2001 busa strange "shutter" issue while holding 70-75 mph

AZIROC

Registered
This problem just recently started out of the blue but I also have not been riding much. Anywho, this issue only starts when I'm going to work (20 miles 1 way). I haven't gone any long rides so I can't say on that. The "issue" is if I'm holding a speed (between 70-75, 6th gear about 4300 rpms) for a long time (10'ish miles) the bike will act like it kicked down into 5th the back I to 6th, all within a 1/2 - 1 sec. It's nothing violent, just rpms will bog down then go right back to where it was.

I checked the oil and it was full. This coming up weekend I thought about pulling the clutch plates and checking them out but I was wondering if others have had this issue ot know what I should b looking for.
 
Does it run good otherwise and make good power?

When it acts up does it run rough?

Does it respond to throttle when it bogs down?

How many miles on the bike?
 
Does it run good otherwise and make good power?
Yeah, runs as smooth as day 1.

When it acts up does it run rough?
No, when it happens it slows me down by a few (5 at most) mph but then it goes right back up to 70-75

Does it respond to throttle when it bogs down?
Same as above. I can have my throttle stay where it is when it happens, it goes down at few mph, and then goes eight back to what speed I was doing.

How many miles on the bike?
Just hit 63k. Purchases jan/05 with 26xx on it. Always maintained. Most of the parts in my sig (and new clutches) went in around 30k.
 
Could be the fuel pump, and/or a clogged filter.
Gen1's, especially older ones are notorious for it.
 
Like sixpack said, take a look at the fuel pump, check the pressure and flow, also if your shop has it, have them scope it to check it electrically.
 
Had one doing same thing. Kickstand was bouncing causing the bike to act stupid. Bypass the kickstand switch and try it again.
 
Has it done this on multiple tanks of fuel or is it the same one?

-D

Now i think about it, it may be the same 2 month old gas. Maybe even even month old. I road home from work and have less than a gal in it so it'll prob just take the whole fuel system apart this weekend apart and check it out
 
Now i think about it, it may be the same 2 month old gas. Maybe even even month old. I road home from work and have less than a gal in it so it'll prob just take the whole fuel system apart this weekend apart and check it out

2months not to old. I've had year old that did fine. Bypass kickstand safety and test again. It's a no cost fix. Only a little time.
 
I just took my kickstand safety switch off entirely, but as a possibility, it seems logical.

-D

I've seen kickstand safety switches cause problems too, but didn't stop to think that could be it.
It definitely could be the problem.
1bondoman always has good input.
 
I've seen kickstand safety switches cause problems too, but didn't stop to think that could be it.
It definitely could be the problem.
1bondoman always has good input.
Thanks man. I try. I always base my responses on past experiences with similar problem.
 
Well, the last 2 days i road to work. besides it happening once on my way to work (when i started this thread) but on my way home and yesterday i had no issues. the only thing thats alittle "off" is my mpg. usually its around 43 but its now around 40-41. Also, i noticed around 70-75 mph, the engine seems alittle louder. im thinking its just cause i havent ridden in a while and just not use to the noise it made/makes. I work today so i wont have a chance to look at it till tomorrow. the kick stand is alittle stiff so ill see what thats about as well as just bypass the switch.

thanks for all the replies. ill update if anything changes..
 
Yeah, I'll prob throw some seafoam.

At any other speed besides mentioned above I've had no issues. I do think it's happened more frequently the more gas there is in the tank.

Mine only did it at high speeds in 6th. If it were fuel related you wld see it anytime you got on it hard.
 
**update**

Wish I could say the problem went away but it hasnt.

Since my last post I've changed out the fuel filter (took the tank off, took out pump), put new gas with seafoam in it, cleaned the plugs, cleaned the air filter, cleaned out the throttle bodies and double checked my map on the power commander.

I've ridden about 1/2 tank worth of gas and had no issues till today. Same situation as before, doing approx 75 mph (about 4500 rpms) and I can hold that speed for MILES, but if I get on it (to pass a car) and I get above 4700 rpms, it bogs down. Unfortunately I didn't see how much the rpms changed as I was literally in traffic and trying to not get hit as my speed dropped atleast 5-8 mph.

Could it b fuel pump? Something else? I'm going to try and do an oil change this weekend and I'm also going to pull the clutches to see if those are somehow an issue. Anything else I should try?
 
Well i got to figure out some more of this issue on my ride home. no cars/traffic on the freeway. It seems if i hold 4500 rpms im fine. i can hold it for ever. the issue starts once i get to about 5k rpms. If i hold 5k for more than 10 secs, thats when the bogging happens. i was able to watch it both times it happened and the tach drops to 0 then goes back up to 5k. i backed off for a mile and held 4500 again and then tried 5500 rpms. same thing happened. dropped to 0, then went back up to 5500. there was no (electrical) power lose to the gauge cluster, the speedo didnt change, the back lighting or the clock didnt change either.
 
Did you ever bypass kickstand safety? Or at least zip tie the switch to the shut position?
I just had ANOTHER one that the kickstand safety was the issue. Last week as a matter of fact.
The guy thought he was going to have to buy a fuel pump and some other stuff. He was so happy when I fixed his bike for free.

Question..... If you ride it like you stole it does it still pull hard all the way to redline? In all gears?
If it's still a beast and and pulls hard to redline in all the lower gears then the fuel pump is fine.
If it bogs when you beat it in the lower gears then you could have a fuel pump issue.
If that is the case I recommend getting a low mile used gen2 assembly. Yes the plug is different but it's easily
spliced.
 
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