Help Find A Cure for Crazcnuk's bike?

[dbeardslee]

Craz - Your mention of weak spark has me thinking a couple things. If you're still running the original coils, then you still have the original high tension wires, right? I know when I took my old coils off I bent the wires and they broke in two. They looked ok from the outside, but inside they were gone. If you don't want to buy new coils, there's a post on here somewhere about grafting new wires into old coils. I just threw mine away, and put the mikes xs coils on. They put out three or four times as much voltage as the stock coils, and also allow you to get rid of the ballast resistor if you've got one. Gotta open your plug gap up to .035" or so if you go that route.

The other thing is the pickup coil gap. I set mine to .56mm, and it helped. I guess the magnets loose some of their magnetism over time, so closing the gap a little will compensate. My 2 cents worth.

In the immortal words of Red Green (another crazy canuk), 'We're all pullin' for you'.

[Geezer]

I don't know if this is the problem but I've seen it on other 1970's Japanese bikes (the first time on an RD350.)

Check the resistance on the spark plug caps, sometimes the resisters blow and it's a real SOB to diagnose since you will see spark at that plug but it won't be enough at running pressures and will bow out.

I know this isn't Canadian legal but I always dump the resistor caps in favor of non-resistor ones.

Geezer

[tiredoffixing]

I say with his atitude of "let it rot" then he should sell it to one of the very helpful ones on this sight with a "good attitude"

[dbeardslee]

Tired - I think we've all had our 'let it rot' days. Craz gets out there quit a bit with advice for those having problems, so let's not give him too much grief over a lull in his optimism.

[tiredoffixing]

didnt mean to come across that way. After all look at my name

[Crazcnuk]

I'd sell it in a heartbeat, but no one is going to pay what I have in it.


AS for the rest:

P/U wire check/repair done
Replaced spark plug boots
Checked the spark plug wires
Checked both manual and vacuum advance units
Checked for vacuum leaks
Tried 110, 115 AND 120 mains (High speed chop showed 120s good, but midrange VERY rich)
Tried 3 different float levels
Changed fuse block
Cleaned wiring connectors (got the signal lights to work at least)
Compression test good
New brakes
New wheel bearings
New Windjammer connectors
Changed headlight relay
Added Vetter Venture package, w/ vetter tour pack trunk
New case guards, carrier rack


Issues
Burns a litre of oil every 200 kms (120miles)
Runs 25-30mpg (US) tops
No passing power at highway speeds
2 screwed sparkplug holes (jury rigged for the moment)
first engine bent valves, spun a rod bearing
Not sure about the exhaust (S&S slip-ons, no xover)

Have a friend with a 79SF, so I know what it is supposed to run like. His burns a fiar amount of oil too, but he gets 38mpg (imp)

[psycoreefer]

I'd look for the cause of the "oil leak" first. I'll assume it doesn't just leak out on the ground. Have you tried doing a compression check and then adding a bit of oil in through the spark plug holes and doing it again. If you've got leaky rings that would cause it to burn oil and may also cause poor performance.

Have you tried doing a leak down test? I read somewhere about someone having good compression but no "performance" and a leak down test revealed that the cylinder was "scored" about 1/2 way down, letting the cylinder build compression but causing the engine to burn lots of oil and have no power. You can build a leak down tester for a few dollars if you have access to an air compressor. A google search should show you how.

The other place oil might leak is the valve guides, not really sure how to check them though, also not sure if it would cause a big performance problem or not.

[Crazcnuk]

Yes, I've done the ring checks. I suspect the valve seals.

[Geezer]

Bad valve guide seals will only cause it to smoke when cold and it will clean up when it warms up.

Geezer

[Crazcnuk]

Well, this one doesn't smoke, except, once in a while, when I give it hard on the throttle off the line.

I can smell the burnt oil behind the fairing at highway speeds.

Also, if I rev it out, then let off the throttle, I will get a little puff of blue, indicating seals.

it is possible that the compression rings are ok, but the oil ring(s) are toast. #1 cylinder overheated pretty good when I first got it going.

[egsols]

I heard somewhere that large bearing clearances can cause excessive oil consumption. Too much oil is being tossed on to the cylinder walls for the rings to handle. Compression test will still look good, under this condition. The only way to check this, without tearing down the engine is to try and see if the outside edges of the piston have the carbon washed off by the passing oil.

Another thought, is your crankcase vent clear? I don't know if high crankcase pressure can lead to extra oil consumption but it can definitely impair performance.

The main thing that scares me about our bikes is the leaking float valves. A lot of people notice gas in the air cleaner but forget to check the oil for fuel contamination. How many of them have ridden with contaminated oil adding 2k of wear on a 50 mile run?

Just thinking out loud.

[Crazcnuk]

My floats aren't leaking. No oil in the gas.


The only two things I haven't checked are the coils, and Rasputin sent me out his old set to try.


Also, there is some question about my TCI box/pu coils

The bike has the proper 2h7 box, for the 80 year, but the motor is out of an 81.

From what I understand the 81 has no mechanical advance, and that the curve is built into the box. (4R0?)

However, this 81 motor has the mechanical advance on it, and when I check the timing at various speeds it is advancing as it says it should in the manual.

I assume this means I have the right p/u's on the motor? I can't find any numbers on them to check that way.

As for the oil burning, I think it's toast any way we look at it.

I may just take it out, and put the top end off my 1200cc one (ie barrels, pistons, head) to see if it changes anything, as all the oil burning would be in those components.

As for large bearing clearances, I have never heard that. The cylinder walls are generally lubricated by 'splash' as the rod journals hit the pool of oil in the pan. This kind of consumption should stop, though once the oil has got too low in the pan for it to splash.

I have had to stop and put nearly 2 liters in it, during trips...

[dbeardslee]

Craz - I checked the fiche, and it looks like you have to take the advance unit off to see which kind you have. The 2h7 has the spring-loaded governor assembly, while the 4r0 does not. Might be another way to tell, but that's all I could see.

[TopCatGr58]

Hey Crazcnuk,

We had this discussion before IIRC, and as long as you have the 80 mechanical cent. adv. mechansim to use with the 2H7 TCI, then it doesn't matter that it's an 81 block! The 80 PU coils with all of the other timing hardware from the 80 should work just fine, as you stated when you checked the timing, it showed it was changing and advancing with the increasing rpms.

Look at this recent post by Ozmodius , I editted and bolded the text that's important. I experienced the same thing when I put the MikesXS coils on MINE as well!!!

But like you said, with worn oil rings it may be contaminating it with enough oil to dampen the performance?? I would think oil would raise the octane, but perhaps too much preventing proper or full combustion!? Yea, I would think putting the 1200 top end would do the trick!

T.C.

[Rasputin]

Hey Crazcnuk Just wondering if anything so far has helped. That and the thread needs Bumping up