alright everyone i need some help...Please
Thread Starter
Senior Member
Superstock
Joined: Jan 2009
Posts: 267
alright everyone i need some help...Please
the other day i swapped my bike to manual ccts (apes) couple things to note here first of all i have a SHORT two brothers exhaust i believe the mufflers are only 11 in long, secondly i pulled the air filter on my way to the cct and found all kinds of mouse crap packed inside the air filter, now i cleaned all that out of the filter so it looked like new again.
after i finished the cct install the back cylinder jumped timing so i reset it or so i thought and rode it, not right at all pulled everything off again reset the timing a second time in the back to make sure it was perfect because the exhaust was a tooth off and then pulled the front to check its timing everything is good, the timing is set.
now when i ride i get a flat spot around 7K it just dies out, i have a really low idle, it backfires any time the throttle is closed with out the clutch being in and the bike just lacks power
so my question is, is the bike still out of timing or because of the now clean air filter and shot after market exhaust does it need to be jetted, or is there something im missing all together
sorry its so long, thanks in advance, i am truly stumped right now
after i finished the cct install the back cylinder jumped timing so i reset it or so i thought and rode it, not right at all pulled everything off again reset the timing a second time in the back to make sure it was perfect because the exhaust was a tooth off and then pulled the front to check its timing everything is good, the timing is set.
now when i ride i get a flat spot around 7K it just dies out, i have a really low idle, it backfires any time the throttle is closed with out the clutch being in and the bike just lacks power
so my question is, is the bike still out of timing or because of the now clean air filter and shot after market exhaust does it need to be jetted, or is there something im missing all together
sorry its so long, thanks in advance, i am truly stumped right now
Senior Member
SuperSport
Joined: Jul 2006
Posts: 655
From: Madison Wisconsin
I would syn the carbs - Set the Idle at about 1200 and put the old exhaust back on and give it a shot. you must not have done any damage to the valves or you would not run at all. Or you could find a dyno and check the jets jmho
Sexual Daredevil
SuperSport
Joined: Sep 2005
Posts: 597
From: Mother Earth- orbiting around Charlotte, NC. But now over the border in S.C.
I would do a compression check on each cylinder. If your cam was out one tooth, it could have bent some valves. If it was ticking, that was the sound of the piston hitting the valve.
ride it out
SuperSport
Joined: Feb 2009
Posts: 745
From: NH
you should have zip tied the rear chain to the sprockets! lol but in my opinion it does sound like you have indeed bent some valves, it is unlikely if you set the timing twice already that you set it wrong both times, well I guess it could be possible. where did you get the info to reset the timing? a manual?
Thread Starter
Senior Member
Superstock
Joined: Jan 2009
Posts: 267
yes i do have a service manual, the more you say bent valves the more i think you're right, after doing the rear cct without pulling the valve cover, (followed the instructions in the knowledge base here) i had spun the motor and heard some ticking at that point i pulled the valve cover of and reset the timing on the rear (i never Started it) so i reset the rear timing and rode it and it wasn't right so i re set the back again and and then checked the front the front was fine no reset needed but i have a feeling the rear ones might be bent
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
Well... One tooth of either way does not neccesarily mean bent valves, since the chain will stretch some during it's lifetime... It's usually the case when you try to align the chain marks that you end up in the middle between two teeth...
Have you done the obvious and cheched the tension on the APE's? Do not set them like in the manual that comes with them... That's so wrong it's not even funny... Set them for a basic setup the way they suggest, then set them by ear, no noise when idling and fully warm means correct tension...
Have you done the obvious and cheched the tension on the APE's? Do not set them like in the manual that comes with them... That's so wrong it's not even funny... Set them for a basic setup the way they suggest, then set them by ear, no noise when idling and fully warm means correct tension...
Senior Member
Back Marker
Joined: Sep 2007
Posts: 153
From: Vancouver, WA
Friendly reminders - stuff I forgot when I did my comp' testing...
Because I am very interested in this thread - just a friendly reminder about the compression testing...
Compression testing on our ride is done with the engine warm/hot/OT - I don't know about an exact rhelm but I'd just get it to the top of OT, or max it out at 210-214F or what have you and then start breaking things down to give yourself a lil' bit of time as you prep for the compression test on each of the cylinders.
Next thing I had forgottenn when I was going in to do my comp' testing last year was I didn't have my throttle wide open, and I didn't have both carb' pistons/slides lifted up (Both at the same time).
So - friendly reminders.
In a bit...
Spaz'
Compression testing on our ride is done with the engine warm/hot/OT - I don't know about an exact rhelm but I'd just get it to the top of OT, or max it out at 210-214F or what have you and then start breaking things down to give yourself a lil' bit of time as you prep for the compression test on each of the cylinders.
Next thing I had forgottenn when I was going in to do my comp' testing last year was I didn't have my throttle wide open, and I didn't have both carb' pistons/slides lifted up (Both at the same time).
So - friendly reminders.
In a bit...
Spaz'
Senior Member
Superstock
Joined: Jul 2008
Posts: 320
Was the bike running fine immediately before? If it was running fine, were the only changes you made the APE's and cleaning the filter?
If both answers are yes, and you didn't pull the carbs, then it really does sound like the timing was off and you bent the valves. Unless the APE's are so loose that the chain is jumping teeth (or so tight that it's causing severe friction), I can't think of what else it would be.
If both answers are yes, and you didn't pull the carbs, then it really does sound like the timing was off and you bent the valves. Unless the APE's are so loose that the chain is jumping teeth (or so tight that it's causing severe friction), I can't think of what else it would be.
Thread Starter
Senior Member
Superstock
Joined: Jan 2009
Posts: 267
well i went to do the compression test got it warm and pulled it all apart and found that the 400 dollar snap on compression tester we have doesn't have a plug that fits the SH, so now that i have it all apart again i'm going to triple check the timing and my shop is buying one of those inspection scopes with the little flexible camera that you can stick in the spark plug hole so on Thursday when snap on gets here ill have a look inside the motor
Senior Member
Superstock
Joined: Jul 2008
Posts: 320
That mouse crap may have been sucked into the carbs. Clean the carbs if you haven't already, and look at what the current jetting is while you're at it. There are whole threads on here about where a good starting point should be for the jetting, so if the jetting is way different, then that might be your problem. Then sync carbs after you get them bolted back up.
I doubt shorty exhausts would cause all these issues, and . . .
You still didn't answer this:
If it was running fine before, then it wouldn't be a jetting issue unless the bike was jetted to only run with a clogged up filter. And it would have nothing to do with the exhausts since they were there before.
If it wasn't running well before, then that opens up a whole lot more possibilities about what could be going on.
I doubt shorty exhausts would cause all these issues, and . . .
You still didn't answer this:
Was the bike running fine immediately before? If it was running fine, were the only changes you made the APE's and cleaning the filter?
If it wasn't running well before, then that opens up a whole lot more possibilities about what could be going on.
Senior Member
MotoGP
Joined: Jul 2010
Posts: 3,871
From: Phoenix, AZ
+1 Way to pick up on a thread a year later like nothing happened!
7K rpm cutoff troubleshooting:
Could be a vacuum issue. Try running it without a gas cap.
Could be the kickstand switch- if it's loose, when the bike hits certain vibrations it will cut out and feel like fuel starvation. Bypass the switch and run it to see if this works.
Check to make sure your snorkel isn't clogged. I had a ridiculous time trying to diagnose symptoms similar to yours when I just wasn't getting air into the box.
Check to make sure your petcock hose is attached correctly- it should be on the horizontal nipple on the back of the unit, not on the little one pointing downward.
Although now that you cleared a bunch of airflow, your carbs may just be way out of synch.
Senior Member
Back Marker
Back Marker
Joined: Mar 2009
Posts: 139
From: Wisconsin
Make sure the mice didn't chew anything like vacuum lines or wiring. It's happened to me before, they chew thru a vacuum line and almost all the way thru a coolant hose. Little bastards!
Senior Member
Back Marker
Joined: Apr 2011
Posts: 201
I had the same problem with my Hawk. Check that the vac. lines to the petcock are installed right, and that there is no leaks in those vac. lines.
If you are getting that kind of compression (difference between the two cylinders), I am willing to bet that your timing is right. If it wasn't, your compressions would be much farther off between the two cylinders. I found this out by mistake when I was a car wrench. I was one tooth off on a OHC 4 cylinder, and coudn't figure out why it was running like crap. I did a compression test, and found that all four cylinders were down on compression by a huge amount. Valve timing has a HUGE effect on cylinder pressure because the timing events that allow the cylinders to fill and empty with air are off.
Pull your crabs back off, clean them up real good. Re-set your pilot screws, put the carbs back on and synch them. I'd reason to bet that after finding the vac. leak caused by the mice and a fresh cleaning/synching of the carbs the bike will run nice. Mine did.
If you are getting that kind of compression (difference between the two cylinders), I am willing to bet that your timing is right. If it wasn't, your compressions would be much farther off between the two cylinders. I found this out by mistake when I was a car wrench. I was one tooth off on a OHC 4 cylinder, and coudn't figure out why it was running like crap. I did a compression test, and found that all four cylinders were down on compression by a huge amount. Valve timing has a HUGE effect on cylinder pressure because the timing events that allow the cylinders to fill and empty with air are off.
Pull your crabs back off, clean them up real good. Re-set your pilot screws, put the carbs back on and synch them. I'd reason to bet that after finding the vac. leak caused by the mice and a fresh cleaning/synching of the carbs the bike will run nice. Mine did.
Thread Starter
Senior Member
Superstock
Joined: Jan 2009
Posts: 267
alright thanks, i got some stuff to look into, yes the bike did run fine before all of this no issues at all, and i did replace my fuel petcock at the end of last year seemed to help a tiny bit but not much, guess i need to pull my tank and check everything for like a fifth time and maybe do a carb sync
and yea sorry its been like a year the bike was stored all winter so i had no way of test riding it because it only does it under load it revs fine in neutral, and ive been riding it, we loose to much of the season here to snow so i figured it ran good enough for me to finish the season last year and i was to excited to get back on it this year but now something needs to be done
and yea sorry its been like a year the bike was stored all winter so i had no way of test riding it because it only does it under load it revs fine in neutral, and ive been riding it, we loose to much of the season here to snow so i figured it ran good enough for me to finish the season last year and i was to excited to get back on it this year but now something needs to be done
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Superstock
Joined: Jan 2009
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