Thunder Tiger 75 Four Stroke?
02-02-2015, 11:24 PM
#202
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Just for info. Purchased one yesterday. The rear orange seal is not installed from factory. The bearing is no longer sealed. Will break her in and repost. I removed covers, and oiled cam, and valve train. Lube should be OK though with no sealed bearing.
02-07-2015, 05:50 PM
#204
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Started right up with three and a half turns. Running a 11x7 prop. Not exceeding half throttle. Smooth rich run. Idles just fine with no LSN adjustment straight out of the box. Opened rocker cover....drenched in oil. Cam gear area... Well oiled. We will see with a few more tanks.
03-01-2015, 12:38 AM
#206
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Five tanks pig rich. Yesterday stated to lean her out for flight without glow attached. Would not keep full throttle and cut out. Starts only at half throttle. This is with no changes from the running in settings on the lsn. Weird, it would not keep a decent idle. Gave her another tank at half throttle on the ground..... Guess it does take a darn long time to break in. We will see. Running her with a 12x6 prop. Optifuel 12% nitro.
03-01-2015, 04:24 AM
#208
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Sometimes you have to check the cam timing and the valve lash on 4 strokes to make sure it is functioning properly. 4 strokes tune different than 2 strokes be aware. If you already knew this I apologize for being redundant.
03-01-2015, 04:30 AM
#210
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Let us know what you found as I am interested. It could be just the carburetor is out of adjustment but, you just have to eliminate each potential problem until you get it figured out. I could be you got some debris in the carb and it will have to be disassembled and cleaned out. I only mention these things as I have had similar problems in the past than kicked me in the backside until I checked everything.
03-04-2015, 12:01 PM
#211
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Yep... Valves where wayyyy off! 0.13mm!!! Starts and idles much better with .03mm valve clearance when cold....
Still some issues with full throttle..... I might need to adjust the idle needle.... Since the pick up is a bit slow....
Running g a 13x4 APC prop now....
Still some issues with full throttle..... I might need to adjust the idle needle.... Since the pick up is a bit slow....
Running g a 13x4 APC prop now....
03-04-2015, 03:00 PM
#212
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What kind of fuel are you running? I run 30% Heli fuel. a little extra oil and nitro. 30% in a 4 stroke is like 15% in a 2 stroke and it really idles great. Glad to hear that you identified a valve lash problem and were able to correct that.
03-05-2015, 05:46 AM
#215
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I ran mine once, about 12 oz of fuel, on the test stand. Then I stuck it in an Ultra Stick 40 and flew it rich and slowly leaned it out. 4 stokes as you know tune differently than 2 strokes.
03-08-2015, 12:17 AM
#216
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Yes I was that they are very cheap on thundertiger4u but it tells me $50 for shipping and I live in the U.S. so Im not sure why so much, they must be overseas. Also I thought that I read elsewhere that it had a nipple on the backplate? Ill have to look into to it, how old is your engine?
03-09-2015, 09:24 AM
#217
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I don't consider my medium sized engines brokein until they have at least a gallon run through them. Most get to a certain point and transform quickly into a smooth running engine. Magnums are the most pronounced but all brands seem to do it . And its true for both two and four strokes.
And yes it does have the breather in the crankcase cover.
04-17-2015, 07:27 AM
#219
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After one gallon....and a tiny tweek on the LSN, the 75 has a deep throaty roar, excellent transition, and runs on fumes. Highly recommended engine. I will buy the TT 91.
It seems TT FS engines need ALOT of break in. I can confirm what fellow members have stated. But excellent engine.
With a 13x4 APC, rpm was 10400....
Will see what it does with a MA K series 14x6...
George.
It seems TT FS engines need ALOT of break in. I can confirm what fellow members have stated. But excellent engine.
With a 13x4 APC, rpm was 10400....
Will see what it does with a MA K series 14x6...
George.
