Liquifire engine rebuilds

Post by **guitardude081** » Thu Mar 12, 2009 11:21 pm

As restoration season starts to approach, many will no doubt start tearing into their sleds. I think it would be a good idea to get a list of common problems and solutions going for Matt to toss into the FAQ section...possibly a new restoration tips page sectioned off by engines, suspension..... this could be general or sled specific. A Dator section would be worth it's weight in gold to those who ride theirs a lot. There are a lot of repeat questions and answers that get hard to find as they start getting buried on the site. There's a lot of knowledge here, we just need to pool it in a common place.

The first thing is to buy the best available gaskets. Cometic makes a set for the Invaders. Use that with Winderosa crank seals made for the liquifire and you're on to a good start. Have your crank checked by a good crankshaft shop for straightness and phase. I'd recommend Crankshaft Services because Jerome is easy to work with and the most meticulous guy I have ever met. Plus his pricing can't be beat. Pack the outside crank bearings with Bel-Ray blue grease and coat the inner lip of the crank seals with a light coat of white lithium grease. I always run a bead of Yamabond on both crankcase halves and then rub it around with my finger to ensure an even coat. I do not put any on the crank seals. You don't have to use it excessively. Once I have the case together I torque it immediately. The next step is to install a new gearcse output seal with lith-ease on the inner lip once again. Assemble the gearcase with new o-rings on the cover, oil and water pumps. I don't know that it matters, but I seem to have a compulsion for oiling my o-rings before installation. Next, intall the ignition system. I use red loctite on the crankshaft threads and torque the flywheel nut to the #4 on the 1/2" drive impact for 10 seconds specification. Next install the base gaskets with NO SEALANT. install the water pipes with new gaskets. Here's the tricky part. Many people find that the head nuts leak after they fire the engine for the first time. Here's the Ed Poets solution. Scuff the head gaskets with medium steel wool. (theres a plasticy coating on them from the factory.) Spray both sides of the gaskets with copper spray-a-gasket and install immediately. Torque the head nuts to 18 ft/lbs and then to 22 ft/lbs. This method has always left me leak free. I use yamabond on the intake boots just to ensure a good seal. I wipe the excess off of the inside so that nothing gets into the engine. Do not use sealant on the exhaust gaskets. Disassemble the temp. probe completely (the big nut will come off of the probe). Clean the threads and install some pipe dope or teflon tape to seal the threads. Make sure to fill the gearcase before installing the engine. It's pretty messy if you do it in the sled. Pressure testing a fresh engine is always a good idea. Seal the exhaust joint with an aerobic sealer such as Permatex Ultra black or that high temp orange stuff. Ceramic sealer cracks and blows out almost right away. Bleed the oil pump and do a good check over before firing the sled. A good clutch torque is 58 ft/lbs. If you have access to a cooling system pressure tester, test it before you fire it. Fill your tank with fresh 92 non-oxy and mix it 50:1 with a good oil. NO INJEX UNDER ANY CIRCUMSTANCES. Fill your oil tank with the same oil. That same oil is the best assembly lube as well. I use Klotz Techniplate snow oil most of the time because it has almost no ash, it lubricates well, it's great for spark plugs and it smells...as Kenny puts it; "Just like victory". Grab a wire coat hanger and hook it around the oil pump lever and pull it wide open. Fix the coat hanger on something so that it will hold the pump open while you pull the rope and adjust the idle. When you fire the sled, keep it running and have an assistant adjust the idle to keep the sled going on it's own. DO NOT USE ETHER IF THE SLED DOESN'T FIRE RIGHT AWAY. Make sure that you're getting fuel, spark and compression. A fresh motor can be stubborn. If you have to help it, put a couple of drops of fuel down the spark plug holes. Once it's idling, don't touch the throttle. Wait until the sled starts smoking a lot, count to 60 and remove your coat hanger from the oil pump. Make sure that the cable ferrule didn't fall out of the lever. Let the sled idle for a few minutes, and then you can start revving it a little. Once it's warm shut it off and check for leaks and proper head torque. If all is good, go out and break it in.

Go easy while breaking it in. The sled probably won't want to rev at first. You'll feel it loosen up after about 25 miles. Make sure your carbs are squeaky clean. Pressue test your needles and seats, or just install new ones to be safe. Install new Powerjet o-rings and new bowl gaskets. Remember anything that isn't metal in these carbs is pretty well rotted out after 30 years, and steel tip needle/seats are a thing of the past. Install new fuel lines, in-tank pickup and fuel filter. You may want to install a shut off valve as well. You can make a pretty good repop of the sport/trail shutoff brackets out of the old Polaris airbox/fuel shutoff brackets. Clean your fuel tank well. I usually wash it with fresh gas and then spray it out with the garden hose. I then let it sit in a dry ventilated place for a week or so to let all of the water evaporate. Clean and inspect your clutches and replace components where necessary. Do not overlook your primary clutch. A 30 year old clutch that has never been serviced is like a grenade waiting to go off. Cleanliness of your engine parts, work area and hands is key when rebuilding any engine. Wash your hands often and well.

When properly and carefully rebuilt with no corners cut these things run very well and are reliable. Cold starting issues can be solved with a hair dryer between the cylinders for a few minutes....just like newer race sleds.

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pj sportfire · Post by **pj sportfire** » Fri Mar 13, 2009 1:00 pm

Good information Jack and I'll add a bit too.

To successfully inspect for micro-cracks in the aluminum parts we build our engines with here, we always use the Zyglo Fluorescent Penetrant Inspection process. If you do it correctly, it WILL find even the most minute hair line cracks in everything it comes in contact with and I'd bet it would work pretty well to fully inspect aluminum primary clutch parts that are subjected to extreme centrifigul loads from spinning at 8000+ RPM.

Below is a photo of the kit we have and you can buy something like this online from any equipment manufacturer.

pj

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ZA_70_Kit.jpg (177.06 KB)

DeereKid9 · Post by **DeereKid9** » Sun Mar 15, 2009 9:03 am

Jack,
I was going to call you but I will throw this ? out here. On the 82 LF, the seal behind the oil pump gear, the manual shows/ recommends removing it all as a whole. I don't really want to split the case. Will a gear puller get that oil pump gear and leave access to the seal?

400brian · Post by **400brian** » Sun Mar 15, 2009 2:21 pm

A Dator section would be worth it's weight in gold to those who ride theirs a lot.

Who would that be? :lol22:

To date not much has been placed in the FAQs directed specifically towards the Kawis, so that is good info.

burt87 · Post by **burt87** » Wed Mar 18, 2009 1:55 am

DeereKid9 wrote:Jack,
I was going to call you but I will throw this ? out here. On the 82 LF, the seal behind the oil pump gear, the manual shows/ recommends removing it all as a whole. I don't really want to split the case. Will a gear puller get that oil pump gear and leave access to the seal?

In my opinion, take it for what it is worth, there is no way to change the seal without splitting the case. You could remove it, but you will never get the new one in without damaging it , or getting it to seal. I recently changed the seals on my 80LF. I had to make the gear tool(JDM-112) to remove the oil pump gear so I could remove the oil pump,to be able to completely disasemble the motor.Making the tool was pretty simple, I bought 5/16 round stock and bent it in my vise using map gas. It's a pain to disasemble the whole thing for just a couple of seals , but I don't see any other way. If your motor still has JD pistons,and they are OK, you can get new circlips from your local JD dealer. As I said, It was a pain, but I found it rather satisfying knowing that I took the time to do it right the first time. I asked the guys on here alot of questions during my rebuild, even though I have a tech manual. It's nice to be able to ask for some tricks of the trade along the way. Good luck on your rebuild.

Rob

A1 SLEDER JIM · Post by **A1 SLEDER JIM** » Wed Mar 18, 2009 7:25 am

i just rebuilt several. you must split the case. you can remove the oil gear pump gear easely by removing the nut and gently tapping with a small brass hammer on the shaft end, remember to remove the waterpump mount to the case and usually you must loosten the actual oil pump bolts while tapping to make room for the wrench to grip. The dozen gears i removed none were on very tight and keyway alwasys seems to stay put. it looks worse than it is. the crank end gear can be removed with a bearing seperator rent one or borrow or buy and return but you need it. also the book says take all off bearing and seal and gear. but i heard of people ruining the gear by trying to just remove it alone. I found that you can use the seals as sacrificial and remove the seal gear together. but i only do this if the bearing is rust welded to the crank and needs to be removed separatetly. otherwise take the bearings off both ends of the crank and replace them. in philadelphia pa the bearings are $15 for the big ones and $13 for the small one good Austrian origin good to 10,000RPM. the gearcase uses the big. easy to change too. Just remember to shim the cases properly. I will do a pix on how to easily do the shimming on another post. Don't forget them center seals you just pull them off the crank I only ever had one that broke by removing and one that was broke discovered when tearing down. You must carefully insert the crank or the case half edge can grip the seal and ruin it when installing. the seals are easilly obtaned at a good auto parts store $1 eachor a hydrauulic cylinder repai rshop 12 for $3. pressure test . did i say to pressue test. very important sometimes the engine test good but the intake may leak and ruin a new engine so just do it!
jim

DeereKid9 · Post by **DeereKid9** » Wed Mar 18, 2009 9:45 am

I spoke with Jack yesterday and all roads lead to splitting the case. So, splitting the case it is.
I think this post has been the most beneficial of all post. At least fo me. Thanks everyone.

427cobra · Post by **427cobra** » Wed Mar 18, 2009 1:35 pm

To get the oil pump gear off the crankshaft you can also use heat. Ive used a torch to heat up the gear and it slides right off. Its works great! Just be careful and try not to take too long...as you will heat the crank up too much...

Then use the torch to heat the gear up again to install after the new seal is installed!

Post by **guitardude081** » Thu Mar 19, 2009 5:59 pm

Since we kind of got on the topic of bearings, if you buy crankshaft bearings and either install them yourself or provide them to the shop doing the work, make sure they are C4 bearings. They will usually have a C4 stamped somewhere on the bearing. Also always remember to triple check that you have installed all of the circ clips in the pistons.

As I told Bob, don't be intimidated by having to split the case. Newer Rotaxes are the most intimidating because they have 2 big giant red center seals. But, they are no harder than anything else. The hardest part of re-doing the bottom end of a standard 2-stroke snowmobile engine is not getting excess crankcase sealer all over yourself when you bear hug the case to torque the bolts. If you take your time and allow yourself a second to think once in a while you'll realize that the bottom end is actually easier to do than getting those darned double ring pistons to go into the cylinders on the first try and not getting a hand cramp after squeezing the rings for a long period of time. When I build an engine I always take a step back after every major step in the building process and make sure I've done everything right up to that point and think about what tools I need and what I need to do to complete the next step. I also put away anything I won't need and throw away any used parts to eliminate clutter and confusion. I'd rather assemble an engine than replace an angle drive bearing any day of the week.
~Jack

Post by **guitardude081** » Mon Apr 20, 2009 4:52 pm

I just read this post over....bored I guess. I forgot to add some very important info! Piston installation. For those who haven't done it before, each piston has an arrow and each ring has a little marking. If the piston has an arrow point either front or back, it always goes toward the exhaust. If it has an arrow parallel to the wrist pin, the arrow goes to the stator side. The markings on the rings are usually found at the ends. The markings always go up. Attention to detail is very important, so before the cylinders go on, make sure that the pistons are installed and assembled correctly.
~Jack

S_Kyle · Post by **S_Kyle** » Mon Apr 20, 2009 10:59 pm

One of my projects this summer is to do the seals in my 80 LF before running it. It currently has acceptable compression in both side so I was going to leave to top end in and just do the bottom. I am new to the whole sled engine rebuilding, should i just bite the bullet and take the whole thing apart and inspect the cylinders etc or am I OK just doing the bottom, I guess seals and o rings would be needed.

Post by **guitardude081** » Tue Apr 21, 2009 10:48 am

To do the bottom end you need to disassemble the whole motor. Get yourself a tech manual if you don't have one. Study it the night before you start you project. It isn't too hard to rebuild an engine. A Kawi LF motor is a good one to start with because it is about as complicated as you can get as far as Deere engines go. Just take your time and follow rebuilding instructions step by step and you'll be in good shape.
~Jack

clem79 · Post by **clem79** » Tue Jun 02, 2009 11:31 am

I can rebuild standard mikunis with my eyes closed, these power jets have me a little curious is all. How much different do these carbs act than a standard(non PJ) 38mm carb?

And where in gods name can a guy find a set of intake boots? Oh and a throttle cable that actually fits?

clem79 · Post by **clem79** » Tue Jun 02, 2009 11:31 am

Oh, and why use Winderosa crank seals and not the Cometic crank seals?

Post by **guitardude081** » Tue Jun 02, 2009 2:23 pm

The cometic Crank seals are hard to find individually and the complete gasket sets for the Invaders have Invader crank seals which are different. That and Winderosa makes a teflon coated MAG seal now. As for the PJ vs. regular carbs, it's really a matter of preference. The 38 standards, when properly tuned will act as a regular carb and pull steadily all the way to full throttle with no bog or flat spots. The PJs, when properly tuned will hit "hard" at around 5500 rpms. The way I describe it is that it's like a very mild turbocharger. What happens is that the main jet function splits and you essentially have fuel coming from 2 angles and it atomizes better. It is also part of the muscle car philosophy of throwing as much fuel as possible into the fire to make it go fast. It doesn't help gas mileage, but it sure is fun. The PJs are finnicky and require constant attention, but some people like the takeoff that they get with them. The ones tuned for the Liquifires from the factory add a "bog" symptom to the low end. This can be clutched out of the equation, or the guts of the carbs can be changed. (See FAQ section) I prefer the PJs myself, but I do see why some people refer to them as "Powerjunk" carbs.
~Jack