So I blew the 88 on my 04 fxd three months ago and I just got it back! I did the 103 transplant and the bike is a rocket now but I am having a problem with the carb. I have a 42mm mikuni that I was using on the 88 and It seems like the bike is ideling way too high now and Im only getting about 60 to 65 miles out of a tank. When I cold start I cant use the choke because it pops and backfires. Should I rejet?

I am laso having a problem with the starter. It sounds like its gringing.

 

Your carb needs work and not just jetting. Obviously it is running way too rich. Have you set the float level?

 

No I put it on the 88 out of the box and just slaped it on the 103 with no adjustments. It is also making king of a shudering sound kind of like the butterfly is slapping open and closed. my intake is a forcewinder.

 

it sounds like you have more than one problem.

the starter grinding is most likely a week battery. fix that first.

then if the bike is idling high and you cant adjust it out, you may have a vacume leak.

the carb jetting should not vary that much. esp. if you had pipes and force winder on the other engine.

your noise issue is curious, and i dont have a good answer for that, unless maybe the valves could be out of adjustment, but that is purely a guess.

 

I would take it to somebody with fine tuning equipement........ 65 miles per tank?

 

you need to set the carb up right... I doubt it is right for your bike "out of the box"
is your started mounted tightly to the primary?

 

Well as far as the starter issue the battery could be the problem from sitting for 2 1/2 months but the battery is prety new. I did ride yesterday with no problem with the starter. Afriend of mine said I may need a starter with more volts for high compression motors and the starter does have 32000 miles on it. He said it may just have to get used to the new motor too.

All of you could be right about the carb but one thing is for sure. Out of the box is the problem. I think im going to take it in for fine tuning and a dyno run. Ive got to know how much power this thing is putting out. I thought the 88 had a lot of power with the things I had done but doing the 103, and 211 cams in addition to the 42mm mikuni 2 into 1 SE pipe (that I got new for 20 bucks at a swap meet) and a force winder intake
this bike is a beast. I will go with bigger cams and head work later when get used to this power and of course when I have a lot more money!

 

Check the enrichment cable and make sure that it is seated all the way. If you have a Mikuni cable there should be a little play, if the play is not there then it is not seated properly and will make the bike run very rich. Also check for a vacum leak, can you slow the idle down with the adjuster?? Starters do not get used to a new motor, sorry. If you have any more questions PM or E-mail me.

 

anyone else think that the 42mm carb may be a bit on the small side?
not saying this is your prob. just an observation.
i know most 95 inch upgrades recomend a 45mm
just a thought

 

Ditto on the dyno runs to check for AFR and your friend may be right about the starter motor change due to higher compression. Put a new carb "out of box" on my Heritage and it ran leeeeaaaannnn and had to re-jet quite a bit.