1978 John Deere Liquifire 440

[rcaustin]

Hey guys,

I have a John Deere Liquifire 440 and it runs pretty good - had it out for the first time this past weekend in Revelstoke for the vintage ride. I wanted to do some more work to it over the summer, not only body work and paint but also some HP modifications. So I was wondering if anybody on here has done anything with the motor? increased compression? porting? twin pipes? etc etc? I kinda thought it would be really cool to get a set of twins made and some extra compression and porting would probably get a guy 15Hp I bet. Anyways - looking for some tips if anybody had done something like this.

Thanks,
Ryan

[idMXLT]

Tough crowd here!


It's really nice when you are modifying a common sled engine that was perhaps designed in the first place for more power (ie Phazer). Breadth of market entices the aftermarket guys (Aaen, FAST, etc.) into spending the cubic dollars required to quantify performance improvements, and they develop a “roadmap” of what’s required to reach a particular power goal. Then the end user (you and me) can circumvent most of the stuck pistons, $100s in jets that weren’t right, and hours making pipes that fit AND work well.

Unfortunately the Kioritz 440 liquid may not fall into this category. That’s not to say it can’t be done, and I encourage you to do so, but in this case the hours of work, heaps of money, and pile of parts that didn’t work will come from you. If you have experience with 2 stroke engine tuning, you will have a leg up.

As someone who has tuning experience, but not much with the 440 Kioritz, I would:
-Get the clutching dead on with the engine stock. There is performance to be had here and you will get to know the clutch tuning process which you will need later on. (http://www.jdsleds.com/community/viewto ... 11&t=16257)

-Get a good port map for the engine. Then you have your port areas and timings as a baseline.

-Consider the Liquidator for inspiration, how did Deere get more from their 340 race sleds? Some of this will apply to your 440 engine.

- Compare your port timings and areas to similar, commonly tuned engines. If there is a similar engine which has significant tuning development, you can apply similar changes and may be able to use the pipes from that sled.


Hopefully someone will chime in that has worked this engine over before.

[skoalmint]

Great Reply! Get everything mechanically perfect, and enjoy it. But if you want to go faster , then play with clutching and gearing. But then you take the chance of destroying a track ,and by the way u cant find anymore. But i cant say anything because i have done what you are wanting to do. I have a dator clone that will hit about 86 to 90 mph ( way to fast for it ) LOL I have done a modern track swap, the engine is pretty much all clutch, other than a little port work and head work. I think Kioritz had these motors pretty much perfect for dependable running engines at 85 to 90 % of there max HP. You can allways make a engine make more power somehow some way ,but how long will it run ? How much will you spend ? is it all worth it ? That is up to you! Good luck with it . Brock

[JDT]

Who was it that simply said "Stock Rocks."

As the 78 L-fire is an almost perfectly enginered vintage model, I think that appiles here.

Fine-tooth comb front to rear and enjoy what you have.

[rcaustin]

Good feedback guys thanks.

Ok so lets start with the basics - clutching and carb tuning.

I haven't taken the clutches apart yet to see what I have in there for weights, springs, helix etc in the primary or secondary. But does anybody have some recommended clutching setup that works well, back shifts well etc etc? I might run this sled around home in a few poker rallys (2000-3500ft). But the main place I will be taking this sled is to Revelstoke, BC for the vintage rides there. So I would ideally be looking for clutch setup for around home, and then clutching setup for around 5000-6000 ft. If I can get something in the middle that works for both then thats fantastic. if not - no big deal i can have parts for both scenarios.

Also - carburator tuning. Now I know this is special art to know how to tune properly. The main jet isn't that hard to get close - but as far as pilot jets, jet needles, needle jets etc etc... does anybody have something close to a ball park starting point? for say 2500ft and -10 degrees C and then @ 5500 ft and -10 to +10 degrees C? I know this might be asking a bit much and if I am thats ok. haha

Anyways - looking forward to hearing responses.

Thanks,
Ryan

[liquitisplit80]

A lot of the info you are seeking can be found in the fine tune manual posted right here on the site.
Or if you want your own, there's one on ebay right now!