Uh oh, losing power above 5K

I got my dyna-s in today! :woohoo:

Any tips or tricks with putting this in? I read the instructions of installation and the wiring is pretty straightforward I believe. Should I be worried about timing? Will I have to retime it or do something about my timing advancer?

Thanks!

UPDATE

The dyna-S was installed with no hiccups or problems!

However it did not solve my issue. I'm still experiencing power loss from about 4-5K and up. The bike actually felt much better and more powerful with the dyna-s, but still the same problem remained.

The next logical thing I am thinking of attempting will be the check and clean the carbs out. Which is awful because I still have the stock airbox. I started to attempt at taking the carbs off on a 90 degree day in a stuffy garage and it quickly became aggravating and I walked away from it. I was thinking of making the switch over to pods.

I know theres a couple of threads out there of stock airbox vs pods. I'm just leaning towards it for ease of removal, workability, and hopefully a few more horses. Also just curious as to what I should use for jetting? I have stock mikuni vm24 carbs, and a vance and hines that is baffled. Any suggestions? Thanks everyone!

Would install brand-new NGKB8ES sparkplugs. And road-test with temporary hotwire direct from battery positive to #2/3 coil (to assure full battery voltage to coils).

Am thinking it's better to first assure all ignition components being up to snuff before addressing the carbs.

Also would assure ample fuel supply available to carbs.
And remember, even perfect carbs can't compensate for shortcomings in ignition or compression or fuel supply.

Having always hated wrestling with the rock-hard airbox hoses, finally ordered a new set from Z1E. The difference is simply amazing as the soft new pliable intake rubbers make removing and installing carbs a non-issue. Quickly and easily off and on. So would urge keeping the stock airbox and retaining its numerous advantages. While avoiding all the additional maintenance, performance and tuning problems inherent with pods.

So IMO, instead of pods, it would be a better investment to obtain new intake rubbers. Click here > Hmmm...Those feel really good!

And if desired, here's a K&N for the airbox. Click here > K&N Air Filter

But a new paper filter is surprisingly good at flowing almost as much air, and cleaner air than K&N. And plenty good for testing. Click here > Paper Air Filter

Would also like to see results of a test-run made with the fuel tank cap left open (not snapped down). Just to assure there's no issue with blockage in the cap vent causing fuel starvation at higher rpm in 4th or 5th gear. There are also other reasons for fuel starvation at higher speeds, but fuel cap vent blockage is a common cause.

Thanks for the progress reports.

Good Luck!

Ahhh I didn't know they sold replacement rubber for the airbox side! I had to buy new rubber on the opposite side (engine-carb) when I first got the bike. I also tried the vent cap and that didnt help.

I'll try the direct coil wire solution, and do a plug check as well, I should just clean the carbs anyway though because I'm just not sure. At what RPM does the main jet take over?

If any doubt about clogged petcock pick-up tubes up inside tank, would remove petcock from tank and clean it, and also flush out tank with fresh gas, and install new in-line fuel filter.

Here are two of the various fuel filters available from Z1E.
3" filter
2" filter

Would like to see plug readings (on brand-new NGKB8ES) after a high speed throttle chop (while pulling hard in 4th or 5th gear, simultaneously close throttle, cut ignition, disengage clutch, and coast to stop). Carry along a short length of rubber hose that fits snugly over plug to aid removal and replacement without burning fingers). The idea is to help determine what's going on inside the combustion chambers at speed, under load, when the performance issue is happening. It's best to do this test before addressing carbs, which affords a basis for comparison without adding more variables to complicate diagnosis. Then can repeat the test following any changes made.

Mainjet ultimately limits maximum volume of fuel available to needle jet at wide open throttle where it has the most influence on fuel mixture. It begins having an effect at about 3/4th open throttle with increasingly more effect toward approaching full open throttle (as the jet needle loses influence due to less and less taper allowing more fuel at the needle jet being supplied through the main jet).

Should also check float bowl fuel levels using the clear plastic tube test before undertaking carb work.

After plug readings from the high speed throttle chop test, might be time to begin a new topic in the carb forum.

Good Luck!

Sounds good! I'll get some time to hopefully run the test today! I'll keep you updated!

Good update!

So I took off the carbs! I didn't get new rubbers between the air box and the carbs. I just pushed the rubbers back into the box as much as i could, and got the carbs off. To get them back on i brought the rubber inserts inside and put them in a heating pad for almost an hour to make them malleable, and that seemed to help some upon re-installation

When I had the carbs off, i checked out the air/fuel screws and they were all over the map! I think it was 2.5 turns out, 2.5 turns out, 3.25 turns out, and 1 turn out. So that didn't help. I took out the mains and the pilots and blew them out with compressed air. One of the pilots was half unscrewed! I haven't fiddled with these carbs ever before, so i was glad to check it out and fix it up!

I re-installed and set the air/fuel screws at 1.5 out each to start. The bike came back to life! it was fantastic! Seems to be running extremely well with the electronic ignition too! I'm very pleased, and at least this experience allowed me to go through and verify everything I needed to verify on the bike!

Thanks for all the help! I'm sure it needed help electrically too, as the points were both pitted as well!

Congratulations! :woohoo:
And thanks for the report!

Good Luck!

I have been in situations just like this. NO FUN ! I have also bench tested coils [resistance] and they have checked out perfect. Thing is with coils and I really don't understand why they recommend a resistance check, BUT many many times I have had perfect readings, and then replace them/it, and that cures the problem. Coils produce spark. The higher the RPM the more spark typically. Bench testing them only gives you a resistance reading. Maybe thats just a starting point? I did NOT read every reply, but what I did read I saw nothing mentioned of backfireing either threw the intake or exhaust? I have seen many times the coil whindings apparently open up when hot. Maybe yours like many others work fine at lower RPM's but default in the higher RPM's. When they do, the vehicle breaksdown [enigine misses] but typically no backfiring.
If its just going flat at the higher RPM's I would make sure the exhaust, as well as the air intake systems are not blocked by a nest or the likes. Sometimes it is just the simplest things. It appears you have checked all the essentials, but I personally would not have any faith in the res. test.
Dble. ck. your cam chain adjuster, air and fuel system, as well as exhaust. It will be something stupid......LOL
Good Luck