Yet another KLRE650...

Some work on the bike this weekend.

Trying to turn the spine into an airbox - some work left - the only thing that makes me nervous at this point is whether the spine reinforcement with be enough or not - guess I'll find out soon enough. 3/16" angle iron, btw. I can add more steel to the top if need be, but if I find out I need more it's probably too late. :eek1

Finally finished up the intake, and thought I had to beat in the tank a bit more... so I did, and made a little hole.

Had to wash out the tank an brazed it up, which was fine. Bike was starting and idling OK, but some residual water got in the fuel, so I drained everything out, and the bike stuttered and died after a weak idle.

I redrained the fuel after letting it sit, and I"m pretty sure I got all the water out. No joy.

Pulled fuel rail and injectors, cleaned them out for good measure, but they are spraying just fine. Pulled and cleaned the plugs, which looked pretty good. Plugs were firing well. I pulled the air cleaner, but that makes no difference.

I've got the battery on a tender, and the bike is cranking well. I don't have a way to measure compression, but it sounds ok and air was coming out of the plug holes when cranked w/o them... not a helluvalot, but it's not a single, which is what I'm used to, so I figure that's ok. I figure if it were weak compression the bike would at least pop.

Wiring? It's getting spark, turns, fuel pump works, and the dash works ok, no dummy lights on... so I'm stumped. Major internal stuff (no funny noises though) or something completely simple and stupid are my guesses now.

Bummer, I was really hoping to put her back to work.

Tried another fuel pump, made sure the timing marks check with piston position and cam position. Resistance on the timing sensor seems to check out.

New coil sticks, new plugs.

Rechecked spark, injectors are spraying fuel. Spraying fuel down the intake with a spray bottle does almost nothing (got it to pop ONCE, could not duplicate). Once in a while it'll shoot flames up the intake - seems like spark isn't going at the right time. Plug wires are numbered, 1 and 2, so that's not wrong. Injectors are correctly hooked up as well, though I played around just for kicks - no joy.

Seems the spark is going at the wrong time - once in a while I can get flames to shoot up the intake. I tried a new ECU as a last ditch effort. Again, no change. I don't have anything to measure compression, but I can feel sucking and blowing through the intake and plug hole when the plug is out.


Ideas, anyone? I'm thinking about buying a fleabay wiring harness,but again, that's just desperately throwing money at the problem.

EDIT: If I open the throttle WFO - the injectors stop spraying. I wonder if this is supposed to happen, or if it's a TPS error of some sort. I dont' see anything about it in the service manual.

hey as for the no fuel during WOT cranking my guess is that it is "flood clear" like on most jap cars IMHO
I'ma toy tech and use it mostly in the winter with idiot customers that think they need to pump the gas to start

bikes looks so cool i hope you get if figured out. I have / had a KLR today i decided its time to part ways. but oh well.

on the bike not starting there is a sensor that tells the bike when to light the spark. just a idea, but it seems you have done most everything i would do. but one question is can you get it to run on starter fluid? iv had motors run on that i just have to keep sparying it in. will tell you if you have a fuel problem or other issuse. just a idea.

Thanks for the ideas.

There's a timing sensor on the bike. The resistance checks out IAW the service manual, but I didn't check the running voltage yet. I took the right side cover off, and the sensor looks clear, and it reads off the a timing sprocket, which is marked TDC for cylinders 1 and 2 - I checked that the timing sprocket is indicating correctly IRT piston position.

I didn't try starter fluid, but I did try a spray bottle with gasoline. I got a nice big POP once, but was unable to to get it to catch again. As before, if anything, I got flames up the intake, so something's amiss, and I think it's timing... either fuel spray is off, or spark is off.

I found a wiring harness for under $25 shipped on fleabay, so I'm gonna give it a shot in case there's a short somewhere.

If that's not it, I'm really at a loss...

No joy with a new wiring harness.

Tried a new timing sensor - even though I thought it wouldn't fix the problem.

I need to check the compression if I can find a gauge to fit the MC sized spark plug hole locally... guess I shoulda done this already by now.

I have a new engine lined up, but I'm not convinced that will solve the problem.

I put a new ECU on with the old wiring harness on - so maybe that refried the ECU (doubtful it was the ECU to begin with) or it could be something else completely.

This is getting old.

OK - bought a compression gauge - ~70PSI per cylinder at a regular starting crank.

Manual calls for 139-213PSI @ 400rpm.

I've never had a compression problem. The numbers are obviously well below spec, but not sure how picky people get when it comes to this stuff. I would guess the timing is off, but it looked good when I checked it.

You have alot of stuff going on at once here. You have given us 2 important clues. 1) fire out intake 2) low compression

The most important step in trouble shooting an engine problem like this is confirming the mechanical parts of the engine are correct. I am going to assume you have not removed the camshafts since the engine was running last. If you did have the camshafts out the engine you must confirm they are timed correctly and you have proper valve clearance.

Next comes compression and leak down tests. You already did the compression test, it says you have a problem. First was the compression test done correctly? Does the manual specify open or closed throttle? Did you measure it the way the manual specified (open or closed throttle). Confirm this.

Next, is the compression gauge a known good working gauge (has it given good results on a known good engine). Compression gauges have a check valve in them some times they leak and give bad readings. if you are confident in your gauge and your test method you have a compression problem. You state there is fire coming out the intake, so I am going to assume your blue rags are not stuck in the intake tract giving you bad compression readings.

A leak down test needs to be done to determine where your cylinder leakage is. This test will show you if you are leaking
past your intake valves (possible, you have flame blowing into your intake port), exhaust valves or rings.

Incorrect cam timing can also cause low compression but on an DOHC shim under bucket engine if your cam timing is off by much you will likely have bent valves and that will show up in the compression test and the leak down test. In fact, if given only this information, low compression on both cylinders and fire out the intake, my first guess would be the cams are timed wrong and you have bent intake valves, but if you never had the cams out of the engine this is very unlikely.

Don't spend any more time or money on ECUs, wire harnesses and sensors until you can explain the low compression.
Don't use starting fluid on the engine, it accomplishes absolutely nothing. There is something wrong, identify, fix it and the engine will fire up instantly.


Is it possible, while you were working on it, something fell in the intake tracts and made its way into the cylinder and caused piston/valve damage? This does seem like a stretch since both cylinders are low on compression.

Some of this advice may seem very basic, but I am not sure of what you have and have not done. If any of it helps great, if not ignore. Good luck.

Great to hear advice - thank you. Very clear and concise.

I haven't done a leak down test, nor have I checked the valve clearance - I'll look into those.

As to the other specifics - I didn't move the cams at all. I did check them though, and all the marks line up exactly.

The compression gauge is brand new - cost around $40. Definitely not top of the line, and unproven. I initially did the checks with throttles closed, which yielded about 60 PSI - I rechecked with throttles open and got 70 after I noticed that detail in the manual.

Anyway, thanks again.

UPDATE: I don't (yet) have the specific leak down gauge, but interestingly enough, if the motor is turned by hand with the compression gauge hooked up, NO PRESSURE registers on the gauge for either cylinder. I don't know if it's b/c the pressure isn't building up at all, or the check valve is just too strong. Any thoughts???

So did it die from water contamination or not? the sequence of events has me confused as to why the ignition or cam timing would have to be checked on an engine that was previously running fine.

Don't know... it's possible, but I don't know that it would have really killed the motor permanently since it was just at idle.

B/c it WAS running fine, but is no longer. I thought it was water in the fuel at first, but fresh fuel and plugs didn't fix the problem, so I'm looking to other things. If you think I should be looking looking elsewhere, I'm all ears.

I have never measured compression just by turning the engine by hand, so not sure if you would get a reading or not. That said, 70 psi WOT cranking is not good. I have not measured compression on my ninja motor, but I have on similar displacement liquid cooled twin cylinder DOHC 11:1 ish CR engines and 200 psi not uncommon. Heck, old air cooled 2 valve 8.5:1 CR engines will crank out 130-140 psi.

One more thing on the compression, what altitude are u at? If you are 12,000 ft you might get a reading of 70 psi.

You could possibly make a temporary leakage check tool from your compression gauge or from an old spark plug, I have done both. Remove the gauge and check valve from the hose of the compression tool. Find some fittings and hoses to connect regulated compressed air to the gauge end of the hose. Now you can apply compressed air (100 psi is good) to the combustion chamber. Set piston at TDC and apply the air pressure. Listen and feel for air escaping through the intake, exhaust and oil fill. There should be only a very small amount of air coming from any of theses openings. This will not give you a leak % value, but will identify gross leaks. If your compression reading of 70 psi is correct, this will find your problem.

Using an old spark plug is similar. Break off the top of the plug and gut the hex and threaded part. Weld or braze a 1/8" pipe coupling to hex section (of course the weld has to hold air) and you have an adapter to get compressed air into the engine.

i think the key is that both cylinders read the same. anything catastrophic would probably only affect one jug. i guess if the cam chain jumped timing you could see this but it looks like you checked this out ok.

raw gas dumped down its throat could cause the intake backfire in a normal engine. i think spark occurs on the exhaust stroke as well and there is probably valve timing overlap so raw gas sitting there is going to go poof back through the intake

I would keep hunting for a fuel problem but if you have the opportunity, test your compression gauge on a known good running cylinder

sorry if i sounded annoyed, i was merely confused

I'm at about 10' above sea level. Ocean view, baby.

Good idea - I'll get into it that as soon as I can. Workin' this weekend, but I'll see what I can do soon.

I don't think I mentioned it before, but down the intake you can see the fuel spraying (spray pattern looks good to my eye), however, for whatever reason (possibly bad timing, possibly not enough air getting sucked down the intake) fuel is accumulating in the intake port.

No apology necessary, your point was valid to the max, and if anyone ssounds annoyed here, it's me, since I've been fighting this for the last month.

All input is appreciated.

Tried out the gauge on a buddy's 70's R90/6, which registered 120psi. It's a 900cc twin with much lower compression, for those curious. Point being that I believe the gauge to be working just fine, and I really have a compression issue.

I think the head will come off soon.

OK - I hooked up some air pressure to the cylinders and a good amount of air could be felt/heard in the inspection cover of the side case... so either air was getting past the rings, or to gasket was majorly jacked, or I'm doing it wrong (wouldn't be the first time ).

Right or wrong, I pulled the head. Pics below. The cylinder walls look good to me, but the pistons look a bit nasty.






Gasket is metal - can't really tell if was good or bad.

Head looks fine, though a bit nasty like the pistons. Valves look normal to me...




Anyway - I thought I'd find something obvious. So either I'm obviously missing something, or I'm barking up the wrong tree (again).

So... on to questions:

Am I missing something?

Pistons/head with so much crud - normal or not?

Should I pull the cylinders and look at the rings? I'm thinking yes, but what's the point if cylinder walls look good?

Is there a way to tell if the gasket was blown by looking at it? It's a metal gasket that looks normal to me. No water in the oil that I can see.

looks,like lots of dirt to me. The cross hatch is about gone. Remove the cyl. and measure the clearence.

The head gasket would be eroded or etched at the bridge between the two cylinders if that was the cause for the low compression in both jugs.

I guess you might be looking at bad rings at this point but i would think the thing would have been burning lots of oil before it got so bad as to prevent the motor from running

Pistons look ok to me, clean them, but the head looks like it has a bit of oil on the valves. You are that far, go ahead and pull the cylinders check the rings for breaks and check the ring gaps.