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Mechanics 101 Can't get it to run right? Find a trick to add HP?
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Old 08-05-2017, 03:44 PM   #1
1LE
Tank Slapper
 
Join Date: Oct 2013
Location: Sylvania, Ohio
Posts: 282

Default Running very rough

As mentioned in the "what did you do to your Kat today" thread, today was my first test ride(s) with the new sprocket and chain. It was not unicorns and rainbows.

Ride 1: Bike warmed up fine but was really hard to get rolling, wanted to stall real easy. Give it any throttle and it just makes loud farting sounds. Top speed around 20 mph. Had to use the choke instead of the throttle to get it near home. Pushed it the last short section of street after it died when I tried turning the choke off while stopping. Measured exhaust temps. "Right" (from seated position) bank slightly low, but nothing to get excited about.

Got the suggestion to try fuel selector prime setting.

Ride 2: Started and warmed up fine in the regular "on" fuel position and choke on. Exhausts are all the same temp. Twisting the throttle makes it rev very nicely, still sounds smooth. I roll out using the choke as the throttle so I don't stall it. Take choke off and use throttle. Again with the farting sounds. I run down the road aways, switch to PRI, ride aways. No change, sounds exactly the same. Switch back to on. Decide to fart it all the way back instead of using the choke as my throttle. I slow down in the driveway and as soon as I pull the clutch lever the engine shuts off. Right bank exhausts are cold, left are hot...

No fuel smell, leakage, or other sign of failing to ignite at any time.

So, when the is choke on, everything is solid. However, when the choke is off the right bank is starved of fuel (or potentially air, causing it to drag instead of pulling fuel to ignite I guess). With the choke on though, it's clearly getting fuel (the bike will go faster on choke alone than it will with the throttle). Once the bike cools off I suppose I'll pull the tank and look for really dumb things like any parts that came loose/fell off. Other than that, what should I be looking at? Whatever it is it seems to afflict both cylinders on that side equally.
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Old 08-05-2017, 04:03 PM   #2
rperry03
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Assuming there is no issue with the secondary ignition.
What year and size is it?
With number #3 and 4 having an issue at the same time, if it's a pre isn't there a fuel hose feeding cyl 1 and 2 and another feeding 3 and 4? Check the fuel feed from tank to fuel bowl, maybe hose is kinked or filter clogged. Been a long time since I owned a pre! If it's a post possible a clog in fuel rails, kinked hose, clogged fuel filter.

Off topic, I looked in your profile to see if you listed your bike and clicked on link for blog and saw that you use speedplay pedals. I was curious if the contact area was much greater than a set of Shimano Ultegra's?
Trying to fix an issue with numbness in feet for years over long distances

Last edited by rperry03; 08-05-2017 at 04:03 PM.. Reason: Automerged Doublepost
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Old 08-05-2017, 08:01 PM   #3
Kreylyn
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What make model bike again?

Krey
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Modified Swingarm, 5.5 GSXR Rear with 180/55 and 520 Chain, 750 to 600 Tail conversion, more to come. Long Term Project build thread http://katriders.com/vb/showthread.php?t=96736

"I've done this a thousand times before. What could possibly go wron.... Ooops!"
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Old 08-06-2017, 12:15 PM   #4
1LE
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Quote:
Originally Posted by Kreylyn View Post
What make model bike again?
Argh, sorry, knew I forgot *something*! 1994 Katana 600

Quote:
Originally Posted by rperry03 View Post
Assuming there is no issue with the secondary ignition.

With number #3 and 4 having an issue at the same time, if it's a pre isn't there a fuel hose feeding cyl 1 and 2 and another feeding 3 and 4? Check the fuel feed from tank to fuel bowl, maybe hose is kinked or filter clogged. Been a long time since I owned a pre! If it's a post possible a clog in fuel rails, kinked hose, clogged fuel filter.

Off topic, I looked in your profile to see if you listed your bike and clicked on link for blog and saw that you use speedplay pedals. I was curious if the contact area was much greater than a set of Shimano Ultegra's?
Trying to fix an issue with numbness in feet for years over long distances
I have not yet confirmed secondary ignition, but the symptoms so far seem to make that less likely. It does have the separate 1/2 and 3/4 fuel feeds which matches up nicely with the symptoms (except it runs so nice choke on and won't even idle choke off)... It's plenty cooled off now, need to go pull that tank and start poking around I guess.

Contact area on the SpeedPlays is pretty small really, *but*, it doesn't really matter from what I can tell. It's the shoe that matters as the whole bottom should be rigid. A plus for the SpeedPlays is they allow extra float, which can be better for knee issues. On long rides I have to readjust my shoe tightness a few miles in. What's appropriate to prevent blisters when starting out is too tight (causing numbness) later on...

Last edited by 1LE; 08-06-2017 at 12:15 PM.. Reason: Automerged Doublepost
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Old 08-07-2017, 07:02 PM   #5
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Alright, it could be a carb issue (and a common response here is clean the carbs) but... that aside and not saying you don't need to do that, but... other possible issues...

Check the coil wires are correct. Left coil 1 & 4, right coil 2 & 3.

Check the fuel lines are actual fuel line and not vacuum line. Vacuum line appears to work but will get really soft and collapse when warm (hot engine) and then reform shape when cool (by the time you get the tank off to see what's going on).

No inline filters... the specifics of which filter would work or won't, how it's positioned, and that it really doesn't do anything for you is more than I want to type out atm, but simple of it... don't use inline filters.

Check the petcock is operating correct by using suction on the vacuum line in the on position. Once vacuum is applied, kink the hose. It should stay flowing. If it stops, you have a leaking/ faulty diaphragm on the petcock and that would limit fuel flow. Prime uses a smaller hole, but no need for the diaphragm if the petcock is working correctly, but that may still mean not enough fuel is flowing due to the smaller port on the prime selection.

Make sure the tank isn't building up vacuum / pressure - that the cap vent is working correctly. A simple test is to open the lid when issue is present to see if it continues. Also a lot of noise (venting or sucking) at the gas cap is a sign of a slight issue.

It could also be partial multiples of any issues listed above.
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Old 08-12-2017, 11:01 AM   #6
1LE
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Quote:
Originally Posted by Kreylyn View Post
Alright, it could be a carb issue (and a common response here is clean the carbs) but... that aside and not saying you don't need to do that, but... other possible issues...

Check the coil wires are correct. Left coil 1 & 4, right coil 2 & 3.

Check the fuel lines are actual fuel line and not vacuum line. Vacuum line appears to work but will get really soft and collapse when warm (hot engine) and then reform shape when cool (by the time you get the tank off to see what's going on).

No inline filters... the specifics of which filter would work or won't, how it's positioned, and that it really doesn't do anything for you is more than I want to type out atm, but simple of it... don't use inline filters.

Check the petcock is operating correct by using suction on the vacuum line in the on position. Once vacuum is applied, kink the hose. It should stay flowing. If it stops, you have a leaking/ faulty diaphragm on the petcock and that would limit fuel flow. Prime uses a smaller hole, but no need for the diaphragm if the petcock is working correctly, but that may still mean not enough fuel is flowing due to the smaller port on the prime selection.

Make sure the tank isn't building up vacuum / pressure - that the cap vent is working correctly. A simple test is to open the lid when issue is present to see if it continues. Also a lot of noise (venting or sucking) at the gas cap is a sign of a slight issue.

It could also be partial multiples of any issues listed above.
Coil wires & ignition are good. Rechecked part numbers for the fuel lines (they're only a couple months old and they match up). The bike had a fuel filter before, but I did not install one when I put on the new fuel lines. No kinks in any of the lines. Tank vents are clear and working. Petcock activates properly and shows very good fuel flow (and both sides match).

I guess I'm down to pulling the carbs again. Any last thoughts before I go and do that?
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Old 08-13-2017, 12:08 PM   #7
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Quote:
Originally Posted by 1LE View Post
Coil wires & ignition are good. Rechecked part numbers for the fuel lines (they're only a couple months old and they match up). The bike had a fuel filter before, but I did not install one when I put on the new fuel lines. No kinks in any of the lines. Tank vents are clear and working. Petcock activates properly and shows very good fuel flow (and both sides match).

I guess I'm down to pulling the carbs again. Any last thoughts before I go and do that?
Once your in them, if you find any silt/deposits, you will need to track those down. If it's just a jet vibrated loose... well, that's pretty self explanatory.

Krey
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