bbcmudtruck Posted July 12, 2008 Report Share Posted July 12, 2008 I tore down a good running motor to send out for a dune/hillshooter port job and freshin up. The builder said that they did not need a new bore and honed them. While I had it apart I got some T5s, cool head and a timing plate. When I put it together I was expecting a significant improvement, but it runs no better than it did with a stock port and Fattys. I am having trouble with compression. I first put on a stock head it had 60psi per cylinder. So I put on 21cc domes and a coolhead it had 100psi. Then I put in 19cc domes and it now has 130psi in each cylinder. The ring gaps are within tolerance at .012. The jetting is really close at 330 and 27.5. I tore it back down and after 1 hour of run time I have a scuffed piston. I was running against a 400z and it was right on my ass everytime. It has little to zero bottom end, and bogs between gears. I have been Fn with this POS for over a month, and have missed half of the race season because it. Any ideas of what to try next? Ryan Quote Link to comment Share on other sites More sharing options...
wesw Posted July 12, 2008 Report Share Posted July 12, 2008 ryan you need to check your squish. 19cc you should be way up there compared to what you have. im guessing they are cut to loose. then you can go from there. that or your running way to way to thick of base gasket cause with stock head. i would check that out after rereading your post. Quote Link to comment Share on other sites More sharing options...
Face Posted July 12, 2008 Report Share Posted July 12, 2008 Dude that sucks butt dont give up on her. I had mine doing the same kind of stuff for almost a year and was so pissed I didnt know what to do, but DAMN the payoff is worth it when Shee runs like Shee can. Good luck bro. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted July 12, 2008 Report Share Posted July 12, 2008 Was it a good quality guage, and did you hold the thottle wide open to get those #'s. Did you do some good warm up cycles before you rode it. Who was the builder that did your port work?? You should have noticed a significant increase in power. As said above, you may have put thick base gaskets in her, stock are @.025" if I remember right off the top of my head. Quote Link to comment Share on other sites More sharing options...
duneloon Posted July 12, 2008 Report Share Posted July 12, 2008 What is your deck hieght? Quote Link to comment Share on other sites More sharing options...
bbcmudtruck Posted July 12, 2008 Author Report Share Posted July 12, 2008 I have no idea what deck height is or squish let alone how to check it. I could not find it in the manual anywhere. The base gasket measured .021 after being used. The compression guage is correct, I double checked it with another gauge. I performed the compression check correctly. Here is a pic of the piston skirt after 1 hour of ride time. Is it F'ed? Thanks for the help so far guys. Ryan Quote Link to comment Share on other sites More sharing options...
wesw Posted July 12, 2008 Report Share Posted July 12, 2008 i wouldnt run them that way. better send them back to kevin and get something lined out. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted July 12, 2008 Report Share Posted July 12, 2008 Not lookin so good. :sad: What was your breakin procedure on it??? Almost looks like a cold seize, is it the same on the other sides of the piston? Did you let her warm up a few minutes before you rode it? Those are the factory sized base gaskets BTW, I don't think that was your problem at all. Quote Link to comment Share on other sites More sharing options...
Titan up Posted July 13, 2008 Report Share Posted July 13, 2008 Looks to me like you hammered on the throttle a little too early. It might not be a good idea to start comparing your new setup with your old setup within the first hour of riding. Quote Link to comment Share on other sites More sharing options...
00tbanshee Posted July 13, 2008 Report Share Posted July 13, 2008 you should have alot more compression then what your coming out with.make sure the threads on the part that screws into the head is long enough to go the whole way down flush with the top part of the dome.the threads should pretty much be the same things as your spark plugs threads.i have made the same mistake on compression testers and read alot less then it really was Quote Link to comment Share on other sites More sharing options...
D-man Posted July 15, 2008 Report Share Posted July 15, 2008 i know its not a good idea but you could run it till is doesnt run anymore. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted July 15, 2008 Report Share Posted July 15, 2008 i know its not a good idea but you could run it till is doesnt run anymore. Please don't do that! Quote Link to comment Share on other sites More sharing options...
KEVSWS6 Posted July 15, 2008 Report Share Posted July 15, 2008 No worries. I'm taking care of Mr. Mudtruck. This goes to show you that you cant be too careful in the setup of your motor. The 2 stroke is a simple machine but you still have certain guide lines to follow especially when introducing more power to it. Once fixed I'm sure he will let everyone know how it runs. Quote Link to comment Share on other sites More sharing options...
bbcmudtruck Posted July 16, 2008 Author Report Share Posted July 16, 2008 Kevin is the go to guy. If you are looking for a builder who will take the time to answer all of your idiotic questions and never get frustrated, hes your guy. His costumer service is among the best, not to mention his lightning speed turn around time! I was very close to parting the shee out and cutting my loses. Kevin went above and beyond the call of duty to get me going once more. Ryan Quote Link to comment Share on other sites More sharing options...
gussy78 Posted July 16, 2008 Report Share Posted July 16, 2008 :biggrin: Let us know how things go when your back in one piece. :thumbsup: Quote Link to comment Share on other sites More sharing options...
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