I got it all apart and think I found the problem, as I said before the exhaust valve's stroke looked much less than the intake valve's. I took the cam out and here are the measurements. The intake lobe's narrowest is 0.867" and the peak of the lobe is 1.088" the exhaust's narrowest is 0.867" as well but it's peak is only 0.943" . I read that the stock rocker arms are 1:1 ratio so the intake has 0.221" lift and the exhaust only has 0.076" of lift. The edges of the exhaust cam definitely look worn. Would this have happened due to me installing 0.100" shims under stock springs or just poor quality materials, like I said maybe 10 hours on this new engine and always ran 100% synthetic 10W30. My stock springs are approx 1" long and the new 18lb G200 springs are approx 1.5" tall. The flywheel was spot on and tight, key in perfect shape so ignition timing was not the problem.
Sounds like you found your problem. Possibly the extra spring preload wiped out the cam. I'm thinking just running a good set of 10.8lbs springs would work fine for you.
Ive seen this thread over at 4cycle and maybe this has been said already but you really should have a billet flywheel if your going to run 18lbs springs. Especially if you are installing the stock flywheel with an impact gun. The stockers have been known to fly apart at high rpm's. Do you know how many rpm you are turning as it was in the sled?
Ive seen this thread over at 4cycle and maybe this has been said already but you really should have a billet flywheel if your going to run 18lbs springs. Especially if you are installing the stock flywheel with an impact gun. The stockers have been known to fly apart at high rpm's. Do you know how many rpm you are turning as it was in the sled?
I would believe after reading your post on the snowmobile site and reading this by Installing your .125 shims under the springs Especially the ex.with its oil seal shim You have succeeded in Probably causing Coil Bind or at least near.....You have increased load on camshaft exponentially,Resulting in your cam Failure,At this point I think since you need a cam anyway I would look at a MOD2 From Dyno Cams,possibly have them grind in 4* advance They are a proven torque cam, approx
$ 55.00 I have used many,When getting a cam for these Clones It is WISE to measure the Bearing Journal Dia. as there are 2 Diff. sizes......550+or-a thou &.558+or- another Thou. And the lift is close to stock so no worry about clearance issues
I think you would be pleased with the results.Also check pushrods for straightness and rockers and hardware for unusual wear you may have caused! Put It back together and let your kid have fun before spring.....Dave...... By the way..... Also they have gaskets, you just have to figure out if they are clone or predator style on sidecover I believe the # is 1304 or 1304 P Go to their website Dynocams.com :laugh: :smile: :thumbsup: Also I Don't believe on a sled you will reach Explosion RPM @least not your son!!!!
$ 55.00 I have used many,When getting a cam for these Clones It is WISE to measure the Bearing Journal Dia. as there are 2 Diff. sizes......550+or-a thou &.558+or- another Thou. And the lift is close to stock so no worry about clearance issues
I think you would be pleased with the results.Also check pushrods for straightness and rockers and hardware for unusual wear you may have caused! Put It back together and let your kid have fun before spring.....Dave...... By the way..... Also they have gaskets, you just have to figure out if they are clone or predator style on sidecover I believe the # is 1304 or 1304 P Go to their website Dynocams.com :laugh: :smile: :thumbsup: Also I Don't believe on a sled you will reach Explosion RPM @least not your son!!!!
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Oil seal is one of the first things I toss out.
PEI race oil so decent oil is out of the question....
I think you should look around for some motorcycle oil of the lowest viscosity to get a little better additive package and protect your lobes....
Rottela 10/30 with some GM engine oil supplement added ( say 10% ) would be better than automotive oil too.
Here's the thing now.
Might be worth while to spend a little money and get some stainless valves and upgrade everything replace the retainers and keepers with some good stuff for single spring from ARC.
This will let you sleep at night and its less wear and tear on things because its lighter.
The wrench and I both like Champion rockers.
Very simple and reliable with less drag.
I like the moly push rods too. ( I have a new set to spare BTW in Ontario for cost they are yours )
Kartworks Canada has the PLV flywheels.
Local scrap yard and small engine shops may have the GXV160 flywheel off the commercial Honda mower ( this is as good as billet )
Mr Astrowrench:
These things tend to be drag raced.
All kids of stuff happens sometimes faster than you would expect lol.
In any event when kids are involved my biggest fear is not the flywheel bursting as much as the magnet coming loose and hitting the coil or coild comes loose and hits magnet ect....
At that point the entire engine will break up.
Its not nice to see...
PEI race oil so decent oil is out of the question....
I think you should look around for some motorcycle oil of the lowest viscosity to get a little better additive package and protect your lobes....
Rottela 10/30 with some GM engine oil supplement added ( say 10% ) would be better than automotive oil too.
Here's the thing now.
Might be worth while to spend a little money and get some stainless valves and upgrade everything replace the retainers and keepers with some good stuff for single spring from ARC.
This will let you sleep at night and its less wear and tear on things because its lighter.
The wrench and I both like Champion rockers.
Very simple and reliable with less drag.
I like the moly push rods too. ( I have a new set to spare BTW in Ontario for cost they are yours )
Kartworks Canada has the PLV flywheels.
Local scrap yard and small engine shops may have the GXV160 flywheel off the commercial Honda mower ( this is as good as billet )
Mr Astrowrench:
These things tend to be drag raced.
All kids of stuff happens sometimes faster than you would expect lol.
In any event when kids are involved my biggest fear is not the flywheel bursting as much as the magnet coming loose and hitting the coil or coild comes loose and hits magnet ect....
At that point the entire engine will break up.
Its not nice to see...
Now it is very confusing, I just measured my stock valve springs and the new 18 lb springs. My stock ones with the shims (0.100") compressed length is 0.498" and the new 18lb compressed length is 0.581" so the new 18lb are more apt to coil bind than my stock ones with the shims. If 18lb ones are commonly used then my shims could not have contributed to my lobes wear. I got another cam from an old chinese clone and it's cam is in perfect shape so I am going to put it in but don't want to go through this again. The only other variable is the oil but why didn't the intake lobe wear as well? Also the exhaust lifter has tiny scratches, barely enough to catch a fingernail but I am not sure if this happened with the lobe wearing or if it was like this from the factory and it basically filed down the lobe. I am going to replace both of them from the other clone as well which are very very smooth. Another thing I noticed is that my current retainers look like they are stamped whereas the donor clones are machined, I am going to use these as well.
The ex vlv most likely had a seal under the sprig= less Ht.; 18 lb springs- to many Diff. mfgrs.I won't use them. Check lifter OAL as some are DIFF,and make sure your POSITIVE !!!! that cam is the same- -exactly!!!! And run the engine out of the machine if you choose to use these parts; Unless of course you want to remove the engine again!! Your stock lift @ the retainer should be approx .224 Check the assembled Height w/o springs should be .815 or more.....Dave :shrug: :smile:
I got it all back together and it is working great, lots of power and got the 20mph back BUT it climbs to 20 then drops off a bit after 2-3 seconds, if I let off the throttle and then accelerate it will climb back up powerfully and then drop a bit. Is this a sign that I need a bigger jet? I have the 18lb springs in it.
The engine is from Wajax industrial components, it is called a JF200.
Any suggestions on what size to change the jet to? I also just changed the driven sprocket down 2 teeth and he is getting 25mph, smiling ear to ear, quite an improvement over the 8mph they come stock with the 120cc governed engine. At WOT there is a little vibration and I assume it is just that the clones flywheel is not as balanced as it should be, what type of shop would have the equipment to balance a small engine flywheel? I wish someone made a billet flywheel with internal magnets and ring gear.
Any suggestions on what size to change the jet to? I also just changed the driven sprocket down 2 teeth and he is getting 25mph, smiling ear to ear, quite an improvement over the 8mph they come stock with the 120cc governed engine. At WOT there is a little vibration and I assume it is just that the clones flywheel is not as balanced as it should be, what type of shop would have the equipment to balance a small engine flywheel? I wish someone made a billet flywheel with internal magnets and ring gear.
is the date of manufacture 2006?
Blue and exactly what does the lifter and cam machining and general condition look like.
I am asking you some very pointed questions.
Canada is not a big place and there is a pile of really awful blue electric start clones still getting sold from a 2006 production run.
Obviously this has been played around with by me, but as you can see the stickers just peel away to be replaced with something else,
Blue and exactly what does the lifter and cam machining and general condition look like.
I am asking you some very pointed questions.
Canada is not a big place and there is a pile of really awful blue electric start clones still getting sold from a 2006 production run.
Obviously this has been played around with by me, but as you can see the stickers just peel away to be replaced with something else,
Exact same color, 2 things I noticed on this that are different from many other cones I have seen are that the fuel tank has a gauge built in to it and the air cleaner cover has a primer bulb. Here are some pics of the exhaust lifter and cam. The lifter looks like like it has stress marks or something, they just barely catch your fingernail. When I had the side cover off there was a date that said 2010.5 , the clone I got the parts from was a princess auto brand dated 2005.11 better quality.
Was the lifter perfectly flat or does it have a slight taper to one side?
That does not look like the failure I am expecting.
I was expecting a lifter that did not rotate and was not flat on one side.
Best guess you have a different engine and problems.
Cam looks not half bad I do not see any grinder marks in it chewing at the lifter.
That does not look like the failure I am expecting.
I was expecting a lifter that did not rotate and was not flat on one side.
Best guess you have a different engine and problems.
Cam looks not half bad I do not see any grinder marks in it chewing at the lifter.