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$50 to your paypal account if you can diagnose my problem....

10K views 102 replies 33 participants last post by  maxtrax 
#1 ·
I have a major problem. This is going to be long. First, let me say that I'm a competent mechanic. I have built many quads, cars, rotary engines, street bikes, etc. I have worked in the custom automotive and racing industry for 12+ years. I can turn a wrench with confidence.

Second. The toy in discussion is a 2004 Raptor. I got it at the end of Summer for a decent price, knowing it needed work and knowing we were going to tear it down and build it the way we wanted for my son to race this coming summer in a local drag series. It ran well, but not perfect. It had issues. Wrong nuts, bolts etc. Minor things. A missing clutch return spring, things like that, that just bug me. I like things done right.

What I did: I tore it down to the frame with motor in it. Mostly to replace a-arms, bushings, fix minor issues, replace clutch lever with aftermarket one, brake block off, intake, slip on exhaust, etc. I put it back together, and I cannot for the life of me get it started. I'll try to go through more thoroughly what I did. I put a Vito's jet kit in the carbs. I have gone through them several times and did the clear tube method on them. The fuel levels seems to be perfect. I put a k&n filter with holes in the lid. I did an aftermarket clutch lever, getting rid of the rear parking brake. I did many things to the frame and wiring. Mostly cleaning and refining things. When I replaced the coil with another one, simply because the original had a bad boot, and didn't seal on the plug the way I wanted it to. It did work though. I put a Leo Vince slip on exhaust on. I put everything back together, and nothing. An occassional pop out of the exhaust. I thought it was no or weak SPARK. I tested the spark by grounding the NEW spark plug, and all is well. I even disconnected the regulator to test the stator. Still no starting. I switched back to the original coil. Same. I tore apart the wiring harness from the "computer" CDI, forward to the front of the bike to check for any frayed wires. Nothing. Re-taped everything back together, nicely. I tried again. Nothing. I re-checked clear tube drains. Perfect. It seems like the motor isn't getting any fuel. I am trying to start it with no intake on it now. Just looking into the carbs. What should I be seeing. The right carb seems to seep a small amount of fuel up through the needle valve "hole" and the left, nothing. I tried spraying starter fuel through carbs.....nothing. I have turned fuel screws from 1.5 turns out all the way up to 3 turns out. No help. What am I missing? I do have a question. This bike wasn't well put together when I tore it apart. I know each intake tube, has a hose that runs to the top of each carb. There is a plastic "T" fitting between the carbs that swivels up and down. Where does that go to? I had no hose to it. Oh, I also dremeled out the intake boots to "port match" them to the head. Jetting shouldn't really matter so much to start, but as stated above. It is a Vito's jet kit with 155 and 160 mains, 25 pilots and their needles on the 3rd clip. I have the fuel screws at 1.5 turns out. I should atleast get it started with this. I do get the occassional backfire and flame out of the exhaust, but not even trying to start. I just don't seem to "feel" fuel in spark plug hole with my finger, nor is the spark plug very "wet".

I know this is alot, but I hope the more information I give, the easier it will be to diagnose. This thing ran 1 month ago when I tore it down. I did alot to it all at once, but nothing so major that it shouldn't have started right up. I have a fresh battery, with a charger on it as needed. I will gladly deposit $50into the person's paypal acount that diagnoses this problem and helps me get it running. I promise. Please feel free to call me to discuss and please ask any and all questions or suggestions. I can try anything and get back to you a.s.a.p.

Thank you,
Throttlejunkie
four zero four - 787 - three eight five seven
 
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#2 ·
Seems to me that if you have spark and you are shooting startign fluid in it, you might have one of two problems.

1. Make sure carb boots are snug where they attach into the cylinder (prob obvious but you never know)

2. Timing is off, maybe 180*

If it has spark for sure and you know you are givign it fuel (starting fluid straight into the carbs) it should kick over if both of the above are correct.
 
#3 · (Edited)
First and foremost, you can't get it to fire with starting fluid - this implies something more than just not getting proper air/fuel ratio from the carbs.

Assuming that you ARE getting strong, consistent spark at the plug EACH revolution of the engine (it has no cam sensor so it double sparks), and this spark stays consistent for the whole time you are cranking, then with fuel (or starter fluid) it should try to fire.

Have you done anything to the engine - head removed, flywheel removed, side cases removed/replaced, etc.? (cam mis-timed or flywheel woodruff key left out or sheared is somewhat common - you'll still have nice spark, but at the wrong time)

Have you checked valve lash? As the Rappy valves wear, they tighten up eventually reducing compression until it won't start cold.

Have you checked compression?

You will have trouble starting it without the airbox in place - the reduction in air resistance makes the a/f mixture extremely lean - not what you want for cold starting... however, this is probably not your issue yet, since it won't even try to fire with starting fluid. Just keep this in mind for later.
 
#4 ·
Quadmaniac or Willykiller will get the 50 bucks! My money is on the valves!
 
#5 ·
if you do indeed think it is a fuel issue......have you checked to see if the carb bowls are filling up with fuel?

what did you do with the sensor that was in the OEM clutch lever assembly?

did you crack open the engine at all, or just do external modifications?
 
#6 ·
Is the throttle cable tight, had a Predator while back and if the throttle cable was loose it would allow these contacts to touch in the thumb throttle control, some sort of safety deal, if the contacts were touching (throttle cable loose) it wouldn't let the engine fire. Not sure if it's the same with the 660 but might be worth a look.
 
#7 ·
no, the raptor is not like that....
 
#10 ·
I switched the thumb throttle to a twist. It seems fine though. I never cracked the engine at all. Nothing. The closet thing I did to the engine is remove the 2 little carb intake boots, and dremeled them out to "port match" them to the head. As per the clutch sensors. I traced the wires down, and connected the 2 bullet connectors together and the other one is left unplugged. I can double check the 0-rings at the intake boots, just to make sure they are good. I do seem to have spark, but would have thought that spraying starter fuel into the carbs would have done something. I have double checked the carb bowls with the clear tubes and it settles exactly 3 mm above the seem between carb bowls and carb body. Just like the write up says. I seems to have good spark. My compression gauge doesn't fit that small of spark plug thread. It did ran when tore apart 1 month ago. Started right up and ran fine. Where does the plastic "T" fitting between the carbs lead to. I assume a hose to the intake somewhere. Any help there? All the help is greatly appreciated and I don't mind paying the $50 to anyone who can diagnose this. It's the least I can do. Thank you and keep it coming.
 
#11 ·
If it matters, I can't seem to get the reverse light on. I put it in reverse, but the light doesn't come on. The neutral light is on, and while starting, the temp light comes on, but when I drop it into first, and hold the reverse switch, and kick it down again, no reverse light. Worked before. Just something I noticed, probably not diagnostically helpful. Thanks again.
 
#12 · (Edited)
By all means check the intake boots and the carb to intake boot connection... a leak here will cause lean conditions - NOT what you want for starting... a big leak can keep it from firing at all - only occasionally backfiring.

The T fitting is just a vent for the float bowls.. ignore it for now.

ALso ingnore the carb tuning for the moment - if it won't fire and sputter with starting fluid, the problem is elsewhere.

None of the switches and RPM limiters are an issue, yet. reverse, parking brake, only turn on an RPM limiter - you should be able to at least get it to fire, just not advance in RPM much, even if they were failing. If the reverse light is out (and it's not a function of a burned bulb) then the limiter shouldnt be on anyway.

What color wires did you connect together?
 
#14 ·
QM, the clutch switch is to prevent it from starting in gear. if there is osmething wrong with this circuit, will the engine still turn over, or will it completely be dead?
 
#15 ·
Gentlemen, I appreciate all he suggestions. It is 1:11 a.m. here and I need to go to bed. I will take the carbs off int he morning and check the intake boots. I'll also check the wires that I plugged together. They were the 2 bullet connectors (male & female). I will have more information tomorrow. Thanks again everyone and good night.
 
#19 ·
Gentlemen, I appreciate all he suggestions. It is 1:11 a.m. here and I need to go to bed. I will take the carbs off int he morning and check the intake boots. I'll also check the wires that I plugged together. They were the 2 bullet connectors (male & female). I will have more information tomorrow. Thanks again everyone and good night.
They sound like the clutch switch wires - black/yellow and black.
 
#16 ·
My bet is on a short or a bad ground. I would check your ground and follow your wires make sure nothing is grounding out or shorting into another wire. I had a banshee act exactly like that and it was a wire grounding out to the exhaust.
 
#18 ·
My bet is on a short or a bad ground. I would check your ground and follow your wires make sure nothing is grounding out or shorting into another wire. I had a banshee act exactly like that and it was a wire grounding out to the exhaust.
Banshee's may act that way, Raptors do not. Pay attn: the starter cranks the engine over and he has spark!
 
#20 ·
Guys, I can tell you right now... If he is really getting spark and the engine is cranking over. It is NOT an electical problem. It has nothing to do with wiring.

Your problem is either the valves or the carb itself. I am willing to bet that the carb is the problem since the jet kit install is the only thing different that was installed on the machine that would effect how it ran before the tear down. He said he didn't go into the motor so the timing wouldn't have changed, he said he has spark, so that means the electrical is working. The only difference is the jet kit that was installed and he did the clear tube mod.

Also did you check to make sure the throttle cables are working right? I think the whole problem is the carb. Go over it again.
 
#21 ·
Now this maybe a long shot.

But my uncle had a similar problem on his 660 one day. he took it to the dealer and he ended having to buy a new rear caliper and put that on and it fixed his problem.

i have heard of this before that it wont start, because of something in the caliper or something. not exactly sure tho
 
#23 ·
your uncle has bent over. the rear brakes has nothing to do with starting a quad.

if interested i have a bridge in london im selling, make you a hell of a deal on it
 
#22 ·
Update: I pulled the carbs off to check the intake boots' o-rings. Everything seals up to the head good. No cracks or tears. I looked into the head at the intake valves while "starting" and they cycle just fine. I know that isn't much help, but just making sure. The clutch wires that are disconnected are the bullet connectors (black wire / black with yellow) connected together and the other is a connector left un-plugged with a black wire and a green wire with yellow. I can go out and pull the carbs off and go through them again. I'm at a loss of what to do to them. I have cleaned every jet circuit with brake cleaner and compressed air. I have stripped everything off the carbs. Is there a certain direction that the "plunger" hangs off of the floats? I will turn them around and try that. Please feel free to call me as I'm home now and trying to work on this thing. Again, any and all help is appreciated.

Thank you,
 
#24 ·
I have the carbs completely apart....again. It should make no difference which way the "plunger" that hangs from the floats is as it only fills the float bowls and they fill fine. I just had a gentlemen from the 270 area code call me. I apologize as I didn't catch your name. He is suggesting checking the valve lash, which I plan on doing today. Thank you sir. I'll keep everyone informed.

Thank you...
To be continued...
 
#28 ·
Is there a "lean angle" sensor on a 660 ? If so, repositioning wiring may have got it put back in wrong position, which I know on my 700 caused similar starting issues.

Sorry, do not know 660`s, so if my question is stupid.....be gentle, just trying to help......lol.


~ Sandaddy :cool:
 
#30 ·
Well, I called and spoke to THROTTLEJUNKIE and he seems to be a very nice guy. For the record I made a similar suggestion as ChicagoAtv in that I ask if he checked the valve lash and to make sure the carbs were clamped on tight at every junction with no leaks. He should download the manual from this site today and that will show him how to find TDC and check the valves then make sure he's getting fuel. I also suggested to set the fuel/air screw at 3 turns out and maybe to prime the cylinder with a few drops of gas via the spark plug port and see if it fires.
Oh, I'm not interested in $50 so keep me out of the money loop...however, I am curious as to what the problem is....and if it's that damn rear brake caliper I'm gonna poop my britches!
 
#32 ·
UPDATE: Thank you Bueraptor660 for the suggestion. I took off the "plugs" on the left case. I watched the intake and exhaust valves for a few cycles and found TDC on the compression stroke. I lined up the I with the notch in the small plug. I think this is right. My computer won't download the manual right now (computer issues, another problem to fix at a later time). Please inform me if this is correct. For my information, what is the "H" for in there? Anyway, I COULD NOT get my .0015 feeler gauge in the intake valves. I don't have one smaller. It wouldn't go in at all. I backed off the nut and backed out the center to .004. I will do all of them and then move onto the exhaust and set them at .006. If any of this is wrong, please inform me. I will blow out all the jets on the carbs and put them back together and try again. It will be tonight before I can finish up as I have company that stopped by now.

Again, I appreciate all help and look forward to findout out the problem and all of us learning something.

Side note: BlueRaptor660......I was born in Fort Knox. I lived there on and off while growing up. I'm in Atlanta now and need to go further south.......warmer.

Thank you.
 
#34 · (Edited)
TJ, as described in my first post (along with the request to check valve lash), the Rappy's valves - especially intake - tend to tighten up when they wear, to the point that cold starting becomes difficult or impossible due to lost compression.

It is very common (based upon many posts here in the forum) to go from easy starting, through more difficult starting to no starting at all, over a short period of time (especially in winter) due to this. Once you DO get it started, however, everything runs fine. Since the head is aluminum and the valves are steel, the head expands much more quickly as it warms, pushing the cam and cam followers up and away from the valve stems, opening up valve clearance again. The colder the engine is, the more pronounced the problem.

If your engine started from cold easily in the heat of summer, it is completely possible that it would not in the cold of winter - just enough reduction in temperature for the head to 'shrink' enough to cause one or more intake valves to open a bit.

I hope this takes care of your problem. Sorry you had to go through the carb mess again....

The H is the ignition timing mark, left edge is full advance, right edge is full retard. The I mark is TDC.

Valve clearance is:
Intake - 0.0039" - 0.0059"
Exhaust - 0.0059" - 0.0079"

I usually set the intakes near the max because they tend to close up over time as described above. You are certainly ok for now.
 
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