FZRSupport: the FZROnline Archive

Hey Folks

Been lurking for a while, first time posting, last year i transplanted an 88 FZR1000 engine, carbs and Vance & Hines exhaust into my 87 FZX750, one of the kickers with this is the fact i cant run the stock air box as it wont fit. So i installed a stage 3 kit, so here is my issue. from idle to right around 3000 RPM there is a really bad stumble, so bad that its a little difficult to get the bike moving from a stop, it seems to get worse once the bike is warmed up which leads me to believe its a rich condition, i have tried adjusting the clip and a/f adjustment screws but to no avail. here is my setup:

- 140 DJ mains
- Stock idle jets (mikuni 17.5) had 20's in it prior but would slowly flood out at idle, it actually made a bit of a difference after swapping the 17.5 in
- stage 3 needles on the 3rd clip
- had the stage 3 springs in at first but read that the stiffer fzr1000 springs might be the problem, i have some on order but threw the fzx750 springs in (stiffer but not as stiff as the 1000 springs) and it seemed to make a slight difference.
- A/F set to 2.5 turns out

what i have tried (all of this was prior to the 17.5 pilots):

- tried maxing out the needle in both directions, affected the top end more then anything, didnt change the issue
- tried the stage 3 springs and the fzx ones
- tried adjusting the a/f from 1.5 to 3.5 in increments of .5

im at a loss, i haven't had this much problems on any bike before, ive installed jet kits on multiple bikes (mostly vmaxes) with no issues. dropping the pilots seemed to make the biggest difference so kind of was thinking dropping down to 15's, bike seems to run really good when cold.

Have you checked fuel heights...should be 8.3mm below line on float bowl?

That's the one thing I haven't done yet but was thinking about it the other day. Do you just use a clear hose on the drain and open the drain screw to see if it's where it should be? How do you fill the float bowl after you have filled the hose? Do you turn the pump on?

Yes a bit of clear hose...have the bike as upright as you can and yes, leave the pump on. Connect tube to drain and open drain screw a good few turns. You have +/- 1mm on a nominal of 8.3mm below float bowl line.

Manual mentions running the bike for a few minutes with the float drain open. Should I do this?

Not quite sure why... i certainly never done that on TDM last week and i got the heights spot on....might be worth just draining carbs first to get rid of any crap then check heights

Ok. That's how I have done them in the past. Wasn't sure if the manual knew something I didn't. I will give it a try and see what I come up with.

Are you running a non stock cam? I ran into an interesting situation on mine where after mods including cam and big bore and porting it wanted leaner jets than before. I personally believe it was because the change in velocity in the carbs which was much high so even though there was a smaller jet than before the mods it actually pulls more fuel because of the higher velocities. It did what you are describing with the 140 jet that comes with the stage 3 kit. I believe I have a 130 or 126 in it now and the air fuel is spot on.

Also it could be an ignition issue.

kolederacer wrote:Are you running a non stock cam? I ran into an interesting situation on mine where after mods including cam and big bore and porting it wanted leaner jets than before. I personally believe it was because the change in velocity in the carbs which was much high so even though there was a smaller jet than before the mods it actually pulls more fuel because of the higher velocities. It did what you are describing with the 140 jet that comes with the stage 3 kit. I believe I have a 130 or 126 in it now and the air fuel is spot on.

Funny you say this kolederacer..... i have just done the valve clearances on my TDM850 and all of a sudden had a rich condition in the 2k to 4k rpm region. Had to adjust fuel heights to get her back running with a nice smooth delivery. In my humble opinion, if you do any head work on a carb bike you need to fine tune your carb set up as part of the job.

Schmo9 wrote:
Funny you say this kolederacer..... i have just done the valve clearances on my TDM850 and all of a sudden had a rich condition in the 2k to 4k rpm region. Had to adjust fuel heights to get her back running with a nice smooth delivery. In my humble opinion, if you do any head work on a carb bike you need to fine tune your carb set up as part of the job.

We used to get this all the time when I worked in tuning /race shops.

Service/valve clearances + carb tune...£??? No far too much...doesn't need carbs ...............explanation given....no..too dear... OK.

Rebore/pistons ...2T.+ carb tune...same script....no don't do carbs ...runs OK..just rattles.

Comes back...Here this isn't right...flat spots...smells rich....blah blah blar.

Right,, you were told carbs would require attention after other work.

How much £ ?? now to fix.?

Now job is priced as new work (not incuded with original job) and hence much higher...

Fook me that's much more than original quote...

Full explanation given again and as to why.

Vexed,out of pocket, punter.

Rinse and repeat on a daily basis.

I think you should probably look into this after what everyone else is saying also. After the changes to mine the 140 jet turned the swing arm black in a couple of days when i still had my low exhaust.
You can actually see it in my avatar.

The size of the main did cross my mind. I did start with the supplied 136 in the kit and the bike was running waaaayyyyy too lean. I checked the outside carbs float levels last night (will check the inside too) and one was a little rich at roughly 6mm from the line. The other was close to 8.

As for the cam. I'm not sure if this would have an after market one or not. I purchased the engine and carbs from someone who tore his bike apart and never put it back together. I adjusted the valve clearances and replaced all the gaskets during my conversion to the fzx and installed the stage 3.

hate to resurrect a 2 year old thread but still having issues with this thing. pretty well got the low end stumble tuned out by tweaking the needles by half increments (ended up at clip at the leanest setting with a washer to bring it half way between the the 2 grooves), dropped the mains down to 130 mikunis, a/f at 2 turns out with 17.5 pilots and stock fzr springs. bike seems to run ok, has a hesitation at wide open right around the 6000rpm range that i cant put my finger on, issue is it it sparatically starts to have issues where its hard to get moving from a stop and will start back firing on decel (backfire usually happens after a hard wide open run to redline).

been reading that the motion pro setups are better for these bikes but dont really want to buy another jet kit if its not going to fix the issue (they charge close to $50 just to ship to Canada!)

curious if anyone else has the stage 3 kit in their 87/88 fzr1000?

Maybe move the question to the facebook page ? https://www.facebook.com/groups/524004617675938