Should I run race gas

[love2rideatvs27]

I have a L.A. Sleeve 310 kit in a factory cylinder. I just got it back together from having a bore job done. I haven't cranked it yet but I did a compression test on it and it has 240 psi of compression. This is the first 250r that I have owned that has this much compression. Should I run race gas? I don't want to do any damage to the top end. Thanks for any help.

[gojk]

Originally posted by love2rideatvs27
I have a L.A. Sleeve 310 kit in a factory cylinder. I just got it back together from having a bore job done. I haven't cranked it yet but I did a compression test on it and it has 240 psi of compression. This is the first 250r that I have owned that has this much compression. Should I run race gas? I don't want to do any damage to the top end. Thanks for any help.

It is amazing that you can kick it with that much compression. Anything over 180 is recommended to have race gas. At 240 psi, you better look into getting the good stuff. 114+

[love2rideatvs27]

That's what I was really wanting to know, at what point do you need race gas. I was thinking that was on the really high side. You definitely have to have a set of riding boots on to kick it over unless you want a sore foot. My 265r had 190 psi and it was pretty stiff to kick over. I know the compression will lower once it is broken in but I just don't know how much?

[rooster300ex]

I would run 110 in it to be safe.

[Honda 250r 001]

240? wow. thats gonna have to have FULL race fuel. how far can you go on race fuel before detonation? thats the highest i have heard someone runing compression EVER.

[gojk]

Yes, along with having to run race gas, I am sure you will go through cranks pretty quickly with that high of compression.

[Honda 250r 001]

cranks and pistons and cylinders and rings and bores and heads and. lol. running that high is not a good deal. drop it to 200 and run 50/50 mix.

[love2rideatvs27]

I bought the quad from a guys dad. The guy who owned it was in the military and his dad didn't know much about it except it was a 310. I took the whole motor apart to see what I was dealing with. Everything looked good except the bore needed freshening up. So I had it bored from 72.5 to 73mm. I put a wossner piston in it. I don't know if they are better than wiseco but they sure do appear to be better. The head has been modified for the bigger sleeve but it doesn't look to have been shaved. Correct me if I'm wrong but as far as I know they only offer one head gasket and that is a paper one from Cosmetic. If I could find a thicker one that would be great. I would love to lower compression on it but not really sure on how to go about doing that. I've never had the problem of TOO much compression. lol.

[love2rideatvs27]

with all this hype, I'm beginning to wonder if my compression tester is right.

[86 Quad R]

Originally posted by love2rideatvs27
with all this hype, I'm beginning to wonder if my compression tester is right.

i thought the same thing with a +4mm, stock cylinder i built when she hit the 235# mark. we checked it against a gage that was known to be right and sure nuff...... we ended up going with a oem 3-layer gasket to get it around 205.

[love2rideatvs27]

I wish they made a oem type gasket for the 310 kit. I would happily invest in one. I hate the paper type head gaskets but that's all I could find. I've heard a lot of bad things about leaking head gaskets on the L.A. Sleeve 310 kits. I'm seriously thinking about selling it and investing in a ESR 310 kit. I can't believe the price they have on those cylinders.

[Honda 250r 001]

the 310 kit in the stock cylinder is known for leaking. selling it and getting a esr kit would be a good idea!

[86 Quad R]

you werent able to locate a 3-layer metal head gasket for that b/b oem cylinder? :confused:

[love2rideatvs27]

I have a handful of oem head gaskets laying around but they won't work on the 310 kit. all I can find is the paper type from Cosmetic.

[Aceman]

I have similar compression with an LA Sleeve Pro-X 310 cylinder.

After rebuild before startup: 215 psi
At 5.5 hrs:222 psi
At 16 hrs, just tested it yesterday:238 psi:eek:

I'd say the rings have seated well! I've been running straight 110 leaded in it since rebuild. I would of been worried 110 wasn't enough for the 238 psi, but apparently I've been running it that way!:confused: I assumed it was still around 225 psi or so...:ermm:

[love2rideatvs27]

Yeah I'm kinda lost on what to do. I would keep it if I could get the compression down to around 210. I really don't know what I could do to get it down. The cylinder is already ported for my type of riding so porting is out of the question. I really don't want to buy another head and have it modified either. I want this thing to be reliable and I really don't think it will be unless I get the compression down. I'm not gonna run this thing until I figure something out.

[86 Quad R]

if a thicker oem style gaskets isnt avail you could do one of two things........... either have a stock head moded with the proper CC's or fish around for a aftermarket cool head. :cool:

[Honda 250r 001]

i would have your stocker modified. a machine shop will mill it out for lower compression for you.

[love2rideatvs27]

I didn't think about that. I'll probably just have the stocker milled then. I'm sure that will be my cheapest way out.

[86 Quad R]

if you do go that route, is there someone that you know that can profile the dome as needed for your application?

[love2rideatvs27]

not really. there's not many good machine shops around here.

[86 Quad R]

pm'd you.

[LONG-ROD]

I have the same set up. I run a 3 piece that Duncan racing uses for this application. I am running 215 lbs. call Duncan they will hook you up, I would get a cool head.

[love2rideatvs27]

do you have a cool head "Long Rod"? If so, what dome are you using?

[LONG-ROD]

Yes I run a Duncan power head with 19cc dome and 3 piece gasket. not sure of the squish. do you know how much squish you are running now. maybe the cylinder has been decked to many times. seems high for a stock head. If you call Lauren make sure you tell him what size piston your running so you get the right gasket.

[love2rideatvs27]

I have no idea what the squish is. Will a cool head work or would it have to be modified too? When I put the piston and rings in the cylinder it was really tight. Tighter than any top end I've ever put together. I've never had one bored though so I don't know if this is normal on a fresh bore or what.

[the dude]

To have Pro Design modify the dome for a cool head, costs $85 for the machine work. They put mine @ 25cc.

I never liked that engine, now im building a new ESR 330pv.

The cylinder i have has a fresh hone, a broken head stud, and a modified cool head. I'll sell it to ya, $150 shipped.