sentence, I see $$$!

I would suggest there are better candidates for hopping up. If you look at the '72 engines ( KEC 340 ) and a bit later one, such as a 340/5 , you will notice that the newer engines have more fin area on the jugs and the heads. I think that by itself ought to say something.

I ran '72 400s back when they were new. There were faster sleds, but the Deeres were respectable. We also seized them in stock configuration, I'd be reluctant to push these early engines harder, but to each his own. Others on the list may feel differently.

Our 400 would approach 60 mph on a cold night, and on a ( by todays standards )
unstable mid-mount , that is fast enough for me.

Have fun with it, most folks on the trail have probably never seen a running one.

Deleted User · Post by **Deleted User** » Sat Oct 22, 2005 8:52 am

thanks for the reply. i agree with you on getting it back to a normal configuration. i just thought i would be fun to see if i could beat a few 440s flying around here :ph43r: because honestly they would never see it coming from a john deere. but i guess i will just have to have the satisfaction of being the only john deere in the area

now would it be cheaper to get the cylinders i have bored out to get the scratches out or should i go check ebay for those cylinders??

400brian · Post by **400brian** » Sat Oct 22, 2005 2:32 pm

I'm not sure that oversize pistons are available for the early engines. In the catalogs I have, I see only standard size. As far as I know, Deere only sold std size.
It also depends on the condition of your jug, how bad is it, could you hone it and reuse?
Do you have any idea what caused the damage? If it was lack of lubrication it is probably toast, but if it was a simple seizure, you might be able to salvage it.
Does the piston look scuffed and burnt, or is it just slightly scored?

You could call DK Trader and inquire if they have a piston to go with the jug, originals are touted to be better than aftermarket.

You need to do some research, good luck.

Rodimus Prime · Post by **Rodimus Prime** » Sun Oct 23, 2005 5:47 am

my 75 400 has the engine from a 73 5 or 600 ie 440 engine and its a ball. your out riding and there are these guys on newer sleds who would normally pass you and then you pass them with this green "bomb" and they go off riding into a field or something because they are so surprised/ shocked to see the speed you get out of it. i have all the original engine parts includeing pistons and cylinders but i keep that engine it there just because its fun.. my jdx's on the other hand are all stock engines.

my trailfire and liquifire on the other hand have had some engine work done to them notheing outragous but enough that they are also fun.

on a side note i did have a 440/5 bore .040 over in my trailfire with dual carbs and better exhaust but that was TOO wacky hey when you pop a head gasket and run home on only one cylinder at 50-60 mph thats gotta tell you something. sigh it was the first and probably (not) last time ill go flying over a driveway at 65 mph.. exhailarting until i found out i cleared two driveways side by side.

JDXsand00s · Post by **JDXsand00s** » Sun Oct 23, 2005 8:18 am

I'm pretty sure that in the early 340's and 440's, the stroke was the same though the cranks were different. You should be able to put 440 pistons on your 340, though, without there being a noticable difference. CCW also had the KEC 400, which wasn't in any Deere sleds but those pistons would fit was well. It shouldn't be a hard swap either, you just need something to swap it with. If you want 60 more cc's out for your 400, I have the KEC 400 jugs and pistons in good shape if you were interested in modifying your engine.

Deleted User · Post by **Deleted User** » Sun Oct 23, 2005 6:16 pm

well the cylinder is pretty scratched out. it was from a few years ago when the sled was trying to get running but it had been sitting for like 12 years and it was some gas down the engine, and it started but was gutless driving it around for abit and bang the top of the piston has a gouge in it now

:blink: so i dont think that it can just be honed but maybe. also there is all this gunk down in the bottom which i think was part of the problem i have to rip the whole engine apart to try and clean it out

but oo well i think it will definitly be worth it in the end

so the cylinders would line up on the crank that i have though?? even though they are different? thanks again guys this site is awesome.

Merciless

Rodimus Prime · Post by **Rodimus Prime** » Tue Oct 25, 2005 11:53 pm

the "gunk" is probably tarnish fuel and rust. its just about impossible to clean with solvents..

get crank rebuilt. and have case bead blasted. steel cylinders dont usually gouge so a good honing usually cleans them up nicely then just add pistons.

note aluminum deposits will not hone out and will require miratic acid for removal of aluminum deposits.. sparkle towellet bowl cleaner works great and is not as ... dangerous.

400brian · Post by **400brian** » Wed Oct 26, 2005 1:31 am

I think it is Muratic acid, I forget, anyway it is a common pool chemical from what I have been told. Reported to be nasty stuff when in contact with aluminum, gas is released, avoid inhalation.

But Rodimus is correct, if you have a jug that has seized, you MUST chemically treat the steel liner before installing the new piston. If you do not, you will be looking at a new seizure shortly.

Never heard of the toilet bowl cleaner idea before, What is the active ingredient?

Deleted User · Post by **Deleted User** » Wed Oct 26, 2005 4:09 pm

okay do you think any shop would be able to rebuild the crank or am i going to have to send this away to get done?? bead blasted you say eh......hmmm i am going to have to check what sort of blast they are using at the high school as i could just do it myself for free there

thanks again guys

Merciless

harleysportster · Post by **harleysportster** » Wed Oct 26, 2005 6:56 pm

Take your crank to you local sled shop and tell them what is is from. They may be able to handle it. It will not be cheap. I had mine done by Central Snowmobile several years ago for a few hundred. The rebuild includes all bearings and center seal.

Deleted User · Post by **Deleted User** » Sun Oct 30, 2005 8:20 pm

ouch, i was hoping i wouldnt have to pay a couple hundred in the repair as i am alittle straped for cash at the moment, but i guess you do what you have too

:unsure:

speedy295 · Post by **speedy295** » Tue Nov 01, 2005 11:52 am

Where are you from I have a motor from a 73 ish 400 id like to get rid of. has good compression should be a running motor. It has a brand new duster clutch on it. $75