so i just got my FJ1200 this weekend from a Harley dealership, shes a 1986, but when i got it, it had all these switches on it and i asked what they were, the guy said "the previous owner raced drag bikes and so it could be anything, but we don't know because the wires were clipped" so i was curious/concerned and asked for more information, he said "the fuel in the tank is racing fuel, its like pure alcohol, but if you want to put regular gas in it you have to adjust the ______!" i don't know what he said and I'm about to run out of this crazy fuel!
What do i have to adjust for the bike to run well with standard gas??
Im no expert but high octane gas would indicate high comp and advaced timing.Remove the high comp pistons / cylinders and install oem cylinders and pistons.Bring timing back to normal.If you do run low octane in a high octane motor it wont last long.
What about if i use lower octane fuel, but not the lowest, i just want to be able to go to a pump and fill up and drive away. would that ruin my engine as well?
Like I said I am not an expert.I would do a compresion test to see what comp is first.What octane is in the tank try and find out.I live in cook county Illinois we can get 100 octane at a few pumps and I know one place with 110 octane at the pump.Most of my know how comes from 2 strokes im just got my FJ last June so im learning.A comp test will tell you a lot my 1100 runs great on 87 octane but I have a stock motor.
thanks for all your help, i think im just gonna take it into a yamaha dealer and let them run tests as a watch my wallet become more and more empty haha
Where do you live you might find someone here who could help you.
Put up some pics for us and tell us all about your bike.
I live in Jacksonville, Florida
and its a 1986 FJ1200, shes a beautiful bike but its so darn fast, the previous owner raced drag bikes but this bike was his daily commute to work bike so its not meant for drag but he did some work on it to make it run faster.
(http://images.traderonline.com//img/dealer/rickcase/rickcaseP1263B_1thumb_550x410.jpg)
Quote from: Carterc on March 14, 2011, 09:46:17 AM
so i just got my FJ1200 this weekend from a Harley dealership, shes a 1986, but when i got it, it had all these switches on it and i asked what they were, the guy said "the previous owner raced drag bikes and so it could be anything, but we don't know because the wires were clipped" so i was curious/concerned and asked for more information, he said "the fuel in the tank is racing fuel, its like pure alcohol, but if you want to put regular gas in it you have to adjust the ______!" i don't know what he said and I'm about to run out of this crazy fuel!
What do i have to adjust for the bike to run well with standard gas??
I', going to suggest that it's somewhat critical to find out more info from either the sales bozo (suggesting fuel is like alcohol) or the previous owner regarding motor modifications. If he was running race gas,like C-16, or the like, the motor may have high compression pistons....and if so,pump 93 wont cut it and may case knock/detonation=very bad. Or if it just high timing,not so bad and can be rectified easily.Very nice bike either way..your going to love it!
great idea, ill get the info straight from the guy, he has his own business regarding bike mods. but one thing is for sure, the speed of this bike scares the hell out of me, but i know its just this bike because I've ridin a FJ1200 before, but this ones like a freaking rocket ship!
First off, it's a harley shop. Disregard everything anyone says inside of one.
Second, start by figuring out what you've got. I'd do a compression test, as that'll give you an immediate idea if it's using very high compression pistons, as well as help give you an idea of general health. If it's using high compression pistons, a shim headgasket would be a decent fix for the time being.
Pulling the four screws on the cover on the left end of the crank will show the ignition trigger, and you can post a picture of it, odds are it'll be easy to see if it's advanced or not.
Pulling the valve cover (easier than you'd think) would let you inspect the cams for wear as well as to find out if they're weldups (looking at the side of the lobe, the stock cams are a consistent color, aftermarket cams have a visible bimetal appearance). You can also find out if there's adjustable cam sprockets while you're there.
If it was raced, it might be a good idea to check the clutch to see what's in there and the condition of the fibers/steels. Blued steels is normal, warped steels isn't.
The other thing that'd be a great idea would be to pull the oil pan off, clean off the screen on the oil pickup, and look around for chips of bearings and other nastiness.
The switches were likely for either a nitrous system or an air shifter, or both. Alcohol? Possibly it's jetted for E85 or something. Pop the carbs off and look at the jets. The mains alone would give you an idea of what the guy was doing with it, it should be using something between 110 and 125 jets, if he was running it on alcohol they should be quite a bit bigger than that.
I highly recommend removing that fuel from the tank and running some pump fuel through your fuel system/engine. Race fuel generally is very hard on fuel system components. I have personally seen valve seats rust/corrode to the point of gluing the valve to the seat. This generally on the exhaust side and can happen in just several weeks of a bike sitting idle. The draining and flushing routine is followed by all Superbike etc teams.
Is there ANY chance they can give you the name and maybe the phone number of the previous owner? One quick phone call to the PO would clear all of this up. He sure was sticker happy! Keep us in the loop and welcome!
im trying to find out what the PO's email address is now, i really appreciate all the help! all of you have been a wealth of knowledge. its good to be a part of such a welcoming and helpful community!
I don't know this stuff all that well, but is it not possible to run high compression pistons with normal/ slightly advanced timing on pump gas -even high octane pump gas? Does it depend on how high the compression is for the piston in question?
Andy/ Anyone?
Dan
Quote from: Carterc on March 14, 2011, 09:46:17 AM
if you want to put regular gas in it you have to adjust the ______!" i don't know what he said and I'm about to run out of this crazy fuel!
What do i have to adjust for the bike to run well with standard gas??
fill in the blank . timing or jets.
just put some super pump gas and see what happens. if it pings or knocks you gotta adjust some stuff. :good2:
i dont know what he said, it might have been BS for all i know. and what would i do if i put super pump gas in it and it pings or knocks and im still at the pump? lol
also i dont know how to adjust "some stuff" im new to bikes and know nothing about engines :dash2:
well it sounds like you need a manual and some local help from a fj'er in your area.
most of us will work for beer :drinks:
somebody in your area might come to your rescue.
She is sweet looking.I wish I was close so I could try her out.A compresion gauge from the auto parts store would help tell you what gas to run.Cost you about $40.
Nice bike and easy to work on get those hands dirty.
Quote from: Dan Filetti on March 14, 2011, 01:05:03 PM
I don't know this stuff all that well, but is it not possible to run high compression pistons with normal/ slightly advanced timing on pump gas -even high octane pump gas? Does it depend on how high the compression is for the piston in question?
Dan, it depends on the compression. If you were tuning it to run exclusively on alcohol (ethanol or methanol, but excluding E85), it wouldn't be surprising to aim for a static compression around 15-17.0:1. Running gasoline, even as a mix, in an engine built to that spec is going to end badly. The highest octane fuel that I can think of is VP Import, which runs around 120, approximately comparable to methanol. The other side is that the stoch ratio is vastly different, and I'd be suprised if it ran at all on the "wrong" fuel. Burn rates and flame propogation are going to be different also (and the FJ does not have a remotely efficent chamber for a racing use), so that'll move the timing around as well. However, most of this is moot because we'd be talking about very custom pistons, and they'd be expensive to the point of silly. Most likely it's got wiseco 77 or 81mm pistons in it, because they're fairly cheap and easy to get. If it's got the 12:1 77's in it, it'll work on really good pump fuel, but it'll do better with a thicker head gasket to bring compression down, as there's a chance of overheating at idle in a Texas summer.
I'd guess that there isn't anything particularly exotic about the engine, for a couple of reasons. The pipe isn't a sidewinder, and there's stickers on the swingarm. That would lead me to guess that the prior owner didn't remove an extended swingarm for sale seperately (because that'd have the stickers instead). It's possible that he swapped pipes, but not hugely likely imo. I'd guess that we're probably talking about a pretty typical engine that could even still have stock pistons.
But if it's got "race gas" in it and unused switches on it... my guess is that the prior owner ran nitrous on it and used a high octane fuel to help eliminate detonation at the track. If he drove it as a daily/weekend ride, it'll probably do just fine on pump gas, possibly requiring 91+ if it's got the typical 10.25:1 pistons and aggressive cam timing in it. I'll wager then also that it doesn't have advanced ignition timing, as that'd be a problem while on the bottle.
As before, a compression test will easily give you a ballpark idea of where it's at, popping the oil pan off to clean the oil strainer is a good idea (drag launches can chew up clutches, and that material has to go somewhere), and popping the valve cover off to see what cams/sprockets are involved will all be good ideas. Odds are it needs new valve cover bolt grommets anyhow :)
First a compression test to know for sure what you have would be just as good if not better (the PO may not remember all the details.)
If it is high compression .... octane booster added to premium fuel can get your thru until if/when you want to shim the head gasket.
KOokaloo!
Okay I'll bite, what number on the gauge is too much for pump gas?
Quote from: Travis398 on March 14, 2011, 05:49:48 PM
Okay I'll bite, what number on the gauge is too much for pump gas?
When it detonates :) But when you're utterly blind as to what's in the engine in the first place, it'll give you some idea. If the gauge reads say, 230psi, I'd start with a good 110 and see what happens. It's only one piece of the puzzle.
Having an idea of what cams are in it and where they're timed also plays a role though, as you can bring them together and bleed off cranking pressure... and then get detonation at higher revs. Usually those motors are really peaky though.
ON the positive side, It's almost impossible to find pistons for the FJ with higher than 10.25:1 compression ratio.
Even if the cylinder head has been decked as much as .030" and the cylinder milled to bring the pistons up it's unlikely you'll need anything more than 93 octane pump gas. Now how it was jetted... to run on race fuel? It's ususlly recommended that the jetting be richened up for race fuel. Rich is ALWAYS safer to start with as your unlikely to have engine damage occur. A fouled spark plug is cheap compared to a detonated piston.
Also remember, that if it does have race cams, compression levels at cranking speed may still be in the normal to low side.
A good running Legends car is designed to pump 180 p.s.i which 600 racing claims is 10:1 compression ratio.
MC
Oh yeah, just because it has race gas in the tank doesn't mean it needs race gas.
Some people like to smell fast.
The bike isn';t stretched and lowered, Probably has stock carbs.
Quite likely a stock bike in wolf's clothing.
MC
hey its gots lots of stickers it must be fast... seriously though ... I can't tell but the exhaust doesn't look too modified which is a very important part of the power ... I am with Andy along that lines maybe due to the exhaust being what it is it is not highly modified.
Quote from: fj1250 on March 14, 2011, 07:43:36 PM
".... It's almost impossible to find pistons for the FJ with higher than 10.25:1 compression ratio.
Mike, didn't Wiseco make some 77mm pistons that were 12:1? Those along with a head shave and advanced timing.....
I agree with the Andy:
1) Disregard any advice given at the Harley shop, their strong suite is not FJ's
2) Contact the PO for a full description and advice.
He made it run fast so he know's what he is doing, probably. Wonder why he sold it? Traded it in at a Harley stealership? Naaa
3) If unable to contact the PO, do a compression check. Heck do it anyway.
4) You're *probably ok* with 91/93 octane gas if the PO used it for his daily commuter.
Worst case: You would have to add 1/3 can of octane booster every time you get gas, until you could get into the motor to lower the compression and/or retard the timing.
Yea good point: I wonder if the PO got paid for all those stickers?
alright guys, i appreciate all the help! So its the general consensus that i should get a compression test done, which would tell me what exactly? and it would most likely be "ok" to use the highest octane pump fuel, which could at worst do what exactly?
keep in mind that i have no idea what you guys are talking about but i have google on my side and ive learned way too much from this post haha.
keep it semi-simple please.
Thanks again! :hi:
my 1349 motor has 10:25 compression pumping 200 PSI....... runs great on pump gas. :good2:
KOokaloo!
Good to know,what octane 93.
Quote from: racerman_27410 on March 14, 2011, 11:49:43 PM
my 1349 motor has 10:25 compression pumping 200 PSI....... runs great on pump gas.
That sounds about right. Thinking in simple terms of relating compression pressure vs. surface area of piston:
If stock compression is 180psi (new motor) and stock piston size is 77mm dia. (a= 4654) then Frank's 82mm piston (a=5278) with ~12% more surface area should be able to run ~12% more compression pressure: ~201psi, and have the same ratio as stock.
However, if Carterc's bike has compression of 200+ psi and 77mm pistons.....I would be careful with pump gas.