WAYWARD 1998 944SS - NEEDS HELP

[Brid]

The completely OEM airbox lid and all this talk of upgrades made me laugh.

Did you miss something?

I'm still a bit in the dark here, as I've tried running it without the airbox lid - and it makes no difference. If changing to K&N pods would be an epiphany, we'd be there in a shot, but nobody so far has sworn it will cure the problem. Also, please remember - I 'inherited' this job, after several more folks had their grubby fingers in there, and I'm just trying to be humble and ask folks with better knowledge than me on this particular issue.

[koko64]

Yeah I feel for you as there have been a few cooks in the kitchen before you. I pick up jobs like that all the time after others have well and truly make the beast with two backsed the bike. It's normal business now and I'm used to it.

[koko64]

Some thoughts.
Check the ignition wiring and check which way you went with the pick ups. It sounds like an unwitting rev limiter from some ignition issue. As if it is not advancing.
Or.
Fuel pump ok? Fuel pressure too much overwhelming the float needles? Running the return line with the pump?
What do the plugs look like after all that fuel from the 60 slow jets and 185 main jets? They may be breaking down up higher in the rev range. The 185s would drown it whether the airbox was open or closed.

Don't do pods as a solution, with an unported motor the result is similar to an open airbox. A whole lotta other tuning there. Stay with the closed airbox and SUDCO tuning (although I have often found the 60 slow jets too rich on 41s), or go open airbox and speeddogs baseline which I also use with some variations on needles depending on how much I mess with the airbox.

[Brid]

Some thoughts.
Check the ignition wiring and check which way you went with the pick ups. It sounds like an unwitting rev limiter from some ignition issue. As if it is not advancing.
Or.
Fuel pump ok? Fuel pressure too much overwhelming the float needles? Running the return line with the pump?
What do the plugs look like after all that fuel from the 60 slow jets and 185 main jets? They may be breaking down up higher in the rev range. The 185s would drown it whether the airbox was open or closed.

Don't do pods as a solution, with an unported motor the result is similar to an open airbox. A whole lotta other tuning there. Stay with the closed airbox and SUDCO tuning (although I have often found the 60 slow jets too rich on 41s), or go open airbox and speeddogs baseline which I also use with some variations on needles depending on how much I mess with the airbox.

I re-checked the ign wiring today, and everything seems fine. Strobe shows that it is barely getting to full advance, so my 2 degree retard (an educated guess!) looks OK. Plugs were new before last quick road test (which only lasts a couple of minutes before the problem shows up) so, haven't checked them. As mentioned - new fuel pump, but I've also tried it with just gravity feed -- no difference. Using the return line, which is working fine.

[koko64]

IIRC about 0.7 of a deg advance per 1mm of pick up being slid back. I would go for 3 deg advance so 4-5mm. Also that is assuming the ignition boxes you are using have the stock advance map in them. Some boxes already have a retarded map for hi comp application for example some DP boxes come set up for various states of tune. That could mean the ignition is too held back to rev. Maybe. You might have some testing to do there if nothing else is wrong.

Re the amount of adjustment of the pick ups, Brad Black and my math teacher wife helped me with that one. How much you slide em back?

[koko64]

Someone might recognize those boxes and what's in 'em.

Nowdays I would rather use an adjustable Ignition system like the Ignitech and leave the pick ups alone. Don't lose your way with them. Did you mark where they originally were? Where is the idle advance in the window?

[Brid]

Idle advance is just a tad to the right of the dot, and same with full advance. I bought the boxes off an E-Bay seller, who assured me they had the stock advance curve, and would be fine using the Nology coils. Again - this problem arose with the stock Kokusan boxes (which I changed due to weak spark) so, it seems doubtful the Procom ones are at fault?

[koko64]

I don't know the numbers on them and what maps are inside.

If it had stock boxes before and did not ping then the pick ups may have already been slid back. How much who knows? A pic of the window at idle and full advance will quell my concern or confirm it. That could be an issue if the same people also slapped a Desmoquattro head on it.

LT Snyder doesn't like the Nology coils, something to do with incompatibility issues but I have no FHE.

[Speeddog]

I'm wondering if the voltage at the coils may not be enough to fully charge them beyond 5k rpm.

Which Nology coils do you have?

[koko64]

SD is a Ducati specialist.^

Got an in line spark tester? Spark drop off at 5k?

[Brid]

I'm wondering if the voltage at the coils may not be enough to fully charge them beyond 5k rpm.

Which Nology coils do you have?

Not in the shop (11.37pm here!) so, can't answer that, however - I specifically asked both suppliers (boxes & coils) about compatibility, and can only hope they were honest??  

[Brid]

SD is a Ducati specialist.^

Got an in line spark tester? Spark drop off at 5k?

Yes - I have an inline tester, and will try that tomorrow

[ducpainter]

I'm still a bit in the dark here, as I've tried running it without the airbox lid - and it makes no difference. If changing to K&N pods would be an epiphany, we'd be there in a shot, but nobody so far has sworn it will cure the problem. Also, please remember - I 'inherited' this job, after several more folks had their grubby fingers in there, and I'm just trying to be humble and ask folks with better knowledge than me on this particular issue.

I wasn't laughing at you. Sorry if that's what you thought.

It was just the situation I find amusing. Whoever built that thing with FCR's and a stock airbox with that jetting is capable of any crime. I wish there was an easy answer, but as you've begun to dig into it, you've already figured out there isn't.

[Brid]

I'm wondering if the voltage at the coils may not be enough to fully charge them beyond 5k rpm.

Which Nology coils do you have?

Hey Speeddog, coils are PFC-30-S, 3 ohm. I just ran it with an inline spark tester, and it never misses a beat. In fact, looks like it gets better as revs increase. BTW - when you said 'open airbox' in an earlier post (with jetting suggestions) how open do you mean? Heard of folks cutting the top out - but still running a filter, using K&N RU1750 pods etc. We're definitely not shy about trying anything, #1 - to cure the problem, and #2 - to optimize any power gain from the 944 kit and FCR's.

[Brid]

A bit of an update! I went back into the timing side case to (again) check everything was good with the pick up coils, and found the threads were 'popped' on the top coil mounting bracket (front one) So, although the bottom one was good, the bracket could vibrate with the engine running. I imagine it just caused a 'variable' air gap on the front pick up coil? A quick helicoil job, and air gaps again set at 0.024", and she runs again. Too late to road test it tonight, as I'm going to get dinner before 11pm for a change. Fingers crossed for tomorrow