Problems with new KX100 engine

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Sep 12, 2006
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#1
I just got our KX100 engine back from Eric, I completed the heat cycles and easy break-in rides. The problem is when putting the engine under a load it gets a very high pitched almost crackling sound out of the pipe. My plug is now running leaner than it ever has been, yet I was running the same jetting? Normally I have found fresh top ends to run slightly richer. I am now back to completely stock jetting (no longer leaned out at all) and yet the problem persist. I have sprayed brake cleaner all around the intake, carb and cylinder base, this does not change the idle at all! The bike doesn't seem to run any hotter, not that I can tell anyway.
Do you guys think it is possible that maybe the left side crank seal is sucking air, like maybe accidentaly damaged on install? All I had Eric do was re-plate the cylinder (no porting mods) install a new HotRods brand crank, basically a basic rebuild no mods. Also, this thing runs 20lbs more compression than what I have ever had out of a KX85 or KX100 engine, to the tune of 190lbs! Ideas? I hate to bother Eric over every little thing as he is so busy.
 

Patman

Pantless Wonder
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#3
Contact Eric.
 
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#4
I hope thats not it because kx's cases have to be split to replace the seals it sux.
 
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#5
I was not aware that Eric installed a 2mm stroker crank during the rebuild , so I now have a 105cc and didn't know it. This thing seems to need race gas now, and as long as I put race gas through her she runs fine, but it sure doesn't like pump gas anymore! I didn't know it was Eric's normal procedure to install a stroker crank on the KX100's, I thought it was going to come back stock, that was my intention anyway. I must say that Eric's price was very fair for building a stroker engine, but it is not what I really wanted for our purposes. I have another KX100 engine, that I am going to rebuild so that we still have our stock power band, it just worked so well for my son's trail riding and ran perfect on pump gas too.

If anyone is looking for a 105cc KX100 engine, I will have one for sale as soon as I get my other engine put back together. That being said, my son will probably ride the bike a time or two first, and I have already put about 3 hours on the engine myself performing the break in, and dialing in the jetting. It will probably end up with about 5-10 hours on it total. I would be selling it with out the carb, kicker, shifter, stator and stator cover as I will need these items. I will sell it for what I have paid Eric to perform all of the work plus shipping of course, and I do have invoices.
 
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Sep 12, 2006
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#6
Update

Update - I must say that I was shocked when I came home from work today to find that Eric had sent me a refund check in the mail. I guess this was because of the confusion over what I was wanting done (stroker verses stock configuration). I haven't been able to get a hold of Eric on the phone to thank him yet, but I will ASAP. This man not only does excellent work but has shown me that he conducts business with the utmost integrity!
Thank You very much, Mr. Gorr!
 
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#8
Jasle said:
you can surely mod the head to let it run on pump gas. Eric can do it. ;*)
I would do that cuz you now have a very tight engine built by a very respectable builder that stands by his work. IMO the engine would create much more usable power and still be very reliable

I say keep it but if its not what u want then i'm sure allot of other people on here would love to have that engine.