Author Topic: No Power Below 6K (Read 3394 times)

MasterM3 · « **on:** May 22, 2006, 01:44:13 PM »

Recently, after installing my slip on, I noticed a very dramatic lack of power below 6k. It was quite clear that something was wrong. I thought this might be because I was running lean. Yesterday I had a jet kit installed with the 97 main jets. The carbs were cleaned and synched along with th jet kit install.

Even after installing the jet kit, the bike still bogs dramatically down low. After around 6k, it pulls like a bat out of hell.

But down in the rpm range, it is just ungodly slow. My friend who is quite experienced with working on bikes said that it might be either a coil or bad gas. The gas in the tank has been in there for about 2 weeks I would guess. Can you guys offer any suggestions? What are the symptoms of a bad coil? The spark plugs and wires were changed about 600 miles ago.

MasterM3 · « **Reply #1 on:** May 22, 2006, 01:45:39 PM »

Also, I'm going to run the tank down to the reserve and fill it up with gas. I'm really hoping its a gas issue. I don't think the friend who installed the jet kit followed the tuning instructions that came with the jet kit. Could this be the problem?

stormi · « **Reply #2 on:** May 22, 2006, 02:38:00 PM »

Well I can't help you with the jet kit stuff, but I can tell you the signs of a bad coil.

A bad coil would mean that you're not getting, or not getting consistent spark to 2 cylinders.

Therefore, you can check this by doing a couple of things. Start the bike and run it for a couple of minutes, then turn it off and disassemble for the following:

1. Check the spark at the plugs.
Take the plugs out, one at a time, attach them to the wires (outside of the engine) and then ground them to the engine case ( not next to the newly empty spark plug hole, preferrably) And watch for spark. It should be a nice fat white/blue spark. Check each of the plugs. This proceedure is described in your owner's manual, and is much easier with a helper.

If you're not sure if the plugs are sparking with nice fat healthy spark, compare them to the other 3 (mental note) .

1 and 4 share a coil, as do 2 &3 .

If you notice only one plug seems to be acting up, it could be a corroded plug wire. Take the boot off, cut about 1/4 inch off the end of the wire, put the boot and plug back on and see if that makes a difference. If it doesn't, consider replacing your plug wires first, before you replace the coil. I hear you can get plug wire by the foot at the dealer, and likely other places too.

2. Check the spark plugs.

When you take the plugs out, check to see their condition, are they wet? That would mean that gas was getting into the cylinders, but not being lit off. That would indicate a spark problem.

Spark plugs are often a good indicator of what your engine is doing.

If it's too lean in there, the plugs will show it (of course I don't remember what this looks like, cos it's one condition I've -never- had an engine suffer)

Good spark and fuel mixture, the plug will look used, but not coated with anything
Too rich - you'll see carbon coating the spark plug end
No spark - the plug will be wet.
Of course collision from something rolling around in the cylinder will be really obvious, but I doubt that's your problem.

3. Another indicator of whether you're sparking on all 4, is what's the temp of the exhaust? do all 4 of the headers feel like they're about the same temp after a couple minutes of running? If not, which ones are not as warm will point to you which cylinders have plugs that you need to take a peek at.

If I've missed anything, or gotten any of this backwards, I'm sure someone will jump in.

gsxr400 racer · « **Reply #3 on:** May 22, 2006, 06:04:24 PM »

check to make sure the rubber plugs for the pilot circiuit are still sealing! cheers
jay

Thief400 · « **Reply #4 on:** May 22, 2006, 07:09:09 PM »

If the rubber plugs are in the right place try raising the needles up

MasterM3 · « **Reply #5 on:** May 23, 2006, 12:40:44 PM »

how essential are the tuning steps that factory pro reccomends? could this possibly be what is causing the lack of power below 6k?

Herr Tod · « **Reply #6 on:** May 23, 2006, 02:00:54 PM »

Put the other can back on and see if it is better. I have 3 end cans, each makes the bike run different. One gives more power in the lower revs, which sucks because the whole engine is designed to have power in the high revs. The other gives a little bit extra high end but doesn't take away much from the low end, I prefer this one. The last one is the stock can.

MasterM3 · « **Reply #7 on:** May 23, 2006, 05:50:56 PM »

well, i bought this exhaust off of another forum member so I assume that it shouldn't affect performance that drastically. im going to ride the tank till the reserve and give it some fresh gas. i reallllllllly hope that will fix the problem. The idea of tearing into the carbs again just doesn't appeal to me.

MasterM3 · « **Reply #8 on:** May 25, 2006, 12:33:32 PM »

i installed the jet kit on sunday and experienced the lack of power down low. i didn't have time to ride the bandit until last night. Upon startup she ran perfectly, pulling nice and strong throughout the powerband. I went to a gas station, shut her off and filled her up with gas and the problem came back. im really stumped. I guess I'll just have to tear her apart again this weekend and try a little bit of everything.

sirdarkheart · « **Reply #9 on:** June 14, 2006, 12:39:47 AM »

I know this is an older thread, but I had a similar problem to this. I actually had a lack of power below 7-8K rpm depending on which gear. Whenever I gave it full throttle it would bog and hesitate. This flat spot below 8 k rpm was bad and I thought it was b/c my mixture was too lean. Turns out after a few hours of playing with needle height, that my mixture was too rich. I made it leaner then it was and it runs great on the low end and high end. The middle still has a weird flat spot in gears 4-6 from 6-8K rpm almost exactly in each of those gears. For some reason 3rd gear though still pulls fairly hard w/o hesitation in this mid range flat spot. I hope this helps.
:D