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Os 18 T.m.

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S

scoobydoo2u

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  1. Bashing
hello i recently got my os18tm broke in and during break in i was running a little over 200º during heat cycle but now after break in i am only getting into like the 185-190º range but if i lean out the HSN any more there is a performance drop off now this engine already has INSANE power for what I'm using it for but i would like to see what i can really get out of it so why is there a performance drop off if leaned past 190º also i am using the O'Donnell's temp gun so it should be accurate thanks!!


oh and if i went from stock spur and clutch bell to the highest possible tooth count how many MPH difference about would i see?
 
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What temps are you seeing in your area when you run it? Where are you temping the engine? Remember that temp is a guide to where you are at. Are you seeing a nice trail of smoke? If you can not get it up to temps past 190 than I would try the sock method around the head. Helps to retain some heat.
 
jon2 said:
What temps are you seeing in your area when you run it? Where are you temping the engine? Remember that temp is a guide to where you are at. Are you seeing a nice trail of smoke? If you can not get it up to temps past 190 than I would try the sock method around the head. Helps to retain some heat.
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temps here around 60 but its a little windy. Temping at the plug..Yep! i see smoke.
 
great engine already but want to see what i can get out of it..
 
any one? need to know so i can get back out there.. and thanks jon for what you already said.
 
I'm already running mc59s witch is one of the most suggested plugs for OS18tm. i don't think the plug is the problem..
 
id say seal it, but usually air leaks make you over heat.

how far are you out on the HSN?
 
I tend to lean my OS 18s a bit past where I think they should and or I see no performance gain.....and here is the key ...I then richen them ever so slightly until I hit the Sweet spot....good smoke .....crazy power.....and if you temp it then after a high speed run it should run 240 to 270 ish...depending on outside temps and the lid I am running.


I consider that a good tune........but to each his own.

My 2 cents
 
Dont think there is anything wrong at all. Temp outside is 60 and it is windy, I have been running in similar conditions with the same plug with similar temps, maybe around 220. If you have good power, and it's not loading up when it idles and the smoke is there you are probably close. Do some high speed runs for half a tank or so and check the temp then, if it is still under 200 you could lean out the high speed 1/8 turn or less and try again. My TM seems alittle rich on the bottom and will idle for a minuete or less before it loads up, lots of smoke, I leaned it about a quarter turn and it was way too lean. Tune with very small increments and you should be ok. I think the TM is a great engine!
 
i find that mine heats up quickly, itwill get to 260 after a short high speed pass not even at wot, not too sure if its normal, its 60 plus outside and its windy , I'm doing my break in now. Is it ok to go past 270 , i heard that most engines run up too 300 and its safe , not over long periods of time mind you, anyone correct me if I'm wrong
 
For bashing around 260 is the upper limit, if you are breaking in the engine, about 210 is good. Youshould richen up the low speed needle, and make sure you have cut out part on the windshield and side window so the engine can get some airflow to cool it down. Do you have lots of smoke from a standing idle when you give it some gas? Do the pinch test, let the engine idle for 30 seconds and then pinch the fuel line about a inch from the carb. If the engine dies very quickly it is too lean, richen up the low speed neeldle, it it starts to rev very high and runs for 3 seconds it is fine. Alos if you are breaking in the engine i would give the high speed needle about an 1/8 turn out, your temps are pretty high for 60 degree and windy weather. If you are using the Trinity pipe, make sure the black rubber stinger is removed, I used it one night and had high temps also, once the stinger was removed the temps went back down.
 
well i just took it back out without the trinity and the temps werent even getting to those temps. i had to richen th elow peed to help with the idle, cause if i left it at 1 or 2 mm it would be engaging and reving at high rpms, so now i got it to about 200 210 so I'm good, i just have to keep leaning it out abit and i should get there , I'm not sur ewhy it went so high the first times , beets me!but I'm on tank 4 and its going good , not stalling, no hesitatiopn on acc., si i find I'm doing good compared to my last one.
 
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Did you have the stinger reducer in the trinity pipe? I think you might need that with a SB engine to get decent back pressure and to pressurize the fuel tank.

Also, the trinity pipe is kind of prone to leaking around the head gasket. Some have problems and others don't.

Personally, I liked the header that came with the 18TM. It sealed well and was still flexible since it mounted with a spring so it could absorb a bit of an impact without damage.
 
Yes, I am using the os header and trinity pipe with the metal stinger in place, just took off the rubber extender, it made a big difference in temps, also changed to a Motor saver filter at the same time(was using the stocker) so between the two my temps came down quite a bit. Now I have pretty good power and temps in the 220 range, alittle rich still but close.
 
do you find that the rubber extender to make the temps go down or doesn't do anythign at all
 

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