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August already? How can that be? I hope you're all making the best of this riding season. To begin with I'd like to revisit the penetrating oil subject because I've received two inquiries asking where in the heck can we buy ACF-50. We stock it at the shop for us service guys to use and we also retail it over the counter. We get it from a supplier called "Gamma Sales" who deals with motorcycle, ATV, snowmobile shops.

So try your local power sports shops and if they don't have it, tell them it's from Gamma. They will have to purchase a minimum number of cans, probably at least one case which could be an issue.

It's sold in aerosol cans but I personally prefer to buy it in bulk, (a litre jug) and a small hand pump spray bottle. I also fill a tiny droplet bottle that will allow me to dribble some into an electrical connector or down a control cable without making a mess.

Checking I see it's also sold on line by Fort Nine and Amazon in various sizes. And one final note; I've yet to hear from anyone regarding the ATF/Acetone mixture...

Next up Alex McLean is back and having fun with his 400 triple Kawasaki: I'm in the process of fixing up an old Kawi 400 triple that I got given for free. What could go wrong I thought, clean it up, get it running, have some fun and make a couple of bucks off it eh. Well after hanging the motor (shiny and completely assembled of course) in which I'd fitted new rings, pistons, all the seals except the two center crank seals (naturally eh) I was talking to a friend of mine. He's a guy who runs a small motorcycle shop and is very sharp in my view if a bit cynical. So, he says, did you do the crank? Nope, checked the rods they seemed fine, did the outboard seals but didn't want to spend a bundle pulling the crank apart as this is not something I can do. Oh, says he, probably won't run worth crap 'cause the middle seals will be shot.

Gee thanks Rob! So I go home and ponder, well maybe I should at least do a leak down test to see if those seals are an issue. (Ken can interject here anytime with some real wisdom). I look online at Motiion Pro's kit and $300 US – Yikes. So I watch one of my favourite YouTubers Dale Sweger and get the idea of making my own.

The pics that follow show the result and it works like a hot damn and cost me about $70 with a few different size plugs that I picked up to suit various exhaust ports sizes and shapes. The little black handbulb I got off Amazon for $14, the tubing was some spare gas line I had lying around. The pressure gauge I also picked up off Amazon (0 to 30 PSIG) for $11. I put in a needle valve 'cause I didn't trust the check valve in the rubber bulb but in fact it was not necessary. The brass fittings I picked up locally for about another $10. The plate over the carb inlet I made up of a piece of scrap ¼" aluminum plate with a piece of inner tube cut for a gasket. The plugs for the exhaust are a mix of a few I bought a couple off of Amazon and a couple from a local Automotive Supplier. They're the most expensive component in the build.

The carb and exhaust port plugs have to fit snug but don't have to be super strong, after all max pressure you'll use is 6 to 7 PSI. Contrary to the "Tim The Toolman" school of thought more pressure is not more-better here – 7PSI max, as more pressure risks blowing out the seals. You may on some bikes with injection systems have to also plug the autolube inlets as I did with this KH400.

The basics are seal the two ports (and possibly the oil injection point) then pump it up to 6 or 7 PSI. Watch to see how fast the pressure drops. Rule of thumb seems to be that no more than 1 PSI drop per minute is allowable. If you're losing more than this then you gotta figure out where and soapy water over the seals, exhaust and intake ports, base gasket, head-gasket, spark plug hole, crankcase joints etc is the ticket – if it leaks you get bubbles. In my case - Oh joy, the bloody crank seals in the middle were apparently shot one was weak, the other side leaked down to 0 in less than a minute. So it's off for a rebuild. So much for an easy profit.

This Kawasaki has rubber seals between the crank case sections some bikes (such as the YR and RD series Yamaha twins have a labyrinth seal and I've not done a test on one of these yet so don't know how much impact that would have. At any rate I suppose one could simply block the ports on both cylinders and do both sides at the same time on the theory that the labyrinth seals should not fail. Again – Ken, any comments?

The following pics should give you the idea of how it goes together.

Thanks once again Alex!

Alex is correct in that the labyrinth seal used by Yamaha (and others) will allow a small leak between cylinders and thus needs to be tested as such. He was also correct in suspecting the centre seals may be bad and causing poor running on an engine that has been resting for a few (or more) years. Two strokes need to be relatively airtight to work well and any air leaking in will result in poor running by leaning out the mixture. And worse, possibly holing a piston. Interestingly, Suzuki went a different route with their multi cylinder two strokes by running the centre seals in transmission oil. This means that in many cases your old Suzuki that has sat for a decade or more will only require the outer, easy to change crank seals replaced. The centre seals last due to being kept lubed by the transmission oil.

My 1976 GT500 was an example as I only did the outers and the engine pressure tested fine and ran great. On my 1972 Hustler I didn't do the centres, once again they weren't leaking...however a year and a few thousand miles later one did rupture on my morning commute to work. I could tell right away as the exhaust smoke increased substantially and it was grey and didn't have that nice two stroke smell.

As luck would have it the main road into Espanola was under construction and the young flag girl made the mistake of showing her stop sign as I approached. Sitting idling for a few minutes really loaded up the leaky cylinder but the smoke was minimal until I opened the throttle to get moving. I did so as gently as possible but when I looked in my mirror, I couldn't see the poor girl at all...she had disappeared in a huge grey cloud. I glanced back a few seconds later and she was heading for the side of the road coughing and trying to cover her face. i felt bad and was glad the construction crew had left for the day by the time I was on my way home that night.

Thanks to Alex for supporting the Tech Chat page. Please consider submitting anything that is tech related to me. Your fellow members appreciate your efforts!

Ken Mortimer

kmortimer@persona.ca

Box 99, Webbwood ON, P0P 2G0

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