EvilBanshee Posted August 22, 2010 Report Share Posted August 22, 2010 Iv been tuning my new 421 from vito's, And i put the laser on both pipes to see the how hot they were, and the left side (shifter side) runs about 60-80 degreese hotter then the right side ( Brake Pedal side) ?? Carbs are in sync, same jets on both sides, plugs are gapped the same, Im not sure why they are so much different ? Also i can tell by the plugs the Hotter side is nicely browning up, and the other side is more darker. Anyone eles have this problem? ? My engine only has about 10 minutes of run time on it, and its not yet perfectly tuned. But i would think they should be closer temperature wise. Quote Link to comment Share on other sites More sharing options...
dunner250 Posted August 23, 2010 Report Share Posted August 23, 2010 Had the same problem and it was a nut on the top on the carbs. I'm guessing that one of your carbs has a slight air leak. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted August 23, 2010 Author Report Share Posted August 23, 2010 (edited) Had the same problem and it was a nut on the top on the carbs. I'm guessing that one of your carbs has a slight air leak. I dont think this is my case, i tested it with 28mm carbs, then a few days ago i finally got my 34's together and put them on, same thing. I also checked Compression, pretty much equal on both sides. Im not too sure what it could be? Edited August 23, 2010 by EvilBanshee Quote Link to comment Share on other sites More sharing options...
ddt Posted August 23, 2010 Report Share Posted August 23, 2010 I dont think this is my case, i tested it with 28mm carbs, then a few days ago i finally got my 34's together and put them on, same thing. I also checked Compression, pretty much equal on both sides. Im not too sure what it could be? check your head for any blockage that mite be restricting coolant flow. i also have heard that the right side usually runs cooler cuz the waterpump is on that side but it doesnt make sense to me being that the coolant hose is in the middle of the head but maybe look into that just an idea. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted August 23, 2010 Author Report Share Posted August 23, 2010 check your head for any blockage that mite be restricting coolant flow. i also have heard that the right side usually runs cooler cuz the waterpump is on that side but it doesnt make sense to me being that the coolant hose is in the middle of the head but maybe look into that just an idea. Its the exhaust pipe im checking the temp on. The jugs are a tad different, but not by much. The pipes are way different, iv even swapped plug wires to see if it makes a difference. But it doesnt. Maby its not a big deal though?? im not to sure, i would think they should be fairly equal. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted August 23, 2010 Report Share Posted August 23, 2010 Unless EVERYTHING was exactly perfectly the same, slight differences may appear. Could be as simple as plug ground electrode facing different ways , slightly plugged silencer , yada yada. Silly imperfect world. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted August 23, 2010 Author Report Share Posted August 23, 2010 Unless EVERYTHING was exactly perfectly the same, slight differences may appear. Could be as simple as plug ground electrode facing different ways , slightly plugged silencer , yada yada. Silly imperfect world. Never thought of that, . could have some truth to it Quote Link to comment Share on other sites More sharing options...
sandtazam Posted August 23, 2010 Report Share Posted August 23, 2010 My bike hits on the left cylinder before it hits on the right. Only seems to happen if I'm running rich. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted August 23, 2010 Report Share Posted August 23, 2010 So if the right side runs slightly cooler it will be slightly richer wich in turn will cause the exhaust to be slightly cooler. I would think the rh cylinder would be cooler due to the water pump. No it doesn't directly circulate coolant through the cylinder but it does through the clutch cover. The volume of air behind the clutch cover is also greater than the volume of air behind the stator cover. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted August 23, 2010 Author Report Share Posted August 23, 2010 So if the right side runs slightly cooler it will be slightly richer wich in turn will cause the exhaust to be slightly cooler. I would think the rh cylinder would be cooler due to the water pump. No it doesn't directly circulate coolant through the cylinder but it does through the clutch cover. The volume of air behind the clutch cover is also greater than the volume of air behind the stator cover. Ya i may have to do different jetting on the one side then the other. Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted August 24, 2010 Report Share Posted August 24, 2010 If you only have 10 minutes of run time on a fresh topend then your rings have not fully seated yet. Since your plugs say one side is rich and the other is close, I would carefully break it in, making sure to retorque the head. Then I would make sure it is correctly jetted and ride it. This is assuming you have done a leakdown test and it passed. Quote Link to comment Share on other sites More sharing options...
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