How durable are these engines?? 66cc

You dont need to worry about the chrome in the cylinder its just fine 99.999% of the time and is very durable.

As for as the claim on the upgraded *** bearings and such on the Jake's engine, that is probably true and that does make for a better engine but if you have the tools and the skill needed you can buy a good kit off ebay from rose326a for $139 shipped to your door and then upgrade the upper wrist pin bearing which is the most common to fail for just a few bucks and probably have just as good of an engine for way less money, personally that is the route I would go if those were my options because unless the Jakes engine has had the jug removed and some minor porting work done and the upper bearing replaced with a better one it wont run a bit better than the ebay engine which will benefit from the porting mod and upper bearing upgrade as well, only 2 smoker kit I would pay $200 for would be the kit that dax sells with the high grade bearings and the balanced crank, I have already bought two of the lowers and the one I have running now has 120 miles on it and I'm topping out in the 48mph range on that bike with good porting and a Puch hi hi 70cc head, still running the NT carb which is a bit small but this engine screams at a good bit over 8000 RPM's

Its your choice of course, but just giving my personal opinion on the two.

Best wishes on whatever you decide.

Map

kyle5647 said:

thanks again for all the replies!!

what if i put on a 5.4cc high compression head, you mentioned that the cylinder walls where thin so would that blow a hole in it? lol

also for the silver eagle engine (pk-80) is it really better than those ebay kits out of the box?? cause the description says its a more true crank, and high performance japanese bearings. anyone tried this engine?? or is it just a market scam?

thanks!

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I would still not ignore the fact that if you don't break in correctly or long enough the chrome plating WILL flake and score.

mrfubs said:

I would still not ignore the fact that if you don't break in correctly or long enough the chrome plating WILL flake and score.

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Just curious.....have you had a problem with chrome chipping in your engines?

I run mine about 10-20 miles fairly easy and themln pretty much run thek from that point on the way I plan to ride, I run 70 -100:1, never had a single issue with cylinder damage of any kind and my engines break in and run well.

I undersand what you are saying here but I have seen no proof of it being an issue.

Map

That cylinder was a week old was still running 25:1 and still breaking in. My current cyl is doing good at 25:1 so far but has premature scoring.

mrfubs said:

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That cylinder was a week old was still running 25:1 and still breaking in. My current cyl is doing good at 25:1 so far but has premature scoring.

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Wow...... from the looks of that im gonna say no matter how you tried to break that engine in it would have failed, im gonna say that was a defunk from the get go...... sure looks ugly no doubt.

Map

Chrome and Nikasil failures do occur (a growing number of companies specialize in "re-plating" Nikasil cyliners of all types). However, most of these "failures" are most likely caused by excessive piston clearances, FOD, piston/ring seizures, and high sulfur content fuels rather than a failure of the plating itself. Modern Nikasil bores are occasionally known for premature failure due to manufacturing defects (such as excessively thin plating and improper cylinder preparation prior to the plating process). Otherwise, they're known for lasting through as many as 6 piston changes in high performance engines (in other words, they either fail "right away" or they last "forever" ).

Here's a couple of links with more info on the subject:

http://www.kenoconnorracing.com/Cylinder plating VS Cylinder Sleeves.html

http://en.wikipedia.org/wiki/Nikasil

All I have to say is that I use what I believe to be the finest and the best 2 smoker oil made and the other here that use it have never had any such failures that I'm aware of, if there is a manufacturing flaw with the plating nothing anyone does will likely prevent failure but any failure of the plating that is not related to manufacturing defect is likely caused by improper lubrication and nothing to do with break in procedure.

Best of luck with everyones cylinder plating....... use a quality oil and if you dont have a flawed pert out of the box you'll be just fine.

Map