slant head dead

blueprinted single cylender???

I too noticed when I pulled the slant head off there was more heat going towards the exhaust port. But its probly that way coz thats the only way the heat can go. After noticing the head was warped I had to pull .008" of an inch out of it to make it perfectly flat again. I think I may have warped it from over tensioning the head bolts though..

I just fixed my warped slant head for the second time. Where can you get a head with the verticle plug?

is it warping the same placeas last time? ,,if so could it be running hot (needing more fuel for cooling,,,or muffler restriction,holding heat back toward the engine )

I am running without baffle in muffler and running redline synthetic in the gas at 32:1. It is being caused by irregular fuel burn pattern. The aft part the cylinder head is dirty from carbon and the front is clean like it doesnt even see ignition at all. Also, the motor spits gas and runs with no power because only half fuel is being ignited. Please, will someone tell me who sells a 66cc verticle spark head?

try spookytooth. or just call some of the companies listed on the left and right and i'm sure someone has them...

King's has them for 10 bucks, so I ordered one with a new HG for the 66cc. Many small engines have a slant plug, so I bet the problem is the design and only localized to a few engines (built on Monday). Even if verticle head cover makes slightly less power, it sure looks classic. Maybe it is the way the fuel enters the chamber combined with the angle of the spark plug, probably a fairly complicated issue causing melted pistons. I want my engine to run for a while because even an engine as crude as these HTs will run a while if taken proper care of (good oil, plugs, filter and luck!). Rode mine today in mud, snow and through puddles of water and it just keeps running better!

Just my .02. I have a Raw non-slant engine and I installed a GT5 slant head on it and it really came alive. I'd say an extra 2 to 5 mph's!
On another note, I installed a MM head on my GT5 and gained nothing...

The 26incher said:

Just my .02. I have a Raw non-slant engine and I installed a GT5 slant head on it and it really came alive. I'd say an extra 2 to 5 mph's!
On another note, I installed a MM head on my GT5 and gained nothing...

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2-5!! If I lose 2-5, slants going back on. My engine runs really unpredictably and today it ran great; keeping up with traffic and I even passed a few. Slant head is not dead, seems like it works with some and others not. I can't wait to see if the heat pattern is irregular with the current slant and if the verticle runs better or worse, it's part of the game.

26'', How quick does your bike accelerate to top speed? Can you explain the changes in powerband between the two head covers, like a before and after...more top end or bottom end with the slant as opposed to the vert etc. Got to figure this one out for sure!

FYI…I am a big fan of the slant head design and notice all my builds with this motor seen to run much better. I have not noticed any abnormal issues with this head to this date.

CCC

I have to imagine over tightening the head and a combination of unevenly tightening the head are major contributors.

turn the head 90 deg seems to work good and just looks meaner

I've been thinking of changing my screen name to "Slant Head Dead"

ok im a newbie to the "2stroke-mehoff" engine....but i have read the complete thread and i would like to interject/inject a few things based on my automotive engine building..please bear w/me.....

1) we are dealin with a very extremly loose tolorance massed produced pos

2)i dont know if it would make a difference but what im reading reminds me of an issue of flame pattern/travel. when building a performance "blue-printed" engine an ideal situation with cylender head/cumbustion chambers is to index the spark plug so the electrode is unshrouded towards the intake valve...markin the plug in relation to where the electrode tip is located w/sharpie and then useing various thickness of sparkplug shims to obtain the correct angle of said electrode....has anyone done this?

3)the issue of warpin heads....are we useing a torque value when assemblin?...are we useing the factory hardware?...which i would think is very subceptable to the phenominum of bolt stretch, where the tensile strenght value of the stud is bein lost,... hence a variation in torque readins leadin to warpage...the only way to avoid this/eliminate it would be to use hardened studs as well as washers and nuts...

4)the quality of the metal/aluminium bein used to cast/manufacture these parts...comon guys this isn't air-craft quality t-6, nor are they forged....these engines are essentually used as a method of transporting an average 5'4" 100lb person of asian disent to his factory job....not to do an 11second run in the quater mile....

5) so that bein said, unless you've takin away all of the controlable issues you will never be able to have a true indication of one bein better than the other.....and in essance you have nothin but a "crap-shoot"...it worked for this one an not that one.....yada yada......please dont take any of this personal...it is just what it is........in my opinion and experience

I don't think it should make any difference. The combustion chamber is over the center of the piston whether it's an angle head or straight head. The spark plug electrode is in the same place either way.

all i knows is i tested it by swapping heads back in june. my flat head worked much better.

i never posted the update to my post on page 2 about it, 'cause i guess it didn't matter too much to me. but since this keeps getting brought up...

i put a GT5 slant head onto my GT4 motor for one day back in June.

the heads mounted exactly the same, so there's no tolerance or incompatability issues.

the slant head was slower all around. slower accelleration, slower top end.

after a mile ride i "hot-torqued" the head (which was just hitting every nut with a 10mm wrench after it was warmed up. moved every nut about 1/8 of a turn.) and took off for a longer ride.

overall, the bike performed well, rode smooth, but was noticeably slower by at least 5mph.

the next day i switched them back.

plug color was normal, and there was no evidence of head gasket probs, and i checked for warping by sanding it a tiny bit on a piece of glass to check for hotspots, and it was fine.

after putting the flat head back on, the performance immediately went back to normal.

i have no scientific way of knowing why there would be a power loss, and can only speculate that the squish band may be slightly different, or that the plug firing a certain way had some effect, or that the head, not being made for the GT4 (the barrels are slightly different) just made it slower.

the one test i didn't do is put the flat head on the GT5 motor to see if the performance would increase on that bike. i may do that sometime in the future.

i proved to myself that buying a slant head to increase the performance of my engine is a complete waste of money and time, though, and that's what matters to me.

bairdco said:

all i knows is i tested it by swapping heads back in june. my flat head worked much better.

i never posted the update to my post on page 2 about it, 'cause i guess it didn't matter too much to me. but since this keeps getting brought up...

i put a GT5 slant head onto my GT4 motor for one day back in June.

the heads mounted exactly the same, so there's no tolerance or incompatability issues.

the slant head was slower all around. slower accelleration, slower top end.

after a mile ride i "hot-torqued" the head (which was just hitting every nut with a 10mm wrench after it was warmed up. moved every nut about 1/8 of a turn.) and took off for a longer ride.

overall, the bike performed well, rode smooth, but was noticeably slower by at least 5mph.

the next day i switched them back.

plug color was normal, and there was no evidence of head gasket probs, and i checked for warping by sanding it a tiny bit on a piece of glass to check for hotspots, and it was fine.

after putting the flat head back on, the performance immediately went back to normal.

i have no scientific way of knowing why there would be a power loss, and can only speculate that the squish band may be slightly different, or that the plug firing a certain way had some effect, or that the head, not being made for the GT4 (the barrels are slightly different) just made it slower.

the one test i didn't do is put the flat head on the GT5 motor to see if the performance would increase on that bike. i may do that sometime in the future.

i proved to myself that buying a slant head to increase the performance of my engine is a complete waste of money and time, though, and that's what matters to me.

Click to expand...

For a true test you would need to cc the combustion chambers of both heads and make sure they're the same size before testing. My guess is your flat head may have slightly higher compression.

could be. but i don't care enough.

the main point is that a lot of people think it's a performance upgrade they can buy and bolt right on, when it isn't. it just makes your engine shorter.

bairdco said:

could be. but i don't care enough.

the main point is that a lot of people think it's a performance upgrade they can buy and bolt right on, when it isn't. it just makes your engine shorter.

Click to expand...

I can totally agree with that. I don't see any reason why there woulld be any difference all other things being the same.