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2007 DL1000
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Discussion Starter · #1 · (Edited)
Hi all, recently picked up an 07 DL1000 with 18k miles. It has a fairly consistent lack of power, and an occasional backfire I can hear coming back through the intake below 3500 rpm. seems to run ok above that, as far as I can tell, having never ridden the bike before. Seems a little down on power compared to my 98 superhawk, but that might just be the weight/gearing differences.

Starting to run out of things to check. Some background on the work done one this bike in the past couple weeks since I bought it.

-It had been sitting for 4 years and had a serious mouse infestation above the air filter, with some of their excrement leaking down into the front intake, causing it to be stuck in the closed position. To remedy this, I had to fully disassemble the the front throttle body, gave it a soak in some carb dip, followed by cleaning the throttle shaft and plate will some 1000 grit sand paper and oil, seems to function smoothly. TBs went back together and on the bike.

-Set TPS and STPS per manual

-Fuel tank was seriously crusty inside with mostly varnish, with maybe a little bit of rust in a spot or two, I cleaned it out with some denatured alcohol and a bunch of steel hardware, shake it every couple hours for a couple days. The full fuel pump/filter assy was replaced (to the dismay of my wallet), as well as the two fuel hoses.

-I checked the valve lash and replaced one of the front intake shims to tighten that up, it was slightly out of spec.

-New iridium spark plugs

-At this point I got the bike running, and took it out for a ride, where I noticed the miss.

- At first I thought it was just the TB sync, I did not have my gauges handy when I first got it running, but they have since been synced, and still have the miss.

-I checked for air leaks below the TBs, sprayed carb cleaner and listened for an change in RPM. There was a slight response at the front TB, although in hindsight it might have just been the fumes getting sucked into the intake above. Either way, I took the intake pipes off, and as temp fix to test the issue, I cleaned them and applied a thin coat of RTV, will get fresh o-rings with my next parts order.

-I found the front spark plug boot was barely on (honestly not sure how it could have been running with it so far off) and I thought I found my smoking gun. I fixed the routing so that it sat down all the way. still no dice.

- At this point I thought I maybe screwed up the valve timing when I put the cam back on, but everything seems to be in order, I just double checked the lash and cam timing, all good here.

- Got an adapter for my compression tester to the 10mm plug, both cylinders are at 180 psi warm.

-Ran through the diagnostic tests for the IAT, ECT, AP and MAP sensors, even though there were no codes, all seems in order there

-Cleaned the TPS internals as a last ditch effort, no change.

At this point I am kind of at a loss. leaking and/or clogged injectors? I am going to run some injector cleaning through it, but beyond that where do I look next?

Thank you all for all the great resources you already provided, hoping you all might have some other things I can check. Also sorry for the long post, lots of info to get across!
 

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My 08 has a PC5, K&N, Two Brothers pipes and it had a small backfire through the intake every once and a while with light acceleration at around 2500 RPM. Not all the time but often. After a valve adjustment, new plugs (old ones looked fine), air filter service and a throttle body sync it has vanished. My bike pulls smooth from 2000 rpm with light throttle and at 3000 it pulls like a train. I can't say for sure what fixed mine since I did all those things at once. I would guess it was the valve adjustment as I set every valve to the most clearance possible. Second guess would be the TB sync but I never checked it before so they could have been in sync before the valve adjustment.
Seems like you have addressed all those things though.
 

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Discussion Starter · #3 ·
My 08 has a PC5, K&N, Two Brothers pipes and it had a small backfire through the intake every once and a while with light acceleration at around 2500 RPM. Not all the time but often. After a valve adjustment, new plugs (old ones looked fine), air filter service and a throttle body sync it has vanished. My bike pulls smooth from 2000 rpm with light throttle and at 3000 it pulls like a train. I can't say for sure what fixed mine since I did all those things at once. I would guess it was the valve adjustment as I set every valve to the most clearance possible. Second guess would be the TB sync but I never checked it before so they could have been in sync before the valve adjustment.
Seems like you have addressed all those things though.
Yeah, there are brand new plugs in there too, forgot to mention that in the original post. The valve adjustment is all within spec, and only the single intake valve that i had to go one size thicker on is more towards the low end of the range. all the rest are mid range to top end of the spec.

This bike is definitely not smooth before 3500, and really doesn't pull hard until well over 4k.

Even though it is not throwing codes for them, I did do the electrical tests on the IAT, ECT, AP and MAP sensors, everything seems in order there.

I also put a multimeter on the TP sensor, as part of the diagnostics procedure, and the value at throttle closed (1.1k ohm) was a bit off. I took it off the bike and drilled some holes in it to clean the insides with contact cleaner as a last ditch as someone posted doing that on VSRI. Unfortunately that did not solve the problem.

Interestingly, if I set the TP sensor to the approximately 1.1k ohm at closed throttle, if you put the bike in dealer mode, the line is at the lower bar, not the middle bar. I rode it this way last night, no change. I was going to put it back to the middle bar and ride it today.

I am seriously at a loss now. I ran a can of seafoam through the intakes, and there is a bottle of injector cleaner in this tank, but I really am not expecting this to work.
 

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Check to see that the boots from the airbox are seated firmly on the throttle bodies. Pop them off and clean where they connect, then snug them up firmly. Check for cracks in the rubber. Not unusual for this bike to backfire through the airbox, and knock the boots off the throttle bodies creating an airleak and a too-lean condition.
 

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Discussion Starter · #5 ·
Check to see that the boots from the airbox are seated firmly on the throttle bodies. Pop them off and clean where they connect, then snug them up firmly. Check for cracks in the rubber. Not unusual for this bike to backfire through the airbox, and knock the boots off the throttle bodies creating an airleak and a too-lean condition.
Yeah I checked those for cracks and temporarily resealed the pipes back to the head (in lieu of new orings which I will replace with the next parts order)

After messing around with the TPS, I was getting some weird stumble and dieing while adjusting it so it might have just failed completely. But I still couldn't be sure something is not actually wrong with the throttle bodies and or the injectors, so I bought a used set with all the injectors and sensors on eBay, at least this way I have a couple things I can swap out. Maybe it is just the TPS, but I wasn't getting the warm and fuzzy that that was for sure/only issue. With one injector being ~$200 from the dealer, getting the whole TB assy will be worth it if I need anything more than the TPS off of it.
 

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Discussion Starter · #6 ·
Well, I got the new to me throttle body, complete with injectors, TPS and STPS. The bike runs exactly the same....

I really thought it might be one of the above items. Really disappointed now, the bike runs great above 3k-3.5k, but in that range and below, it honestly struggles to get up out of there and take off some times.

What RPM do you guys run around a downtown/traffic? That is where it is hardest to deal with, a backfire is enough to make me stumble if I am going slow enough and not expecting it.

What now?
 

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I would start with the TPS. Replace with a new one. While drilling holes in it can be a way to clean it in an emergency, water will follow.
At idle the "bar" while in dealer mode should be in the center/middle of the "00" display. VERY slowly raise rpms ( did I mention VERY?) until the bar rises to the top. That rpm should be 1700-1800 rpm on these bikes. Factory spec is higher....and it is proven they simply have better low rpm manners when set at 17-1800.
It is quite common to have a leak in the throttle bodies. Check all ports are covered with a hose or nipple. The usual problem is the rubber boots not seated fully or loose. Might look ok, but still allow a slight leak which leans out the mixture and promotes missing and backfire. When both of these items are checked and right, then do a throttle body synchronization. Set idle to 1300 rpm. Sounds like you have other things in good shape. Setting it to these specs can make a big difference.
 

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Discussion Starter · #8 ·
I would start with the TPS. Replace with a new one. While drilling holes in it can be a way to clean it in an emergency, water will follow.
At idle the "bar" while in dealer mode should be in the center/middle of the "00" display. VERY slowly raise rpms ( did I mention VERY?) until the bar rises to the top. That rpm should be 1700-1800 rpm on these bikes. Factory spec is higher....and it is proven they simply have better low rpm manners when set at 17-1800.
It is quite common to have a leak in the throttle bodies. Check all ports are covered with a hose or nipple. The usual problem is the rubber boots not seated fully or loose. Might look ok, but still allow a slight leak which leans out the mixture and promotes missing and backfire. When both of these items are checked and right, then do a throttle body synchronization. Set idle to 1300 rpm. Sounds like you have other things in good shape. Setting it to these specs can make a big difference.
Yeah I agree that the drilling holes in the TPS is not ideal, but I would have expected something to be different when swapping to a different TPS like I just did, granted it is not known good, and it could have a similar failure.

Boots are 100% sealed, checked it with some flammable aerosol, no RPM rise. I synced the new TBs, not that they were far out, and the TPS was in the middle. I did not check what RPM it moves to the upper one, the factory manual does not cover this at all, just what to set it to at with idle set to 1200 +/- 100 rpm, engine off. I will take a look at that and see where mine is set.
 

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Discussion Starter · #9 ·
Whelp, adjusting the TPS to the above settings did not help for sure, honestly it might have made it marginally worse. i think I will try a new TPS at this point. After that, i have been reading up on the PCIII/PCV. I feel like I shouldn't have to go that route, but it seems to have fixed other peoples problems with driveablity issues, although it didn't seem like anyone else has had it quite as extreme as I have it. What do people think about that?
 
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