stroking Posted January 15, 2012 Report Share Posted January 15, 2012 (edited) got a cub that keeps running hotter on the left side temp is 94 on L and 79 on R after full throttle pass...checked with lasers gun shearers big bore 7mil cub alky 41pwks....tried different carbs and got the same reading compression 210psi on both sides i checked for leaks and found none...(crank-seal..intake-boots...base-gaskets).....except the oring around the pipes flange,but i doubt that would cause this problem also fuel pump line is tapped on right side (cooler side) Edited January 15, 2012 by stroking Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted January 15, 2012 Report Share Posted January 15, 2012 Its not uncommon for there to be a difference in temps from L/R.. what matter is your plugs. If both plugs look good and you want to make them even, add or subtract fuel from one side or the other until they are closer. However at the temps your talking its severely rich IMO. Quote Link to comment Share on other sites More sharing options...
stroking Posted January 15, 2012 Author Report Share Posted January 15, 2012 Its not uncommon for there to be a difference in temps from L/R.. what matter is your plugs. If both plugs look good and you want to make them even, add or subtract fuel from one side or the other until they are closer. However at the temps your talking its severely rich IMO. Whats a good temp for alky....1/8mile runs i thought around 98-100 degrees Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted January 15, 2012 Report Share Posted January 15, 2012 at the 1/4 my cyl read around 140 or so with a few degrees diffrent from side to side as n2o said a little diffrence is common how does the burn look after a full pass on the plugs.you might want to invest in some egt guages ,i personally dont have them but a bike i built and tuned did it was alot easier to see results after a 1/4 mile pass,this particular bike had a safe burn on half the base.close to 1100 degrees on the egt,and 120 on the transf sides of the cylinder so as n2o said extremely rich,have you thought about playing with dome configuration to bring heat into the motor plus i run much lower compression on all my builds Quote Link to comment Share on other sites More sharing options...
Rotax Raptor Posted January 15, 2012 Report Share Posted January 15, 2012 On my McCoy cub motor, I was told to try keeping the temp around 10 to 15 degrees above the ambient air temp. That's after a 300 foot run. That motor is designed for a lot of alcohol to ran through it. Different builders will have different theory. Quote Link to comment Share on other sites More sharing options...
stroking Posted January 16, 2012 Author Report Share Posted January 16, 2012 (edited) On my McCoy cub motor, I was told to try keeping the temp around 10 to 15 degrees above the ambient air temp. That's after a 300 foot run. That motor is designed for a lot of alcohol to ran through it. Different builders will have different theory. 120 sounds hot it was 55 degrees out when i did the runs Edited January 16, 2012 by stroking Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted January 28, 2012 Report Share Posted January 28, 2012 At 55 degrees your cylinder temps arent even comperable to anyone elses. If it is 55 degrees out you should probably never see 140 degree cyl temps. When it is 85 degrees out I rarely will see over 120 degree cyl temps. When I see 135 degrees cyl temps my plugs can look lean. If I want to hot lap I can make my cyl temps be 85 degrees even if its 90 degrees outside. You should be able to run richer than you are. Quote Link to comment Share on other sites More sharing options...
N2deepRacing Posted January 29, 2012 Report Share Posted January 29, 2012 If its 55 out side I will not even crank my bike! Your asking for troubles running it when its that cold out! Your plugs are what you need to be worried about! But you need to treat each cylinder like its a different motor from the other. Have to trust what you see on your plugs and the fill of your motor when you ride it! Quote Link to comment Share on other sites More sharing options...
stroking Posted January 29, 2012 Author Report Share Posted January 29, 2012 If its 55 out side I will not even crank my bike! Your asking for troubles running it when its that cold out! Your plugs are what you need to be worried about! But you need to treat each cylinder like its a different motor from the other. Have to trust what you see on your plugs and the fill of your motor when you ride it! ive done races when it was MAYBE 45 degrees out,so 55 is nothing......alot of races do it around here come to think of it,ive seen more burn plug straps in the summers vs winter Quote Link to comment Share on other sites More sharing options...
N2deepRacing Posted January 29, 2012 Report Share Posted January 29, 2012 Ok its your call. My bike will not even crank on methanol at those temps! Sounds like you got it under control. Quote Link to comment Share on other sites More sharing options...
stroking Posted January 30, 2012 Author Report Share Posted January 30, 2012 Ok its your call. My bike will not even crank on methanol at those temps! Sounds like you got it under control. we have to use starter fluid to get them started the first time also i test 3 other bikes and all of them had a higher temp on stator side,guess thats how they run Quote Link to comment Share on other sites More sharing options...
N2deepRacing Posted January 30, 2012 Report Share Posted January 30, 2012 Starter fluid is killing your motor! It robs your motor of the oil when started! The only way to get the heat the same is to tune the carbs differently from one another. Quote Link to comment Share on other sites More sharing options...
S10RACER Posted March 12, 2012 Report Share Posted March 12, 2012 starter fluid is a no no Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted March 12, 2012 Report Share Posted March 12, 2012 There's nothing wrong with running in colder temps, you just have to know how to work on and tune your bike to do it. I guess if colder temps equalled trouble, no one would be ice racing in Michigan, right? LOL My cylinders usually run around/within 50-75 degrees of each other, but that's using an EGT. If both your plugs look good, I wouldn't worry about it. If you have one that's hot and the other is cold, then you have something to be concerned about. Quote Link to comment Share on other sites More sharing options...
quaddad817 Posted March 18, 2012 Report Share Posted March 18, 2012 I run a e.g.t system on my bike and am able to get the temps within 2° side to side. One cylinder gets about 3/4 of a turn out on the PJ than the other. Quote Link to comment Share on other sites More sharing options...
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