blown head gasket

I did have an issue 2 years ago with the HIGH/LOW switch. When I flipped it to high, no lights at all! Bad at 2am in a canyon. I did take the switch apart and found no corrosion, dirt or signs of moisture. Reassembled and no problems since. Did the same yesterday and found the same non-issues. Just seems strange that I'm having these problems after taking everything apart for the head gasket. And the low beams did work when I took the bike to work 3 weeks ago. But I will try the dielectric contact cleaner.

Well after I thought everything was pretty good and I rode the bike to work for a week, boom! I got off of work at 2:30 am, started the bike, geared up and the coolant smell hit me. I had a nice puddle forming under her and after shutting it down, it seeped out until it ran down the parking lot. Got it home and after using a pressure tester I found the leak-head gasket. I'm waiting for a new one and going over everything I may have done wrong (besides putting the crankcase vent tube on the carb drain!) and I'm sure now that my torque wrench was way off. It is an old one but I've always taken great care to reset it back to zero and put it in it's case when finished with it. Towards the end of all of this though, it would no longer adjust or lock into place. When I torqued the head bolts down, they didn't feel tight enough but I followed all the instructions none the less. I had no loss of power or smoke in the exhaust-and it didn't seem to run exceptionally hot so I'm puzzled as to why it took almost a week of riding in pretty hot weather to start leaking. After getting up at 2:40am to pick me up, the wife was none to pleased! Maybe a new bike in my future!!! So you are all caught up on the saga this has become. Again, thanks for all advice and support.

raybonz said:

When I torqued the head bolts down, they didn't feel tight enough but I followed all the instructions none the less.

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Did you blow all liquids (oil, coolant) thoroughly out the threaded blind-holes in the cylinders?
If not there might be a chance that you'd "trapped" some liquid under the bolts, preventing getting torque on the heads...

I just realized that it's been over a month since my last post. During that time I've been RIDING back and forth to work after changing the head gasket and getting the correct correct torque on the head bolts. Everything went smoothly and re-assembley was easy. After doing it twice it should be! So Wenesday I was riding and had to pull over to tie my boot lace and put my foot on the passenger peg only to see coolant falling on the ground. After having it towed home I've not done anything but curse it in frustration. Suppose I'll get to it soon though. Very unhappy with it at this point....

Wow that bike is just messing with your mind with all of the problems you have encountered. Best of luck with finding the latest problem and we hope it is an easy fix.

I heard a quote from The Outlaw Josey Wales that I try to live by-"I shall endeavor to persevere." I can't stand not knowing if the problem is something I'm doing or a mechanical issue I don't understand or whatever. But I do want to repair it and get back to riding. Even thought about another engine-their are plenty on ebay.

If your coolant was dropping back by the passenger peg it is probably an easy fix. If the tube running from the thermostat to the overflow tub is cracked or leaking, then coolant will fill up in there but will not get sucked back when the bikes cools. You could just have a cracked line and be able to fix that. I hope that is all it is, you have had enough issues already.

Ok, so it's January and I'm finally getting around to repairing my ride. Before I get into it though, I was wondering if anyone out there knows if a newer engine would fit in my 91? Hate to buy one only to find that it won't work. I haven't found anything anywhere that says it won't, but neither have I been able to find anything that says a newer model would fit. As always, thanks!

raybonz said:

...I was wondering if anyone out there knows if a newer engine would fit in my 91?

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There might have been a change of the case vent (moved from aft of the engine forward to the base of #1, hence a different water-pump), and there might be a minor space issue with the rear cover of the 40A alternator, requiring a little clipping...
Besides this a simple drop-in...

The case vent sounds like a small plumbing issue and I'm all about a little clipping to stuff a newer engine in. All of the mounting points as well as the carb controls are the same? And the Pairs system as well? This sounds to easy. Especially considering all the heartache I've had to date.

IIRC the '91 already had the relocated case vent (the '90 models were different there), PAIR system should be there (it is there thanx to Cal emission laws, noticeable by the chrome plumbing on the heads), starter, neutral switch, timing pickup, etc... all seems identically, not familiar on your tank- and case-vent recycling circuit and the altitude controls you guys have, as I'd never saw them live, but again: their implanted due to your emission regs over there...
Engine, gearbox, etc... hasn't changed over the years, always the trusty SC26 plant...

The USA 1991 model year (the first) had the external crankcase breather chamber. The water pump is unique and no longer available new stock, although '92-'95 pumps can be fitted without problem. A salvage water pump from a USA '91 cannot be used on any other model year.

John
via iPhone 4S

John OoSTerhuis said:

The USA 1991 model year (the first) had the external crankcase breather chamber.

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I'm never quite sure if this change was completed within the '90 series, or continued into the '91 models...
It however wouldn't matter when he installs a later engine, simple reroute and shorten the breather-line to the RHS forward section and/or get the hose in question with the replacement unit...

Sorry Irish, I'm sure my e-mailing skills are to blame. Computer savy I'm not. I need an engine! if you still have it, it sounds like the answer to my ongoing problem. Was wondering how much you sell it for?

I would hold off on a new ( used ) engine.

You may have something as simple as a warped head or block. I suggest that you remove the leaky head and either check for warpage yourself ( using a straight edge & feeler gauges ) or take it to your local machine shop. Shouldn't have more than a few thousandth's clearance along the straight edge. If more, DON'T let the machine shop mill the head. Get a 1/4 " glass plate about 4" x 12" from the hardware store and some 80, 120, & 220 wet or dry . Wrap it around the glass plate ( starting with the 80 wt. ) & sand ( mill ) the surface of the head - it works great !! And doesn't take long and best of all, it's a cheap way to go and you only need to take off a minimum amount of aluminum. Even if you have just a little warpage, I would still re-surface it while you have it off.

I would also spray the new head gasket with some "Copper Coat" before you install them. And if the old ( new ) head gasket looks good, there is no reason why you can't re-use it, if the head & block surfaces aren't warped.

I have done several auto heads this way. After doing this, on one head ( 3.0L Mitsubishi ) , I needed to have some of the valve guides replaced at the machine shop. They were amazed how flat those heads were - they couldn't even get a 0.0005 feeler gauge between the head & their straight edge. They were real curious how I accomplished this, and were disappointed they lost a $30 milling job - sorry about that. I'm retired and on a fixed income ..........

That's interesting stuff Jim, thank you. After the second head gasket, which came off without the "rubberized" coating still attached, I kinda thought it might be a warped head. But I've not run the bike hard and can't imagine why or how it could have become warped. I am a serious woodworker and have many quality straight edges so your idea about checking for flatness sounds good. First though I have to take off the plastic and see where it's leaking from now.

Wow. I didn't realize it's been since January that I last posted anything. So the update-all is well! I removed all the plastic, tank, airbox and carbs, rented a pressure tester and found that the coolant line to the head was loose. Tightened it, reapplied the tester and no leak! Then I left the tester on overnight and the gauge never moved!! After re-assembly, I've ridden 2500 miles with no issues. Again, many thanks to all of you for your invaluable help! Now, new tires and a carb synch!

Thanks for the followup. Much appreciated for those of us "invested" in a fellow member's tech issue.

Good news! Instead of replacing an engine, tightening a hose clamp fixed the problem. Time now to "GO RIDE!"

BeST, John
via iPhone 4S

Great to hear that it was a simple fix!! Now it is time to ride that bike.

John OoSTerhuis said:

Instead of replacing an engine, tightening a hose clamp fixed the problem.

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A small culprit that could have easily lead to more fatal issues though...
Shows how important a well done preventive maintenance/annual overhaul can get...