Jetting an FCR with a higher comp motor

[QuadRid3r442]

Hey guys I just had an Athena 435 kit put in running the 94mm piston that came with it. I have an FCR and I'm trying to get it to start but it just won't and guessed that it needs re-jetting. The motor wasn't all stock before and was still running the FCR on it. Does anybody know how far the jets need to be turned or give me a link to a page that does? That'd be great. Thanks

[ifixtheyride]

What do you mean won't start be more specific? I doubt the jetting is off far enough for it not to start with just putting on big bore kit something else is wrong. Mine was starting hard and I did a compression test that showed low so I turned myself on to the Athena big bore kit and when I was done the same thing no start woops I neglected to check the valve clearance when I had it apart and sure enough that was the real problem the the intake valve was shot as is popular with these so now I have kibblewhite valves and an Athena big bore kit. I am not all that impressed with it but I have stock carb where do you get the FCR?

[QuadRid3r442]

Originally posted by ifixtheyride
What do you mean won't start be more specific? I doubt the jetting is off far enough for it not to start with just putting on big bore kit something else is wrong. Mine was starting hard and I did a compression test that showed low so I turned myself on to the Athena big bore kit and when I was done the same thing no start woops I neglected to check the valve clearance when I had it apart and sure enough that was the real problem the the intake valve was shot as is popular with these so now I have kibblewhite valves and an Athena big bore kit. I am not all that impressed with it but I have stock carb where do you get the FCR?

I didn't do the work. BCS Performance of Mass. did all the work. I got all new valves and the only thing im left with is it won't start. When I try to start it, I get it to start cranking and puffs out of the exhaust, but no final start. I think the jets are off just enough to make it not fully turn. I may just need bigger jets like a 118 for a main. I'm not sure where the previous owner got the FCR. If anybody sees this post I still need help so please reply if you can help

[ifixtheyride]

Still sounds like the timing is off was this carb on the quad before you installed the big bore or are you doing this all at same time? Did you add Hot cams? even with wrong jetting it should still fire try spraying starting fluid into carb with air filter off just to see if it fires. The main jet is only used at mid to high throttle the pilot jet and air/fuel mixture is for idle I believe someone correct me if I'm wrong.

[QuadRid3r442]

Originally posted by ifixtheyride
Still sounds like the timing is off was this carb on the quad before you installed the big bore or are you doing this all at same time? Did you add Hot cams? even with wrong jetting it should still fire try spraying starting fluid into carb with air filter off just to see if it fires. The main jet is only used at mid to high throttle the pilot jet and air/fuel mixture is for idle I believe someone correct me if I'm wrong.

It does have hotcams. I had mentioned that I had the FCR before the big bore. I bought the quad used with the fcr, hot cams, and a better piston, yoshi pipe, etc.. but I'll try the starter fluid but do you think my spark plug is shot? Is it a good idea to take it out dip it in gas and put it back in? I haven't tried it yet but please reply back.

[airmobile101]

You dont need bigger jets!! The damn thing should still start. Do you have spark?? If so, do a compression check. Just because you have a shop do your head and piston doesnt mean its done correctly. As for the Hotcams, if I remember correctly, Its a tooth short with the Hotcams. Check Z400CENTRAL.COM for install. Oh heres one for yea, with it being warm and all, make damn sure the choke isnt on!! Lets us know!!

[dan42684]

try a bigger jet. my z wouldnt start due to that reason. when i put the bigger jet in, it fired right up.

[QuadRid3r442]

Originally posted by airmobile101
You dont need bigger jets!! The damn thing should still start. Do you have spark?? If so, do a compression check. Just because you have a shop do your head and piston doesnt mean its done correctly. As for the Hotcams, if I remember correctly, Its a tooth short with the Hotcams. Check Z400CENTRAL.COM for install. Oh heres one for yea, with it being warm and all, make damn sure the choke isnt on!! Lets us know!!

yeah well 1st of all i dont think theres a choke on the fcr to be honest and never used a choke on it so it's on whatever it was before. And believe me, I think the shop know's what they're doing. Main sponsor of NEATV-MX series and have a bunch of sponsored riders so my trust is with them. However, The guy that posted after saying you need bigger jets is probably correct. There's puffs out the exhaust, checked the spark, and everything seemed to be running good. So I think I'm just gonna get bigger jets.

[QuadRid3r442]

Originally posted by dan42684
try a bigger jet. my z wouldnt start due to that reason. when i put the bigger jet in, it fired right up.

nice. can you tell me what jets you had before and what jets you had to put in and adjust to start it? I can't see how your gonna go from maybe an 11 or 12:1 comp ratio and 400cc up to whatever ratio the athena throws out and your also bumping things up to a higher cc i think it's gonna require a little more gas/air.

[cataway]

well now just so that you have some sort of base line to work from ,if in fact it is the jetting , this is what works for me
160 mj
48 pj
2 turns out on fuel screw
4th clip on the needle
on the leak start with a #35 ,i plugged mine to get the full shot
all this is with no air box .
with this jetting my spark plug is a touch darked than what would call perfect ,yet when run on a dyno with AF it was right on the 13 line.

have you in fact rechecked the timing of the cams and the valves clearances ?
if you using hotcams how many chain pins do you count between the timing marks ?
BTW some pic's would be nice

[QuadRid3r442]

Originally posted by cataway
well now just so that you have some sort of base line to work from ,if in fact it is the jetting , this is what works for me
160 mj
48 pj
2 turns out on fuel screw
4th clip on the needle
on the leak start with a #35 ,i plugged mine to get the full shot
all this is with no air box .
with this jetting my spark plug is a touch darked than what would call perfect ,yet when run on a dyno with AF it was right on the 13 line.

have you in fact rechecked the timing of the cams and the valves clearances ?
if you using hotcams how many chain pins do you count between the timing marks ?
BTW some pic's would be nice

ok i'll look into the jets thanks. but what do you want pics of? the cams and the carb? or just one of the other? I couldn't see why the shop would make a mistake on the cams. but i'll definately post up some pics for ya

[airmobile101]

Originally posted by QuadRid3r442
yeah well 1st of all i dont think theres a choke on the fcr to be honest and never used a choke on it so it's on whatever it was before. And believe me, I think the shop know's what they're doing. Main sponsor of NEATV-MX series and have a bunch of sponsored riders so my trust is with them. However, The guy that posted after saying you need bigger jets is probably correct. There's puffs out the exhaust, checked the spark, and everything seemed to be running good. So I think I'm just gonna get bigger jets.
Man Im sorry, I was thinking FCR,but visualizing Mikuni BSR36. LOL
Any luck with the jet?

[airmobile101]

Originally posted by QuadRid3r442
ok i'll look into the jets thanks. but what do you want pics of? the cams and the carb? or just one of the other? I couldn't see why the shop would make a mistake on the cams. but i'll definately post up some pics for ya
I think Cataway wants a pic of the cams set at BTDC to verified its timed correctly?

[QuadRid3r442]

Originally posted by airmobile101
Man Im sorry, I was thinking FCR,but visualizing Mikuni BSR36. LOL
Any luck with the jet?

haha yeah it's a keihn lol but like cataway said im prob. gonna need bigger jets as he has listed. where can i pick those specific ones up? like anywhere on motosport.com? I think the shop is gonna jet/dyno it for me so they may have them in stock I just need to find the time to get up there but i posted this cuz the 22nd is gonna be like the 4th race ive missed so far and wanted to get things going quicker. but pics of the cams are on there way i just need new batteries for my camera

[airmobile101]

You can get FCR jets from DennisKirk.com . I think RMATV sells them also, but not for sure.

[ifixtheyride]

It's killing me have you found the issue yet? I'd be really really surprised if it were the jets I still think it would start.

[QuadRid3r442]

Originally posted by airmobile101
You can get FCR jets from DennisKirk.com . I think RMATV sells them also, but not for sure.

thanks for the info

[QuadRid3r442]

Originally posted by ifixtheyride
It's killing me have you found the issue yet? I'd be really really surprised if it were the jets I still think it would start.

haha sorry bro i havent posted stuff in a couple days. i actually brought the bike up a couple days ago to bcs performance in mass. to have it jetted/dyno'd. but thank you everybody that gave the info that you could.

[2muchquad]

old post but i BET it wasnt the jets...:D

[juice420]

Originally posted by QuadRid3r442
I didn't do the work. BCS Performance of Mass. did all the work. I got all new valves and the only thing im left with is it won't start. When I try to start it, I get it to start cranking and puffs out of the exhaust, but no final start. I think the jets are off just enough to make it not fully turn. I may just need bigger jets like a 118 for a main. I'm not sure where the previous owner got the FCR. If anybody sees this post I still need help so please reply if you can help
If I were you i'd take it back to who did the work so they can fix it. Am i the only one who notices this?? And they should fix it for free too.

[QuadRid3r442]

wow this thread is old. yeah I sold that bike like two years ago, and they said it was some sort of electrical problem. but when it ran it kicked ***. but thanks for the reply.