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Discussion Starter #1
Hello all,

I am new to the forum and would like to say thank you in advance for any help you can give me.

I purchased a 2005 Raptor 660R that had no compression at the plug, with compression checker, but was def blowing air out the exhaust. I got it home and found that the center valve was stuck open due to being bent.

I replaced all 5 valves and made sure to lap them during the replacement process. The cylinder looked ok to me so I only replaced the Piston and Rings along with the valves and all necessary top end gaskets. I checked the top ring gap at 2 inches into the cylinder before installing the cylinder and piston. Top ring gap was well within spec' at around .40 mm.

After installing, cylinder, new piston and head with new valves, I installed the timing gear and cam shaft and set the timing. When bolting the timing gear to the cam shaft, I was sure to keep the fly wheel lined up with the "l" mark on the engine case, the cam shaft lobes down with outer two holes facing up, then lined the cam gear outer punch marks with the top edge of the head and the third punch mark up. I was also sure to put the punch mark of the decompressor in the up position and the two decompressor pins in the cutouts of the actuators.

Once everything was assembled, I did a compression test. While doing the compression test, the battery went dead. I hooked jumper cables up to my TRX450S and retried compression test. I could only get to 90psi then the starter relay would just crackle. I bypassed the starter relay by placing the jumper cable positive on the output side of the starter relay (the side where the cable goes to the starter). I decompressed the cylinder by pressing the release button on my compression checker and retried the test. I could only get to 90psi and the engine would just seem to lock up. I removed the compression checker and retried turning the engine over to make sure it wasn't actually locked up. It turned over without stopping leading me to believe the starter was too weak to turn the engine over above 90psi.

Next I figured the starter was just weak so I thought I'd reinstall the plug and try pulling the bike with my TRX450S. When my friend and I tried this, the back wheels would just lock up and skid across the pavement, even in second gear.

I am at a loss guys. If I can't get the bike to turn over continuously, I can't think of any way to troubleshoot the "won't start" issue. I did check for spark and it has spark. When I remove the plug, it smells like gas so I'm pretty sure I'm getting gas. The problem is it will only turn over a couple times before locking up (or whatever is happening). NOTE: the positive jumper cable is pretty hot after attempting to jump the bike.

Pleas help!!!!
 

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Master of the Electron
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Any chance you’re hydrolocking?

90psi is not out of the ordinary when the decomp is working, just a bit low. What is valve clearance set to?


Welcome to the forum!
 

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Any chance you’re hydrolocking?

90psi is not out of the ordinary when the decomp is working, just a bit low. What is valve clearance set to?


Welcome to the forum!

At first I was like "What is this idiot talking about, Hydrolock?" Then I looked at who posted it. My next thought was "Well, hmm...." Then it hit me how that could be and I was all "AH!!!" :wink
 

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Master of the Electron
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Just drawing at straws... OP has done a pretty good job of covering most other possible causes.
 

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Super Moderator
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How about gapping the rings upon install?

Never mind, I re read your post and you did this task..
 

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I may be getting older, but I refuse to grow up!
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Was your 450 running when you jumped the other battery? If not the low battery could draw down the good battery, as indicated by the hot jumper cable. Try jumping from a car battery with the motor running.

With the plug out, turn it over several revolutions with the starter to clear any gas in the cylinder.

When bump starting if the tires don't roll try a higher gear, and just as you engage the clutch, bounce down on the seat with your butt.

WELCOME TO THE FORUM.
 

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Discussion Starter #8
Thank you to everyone for their input. I am going to try jumping with my truck today. I will be sure to take the plug out and turn it over a few times to clear the cylinder. Maybe it's bad connections between the starter relay and the starter or just a weak starter all together.

I am not familiar with Hydrolock. I will look it up today.
 

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Discussion Starter #9
So, I am now "hydrostatic lock educated". Lol. I apologize for my ignorance. One would think it should be fairly easy to detect a hydrolocked condition. Since, in order to hydrolock, the cylinder must be filled with a volume of liquid greater than the volume of the cylinder at minimum (with piston a TDC) I should be able to rotate the crank until the piston is at TDC and stick a q-tip down the spark plug hole. If the q-tip is wet it is possibly hydrolocking, if not then unlikely. Correct?
 

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I may be getting older, but I refuse to grow up!
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Cranking the motor with the plug out will normally clear any hydrolock condition. No reason to feel ignorant, just keep learning as you go thru life.

Three most common reasons for a no start;
Discharged battery.
Dirty carbs.
Starter relay burned up because battery is discharged.
 

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Discussion Starter #11
Also, after looking at the manual, I don't see anything about 95psi being normal for the 660R. The manual says 181 is normal with a min of 149 and max of 192. That being said, I'm not really concerned about compression right now since I haven't been able to turn the motor over enough times to generate those compression values.

I would think the motor would have to turn somewhere between 6 and 10 times to get an accurate compression reading. Anyone disagree?
 

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Discussion Starter #12
Ok, so retried with my truck battery and was able to get it to turn over multiple times although it did not start. I removed the spark plug and reattached my compression checker.

I was able to generate 110psi after about 6 turns. More turns did not result in any higher compression than 110psi. I can figure the starting issue out from here accept one part. Is it true or not that 110 is enough to crank this bike? As I stated, I don't see anywhere in the manual where it says 95psi or even 110psi is sufficient. Also, it says compression checks should be done warm as I imagine that would allow ring expansion resulting in higher compression.

Bottom line: Should I expect this bike to start with 110psi compression when cold?

Also, it appears there is a developing starter relay issue which is easily fixed, as well as the fact that my other two batteries were just too weak.

Thoughts?
 

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Discussion Starter #13 (Edited)
Update:

I reinstalled the plug after getting 110psi on the compression checker, using truck battery to crank. I sprayed starter fluid into the intake manifold, in order to eliminate compression, air and spark as the issue for not cranking, and the bike started right up. I will be cleaning carbs and replacing starter relay as well as battery.

Bottom line:

Bike skipped time and bent valve. Replaced piston and rings as well as all valves and valve seals, made sure to lap valves during install.
After reassembly, could not turn over with battery even if charged.
When performing compression check using truck battery, only got 110psi.
Bike starts at 110psi using starter fluid with no issue.
Clean carbs, replace starter relay and battery.

Thank you to everyone for your assistance. I will be sure to check back often to see what I can help with.
 

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Discussion Starter #14
New Update:

I cleaned carbs and all seemed well except for the fuel mixture screw on the right carb (standing behind bike) was missing the little needle on the end. I found it protruding through the carb body. Obviously need to rebuild/replace carbs.

That being said, I can start the bike with starter fluid and it will idle on it's own, well after starter fluid has been burned off, however it get soooooo hot so quick. within 30 to 45 seconds the exhaust manifolds are smoking. I know coolant is moving because the radiator is hot. Any ideas?
 

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I may be getting older, but I refuse to grow up!
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110 is plenty of compression to start. You won't get a true reading because of the decompression mechanism.

Be sure to put your new battery on a trickle/float charger for a few days.

When cleaning carbs run a small copper speaker wire thru all body orifices followed with a spray cleaner.

Yes, the exhaust will get hot. Do you have any mods? Intake or exhaust? How hot does the coolant get?

If hard starting, check the intake valves clearance.
 

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Discussion Starter #16
No, I don't have any mods. This bike is all stock. I just ordered new carbs.

I'm not sure how hot the coolant is but I don't think the fan was running. I'm probably gonna wire it to stay on all the time like I did with my TRX450S. I've read like 20 posts that say those manifolds get HOT! Seems a little weird to me but Ive never had a bike bigger than a 450 so I guess I don't really have any reference.
 
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