78 liquifire problems

Deleted User · Post by **Deleted User** » Fri Oct 14, 2005 2:06 am

I am new to sleds and don't know much about them. My 1978 liquifire wont rev up. It goes up to 2500rpm and wont move. My brother rode it last and said it needed a new belt. Put a new one on and wont move. He said it is my pistons and rings. I say carbs or rusted track, any suggestions.

81spitfire · Post by **81spitfire** » Fri Oct 14, 2005 2:28 am

try turning the secondary clutch by hand and try turning the track by hand if they wont turn try some penitrating oile like pb blaster to get them turning if they do turn then i have no clue. good luck and happy trails

JDXsand00s · Post by **JDXsand00s** » Fri Oct 14, 2005 9:15 am

I had a 78 Spitfire with the same problem. My carb was cleaned several and that made no difference- it still wouldn't move. The drivetrain is all free and in working order as well. I pulled the engine and my seals were terrible. I'm assuming that that is my problems as I really don't know what else could be wrong, just that it sucks too much air as it revs up. I don't have my engine rebuilt yet but I'm 90% sure that my problem will be fixed. I beleive that seals could be your problem. Good luck.

Deleted User · Post by **Deleted User** » Fri Oct 14, 2005 10:21 am

i picked up the back and the track started spinning. on the ground it just boggs.

81spitfire · Post by **81spitfire** » Fri Oct 14, 2005 6:48 pm

i think it sounds like the sills are the problem check them (however you do that)

harleysportster · Post by **harleysportster** » Fri Oct 14, 2005 6:54 pm

Start by checking the simple things.
-Check for spark on both cylinders. If the engine has a dull exhaust tone and smokey, one cylinder may not firing.
-replace spark plugs
-check/replace fuel filters
-check compression
-clean carbs

Deleted User · Post by **Deleted User** » Thu Oct 20, 2005 3:25 am

I checked the compression, 75 on the left and 0 on the right. Pulled the head and there was a hole right thru the piston. New pistons, rings, and gaskets to arrive on Tuesday. My first time doing this and I hope it goes together as easy as it came apart.

harleysportster · Post by **harleysportster** » Thu Oct 20, 2005 9:52 am

The hardest part of your rebuild is removing the piston connecting pins and reinstalling them. The proper way is by using a piston pin tool. I made one and I can send you a picture if you like.
If you do not have a service manual, get one before attempting the rebuild. It will save you time and explain what you need to know.

Deleted User · Post by **Deleted User** » Thu Oct 20, 2005 1:29 pm

I do have a manual and yes I would like to see a pix of your tool. I didn't try to take the pistons of yet so I hope it helps. I was also wondering if you know the equivalent to CHAMPION QN-1 spark plugs?

harleysportster · Post by **harleysportster** » Thu Oct 20, 2005 5:14 pm

Here is a picture of my hoomemade piston pin tool.
http://home.comcast.net/~psshd/pistontool1.JPG
It consists of 9 inch length of 1/4 x 20 all-thread rod
3 1/4 inch nuts
4 1/4 fender washers
1 craftsman 12 mm deep-well socket( 1/4 inch drive)
3 inch 3/4 pvc pipe( with one end contoured to fit the side of the piston)
To remove the piston:
-Place shop rags down into the crank to prevent anything from falling in
-Assemble as shown in the picture, with 2 nuts jamed together on one end of the all-thread and place the socket with the drive end against the pin
-tighten the nuts on the all-thread, which pushes the pin out into the pvc pipe
-after the piston pin is pressed out, remove the all-thread
To reassemble:
-Install the connecting rod bearings in the rod( lubed with 2 stroke oil)
-Start piston pin by hand and place piston over top of connecting rod
-assemble the tool as before but without the socket
-tighten nuts, pressing the pin flush against the side of piston
Remove nut and washer and place socket over all-thread with the drive end against the pin
-Tighten nuts until the pin is pressed inside past the retainer clip grooves
-install retainer clips
You mentioned you bought new pistons. Did you also buy the correct connecting rod bearings which are 23 mm dia.. The bearings that come with the new pistons are 22 mm dia., which are for the /22 series cyclone engine. THe pistons are the same but the bearings are different between the fan and liquid engines. Now is the time to install new crank seals too. A bad seal is what problably burned a hole in the piston to start with.
The QN-1 spark plugs are a thing of the past. A common spark plug to use now is NGK B9ES or BR9ES in the liquifire. If you want to buy a pack of 14 NOS QN-1 plugs, DK-Trader had them on ebay.
http://cgi.ebay.com/ebaymotors/SPARK-PLUGS...itemZ4584099834

Deleted User · Post by **Deleted User** » Thu Oct 20, 2005 11:37 pm

Thanks for the picture and instructions. I think the piston set is correct, I ordered the set from Dennis Kirk for 1978 440 liquifire. I will replace the crank gasket since it is included in the gasket set. I wont be working on it until next weekend. The parts should be here during the week but I don't want to get started and then have to go to work (I start at 3 pm). It ruins my momentum.

harleysportster · Post by **harleysportster** » Fri Oct 21, 2005 8:08 am

Gary,
Test fit the piston needle bearings on the upper rod. I discovered the difference when I rebuilt my engine a few years ago. If you have the DK cat., look at page 246. Needle cage part # 14-313 is listed for the 78 liquifire. The specs are 18x23x22. I believe the needle bearing that comes with the kit you ordered is # 14-310, 18x22x22. To decifer the numbers, the first number = the inside dia., the second=the outside dia.,the third=the length of the needle bearing.

Deleted User · Post by **Deleted User** » Fri Oct 28, 2005 1:19 pm

I just put the motor together yesterday afternoon. I had to go to work so I waited till I got home to start it. It took about 20 pulls till it started up and seems to be running perfect. I still have to add collant and water to make sure all the air is out of the system though. I also want to do another compression test. Do you know what the reading should be? And do you think I should run 50/1 to break these parts in?

harleysportster · Post by **harleysportster** » Fri Oct 28, 2005 6:11 pm

gary99z28,
There is a vent screw behind the pto side spark plug that will aid in filling the coolant. With the screw removed, add coolant until it flows out the hole, then install the plug. Add coolant until it is full to the bottom of filler neck and 1 inch in the recovery bottle. Install cap, warm engine and check for leaks.
The compression should be 120-130 with a fresh engine for serial number 70001 and up.
What did you have to do for the rod needle bearings.
The break-in fuel ratio should be 40:1, which is 1 pint(edited) of oil to 5 gallons of gas. After the first tank full, then switch to 50:1 which is 1 pint(edited) of oil to 6 gallons of gas. If you have a ratio-rite measuring cup, you can mix up any amount of gallons that you have a container for.

400brian · Post by **400brian** » Fri Oct 28, 2005 11:38 pm

Pat

I think you mis-spoke. A quart to 5 gals is 20-1. I think you mean a pint.
20-1 is what we ran back in '72.