cylinder

[number5]

Just got my cylinder back from machine shop. I told them not to touch the ports. So they left about ten thousands for screw ups and gave it to me before they finished the boring. Only took about three days to port this. I still have some work to do in the exhaust. After grinding and using cartridge rolls I switch to scotch bright on a mandrel. Then buffing wheels using three different compounds.

[number5]

more of it.

[number5]

exhaust before scotchbright.

[number5]

Intake. The cylinder is a 300 now.

looks good bro....let us know how she runs!!!

[number5]

just got done puting cylinder on. going to finish it sometime.

[number5]

Ok started it and been breaking it in. Jetting seems rich. I thought with the bigger piston it would be lean but not the case so far. Im using a 165 main. I also think the jet is worn out.

[wilkin250r]

Originally posted by number5
I also think the jet is worn out.

I doubt it. Gasoline isn't very abrasive, I can't see it wearing on the jet.

[number5]

I figured it was from the needle. I tried a162 but it was too lean.

[number5]

Ran it today for an hour. It boils over bad. It didnt do that before. The plug is black too. Black oil coming from exhaust. I think Im going to try some good radiator fluid. Engine ice or something. Just more money

did you mix the antifreeze 50/50 with water??

[86 Quad R]

boiling over can be a sign of compression getting into the coolant system or a bad cap.

do ya feel as tho it was runnin hot?

[number5]

The compression getting in the coolant might be it. I didnt seem to be hot. I could touch the pipe for a couple of seconds. The cylinder felt okay. Im using a copper gasket right now. Im going to try a new one tomorrow. See what happens.

[number5]

What is this from? Im using the same jet as before when it was 67mm

[BLACKeR]

lmao, yep it was getting compression in the cooling system...

[86 Quad R]

...... and lots of it. also, when was the last time you done a leak down test? that seems mighty rich to be jetting. what pilot are you running?

[number5]

I just did a compression check and the readings are all over the place. Its wot and how many kicks?

[86 Quad R]

so you've already cleaned the surfaces and installed a new gasket ehh?

btw its wot and ya kik it till it stops reading.

does the gage hold its reading position between kiks?

[DPR250R]

Originally posted by 86 Quad R


does the gage hold its reading position between kiks?

Most comp gages I have used have a check valve that holds the reading.... in others words they are not a good way to measure leakdown (which is what I assume you meant by that)...

You are right though... it does seem rich...

You keep kicking til the reading does not rise anymore... (it takes time to build pressure within the gage line)

I would build a pressure tester... maybe check check cooling system pressure too....

On a positive note... I like the port work you did....

[250r4life]

what the heck do ya'll mean by getting compression into the cooling system?

that the outer head seals but the inner head doesnt, and thus compression gets into the cooling system?
ive never heard anybody say that before?

[86 Quad R]

you've never had a head gasket or o-ring to blow just to have the engines compression pumped into the cooling system?

[DPR250R]

Originally posted by 250r4life
what the heck do ya'll mean by getting compression into the cooling system?

that the outer head seals but the inner head doesnt, and thus compression gets into the cooling system?
ive never heard anybody say that before?

If you look at the pic... you see carbon buildup between the water jacket and the combustion chamber....

The head gasket could have been leaking and when compressing the air/fuel mix some of it slips past the gasket and into the cooling system... this builds pressure in the cooling system...

Coolant can also be sucked into the cylinder and wipe out the piston and rings....

I have honestly only seen it happen one other time and the result was not pretty...

[86 Quad R]

right---^ and if gone unnoticed for tooo long can cause rod bearing failier <sp aswell :scary:

[number5]

[QUOTE]Originally posted by 86 Quad R
so you've already cleaned the surfaces and installed a new gasket ehh?

btw its wot and ya kik it till it stops reading.

does the gage hold its reading position between kiks? [/QUOT+
E]

It does hold. I can get it to read anywhere from 200 to 240. I guess I need to cut the head some more. The average is 220. Im running straight av gas right now. Im going to the machine shop wed. to have the head cut. I guess I need alot taken off.

[number5]

Originally posted by DPR250R
Most comp gages I have used have a check valve that holds the reading.... in others words they are not a good way to measure leakdown (which is what I assume you meant by that)...

You are right though... it does seem rich...

You keep kicking til the reading does not rise anymore... (it takes time to build pressure within the gage line)

I would build a pressure tester... maybe check check cooling system pressure too....

On a positive note... I like the port work you did....


Thanks on port work. Its been awhile since I did it. I used to port mostly Banshee cylinders back in the day. This is my first R

[86 Quad R]

what compression are ya wanting to achieve out of it?

[number5]

Around 180. I want to keep close to that for reliability and pump gas.

[number5]

Also what head gasket am I best off with?

[86 Quad R]

which gasket are you currently running on there? what does the squish band now measure?

[number5]

I went from a metal three layer that leaked coolant to copper that leaked compression into coolant system and not this paper one that seems to be holding.

[86 Quad R]

when's the last time you lapped the head and cylinder surfaces? what compression did the engine have with the thick 3 layer metal on it?

[DPR250R]

I am confused....

Why are you going to mill your head?

You said that the compression was at 200-240 psi and you want it at 180...

Maybe I did not read your post properly....

[86 Quad R]

i think he's going to have the squish band recut and chamber reshaped. from the pics it would appear that the head surface has already been milled?

[C-LEIGH RACING]

According to the pic of that head, either the cylinder deck needs machining or the head around the gasket surface because its surely leaking.

Read this & you can take it to the bank, theres a sealant called Three Bond # 1211 that will seal that gasket, wheather either surface is flat or not.
Take a new gasket & put a lite coat on both sides, mount the head & torque the nuts to 21ft lbs, let engine sit at least a day & night before adding any coolant or running the engine to allow the sealant to cure out.
This stuff works, dont look that good or pro looking but hey, if it works ok.
I been useing it for years to seal up high compression engines.
Neil

[number5]

So where do you get this sealant? As far as the head Im justing getting it cut. I dont know about the squish band.

[86250rbanshee]

pARTS UNLIMITED HAS IT ANY GOOD BIKE SHOP HAS IT, THAT STUFF WORKS AWESOME i KEEP ABOUT 3 TUBES AT USE AT ALL TIMES, AND USUALLY THAT MANY ON THE SHELF FOR PEOPLE.

[C-LEIGH RACING]

Check at some of the better auto parts stores like a high performance shop, if they dont have it in stock, they could probably look through some books & find it & order it for you.
Dont let them talk you into try useing something else, everything else is junk & wont work like the Three Bond.
I get mine from McDonald ATV out in Little Rock AK, runs about 21.00 a tube.
Neil

[number5]

found it here. http://www.pro-flo.com/three_bond_products.htm#Sealants

[BLACKeR]

it sounds to me as though your going to cut more metal off the bottom of your head? maybe im missunderstanding you but you said you dont know anything about the squish. so it sounds like thats not what your milling. if you cut off more metal your compression will only go up. also the compression going between 200 and 240 sounds fishy. i would check your head on a flat surface, it may be warped which is why you cant get a seal on anything.

[DPR250R]

Originally posted by BLACKeR
if you cut off more metal your compression will only go up.

Exactly why he had me confused....

[number5]

sorry I meant that Im having the chamber cut. Not surfaced.

[beerock]

how long did you run it with the leaky gasket? you may have worn the bore down a bit

[number5]

About a half hour at the most. Is it possible to use to base gaskets?

[beerock]

Originally posted by number5
About a half hour at the most. Is it possible to use to base gaskets?

huh?

re use? i dunno once the motors been running im not a fan of reusing them

[BLACKeR]

technically yes, as long as they arnt torn, but for $20 is it worth the risk?

[number5]

I meant two base gaskets.

[number5]

I tried the three layer gasket and Im reading 215 psi. So I called the machine shop he asked me how much more to cut out the head. I told him Dont know Ill get back with ya. Im guessing .006 to start with? Think that will get me down to 185

[86 Quad R]

Originally posted by number5
I meant two base gaskets.

why would ya want to?

you really need to know what the squish band measures(should be a minimum of .035) with the head and head gasket that you are going to run on it. also, its a good idea to have the chamber dia. the same as the bore's dia. and have the squish and chamber cut accordingly. has the head been reworked for the bigbore piston?

[number5]

My self head mod. machine shop said I wouldnt have it until next week. I need it this weekend. Its not pretty but it works. I put it on the cylinder and scribed it and sanded to the scribe mark. Im down to 185 now compression. Thanks Everyone!

[86 Quad R]

can ya post a shot of it (with less glare) tilted a little. i'm curious to see how the squish area looks.

[DPR250R]

And also... let us know how it turned out...

Porting work... head gasket leaks... all that stuff....

[beerock]

bas gaskets can alter the way the motors powerband comes on, if you go thicker you will have more top end if you go thinner you will have more bottom end.

or perhaps its the other way around i really forget.... I know it does change the exhaust timing though...


also, I use to play around with low compresion(180ish) and did back to back comparisons with 210-220ish psi...

and the difference is noticeable BUT the mid compresion of say 210-220(not high like 240-250) is usually the best psi you can run in s stock jug....


the 180-190 psi is great for higher revving but when your dealing with a small piston(even a 295) the low compression is really hampering the ability of the motor. you will get more low end/ mid end with going higher like say 210 220 without sacrificing to much top end

It also makes the bike easier to ride the low compression(180-190) motors always want to be revved WOT or at least 3/4 and it does take a toll on your stamina, but makes for some thrilling riding...


I think your at a great spot with the head, if your using the 3 piece gasket and your at 185 then thats perfect cuz now all you need to do if you want to experiment is take a 3 piece gasket apart and either use the center piece(which i have done with permatex copper spray or 3 bond)IMHO i dont use the 3 bond because of the mess when dissassembly time comes and you have to clean it up, the permatex peels right off.


but any way, you have 3 compression stages with the 3 piece gacket

1, all 3 which looks like (185psi for you)

2 the center piece of the 3 piece gasket which would bring you around 205-210

3 the thin 3 piece part which would bring you to 215-220


lastly ALWAYS USE HONDA HEAD GASKETS if you can... cometic gaskets are ok but ive seen my fair share of them not even made right.....

[number5]

Sorry only took one picture. Where do you get copper spray at? I ran it for awhile and it started leaking out one side of the gasket. Not inside this time but out. One thing after another. I have tried all three gaskets now and they all leak.

[beerock]

how are you applying the copper spray gasket? your suppose to spray the entire gasket on both sides and let it get tacky and then install it

are all the gaskets leaking in the same spot or diff? Maybe you need to get a new torque wrench? or try a higher setting like 25 ft pounds

[number5]

I didnt use the spray I asked where do you buy it. The gaskets are leaking in different spots. My torque wrench is fine. I like to use a dial because of a typical 6% error on clickers. Torque is good. I was thinking of using iconel bolts and stretching them. Just kidding Im just a fustrated you know. I have copper silicon thinking of spreading that thin on the gasket and letting it sit for awhile.

[beerock]

yo, go to the autpo parts store and ask for permatex copper spray, pretty easy...

[number5]

Ok thanks didnt think of going to an auto parts store. That does sound easy.

[86 Quad R]

your having toooo many instances of leakage. i think its time that you atleast lap the head surface. your cylinder deck may need it aswell. are you thoroughly cleaning both sides of gasket, head and cylinder. and yea you need to apply some sort of sealant. afterwards let it sit a spell. :cool:

[number5]

I put copper sealant on late last night. Going to try it today.

[bwamos]

I agree with the others.. you need to check the sealing surface for trueness. Something isn't matching up right.

[number5]

Ran it for awhile and fixed my jetting. My carb was clogged. Took the head and did figure 8s on 360 grit paper on glass. I found the copper spray used it. Seems fine now. Blips nice now. No leaks.

[86 Quad R]

good deal :bandit:

[number5]

Just ran it again for about an hour and its awesome. A big difference over stock cc. My race is sat. Ill let you know.

[iamjasyn]

By the way, a quick way to check if you have a leak between the coolant system and the combustion chamber is right before you start the guy up, feel how much tension is in your coolant hoses by pinching one with your fingers. Start it up and give the throttle some good blips. If the hose stiffens up, you probably have exhaust pushing pressure into the system. Shut it off and pull the radiator cap. You would hear it release pressure and your hoses will soften back up.

Compression should be checked from what I understand, by kicking the motor wot till the needle stops going up. My Honda manual says to do with the engine warm, but I haven't read that elsewhere yet. You shouldn't get different results unless something changes something in between readings. If your gauge doesn't hold the pressure in between kicks, you seriously need a more precise gauge and way to read compression...

Also I bought a flat stone that I tape wet/dry sandpaper to, to lap gasket surfaces and use a machinist gauge to check tolerace. It's a nice tool to remove speculation (not to mention leaks).

Lastly, if you haven't aleady, find some instructions on making a simple leak down tester. It's another tool to remove speculation and doubt. It's SIMPLE to use. There's no good reason not to have one.

[number5]

Ok thanks. I doesnt seem to leak now even after my intense race yesterday in Orlando. Started at 1:30 very hot out. Hour and 40minutes long. 9 mile course. My rebuild and everybodys help kept me in the race. I didnt have any problems. Someone I know was letting me know everylap what position I was in. 3rd lap he told me I was in 3rd. So I tried to keep the pace even though I wanted to stop and pass out. It paid off. I found the last two guys together going through the trees in the distance. I thought I need to gather every last bit of energy and come up fast on these guys and yell for them to get out the way. I was worried that if they seen my yellow background # they would speed up. I tried it and it worked. Came up from behind like a freight train and they moved over. So I got first place out of 22 in my class. The r still rides on. I was the only two stroke.

[number5]

Found a new place for my extra stabilzer while I was doing a topend inspection. The one I have seems like I could use more (stabilization).

[number5]

got one up top and bottom.