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Discussion Starter · #1 ·
Hey guys, a while back I picked up an R1 that has been wrecked pretty bad. I have since replaced everything to get it riding, but it feels very down on power compared to my CBR600. In warm weather here in Florida, the bike will crank a bit then finally start (choke will make it not start at all). It rev's freely when not under load, but as soon as I ride it and do a pull it accelerates somewhat normally (although slow compared to my CBR) until about 4k RPM. Then it will hesitate/feel down on power a bit until about 6k, but takes off really quick after that until around 10-11k RPM when it will basically cut out completely like I hit the limiter. If I stay in the throttle it will work past it eventually but I didn't want to push it in case it was running lean.

Along with this issue, it has been coldish here in Florida recently. When I tried to start it in around 45 degrees it just cranked and sputtered, no start at all, it wouldn't even sputter with choke on.

The bike only has 18k miles on it, a shorty exhaust with very little baffling, no idea what air filter is in it, or if it is jetted for any of the mods. But there is almost no popping on decel so that points to AFR being in the ballpark. It was also sitting for around 6 months after the wreck and the gas smelled pretty varnishy, which has since been replaced with fresh. I have not inspected the carbs so I am not ruling out a clogged jet or 2. But since it runs ok in certain RPM's I thought I would ask for some opinions to see if there is anything else that could be causing this before I take them out and clean them. I would also inspect the plugs at the same time. I have confirmed the exup valve is present, but have not been able to check for correct operation.

Any help would be much appreciated, thank you!
 

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Take it to a reputable mechanic for a tune up. IMO the fuel delivery system needs to be gone through and the engine should be inspected (valve lash, compression and leakdown etc). The plugs should probably be changed as well. I would stick to the copper core plugs myself. I hate iridium plugs.

With the age and the mileage don't be surprised to find the tank rusted, the carbs impacted, the filters clogged etc. Hopefully the compression is good and the valve seals are good. If it ever got water in it though, there is no telling what you will find when you get to inspecting it closely.

I wouldn't recommend working on this yourself unless you are very comfortable working on bikes. Don't be surprised if the project gets very involved.

Do you know when the last time the suspension was refreshed or the brakes were serviced bud? You may want to add that to the list.
 

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Discussion Starter · #3 ·
Take it to a reputable mechanic for a tune up. IMO the fuel delivery system needs to be gone through and the engine should be inspected (valve lash, compression and leakdown etc). The plugs should probably be changed as well. I would stick to the copper core plugs myself. I hate iridium plugs.

With the age and the mileage don't be surprised to find the tank rusted, the carbs impacted, the filters clogged etc. Hopefully the compression is good and the valve seals are good. If it ever got water in it though, there is no telling what you will find when you get to inspecting it closely.

I wouldn't recommend working on this yourself unless you are very comfortable working on bikes. Don't be surprised if the project gets very involved.

Do you know when the last time the suspension was refreshed or the brakes were serviced bud? You may want to add that to the list.
The main issue I have with taking it to a shop is I am led to believe the bike was running fine before the wreck, and I can also do the work it needs myself as I am relatively mechanically inclined (I am just used to EFI systems). It was taken to a shop right before the wreck to have all maintenance done, which I have the record for, and doesn't mention anything about a hesitation. That combined with the low miles on the bike lead me to believe if it is not something external because of the wreck, it might just be because the carbs are gummed up from sitting. I am going to check the EXUP valve to confirm operation to rule that out before I do anything else.

The tank is confirmed good other than dents, no rust in sight thankfully. I definitely have not ruled out the carbs. I just think it's weird it will hesitate, then clear up, and hesitate again a couple thousand RPM later. I would think if a carb jet is plugged it wouldn't clear back up. Fuel filter is on the list to replace as well, I am not sure if that is old as of now.

I am pretty comfortable with the service manual and working on bikes, so I feel good enough to take this challenge on. I am expecting a carb cleaning and spark plug change to be pretty labor-intensive so I just want to eliminate anything external first.

I am not aware when the suspension would have been refreshed or brakes done. But there are no leaks from the fork seals, and no clunks when going over bumps it rides great, so I think that should be good for now. I had to replace the front master cylinder as the elbow was snapped so I know front is bled properly, but need to rebleed the back to be safe. Pads are about 20% used too so I'm alright on those for now, just need to get it running right first.
 

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Discussion Starter · #4 ·
Take it to a reputable mechanic for a tune up. IMO the fuel delivery system needs to be gone through and the engine should be inspected (valve lash, compression and leakdown etc). The plugs should probably be changed as well. I would stick to the copper core plugs myself. I hate iridium plugs.

With the age and the mileage don't be surprised to find the tank rusted, the carbs impacted, the filters clogged etc. Hopefully the compression is good and the valve seals are good. If it ever got water in it though, there is no telling what you will find when you get to inspecting it closely.

I wouldn't recommend working on this yourself unless you are very comfortable working on bikes. Don't be surprised if the project gets very involved.

Do you know when the last time the suspension was refreshed or the brakes were serviced bud? You may want to add that to the list.
Also I do want to mention when at WOT around 10k the tachometer goes crazy. It jumps to 0 then back to where it was, and repeats that until I bring the rpm back down. I am aware the tach displays error codes, but it goes back to where it was, no code I could see. So I was thinking either loose tach signal or possibly the TPS? Not sure if that is part of my issue, but it seemed worth mentioning.
 

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Error codes:
3000 rpms: Throttle Position Sensor
7000 rpms: EXUP related
8000 rpms: fuel level indicator light

I would guess your EXUP or TPS is bad when you hit the upper rpms. There's a procedure in the manual for testing the TPS and adjusting the EXUP. As far as the bike running funny, your carbs need a good cleaning especially since it has been sitting.

Mark
 

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Discussion Starter · #6 ·
Error codes:
3000 rpms: Throttle Position Sensor
7000 rpms: EXUP related
8000 rpms: fuel level indicator light

I would guess your EXUP or TPS is bad when you hit the upper rpms. There's a procedure in the manual for testing the TPS and adjusting the EXUP. As far as the bike running funny, your carbs need a good cleaning especially since it has been sitting.

Mark
Unfortunately there are no error codes displayed. The tach just goes back to the rpm I was at. I just checked with the engine off and no codes are displayed. I’ll have to check the manual to test the tps however to see if that is functioning correctly.

I have been tearing the bike apart and have made the following discoveries. The exup valve is operational and seems to be doing its job, it goes about a 1/4 open when the bike starts and it adjusts as I rev the engine.
The spark plugs look to be relatively new NGK iridium plugs with the gap in spec. There’s no evidence of a lean/rich condition on them, although cyl 1 had a little sludge on the housing (I attached pictures). I also inspected the fuel filter and pump. Filter is a bit dirty but has more than enough flow (going to replace anyways), and the pump’s contacts look good and very clean under the hat so I assume it is fully operational.

I am in the process of removing the carbs now to clean and inspect them.

Unfortunately no change in running after everything before the carb clean that I’m about to do. It still barely runs when cold (lumpy idle/any throttle and it dies), and applying the choke still makes the bike backfire/want to die.
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Plugs should come out dry at the threads. Oil up the threads says poor ring seal.

Right now, take a quick compression check without going thru the valve settings. 170psi or less, she's due for new rings, valves, and seats cut at the minimum.
 

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Discussion Starter · #8 ·
Plugs should come out dry at the threads. Oil up the threads says poor ring seal.

Right now, take a quick compression check without going thru the valve settings. 170psi or less, she's due for new rings, valves, and seats cut at the minimum.
I appreciate the comment. I will check compression if the carb cleaning doesn't clear it up, but I believe the oil is from the wreck rather than rings. The bike flipped and came down on the rear subframe, where it sat for who knows how long, possibly running for a bit. Although, if it is low on compression the conditions I'm experiencing don't line up with it. The starting I could see being related, but considering it runs good between 1-5k and 7-10k, it seems to point to something else being wrong. I also found oil in the airbox/filter, so I would not be surprised it got on the plugs as well. I cleaned the plugs and airbox.

When taking everything apart for the carb cleaning, I found the air filter to be incredibly old, dirty/nasty/had oil on it, the foam completely broke down it was almost a goo, and the element was wrinkled like it was struggling to pull air. I have a new UNI replacement on the way for it, so hopefully that should help. Unfortunately one of the pilot jets seemed to be off-brand and when reinstalling it, it snapped off. I thankfully got it out of the carb, but I have to wait for a genuine mikuni one to show up. The parts should be here early next week so I will get it back together then and see if the condition improves.

Fingers crossed once the other issue is solved I will find the compression to be in spec.
 

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This comes from empirical knowledge of a battery showing a simple move as PUSH to decide how the battery holds a charge, to dumping oil into a cylinder, rechecking compression to see either of 2 moves:
1st move is no change in compression. That says bent valve.
2nd move is a rise in compression and that is the oil coating the ring and groove to seal it up some. Whereas, the empirical runs it down the street to get it to fire off, but that oil was short lived as if you can hold that seal in a liquid form?

So you might want to think that cleaning the air cleaner chamber, a new air cleaner, new plugs that were pulled out and look as they do, that would have cleaned up 5 blocks away and showed tan plugs in other words. The next question to ask is if the bike idles, starts right up when hot or cold, that [empirically] says all jet circuits are clean... look elsewhere.

But if we are saying it's hard starting, have to use the choke to keep it running, that says clogged jet circuits... then yes, clean carbs. However, this is were the wallet meets the compression test is the first move forward, not drop a float bowl or... uncross the fingers, you are going at this backasswords.

First trick being a pro at it... CHECK COPRESSION FIRST! It will bite you every time you don't... ask me how I know...

Signed,
NOLTT (no one listens to turtle)
 

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Discussion Starter · #10 ·
This comes from empirical knowledge of a battery showing a simple move as PUSH to decide how the battery holds a charge, to dumping oil into a cylinder, rechecking compression to see either of 2 moves:
1st move is no change in compression. That says bent valve.
2nd move is a rise in compression and that is the oil coating the ring and groove to seal it up some. Whereas, the empirical runs it down the street to get it to fire off, but that oil was short lived as if you can hold that seal in a liquid form?

So you might want to think that cleaning the air cleaner chamber, a new air cleaner, new plugs that were pulled out and look as they do, that would have cleaned up 5 blocks away and showed tan plugs in other words. The next question to ask is if the bike idles, starts right up when hot or cold, that [empirically] says all jet circuits are clean... look elsewhere.

But if we are saying it's hard starting, have to use the choke to keep it running, that says clogged jet circuits... then yes, clean carbs. However, this is were the wallet meets the compression test is the first move forward, not drop a float bowl or... uncross the fingers, you are going at this backasswords.

First trick being a pro at it... CHECK COPRESSION FIRST! It will bite you every time you don't... ask me how I know...

Signed,
NOLTT (no one listens to turtle)
Ok fair enough points, I just figured it was good with the low miles and it running (presumably) good before the wreck. But I took your advice and compression tested it anyways so I didn't waste money on parts if the engine was bad. However, it has fantastic compression across the board.
Cyl 1: 210
2: 225
3: 225
4: 215

It may have a slight valve cover gasket leak which would explain the oil on the spark plug threads, as I saw some oil residue around it on the head, but that also could have been from the wreck. I cleaned it off so I will take note if it starts leaking again. With this discovery are there any other things I should check? I'm with you, I'm not convinced that the new air filter and carb clean will have solved this issue. But I am not really sure what else to check other than possibly the coils? When I was compression testing with the tps unplugged it was throwing the 3k RPM code on the tach so I know the diagnostics are working. But with it plugged in I never get the code so I believe the tps to be good, but I need to test it per the manuals instructions. But is there maybe some electronics on the left side of the bike that could be causing this? Because the kickstand side got messed up pretty bad, I believe I have fixed everything on that side but I could have missed something.
 

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There are no coil problems. It sparks until it doesn't. It's one coil, two plugs out. That too says, it's one continuous wire going in and coming out. Meaning, the two wires connected to the coil from the harness. One coil is bad, so is the other side of the same coil sharing that one wire. Keep the wallet closed on this if that made sense.

Rubber cover gaskets can seal for so long, go thru heat cycles, hardens, loss of memory to push against. So address those with new or the bike lights on fire with an oil leak. Now get the wallet out.

Here's the tune up;
1. Check compression first. The closer the numbers, the less one carb is open more to compensate and a high idle coming down is way out of range compression wise. 15% of each other and it's teardown time.
2. Set valves. Want torque, cooler valves, set the valves at the loosest range the book gives you. Want overall performance, adjust the valves in the middle range of the hi/low book numbers.
3. Install plugs per book's NGK range, etc. If these are iridium, they are changed every 7,500k miles. High performance bike takes high performance plugs. Bike was engineered for these rated plugs, not someone's opinion using some other plug.
4. Change to a new OEM air cleaner. Washout the ram snorkel paths. Take those apart if they have those chambers filled with who knows what. It's now all about cylinder wall/seat integrity. The bigger spread of the racing pleats, the larger the micro, and just pick up a rock and run it down the cylinder wall. It's still a rock said the incredible shrinking man, so now line up those lines; and is there an oil path the ring can no longer cover over?
5. TPS adjustment is a book call. Tampered with who knows. I'd follow the book if out of range. The code clear says it's within spec, however. It has no clue if fuel came out or not, it follows crank speed for ignition curves per say.
6. Carb sync is last on the list. The bike has to light right off cold. Choke says it's passages are clear and the choke can be turned off so the bike idles once it can [quickly] take fuel within seconds; and without the choke being on. The next is to turn the bike off, and is warm enough to start without the choke, no hand on the throttle, just a push of the start button and it lights off... Clean carbs. Proceed to sync per book instructions after cleaning.

You can proceed to now follow the the flow path:
1. Tank vent. This is to top the tank off so the gas submerges the bottom of the gas cap.
2. Vac assist. If this applies, you are going to take some hose off one of the cylinders that goes to some gas line loop, pull some vacuum with a tool, the gas line to the carb is off and pointed into a plastic drinking bottle; start making vac so you mechanically open something to pull gas out into the bottle.
3. Fuel pump. If this applies, then key on, watch to see if the gas goes into the bottle as you pull vac to now see if you can put gas into the carbs.
4. From cap to carb, you have gas going out of the tank as per loop and all the hoops getting there. This now say it's a carb issue at the jet holes. Clean the carbs with NAPA carb dip in a can [w/parts tray], 12 bucks. It eats rubber so no float needles with a rubber tip, the vac slides if apply, and 20 minutes in the soup, wash with water. Works like a charm.
 
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