Thread: Need Help
10-26-2009, 03:29 PM #1
I have a rebuilt 1200 ultra 150 motor from SBT. I am on the third tank of fuel, performed correct break in for first 2 tanks.The pto side of block is heating up to the point you can not touch with your hand and the front (flywheel) side of block is warm but you can touch it. All three cylinders and heads feel like they are around the same temp. I have flow tested the oil pump to this cylinder and to the crank, pto side, and both were within specs. I checked the coolant flow from this cylinder and its fine. SBT said the carb on pto side may be running lean but it seems to me that if this was the case the hole cylinder and head would also be running hot. I have two 99 ultra 150's that I am going to part out so I will pull the carbs of of one of them and see what happens. If would appreciate any help with diagnosis. Worst case I have 7 months left on warranty I guess I could run it till it blows and send it in for warranty.
11-02-2009, 01:48 PM #2
I am no way an expert, just a beginner, but I would say that the main cooling agent on this motor is water. The oil pump would aid in the lubrication of the moving parts. The cylinder may have a partial clog in the water jacket? Just a thought....Does your plug on the pto side indicate a lean condition? Also one of the more knowledgable members (digger) tells alot about engine performance by the piston wash. A search would find his post on this topic. Good luck and keep us posted.
11-02-2009, 10:33 PM #3
It's hard to get an accurate temperature with your hand. I would suggest you get one of those non-contact temperature guns (Harbor Freight has them, http://www.harborfreight.com/cpi/cta...emnumber=96451 ).
If the difference is only a small amount, I wouldn't worry about it. If the rear cylinder is, say 100°F, I probably would worry.
11-02-2009, 11:20 PM #4
First im no fan of sbt motors for ultras in particular. They use steel sleves in the cylinders instead of nicasil plating like factory. The steel doesnt wear or transfer heat as well as the plated cylinders. I know of several that have tried them and couldnt get one to last.
As for your problem it sounds like it could be a balancer bearing or rear crank bearing heating up. I wonder if the filled the rear balancer with oil like the manual calls for? That would cause it to heat up if it Didnt have the 60ml of oil like it was supposed to have to start with.
I would hang on to enough parts to build a good motor off the 2 you are going to part out. Then go run the crap out of the sbt motor and see if it blows. My bet is it will
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