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Post by mauibird on May 21, 2016 23:04:04 GMT -5
Took it out today and ran her HARD for a few miles, and boy did she get hot. 500 on the CHT. She liked to stay between 400 and 500. I could wrap the throttle several times and cool the cylinder down to just below 400 but as soon as I got back on it it would hit 500 again easy. I guess its a pretty solid cylinder to handle that and not seize. I'm using 91 octane, ethanol free gas. I wonder if I added some octane booster if it would help keep it cooler. So I checked the compression, and 193 psi. I guess thats a bit high. It was really hot today too. Maybe I'll have to add a head gasket. Any suggestions are welcome…  |
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Post by mauibird on May 21, 2016 23:06:17 GMT -5
Here's my max rpm, pipe sounds good. Only got to about 65 though. I'll check the variator for full cycle later  |
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Post by mauibird on May 21, 2016 23:08:57 GMT -5
Plug looked good. Sorry for the poor picture quality. That light colored stuff on the tip is where the soot was rubbed off. NGK B8HS  |
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Post by oldgeek on May 21, 2016 23:20:52 GMT -5
Took it out today and ran her HARD for a few miles, and boy did she get hot. 500 on the CHT. She liked to stay between 400 and 500. I could wrap the throttle several times and cool the cylinder down to just below 400 but as soon as I got back on it it would hit 500 again easy. I guess its a pretty solid cylinder to handle that and not seize. I'm using 91 octane, ethanol free gas. I wonder if I added some octane booster if it would help keep it cooler. So I checked the compression, and 193 psi. I guess thats a bit high. It was really hot today too. Maybe I'll have to add a head gasket. Any suggestions are welcome… Wow! That is pretty hot. Compression does not sound crazy high to me but I don't know anything about that kit. What is your squish currently set at? I read somewhere on here that you should keep your squish tight as possible and enlarge the chamber to reduce compression if necessary. I was looking at octane boost myself today and wondering if it would help. I also saw 5 gallon cans of 110 octane race fuel at the parts store for about $55  |
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Post by mauibird on May 21, 2016 23:49:58 GMT -5
Took it out today and ran her HARD for a few miles, and boy did she get hot. 500 on the CHT. She liked to stay between 400 and 500. I could wrap the throttle several times and cool the cylinder down to just below 400 but as soon as I got back on it it would hit 500 again easy. I guess its a pretty solid cylinder to handle that and not seize. I'm using 91 octane, ethanol free gas. I wonder if I added some octane booster if it would help keep it cooler. So I checked the compression, and 193 psi. I guess thats a bit high. It was really hot today too. Maybe I'll have to add a head gasket. Any suggestions are welcome… Wow! That is pretty hot. Compression does not sound crazy high to me but I don't know anything about that kit. What is your squish currently set at? I read somewhere on here that you should keep your squish tight as possible and enlarge the chamber to reduce compression if necessary. I was looking at octane boost myself today and wondering if it would help. I also saw 5 gallon cans of 110 octane race fuel at the parts store for about $55 Im running .95mm squish right now |
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Post by oldgeek on May 22, 2016 0:06:39 GMT -5
Wow! That is pretty hot. Compression does not sound crazy high to me but I don't know anything about that kit. What is your squish currently set at? I read somewhere on here that you should keep your squish tight as possible and enlarge the chamber to reduce compression if necessary. I was looking at octane boost myself today and wondering if it would help. I also saw 5 gallon cans of 110 octane race fuel at the parts store for about $55 Im running .95mm squish right now You could tighten it up a bit but you might have to lower compression then. |
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Post by niz76 on May 22, 2016 0:15:38 GMT -5
Wow I can't believe it didn't seize at 500! Ya that cylinder must be great at heat management. I've seized (and blown a hole in the piston) the steel Hoca 54mm at around 440 but I was pushing the envelope with timing advance...
EDIT: Actually no I got that wrong- I've never seized my steel Hoca 54mm, that was a 52mm that I blew a hole in.
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Post by mauibird on May 22, 2016 1:01:53 GMT -5
Im running .95mm squish right now You could tighten it up a bit but you might have to lower compression then. How would I lower the compression? Port †he Head? |
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Post by oldgeek on May 22, 2016 6:30:35 GMT -5
Yes, open up the combustion chamber a bit. Brent has a thread about doing it somewhere around here, I will see if I can find it.
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Post by 90GTVert on May 22, 2016 6:33:02 GMT -5
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Post by mauibird on May 22, 2016 15:33:28 GMT -5
I think I might try the drill press and stone. Whats ur technique for grinding? |
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Post by mauibird on May 22, 2016 22:29:32 GMT -5
So, I took all the bbq paint off my cylinder with laquer thinner. It wasn't flat black and it should be to aid in cooling. This might have been a contributing factor to my over heating. I took the head off and Put a .2mm head gasket on and checked the compression. It was at 195 psi, higher than before (193) without a gasket and just copper spray. So I took the white ball and drill to the head chamber. Sanded it down, slapped it on with the head gasket. Now I'm at 180 psi. A little taller on the squish, so we'll see how she runs tomorrow, after the copper rtv, for the exhaust cures.   |
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Post by mauibird on May 22, 2016 22:39:17 GMT -5
I wonder if I'll have to change my jetting…
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Post by 90GTVert on May 23, 2016 9:34:56 GMT -5
I think I might try the drill press and stone. Whats ur technique for grinding? Grinding what? If I need to get the head shaved down, then I'll only grind if there's a lot of material to remove. Keep as even as possible. Leave a little of what you want gone to be safe. Then mark the sealing surface and use sandpaper and glass to true the head so it will sit flat and seal. Sorry if I just answered a question you didn't ask. I haven't changed jetting with small changes in compression. |
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Post by mauibird on May 23, 2016 19:57:17 GMT -5
So at 180 psi, the bike still runs good. Didn't get as hot as quickly. But it still hit 500 for a split second. With the correct throttle position I could keep it around 400. This was pushing it pretty hard, up a small grade, against 20mph winds, and maintaing 55mph. So, how low could I go with the compression, to keep this thing cool, and still running good?
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