89 CR250 head gasket on ATC 250r

[Howard]

I'd like to know more about this mod, using the CR gasket, i was told it is thinner and will boost the compresion a tad as if you shaved the head. said something about use some copper cote too?
anyone have some more info on this?:shrug:

[don250R]

howard, i saw this question already answered either here or on 3WW
shaving not necessary because the thinner gasket automatically bumps compression.
the copper cote was to be used on the metal one you got from taking the factory three piece head gasket apart(either by grinding the tabs or cutting them).
Am trying this on my '85 myself.

[deathman53]

if you use a cr gasket, I hope you like paying $7/gallon for race gas

[Howard]

Deathman53,
just how much do you suppose it bumps up the compresion?

[dunerash]

When I did the cr gasket my compression went to over #200. You can also do the mod above with the stock gasket, throw out the center piece and use BOTH of the thinner ones and you dont have to run race gas. I've never put coopercoat or anything else on head gaskets.

[YAMAHONDAMAN]

you can also use the Copper Coat on your Bumper ... Nathan told me so !! :thumbsup:

[Breastman569]

if you use a cr gasket, I hope you like paying $7/gallon for race gas

or you can just run AV gas at 3.80 a gallon!

[Dammit!]

or you can just run AV gas at 3.80 a gallon!

I've heard conflicting reports on that stuff. Some people say it's bad for the bike, others say it's fine. Anybody know for sure?

[Breastman569]

ive been running if for a while and my dad for about 20yrs and never had any problems thats what they use to use back in the day before all this race gas at 110 octain was availble but mainly only at the dunes when your wide open throttle. also av gas has lead in it there for making the engine run at cooler temps. second theres no reason to run that high of octain if you dont need it.

[Dammit!]

I don't know much about AV gas. What octane is it and where can you get it?

I ran 50/50 91 and 110 last time out to Glamis. It did help with the detonation under heavy load. Didn't eliminate it 100% though. I'd probably have to run it straight to make that go away completely.

[Howard]

so what comp. is it sujested to run race gas?

[Breastman569]

most people run av gas and mix it with 91. the only reason for that is cost issues. thats not alway a good idea cuz you never really know how pure the 91 really is. av gas is 102 octaine and its 3.85 a gallon at flacon filed in mesa and you dont pay highway tax on it. its not really all that much more expensive then 91 and is a way better grade of fule being its made for aircrafts.

[Howard]

anything special needed to purchase AV gas? is the lead ok for the trike motors, parts. said it runs cooler with the lead?

[Breastman569]

nope nothing needed to buy i thought you might need a pilots licens but you dont its just walk up to the pump and take what you need. your going to get the option of many differnt types of gas your going to want the 102 ll or low lead they also offer 110 130 140 or JET!!!! but just get the octaine your bike needs. people will tell that the gas is bad for the engine becase its made for aircrafts and they fly at high alt. so they need fule additives to stop the gas from freezing but the additiive is lead which keeps the fule at a consistant 102 no matter how high you go. hope this helps

[Breastman569]

also the lead keeps the engine from pre eginiting for higher compression and helps lubercated the vavles on 4storke and you can change your egine timming for more efficiency.

[Dammit!]

I don't suppose you know of a place on the west side where I could get some do you?

I think the closest air field is up on Deer Valley.

[YAMAHONDAMAN]

smells good while your weed eating when its in the weed eater !!!
iv'e never had a problem with AV Gas but Paul Turner over at Duncan doesn't like it

[Breastman569]

smells good while your weed eating when its in the weed eater !!!
iv'e never had a problem with AV Gas but Paul Turner over at Duncan doesn't like it

that probly because he sells race gas and can sell it for 9$ a gallon vs. the 6 he probly pays for it.

and hell yes it smells good!

[Breastman569]

I don't suppose you know of a place on the west side where I could get some do you?

I think the closest air field is up on Deer Valley.

i just talked to my firend thats pilot and he said that theres is Glendale Airport a Deer Valley and Buckeye Airport and he said any airport should have 101 LL or they dont deserve to be an airport.

[Red Rider]

anything special needed to purchase AV gas? is the lead ok for the trike motors, parts. said it runs cooler with the lead?When these trikes were built in the mid-80's, leaded gas was all that was available. When every gas station went unleaded in the late 80's or early 90's, we all asked the same question, "Is this stuff (unleaded gas) safe to use in our trikes?" The ability to purchase AVgas will differ from airport to airport. Most airports have increased security to keep out people who don't belong there, others don't. Here in Las Vegas, the closest airport is North Las Vegas, and I purchased AVgas, for my bike, there a few times, but about 1 year ago, they locked all the gates and wouldn't let you on the field unless your aircraft was tied-down there. I have a pilot's license & an airline employment badge, but none of that made any difference to them.

Also, the most common type of AVgas you'll find is 100LL (100 octane Low Lead), and possibly 115. You'll also see Jet-A, which is kerosene, but don't put that in your bike unless you want catastrophic results. I've personally never seen or heard of 101 or 102LL.

[Breastman569]

CHEVRON FUEL - Falcon Fuels: 480-832-2582.
Open 24 hours - 100LL, Jet A & 100/130.

good call on the 100LL i dont know what i was thinking my mistake.

[Dammit!]

Is it safe to mix AV with normal gas? I still have a few gallons left.

[Breastman569]

i know guys that do it but the only reason for it is to same money so if you want do it and jet it right then run stright av gas and re jet again and you will notice a huge difference.

[Dammit!]

I can't imagine why you would need to re-jet. It's effectively just a different octance fuel right? I've never re-jetted for different octanes before. Just different pre-mixes and mods.

[YAMAHONDAMAN]

no re-jetting .... just keep an eye on your plug.... with some oil's the color might be funny looking ..........:eek:

[NOS_350X]

I run AV gas in my 350x for over a year now, everything seems A-OK. I think the bike performs better on the av gas then the 110. And is almost half the cost of the racegas. I just started running the av gas in my banshee, and going from 91 to the av gas i didnt notice any diffrence in the way the bike ran.

[Breastman569]

really i noticed a huge difference in my friends banshee but that could be its also a 4mm stroker.

[77charger]

I bought the cr gasket kit from cal atv.I dont know what year cr gasket it is i have heard 85??Mine was a thin steel gasket they gave me it came with 2 base gaskets too i only used one.

As for the performance yes it improved quite a bit i also added a fmf pipe at the time too.The race gas can be a pain sometimes but i dont ride my trike as much anymore plus we have race gas at work for our drag boat so to get 1-2 gallons here and there is no prob 114 octane then mix 50/50 with 87 or i can go down the street and buy 100 oct from the pump for 6.99 gallon

[86waterpumper]

the gasket that I always buy and use is the 1989 cr250 gasket. It is not a three piece design, the three piece design is what the older cr's had, like the mid 80's ones etc. I have put the 89 gasket on both 250r's I have had and it worked great, and added a good bit of power plus made the bike easier to crank it was harder to kickstart by a bit obviously but seemed to fire off and crank much faster than with the stock gasket. I've not ever bothered with running race gas, always just 93, and I haven't noticed any detonation or pinging, but I will be honest and say I didn't put tons of miles on either bike. However it doesnt' take much detonation to grenade a motor pretty quick and I've run them in the summertime etc so I think something would have happened by now if it was going to. I can see it going over 200 if the bore and piston were tight and brand new, but on a motor that has already had some use I doubt it's as big of a concern but it's easy enough to check compression if in doubt. I have always used copperkote with these particular gaskets simply because they are pure metal and very thin, and alot of times on a 20 something year old motor the head especially isn't always 100 percent level, it is the equivalent of using heatsink paste on a computer cpu etc.