O/T Any Two Cycle Mechanics on here?

DrDan · Post by **DrDan** » Wed Apr 09, 2008 11:41 pm

I'm rebuilding a 1974 Attex 6WD amphibious ATV that has a two cylinder JLO Snowmobile motor in it. I am going to bore the cylinders and fit it with oversized pistons but wonder what the proper clearance is between piston and cylinder wall? Seems to be experts on everything on this forum so just thought I'd fire this one out there.

This Attex is quite a machine! That motor will kick out 40 HP and will go 50 MPH if yah got that kind of guts. Not me!

Fox · Post by **Fox** » Thu Apr 10, 2008 12:55 am

Are you boring it yourself or taking it to a shop?
If you are taking it to a shop get them the pistons and they will give the proper clearance. I am not sure what they are exactly, I think it differs from engine to engine.

I have never heard of that machine, you have any pics?

My grandpa has a couple old Terra Jets, those things are cool, I need to get my hands on it when he is done with it.

DrDan · Post by **DrDan** » Thu Apr 10, 2008 2:18 am

LOL Thought you'd never ask!

Here's an action shot...

And a still...

I have mine all repainted in camo but the popular color in the 70's was yellow. They quit making them (probably because they were so overpowered) in late 70's. Lots of fun - will really throw the mud!

DrDan · Post by **DrDan** » Thu Apr 10, 2008 2:23 am

Yes I'll take it to the shop for machining. I measured the taper in bore awhile ago (forgot what it measured) and it was significant. I'll have to find oversize pistons first and then take them and the block to the shop. It's a "B" finding parts for engine since it is a JLO engine (made in Germany) and the company was bought up by Rockwell in the USA and hasn't been built for quite sometime. You know, nobody likes 2 cycles anymore since they smoke (and also have tremendous power). Might smoke a treehugger when you blast by.

Doe Master · Post by **Doe Master** » Thu Apr 10, 2008 6:21 am

Dr Dan try here ,I found these parts.

http://search.ebay.ca/jlo-engine_W0QQcr ... oQ20engine

Fox · Post by **Fox** » Thu Apr 10, 2008 1:19 pm

Me likey

Generally 2-stroke pistons are very similar as long as the ports line up, check out that link or you may be able to find parts through a generic shop.

I love vintage things, I have a 78 snowmobile, 78 Suzuki dirt bike and they are both yellow, ha ha, just a bit of a pain to keep them running.

Hi5 · Post by **Hi5** » Thu Apr 10, 2008 2:48 pm

That sure looks like the 6 wheeled Argo. I had reliability issues with my 8 wheeler. Be very, very, carefull. They can take you places where you would need another similar machine or a helicopter to come and rescue you if there's a breakdown.

DrDan · Post by **DrDan** » Thu Apr 10, 2008 7:56 pm

Fox

Yup me too - I have an Argo Bigfoot for reliability issues with a Vanguard engine, but this old Attex is just an overpowered toy. I must have 200 hours in the body work and it is done now. Took her completely down and sand blasted chassis and repainted with Mil Spec anti-rust paint. Got new bearings and axles on all wheels. Now I refuse to put that engine back in without a complete rebuild - same with the Borg Warner skid steer transmission. I just enjoy rebuilding machines. Just finished with two rototillers. It is such a rush when you run them and they perform flawlessly. This Attex has been quite a chore though since parts are rare. Of course I have a metal lathe and milling machine combo so I can make lots of parts.

Something to do when nothing to hunt or fish for.

frisky · Post by **frisky** » Thu Apr 10, 2008 8:25 pm

Use the piston manufactures RECOMMENDATION for the clearence. This is IMPORTANT!!!

Bow Life · Post by **Bow Life** » Thu Apr 10, 2008 11:50 pm

Ive been working on outboard motors since i was 8 with my dad. Grew up on a marina. We got outta the business cause they want big dealers with high volume, no more ma and pa stores that give good service.

Anyways ive worked on alot of 2 cycle engines and id suggest you talk to the guys doing the boring out and go with the manufactors suggested clearance.

JLO also made engines for snowmobiles i believe. They were kind of a ... well a lemon as far as i know. If its a similar engine id almost be tempted to put in a more reliable snowmobile engine such as an older arctic cat of the same size.

Hope that helps.

Bow Life · Post by **Bow Life** » Thu Apr 10, 2008 11:52 pm

Just re read your first post and realized its a snowmobile engine. Like i said id be tempted to get something similar yet more reliable/easier to find parts for. Just my 2 cents.