Craig_b Posted February 28, 2016 Report Share Posted February 28, 2016 Hey all, just wondering if anyone out there has had any issues with a 421 serval getting up in engine temp when not flat out, ive noticed the temp getting up there when i get into tight slow trails, and hot weather dosnt help either.on my set up for cooling ive got a noss cool head and a gpi alloy radiator (that im not impressed with).i do have a mull high flow impeller sitting there but not fitted to the bike.interested to hear what others have done. cheers Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 28, 2016 Report Share Posted February 28, 2016 If the pilot is lean you will suffer severe slow speed overheating. 1 Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 28, 2016 Report Share Posted February 28, 2016 Is the exhaust turning dark blue to gold where it first comes off the motor? Some light coloration is ok, but if it's dark and beyond the flange like a foot, there is an issue. Quote Link to comment Share on other sites More sharing options...
Craig_b Posted February 28, 2016 Author Report Share Posted February 28, 2016 Is the exhaust turning dark blue to gold where it first comes off the motor? Some light coloration is ok, but if it's dark and beyond the flange like a foot, there is an issue. has been dyno tuned with air/fuel measured when tuning. no discoloration on pipes at all. i could go larger in jet sizes next time its out to see if it helps if i start having issues though Jet it right and don't ride slow. i want to go fast all the time, but sometimes its just not possible haha Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 28, 2016 Report Share Posted February 28, 2016 Few issues with dynos that take a good operator/tuner to overcome, yet I selfomly see it happen. First, some dynos don't produce a legitimate load, or an operator doesn't load it fully in an effort to boast about numbers. Second, were they running it on the dyno at full throttle? How can you expect to dial in the pilot if the carb is wide open each pass? Quote Link to comment Share on other sites More sharing options...
Craig_b Posted February 28, 2016 Author Report Share Posted February 28, 2016 Few issues with dynos that take a good operator/tuner to overcome, yet I selfomly see it happen. First, some dynos don't produce a legitimate load, or an operator doesn't load it fully in an effort to boast about numbers. Second, were they running it on the dyno at full throttle? How can you expect to dial in the pilot if the carb is wide open each pass? 1/4, 1/2, 3/4, full throttle passes were made. see how the jetting was set up. then some full throttle passes made for power runs i guess you would call them. 3hrs spent for dyno time, includes setting up bike and jet changes etc. it wasnt a quick throw it on, make best highest number and leave. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 28, 2016 Report Share Posted February 28, 2016 Hmmm, look for an air leak. Something is fucky if it was jetted right, it should t be getting hot like that. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted February 28, 2016 Report Share Posted February 28, 2016 So how's that impeller working for ya? Might be good time to rule out a bad impeller. Quote Link to comment Share on other sites More sharing options...
bluebanshee98 Posted February 28, 2016 Report Share Posted February 28, 2016 1. Use engine ice as coolant 2. Get a over sized radiator on eBay for 65 bucks 3. Over sized impeller like chariot is very beneficial 4. Check for air leak. What was your temp at on the bike? Are you sure it was getting hot as you think? Quote Link to comment Share on other sites More sharing options...
Craig_b Posted February 28, 2016 Author Report Share Posted February 28, 2016 Hmmm, look for an air leak. Something is fucky if it was jetted right, it should t be getting hot like that. yeah will do as ive got a leak down tester, will take some extra jets next time just incase it gets hot and swap them out to see if a difference is made So how's that impeller working for ya? Might be good time to rule out a bad impeller. that was the first thing i inspected as still has the oem plastic impeller (which looks in good shape ), the mull impeller should flow more but that dosnt mean its going to cool the bike down more. i did have a crack in the radiator which i thought was the issue as it wasnt pressurising the system, but now thats been fixed the issue is still there. Quote Link to comment Share on other sites More sharing options...
slobanshee Posted March 1, 2016 Report Share Posted March 1, 2016 As odd as it sounds. Mine would try and get hot while trail riding but never when racing in the flats. I went 2 notches richer on needle and cured everything. Didn't run or act any diff. Quote Link to comment Share on other sites More sharing options...
guns4children Posted March 11, 2016 Report Share Posted March 11, 2016 If it's jetted right it shouldn't over heat. I trail mine in tight places riding with kids, girls and old people. Lots of putt putting around and it never gets too hot. (Knock on wood) Quote Link to comment Share on other sites More sharing options...
coryv4 Posted March 11, 2016 Report Share Posted March 11, 2016 i ride mine in areas where 2nd gear starts getting to fast for the trail and dont have an issue with heating. 421 serval. i did have a heating issue a while ago when i had a pinched oring in the head, after 20 minutes the overflow what pouring steam out. Quote Link to comment Share on other sites More sharing options...
Craig_b Posted April 20, 2016 Author Report Share Posted April 20, 2016 bit of and update on this. yesterday i had the chance to put the bike on its stand and pull shit off, having done a leak down test it will lose 2 psi in 4 minutes. im not 100% confident in the way the pressure gauge attaches so ill be looking for another option today. with 6psi in the motor i am unable to find a leak, inspected intake,exhaust,around the head and base gaskets, top/bottom case seam, pto side seal and shaft, stator side seal, around trans breathers, blocked trans breathers,cooling system.might be parked up for a wee bit as its time for some bike maintenance as i need a new tether kill switch as the tusk one i got shat its self, want some bar risers, need to address the lack of braking, need to make mounts on swing arm for skid plate, and probably make a full body skid at the same time Quote Link to comment Share on other sites More sharing options...
Craig_b Posted April 20, 2016 Author Report Share Posted April 20, 2016 (edited) i cant edit my previous post, but a couple of weeks back i found the oversized radiator had a crack in it, i repaired that and also went up 1 pilot size and it is still getting hot, this is how i got to the leak down test now as i thought the cracked radiator was the issue. im still running oem water pump drive gear and oem impeller, but do have the mull alloy drive gear and high flow impeller sitting here but i dont believe this will help my situation. externally the radiator is clean, there is no debris stuck in the fins etc.faults are either air leak, internally blocked radiator, fucked radiator cap Edited April 20, 2016 by Craig_b Quote Link to comment Share on other sites More sharing options...
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