Help with engine rebuild
Randall
My 1992 Safari 377, with 12 000km, found that it was noisier than my wife's
and was making some knocking noise when the crank was turned back and forth
by hand. I tried the same thing on her's and it did not have this noise.
Took the top end apart and found that the pistons "seemed" to be a bit loose
in the cylinders. The wrist pins were loose between the circlips, able to
slide sideways effortlessly. After taking the circlips off, I then pushed
the wrist pins out but had to press them out using a c-clamp and sockets.
The cage, needle bearings and wrist pins were in good shape and the crank
and axial play in the big end of the rods were within specs.
What I'm wondering, is the wrist pin supposed to be "loose" in the piston
between the circlips? Since I had to press them out through the part of the
piston that was unused past the circlip, I'm wondering if the bore where the
wrist pins are got worn or stretched. Are they supposed to be able to slide
sideways between the circlips without resistance? I figure it's the cage
bearings' job to provide the wrist action.
I plan on replacing the pistons since there is too much clearance between
the piston and cylinder for my liking. They measured the 61.96 as marked at
the skirt end but in the ring area, it was more like 61.73, which is out of
specs (max 0.20mm clearance). After a quick honing, the cylinders measure
to 62mm. Checking the Royaldistributing catalog, the std. replacement
pistons are available at 62mm. Does this mean that they will really be 62mm
or will they be like the original 61.96? Should I order .010 oversized just
in case? The manual indicates 0.05 -0.07 clearance.
I've done car engines in the past but my first time doing a 2 cycle sled
engine. The Bombi manual is a bit thin on details so any help would be
appreciated.
Thanks.
--
Randall
92 Ski-Doo Safari L 377 (His)
92 Ski-Doo Safari LE 377 Electric (Hers)
Also posted to ott.rec.snowmobiling
Dave Ward
pistons and rings have worn to the point that the piston now rattles around
in the cylinder. It is time to replace the pistons. It would be best to
have a machine shop hone the cylinders so that they are .010 over and then
buy the next largest size piston. I recommend staying with OEM pistons.
You should be able to get a set that are .010 over from your local dealer.
It is a good time to replace the wrist pin and bearings at this time as
well.
As far as the pins being hard to press out, that is normal and the free
movement of the pin inside the piston between the circlips is normal wear.
You did good with 12,000km. on original pistons. Check your track as well -
they usually have a life span of 12-14,000km also. Good luck...
"Randall" <das_...@mooseman.ca> wrote in message
news:35e7q9F...@individual.net...
Randall
Thanks for your advice. I checked with the dealer and the OEM pistons are
$160 CAD each and don't come with rings, wrist pin or circlip. Kimpex have
everything included (except the bearings) and are only $60. Hell of a
difference especially when you have to buy two of them. Is there really a
big difference? Remember, this is for an older sled mostly used for trail
riding, I don't abuse it and is not high revving or high performance.
BTW, I check the track before every season. Except for replacing a few
clips, it's in good shape.
Thanks.
Randall
"Dave Ward" <d_w...@telus.net> wrote in message
news:FomId.13965$u_1.3006@edtnps91...
Bob
Sounds like my safari, 90 L377. I just replaced the pistons and rings(std
62) c/w wrist pins and c clips. I ordered the wrist pin bearings and
complete gasket set along with a gasket set for a 340 rotax at the same
time. The total bill was only somewhere around $220cdn.I just honed the
cylinders and slammed it back together, the compession is 110pto/115mag.
Pto side has a couple of very minor scratches i do not consider it need for
a bore, yet! I have the same thing with the track, seems to need a couple
of clips every year!!!
Good luck with what ever decision you make!
Bobby
90 safari L377
83 polaris sport440
80? citation ss 377
P.S. Doug in Wentworth, are you ready for some more snow????????????
Repairman
Had a skirt break off one and total the bottom end using them because I was
being cheap and not putting back in the Wiseco's that I had burnt from a
lean down. Was using the Wiseco's because I could get them quicker than the
dealer could in a .10 over size. This was the sled I cut my teeth on
learning jetting & clutching as the good deal I got needed tuning to run
right with the pipes it had on it.
I'd still would have it today if it wasn't for the Krapex piston blowing.
If your gonna fix and sell the sled put the Krapex in, If your gonna keep it
for a while I'd use the good stuff, that's why OEM and Wiseco cost more, and
that's why the OEM ones lasted this long and wore out instead of
catastrophic failure like coming apart at 8000 rpm. .
Every sled is high revving, that's where the power band is.
Wiseco need a proper warm up before hammering the gas because they are
forged, not as forgiving as a OEM cast piston is due to dif. expansion rates
of them.
--
John
"anything you say can & will be misquoted & used against you"
'01 FLHR ''Red"
'04 MXZ 600ho
'99 XC700
BRC mem
"Randall" <das_...@mooseman.ca> wrote in message
news:35fghsF...@individual.net...
Randall
How long since that rebuild? Is she still holding together?
"Bob" <rgr...@accesswave.ca> wrote in message
news:1im3x6l0jq14s$.7g9lnedno4bu$.dlg@40tude.net...
Randall
yeah, expect it to blow up. If you're tuning it, changing clutching, etc,
then it must be a higher performance sled you had (you didn't mention the
model or engine).
My little 377 probably can't even get that high an rpm. Before I sink
another $500 in this old sled, I'd sell the parts off it and get another
good used sled or find another cheap engine to put in it. Even if it's in
relatively good condition, it is 13 years old, has 12 000km and is worth at
most $1000 in good running condition.
If I can get a couple more years out of it, I'd be happy.
"Repairman" <repai...@earthlink.net> wrote in message
news:QPOId.8119$rp1....@newsread3.news.atl.earthlink.net...
Bob
that my spark plug gap was WAY off, for some reason,i fixed that ond it
runs great.For some reason it does'nt seem to like deep powder though. I
had planned on going for a ride yesterday but as always, plans get screwed
up. Was going to go today but we are getting our asses kicked with a
blizzard(Atlantic Canada) right now and my sled is a good 1/2 hr drive from
here on a good day.
Randall
base but little snowfalls (5cm) and the cold don't make it really good stuff
for riding.
Yeah, the Safaris were never known as good trail breakers; heavy with a
short track and underpowered with the 377 for deep snow. It's a nice little
machine for trail riding and not too deep trail breaking. Cheap on gas too
which is a bonus these days.
I ordered the parts tonight and should be in the latest Wednesday. Should
get her back on the trails by the weekend. I'll post on how the whole thing
went and later on after the break in.
Thanks.
--
Randall
92 Ski-Doo Safari L 377 (His)
92 Ski-Doo Safari LE 377 Electric (Hers)
"Bob" <rgr...@accesswave.ca> wrote in message
news:1f87v7dazttcc.3...@40tude.net...
Bob
Agreed, it is great on the trail but in the powder she ain't to hot, looks
more like a snow plow instead of a sled!
Who did you order from?
Let us know how it goes!!
90 safari L377
83 polaris sport440
80? citation ss 377
Randall
benefit of anybody searching in the newsgroups.
Randall
"Bob" <rgr...@accesswave.ca> wrote in message
news:1n0vvwfkkypey$.wu6w735uzi31$.dlg@40tude.net...
Randall
Here's my story. Got the parts on Tuesday. Checked ring gaps and all
that, all fine. Put the rings on the pistons, put the roller cage in the
rod, then put the the first piston on the right rod. Slide in the pin and
"try" to put on the circlip. I still had the studs coming up from the
crankcase. Anyway, the screwdriver slipped, the piston hit the stud and
broke the lower ring. CRAP!
Lesson 1: Only install the rings on the pistons AFTER the circlips are on
and you are ready to install the cylinders.
Then, I had originally ordered a top end gasket set thinking that if you're
doing the top end, then necessarily you have to remove the intake and
exhaust manifolds... WRONG!
Lesson 2: Order full engine gasket sets
At this point, I needed to order a new set of rings and gaskets so I went
ahead and installed the one cylinder to practice and in case I need to order
more rings. That one went relatively easy, holding the rings with my
fingers and sliding the cylinder onto it.
Thursday, the rings and gasket set arrives. Checked the ring end gaps and
installed them on the left piston. I was having a harder time with this one
so I removed the studs to give me more room for my big hands. Holding the
rings, I slid the cylinder on but when the first ring went in, the cylinder
went down and hit the lower ring which was not fully into the ring groove
and broke it. CRAP!
Lesson 3: Order more rings than you need and/or use a proper piston ring
compressor
At this point I said "flock this" and put in one of the used rings. Since
it's the lower ring, I figured it wasn't as crucial for cylinder sealing.
This time, the cylinder actually went in relatively easy and it wasn't for
lack of tension from the old ring. The rest of the rebuild went smoothly.
Unfortunately, I didn't do a compression test before the tear down but my
compression (before startup) was now115 PSI on the right and 110 PSI on the
left (with the old ring). Not bad.
I started her up, no problem. Adjusted the idle and saw I had a broken cam
slider shoe in the secondary clutch pulley. After running to the dealer for
parts and fixing this up, went for the break in ride. Now you'll think I'm
nuts, but I rode it full throttle almost all the way. I used the info from
this site to base my break in method:
http://www.mototuneusa.com/break_in_secrets.htm
The engine didn't blow up. None of the Kimpex piston skirts broke off. She
was really prime now with lots of pep after the 50Km ride. Rechecked the
compression and it was now 115 PSI on both sides. Sweet!
--
Randall
92 Ski-Doo Safari L 377 (His)
92 Ski-Doo Safari LE 377 Electric (Hers)
"Randall" <das_...@mooseman.ca> wrote in message
news:35ln6pF...@individual.net...