Brett Corwin
New member
Whammy said:
Thank you, will do! That was the reason I tested it warm, to see if the rings were holding well. So I'll test it cold but it won't be at room temp! It will be closer to 40 deg. to use the same gauge (its not in my possession but I will have the sled where it is that day). Maybe I should warm it up and let it cool until I can comfortably put my hand all around the engine? Say maybe an 1/2 an hour to an hour after? Will do a leak down also. So I will get a good look at the cylinder walls and with any luck around the ports (I know I can't see the bottom of the ports) at that time.
I will be doing the head gasket, reed and can mod the same day, also Hauck clutch kit #3 and Hauck Boost Bottle kit.
Brett
Do it cold, as is. Don't warm it and let it cool to 60-70, as you will get a false reading. 40 is not going to really affect it.
Brett Corwin
New member
dwarf717 said:
Will do. Thank you.
Previous owner may have had the cylinder head cut as to not have to peal the headgasket. I would leave your compression right where it is as you will not gain any more performance. If you really want more performance and want to go full out.... you'll have to tear the motor down and have a reputable shop inspect to see if your sled has not ported, if its not, you can have it ported and you'll gain about 10-12 hp and will need to rejet, re-clutch and so on. BUT, This is NOT the cheap horsepower that you are looking for..... Then again your sled may have been already done for you...
Brett Corwin
New member
Sxr700Bandit said:
You may very well be right. The previous owner is a friend he bought it from the original owner, he the original said there was a lot of work done to the sled. There is one small Yamaha performance sticker on the hood under the gauges, one I have not seen before, may have come with a kit.
We'll have the heads off and we may have to pull the jugs and check it out, we will almost be there anyway, pipe off, carbs off head off, its not that much more to pull the jugs and check. There is a 600SXR motor there (stock), can I mic up the head and check it against that one??? If not do you know the depth or deck height of a stock 700 head?
Brett
Brett Corwin
New member
OK, Did it.
Dwarf, I did the compession test cold, with throttle wide open. In a garage at about 55 deg's, it was in there for a couple of hour prior to doing the test. Only 3 full pulls and we got 157lbs. to 161lbs on all 3 cylinders.
We took the guage to the local car dealer and check it on the compressor with a graduated pressure regulator (were they test there guages) and it was spot on! We asked one of the tech's to check there gauge and it was the same.
I didn't touch the head gaskets, all three layers are there!
Now what? Is that to much compression? The plugs are burning brown/tan. Got more info from the person I bought it from and they said there was alot of work done. But they could not remmember exactly what the original owner told them..... They bought it from him in April, he had bought a new four stroke and wanted to sell the SXR. Thats all the info I have on it.
Please post and tell me what you think.
Thank you,
Brett
dwarf717 said:
Dwarf, I did the compession test cold, with throttle wide open. In a garage at about 55 deg's, it was in there for a couple of hour prior to doing the test. Only 3 full pulls and we got 157lbs. to 161lbs on all 3 cylinders.
We took the guage to the local car dealer and check it on the compressor with a graduated pressure regulator (were they test there guages) and it was spot on! We asked one of the tech's to check there gauge and it was the same.
I didn't touch the head gaskets, all three layers are there!
Now what? Is that to much compression? The plugs are burning brown/tan. Got more info from the person I bought it from and they said there was alot of work done. But they could not remmember exactly what the original owner told them..... They bought it from him in April, he had bought a new four stroke and wanted to sell the SXR. Thats all the info I have on it.
Please post and tell me what you think.
Thank you,
Brett
I think WOW!!! That is one Helluva a motor you have there. With that type of compression, I would have to say the head has been milled. You will be running premium for sure. If the plugs are burning brown/tan right now, you will be running lean when you start running that thing in the freezing temps. Keep an eye on it. I would thoroughly clean the carbs before the snow hits as well. I bet the original is kicking himself for selling it.
The monoblock head is amazingly hard to get an even cut across. Never even seen it done.Most guys decked the top of the cylinders as it,s a lot easier & consistent.
daman
New member
This is how an engine IS in real world operations,when it's being operated/USED!Whammy said:
a comp test should be done @ operating temp throttle wide open.
bluemonster1
LIFE MEMBER ONLY ONCE!!!
daman..how come I knew you were going to say that. I do my compression testing 15 minutes or so ..after the motor is shut down.
Brett Corwin
New member
bluemonster1 said:
Bluemonster1, I did the compression test 20 after it was at operating temp and it was 145lbs.-150lbs. The cold test was done today as per many members told me to do a cold test and it was 157lbs-161lbs. throttle wide open. Three full pulls done by another person as I held the guage and throttle.
Turk says it sounds like the jugs were decked! So what do you think?
Brett
Brett Corwin
New member
Well I ordered stage 3 clutch kit from Hauck (set for my weight and riding style) and the boost bottle kit. That will be going on next week. I cut the silencer bottom and will be doing the reed stops. We may pull the jugs to see if its been ported, I'm betting they are, it would almost have to be to flow with all that compression. Maybe I won't 
with it and just ride it like I stole it!
Any comments?
Dwarf, Thanks, I will keep an eye on the plugs, The carbs are out and will be opened and cleaned before re-install (double checking jet sizes and will confer with TY members!).
Should I be concerned with the HIGH compression?
Well wish me luck all!
with it and just ride it like I stole it!Any comments?
Dwarf, Thanks, I will keep an eye on the plugs, The carbs are out and will be opened and cleaned before re-install (double checking jet sizes and will confer with TY members!).
Should I be concerned with the HIGH compression?
Well wish me luck all!
Brett Corwin
New member
HIGH compression?
Turk, any reason to be concerned with the HIGH compression?
Any reason I can't use carbon fiber reeds after I cut the reed stop? The main jets are 145, I'm also adding a boost bottle.
Recomendation or suggestions before cutting or adding the bottle?
Brett
Turk said:
Turk, any reason to be concerned with the HIGH compression?
Any reason I can't use carbon fiber reeds after I cut the reed stop? The main jets are 145, I'm also adding a boost bottle.
Recomendation or suggestions before cutting or adding the bottle?
Brett
Last edited:
Brett Corwin
New member
dwarf717 said:
Dwarf, main jets are 145.... Going to cut the reed stops.
Hey I'll trade testers with U ,,, then I'd feel a little better for sure.....hehe test how U want ,,,know what I got.
Brett Corwin
New member
Whammy said:
Whammy, what do you have? Please read the post I replied to Turk. Would you give me your oppinions or can you answer my questions I asked? The compression being to high the carbon fiber reeds, the boost bottle.... Please
I'm not trying to boast about the compression! I'm worried about it being to high! I check the gauge then double checked it! I just want a good running sled with some get up and go! Reliable and fun thats all. I can only post the readings I get.
Then ask the members that know a whole lot more about Yamaha's than I do!!!!!
Thanks,
Brett
If I were you,, I'd try to get at least two different testers to compare with.... That's all.... That's just a little to high for comfortable running.......
daman
New member
Well if the head wasn't cut striate as per turk comment you'll risk a HG failure,and with that high of comp you'll need premium fuel always higher then 92.