More questions

[teck_mountain]

Oil pressue

Okay, that makes sense. Thanks topcat gr58.

[teck_mountain]

Oil pressure

Okay I think the oil light is due to the sensor. It goes on strong, flickers off then becomes very dim and etc.


I have the bike running very well. Pulled the plugs and they are dry and light brown to grey in color. Merc sync is even across the all four. Idles great.

After 10 minutes of running she burns smoke, light blue in color. did a compression test and my number 2 is 130 increased to 150 when is shot some oil into it. waiting for the bike to cool to test again.

Question; If this cylinder is bad shouldn't if burn blue from the onset? Could I be missing somethings?

Teck

[teck_mountain]

Number three cylinder

Okay the bike has cooled a bit and I retook the compression. Went up to 135.

Could I have to thin valve shims?

[sixtysix]

I had one low cylinder on my bike, i think it was 120....the rest were 145-150. Bike ran great and no blue smoke. The compression would be lowest when bike is cold. You should have blue smoke at start up, if it is a compression problem. It seems funny that the blue smoke and oil light come on at the same time. Like the oil is getting thinner or something

If the adjustment of the valves were bad then you would have a perfomance problem, bad compression, not blue smoke. Bad valve stem seals could cause this.

Still thinking...oil is fresh and still at proper level?

[teck_mountain]

Blue smoke

Hi Gary

Valves were done this year, all seated. Just changed the oil and filter.

I'm finding this very odd. The smoke is a blueish to gray type color not true blue. But the bike has to be runing for 5 ot 10 minutes before it starts.

My compression went up when the bike cooled down.

Teck

[TopCatGr58]

Hey there Teck,

I just reread the entire thread to recheck a few things. You've barely had this bike running since you got it back from the mechanic after getting the valve job and I thought 1st oversize pistons and rings. Then you had stated that you took it out for only a 150km run, about 100miles? Don't know how many miles you have put on it since you got it back, but I'm thinking not many. If that's true, then worrying about compression and puffs of smoke before it's broken in and the rings are seated is kinda wasting your efforts.

Also, once it's broken in, Gary is right in recommending the multi-visc 20/50, but if it's not broken in yet, then using that oil will actually cause it to take longer, and might even cause it to NOT properly break in, glazing the cylinders. Hopefully you haven't really torqued the throttle too much during this time. I know many folks recommend breaking it in the way you want to ride it, hard and fast, but I prefer the gentler kindler approach allowing the surfaces to get smoothed out easily, then they can handle the rough stuff better later!

Also, if it isn't broken in, then that might explain the reduced compression after getting hot, the cylinders expanding and the rings not making as good a seal, especially since they are worn to a matching contact of surfaces, cylinders and rings!?

Once you've confirmed your oil pressure situation, then take it out a put several hundred miles on it with a single grade oil, drain the new 20/50 and save it for after the breakin. Then see if the blue puffs don't diminish and your compression equalizes or stabilizes!?
T.C.

[teck_mountain]

Breaking in my bike

Hi Topcat

Okay will not worry. I'm thinking the smoke is related to too rich a mixture and I'm seeing more blackish type smoke. It was some what difficult to tell in the bright sunlight but this evening I went around the block. Not as bad, hardly noticalbe at all for smoke.
When I got home I could see more black than blue smoke when I throatled up. This make a bit more sense to me as it was running okay, but still hesitates and has been backfiring, small pops when I reve up.

I have to admit that things have been looking up since I got the merc sync tool. However, I'm still have trouble equalizing the four tubs, to much up and down motion. It seems that this smoking problem started around when I sync the carbs.

I have the merc sync tool. I can get a vacuum gauge, Found one at a local store. What would be better to solve this issue. If it is the vacuum gauge what PSI level is acceptalbe?

Teck

[John]

It's not so much what the number is, but try to get the best reading you can, but more important is that all four cylinders have readings that are as close as possible. On a car, 23-24 inches of mercury would be a good vacuum reading, so I would assume that would be good for a bike also. Especially with all of the fresh parts you have in there.

[ratbyk]

Vacuum Guage

I would think that 23-24 inches of vacuum would be a very high reading. Considering the cams in these bikes I believe your readings would likely be more in the 15-17 inch area. Also if you only have the one vacuum guage it is going to jump all over the place if it is only hooked up to one cylinder at a time. Suggest that you put some sort of restriction in the vacuum line to soften up the impulses between each round of strokes. Possibly a very small carb jet or something similar.
I agree with TC on the break in. Take it out and ride it to get it settled in. Running time and the experience you get from riding it will help a lot on your diagnosing.
Ken/Sooke

[pgg]

Tek, a single vac gauge is too much hassle for carb balancing. You can do it, but a 4 gauge set is waay better. But, as you've got a merc set, you don't need vac gauges anyway. Aquarium air hose taps are good for damping the pulses.

[teck_mountain]

Carb Sync

Okay, I will keep at it with riding and tweeking. What should I do with the back firing? Leave it for a while? turn up or down the needle value?

[ratbyk]

Back Firing

Is it backfiring out the exhaust or the carburetors?
If out the carbs as you crack the throttle indicates a lean condition. Back the idle mixture screws out a bit.
If out the exhaust could be a couple of things. Air leaks in the exhaust system, particularly around where the header pipes connect to the head. Possibly a Little farther down stream where collector pipes would join onto the muffler. Any unburned fuel (particularly on coast) will then have oxygen to burn up. Backfire is more of a pop, pop, pop.
If the back fire is a LOUD bang out the exhaust indicates a lot of unburned fuel collecting in the system that goes off all at once. Things are away too rich.
Ken/Sooke

[ratbyk]

Back Firing

Further on backfiring. If it appears to only backfire out of one or two carbs, the same one/ones every time check closely for vacuum leaks. Possibly a vacuum port cap left off. A crack right through on the intake manifold, where the manifold connects to the head or even a fold in the manifold where the carb slips into the intake side of the manifold. Anything that would allow that area to draw air in without all of it passing through the carb/carbs.
Ken/Sooke

[teck_mountain]

backfiring

Okay

The back firing seems to be coming form underneath the seat so I'll assume the carbs. I turned the carbs in thinking the mixture was to rich. Will fix that error shortly. Will take a good look for cracks or other air leaks.

Thanks again

Teck

[teck_mountain]

Wow, It think it working

Thank-you all. Thank-you for your patience, tolerance of a newbie, your experience and expertise. I think I have over come the carb adjustment issue and finished this top end rebuild adventure.

I believe the issue was way to lean a mixture as well as the carb adjustment screws were set to far in. Also, whoever recommended to use aquarium valves to reduce the pulsating mercury sync tubs,…..it worked, great.

I got my bike idling and sounding great. No backfires or carb pops. Ran around town and experience a little, and I mean very little, hesitation around 3000 RPMs. Nothing that I’m going to worry about for now. Runs hot but I’m hoping this is related to the new pistons, rings and such forth and hopefully will settle in after the break in.

No smoking????????? I still cannot figure this one out. However, no smoke observed at all during the adjustment or run around town.

Oil pressure is okay and I’ve ordered a new oil sensor.

I’m going riding,…..Thanks for all your help

(Will be back soon as I’m sure I’m going to have more questions)

Teck