Strange Leaness Issue.....

deerefanatic · Post by **deerefanatic** » Mon Dec 31, 2007 10:51 am

Well, I finally broke down and put the good engine from my 77 in the good chassis of my 78 so that I'd have AT LEAST one sled to go riding with. Took it up north this weekend to a family christmas... Ran it saturday afternoon giving the kids rides in my uncles property (overgrown Christmas Tree farm....) and the old sled worked like a champ. I was running BR9ES plugs in it, and it never seemed to "load up" or foul, and when I'd punch it, it'd fly like mad.... (Nearly had some close scrapes too!

:o )

Stayed overnight at my Grandpa's house, then went snowmobiling in the fields around his place Yesterday... Sled ran great for the first hour or so... I hit a GPS Verified 81.3 mph on the ice-covered road he lives on!! Then it started acting like it was running out of steam on the top end.... I just wouldn't top out.... Had lots of acceleration, but on a snow-covered hay field it'd only hit 50-55 mph and about 6500 - 7000 rpms..... PTO side plug was a light sandy color, mag side was the correct dark brown... So I took it back to my grandpa's house and swapped the two carbs around and took it for a spin. No difference; PTO light, MAG Dark..... So I got some starting fluid and sprayed the crankshaft right where the PTO side crank seal is.... Engine didn't rev up or anything.. (Shouldn't either, seals are only 2 years old and I installed them with grease in the lips..)

The carb boots are also only a year or two old. And the impulse line to the fuel pump is a soft black-rubber line that was used, but didn't have any cracks in it when I installed it.

I'm going to go over the carb boots and impulse line with starting fluid yet, didn't do that yesterday......

Incidentally, at part throttle, the plug color on both sides is correct..... Just at WOT does the PTO side lighten up.....

I have pics....... Will post.

deerefanatic · Post by **deerefanatic** » Mon Dec 31, 2007 5:25 pm

Hmm... I was told the B10 or BR10 was an exact drop in for the N-1 or QN-1.... I have some BUE's as well.

I didn't do very much WOT with the BR9ES's at all.. Mabye 30 or 45 second bursts... That's it. I was told by someone that BR9es was a good choice for trail.

ALL of my heavy riding was done with BR10ES plugs in place. I will check the pistons then.. Probably do a compression test first as that will tell a lot.

deerefanatic · Post by **deerefanatic** » Mon Dec 31, 2007 9:49 pm

Ok, checked compression on both cylinders. 100 psi on mag side, 103 on the PTO side... Same as it's always been. So no change there..... Will look down the spark plug holes tomorrow as well as go over the intake tract with starting fluid and see what happens......

deerefanatic · Post by **deerefanatic** » Mon Dec 31, 2007 9:53 pm

Here is a picture of the BR10ES from the engine yesterday after a 1 mile WOT run....

deerefanatic · Post by **deerefanatic** » Mon Dec 31, 2007 9:53 pm

And the PTO Side........

deerefanatic · Post by **deerefanatic** » Tue Jan 01, 2008 4:06 pm

Ok. so I checked the boots and intake with starting fluid..... No response from the motor. so I put the BUE's in for a spin.... Got her up to about 68 mph on the road (icy with about 3 inches of snow on top.) Topping out about 6500 rpm... Plugs looked ok.... A little light maybe, but exactly the same color. (Very hard to tell on BUE's)...... So I put the 230 main jets I have in.... Ran a lot richer... Does a lot of pop and sputter at mid throttle... Didn't seem to have much of any effect at top end.... (Once again, hard to tell color on a BUE)..... So I put the BR10's back in... At part throttle, both were very dark -- almost black and somewhat wet. Opened her up and guess what...... One dark plug, one light plug!!

BUT, it was the mag plug that was light that time.. Sooooooo........... I swapped plugs and the same plug stayed light versus dark.... It appears that the plug is bad somehow???

So, I dug out my trusty, ancient set of Champion N-1's and took them for a spin (with the 230 main jets installed)..... It runs real rich at mid throttle, and tops out about 6500 - 6800 RPM's..... Running 70ish on the road and 60 ish in the deep stuff. So I measured my belt width..... 1-3/16"...... A little worn, but not real bad.. (Though it does sit down in the secondary a little bit.. Not much, just a little....)

The temp outside (which I didn't know at the time) was between 34 - 38 F so the snow was also quite sticky..... AND... Finally, I have a leaky exhaust doughnut (leaves a scorch mark along the mag side pipe.)

I'm wondering if the combination of leaky exhaust doughnut, slightly worn belt, bad plug, and sticky snow is my problem? The engine was definitely working hard because I could send the coolant temp up to about 175F easily on a WOT run across a field of deep snow.

What do you guys think?

harleysportster · Post by **harleysportster** » Tue Jan 01, 2008 4:37 pm

Don,
I thought you couldn't read the color of the insulators from surface gap plugs. On a fresh motor, the compression should be betwen 120-130 lbs. for serial # 70,001 + liquid cooled. Since you are down around 100 it sounds like you are getting all you can out of it. What were the main jets, 220's.
It appears you could have faulty plug. Pu the original mains back in and run the N-1's for a while and check them.

deerefanatic · Post by **deerefanatic** » Tue Jan 01, 2008 8:14 pm

Yes, they were 220's........

So run the 220's with those old N-1's, read color and decide from there..... If engine won't "open up" it's just cause it's tired........... Is that what you're saying?

Sounds good..... I REALLLLLLYYYYYYYY don't want to melt down my last running sled!

What about the exhaust doughnut fitting? Will that hurt my performance any or just make extra noise?

harleysportster · Post by **harleysportster** » Tue Jan 01, 2008 9:00 pm

deerefanatic wrote: Yes, they were 220's........

So run the 220's with those old N-1's, read color and decide from there..... If engine won't "open up" it's just cause it's tired........... Is that what you're saying?

Sounds good..... I REALLLLLLYYYYYYYY don't want to melt down my last running sled!

What about the exhaust doughnut fitting? Will that hurt my performance any or just make extra noise?

Matt,
Go easy on the sled until you are satisfied with the plug color. A minor exhaust leak would have a minimal effect on the performace. If the connecting ball & socket broke off, then yes, it would have a major effect. There is no donut to replace like on a automotive exhaust. Remove the pipe and clean all the oil out of the ball & socket and apply a bead of high-temp. silicone inside the socket and install the pipe. let it dry for 24 hours before starting the engine.

deerefanatic · Post by **deerefanatic** » Tue Jan 01, 2008 11:39 pm

No, not broke off.. Just leaky.........

Ok. Will Do on the silicone.....

I've been taking it easy...... But you have to open it up to check the WOT plug color......

Not alot of room to do that around here either.......

deerefanatic · Post by **deerefanatic** » Wed Jan 02, 2008 10:21 pm

Well... I underestimated how much room I'd need... When the snow is almost 2 foot deep of nice powder, you don't need much room as even WOT you don't move very fast!!

Opened her up for a pass up the field and back to the road then shut her down. Checked both plugs (My trusty old N-1's..) and they were nice and brown.. This is with 220 jets... Took it for about a 5 minute WOT run around in a big circle in the field and checked again... Still nice and brown...... now just gotta get my new windshield on and I'll be set..... And adjust the suspension to better take this powder......

Danzig · Post by **Danzig** » Wed Jan 02, 2008 10:43 pm

DId the silicone permatex hold at the ball and socket union?

I had no luck doing this, I put it on my L-fire and it blew it right out the socket.

400brian · Post by **400brian** » Thu Jan 03, 2008 2:46 am

Glad to hear of the progress. I would check it again after a run on hardpack
( if you ever run that way ). It may go leaner on hardpack, as the load should be reduced, and RPMs might come up.

Just my $.02

deerefanatic · Post by **deerefanatic** » Thu Jan 03, 2008 11:41 am

I Havent sealed the exhaust yet. The key though is letting it sit for at least 24 hours to seal. It can do that this weekend when it's supposed to hit 50F....

deerefanatic · Post by **deerefanatic** » Thu Jan 03, 2008 11:50 pm

Well, put on 21 miles today (actual, gps verified..). Did something I've wanted to do for years......... Rode down to the local campground/community center that my friends in the homeschool group played basketball at..... Decided if I didn't do it today, it might not get done. Conditions were great. Lots of loose fluffy stuff....... Only got stuck a few times and got thrown once... All around nice ride. Got her up to 76.7 mph on the frozen road.......

one thing I noticed... Going across a very large long field.... Snow was about 2 feet deep so the machine really had to work to get through it.... The temperature kept climbing... At one point I looked down and it had hit 190F so I backed off and plowed across the snow about 20 mph for 10 mins or so and it got down to around 170 or so..... Then took it out on the road (minimal snow, just enough to lube the track slides) and opened her up (for the 76 mph run! lol ) and at the end, the temp had dropped to well below 160.....

Now, it seems to me that in all that deep powder being thrown on the heat exchanger should cool the engine more effectively than that puny radiator in the hood... What do you think's up?

Thanks guys.