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Discussion Starter #1
So I did the head gasket, she started great the first few times. No more bubbles in the coolant bottle and sounded great. No leaks. Compression test came back 92psi for a stock bore with Wiesco 11:1.

So I raced about 5 minutes and she started breaking up pretty bad and then finally just died (like it was doing before). I was able to start it long enough to get it back to the trailer but when we got home I couldn't even ride it to the garage. It's cutting out and won't stay running. I have an engine guy I'm going to take it to that says it may be the valves but now he's not sure since it won't even run.

I searched some things online and found that you can pull codes from these old OBD I set ups. How? Also I was thinking maybe the coil is bad. It feels electrical to me not mechanical.

How often do you guys that are racing raptors have to replace valves? Honestly I didn't know they wore out. I've been racing her hard for 4 years.
 

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Do you have spark? Do you hear the fuel pump?
 

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tps sensor? when I pulled mine apart last winter I didn't plug my tps sensor in securely during re-assembly. ran like crap. sputtered, wouldn't idle without giving it gas, and it finally died. Then I found my tps sensor not plugged in all the way. plugged it in and it's been purring like a noisy sewing machine ever since.
 

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Discussion Starter #4
This is why I love this place. Great ideas I will go back over my work after I clean her off tonight. What's a good way to check for spark? ground plug to head while plugged in and hit button?

thanks
 

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That will work.
 

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mine kept cutting out and and running poor. It seemed like it would run hard for 10 min or so and finally load up on fuel and foul a plug and then would die. It also would lose spark sometimes and I eventually found out after lots of chasing I just had a bad connection on my coil. The spade connector on the the coil was making a very weak connection and giving little to no spark.
 

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Discussion Starter #8 (Edited)
Ok here's the deal she ran pretty well but a little low on power for the first 3/4 of a lap. Then died and would barely run to get me back to the trailer. So after about 7 minutes of hard running it dies right? Well I get home after the 2hr drive and it still won't run/start and idle.

So I let it sit all last night and today, get home to wash it and she fires right up. I'm thinking oh good it's electrical maybe I can figure it out. I take the coil connection off and it's dirty of course. Anyway I ride it out and wash it. It's soaked but still fires right up.

Is there a chance that when it heats up the coil craps out? What would die out when it heats up?

Checked the TPS and spark both good. Tune came from High Desert Dyno
 

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have you checked your plug? could be loading up on fuel because of weak/ intermittent spark. thats what mine was doing
 

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It's possible that the coil is bad, You need to run it until it shuts off and won't start then check for spark. I had a coil go bad on my '06 and it would start up fine run for a little while just fine then it would start to lose power and hesitate then it wouldn't idle then it would just die and not start until it sat overnight. Also make sure your valves are not to tight, when they are it will run better cold and as it gets hotter it will start to run like crap but I don't think valves are the problem since it died and still did nothing 2 hrs. later, it should have tried to start. So I'm going with electrical problem. The TPS could be bad if it's not the coil I have seen them cause the problem you are having also so the key is if it has spark during the time it won't start.
 

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Discussion Starter #11 (Edited)
Thanks team. Checking it out more today. I have a stock of plugs and they get changed constantly. Yeah I put a new plug in it that day.

I will report back with my findings. On the up side I know now how to replace head gaskets on these quads and it's much easier than I thought. Had it done in 4hrs. Keep in mind my 3.5yr old daughter was helping so ya know. :lol:
 

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Thanks team. Checking it out more today. I have a stock of plugs and they get changed constantly. Yeah I put a new plug in it that day.

I will report back with my findings. On the up side I know now how to replace head gaskets on these quads and it's much easier than I thought. Had it done in 4hrs. Keep in mind my 3.5yr old daughter was helping so ya know. :lol:
:thumb: good deal.. you going to make it to indiana this weekend?
 

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Discussion Starter #13
nope I'll be happy if I make Snowshoe
 

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Discussion Starter #14
Ok so it looks like the problem.......was the gas tank breather tube. :lol::lol::lol: We'll see I'm still waiting to get it back. I had my dude do the valves anyway. But hey at least now I know I can replace head gasket on this beast myself now. And I was loosing compression through there.

I changed out the coil replaced the head gasket never thought to check the breather tube. The simple things escape me I guess.:banghead:
 

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Ok so it looks like the problem.......was the gas tank breather tube. :lol::lol::lol: We'll see I'm still waiting to get it back. I had my dude do the valves anyway. But hey at least now I know I can replace head gasket on this beast myself now. And I was loosing compression through there.

I changed out the coil replaced the head gasket never thought to check the breather tube. The simple things escape me I guess.:banghead:
:lol: i know the feeling bud.. i have had the same thing happen to me.. i also traced wires for 4 hours when mine wouldn't start once.. needless to say the gas jug came into play and she fired right up.. talk about being pissed and throwing shit in the garage!! :lol:
 

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Discussion Starter #16
HAHAHA sucks lost race time and all that but what ya gonna do
I think this is a lost year I'm gonna have to come back strong next year.

My knee is still all trashed from the hamstring ACL graph (racing on a torn ACL is bad). They think they're going to have to go back in now that the screws and staples are holding, they need to completely replace the medial miniscus that's three knee surgeries in less then a year. :banghead::banghead::banghead:

If the quad isn't broken I am:thumbsdown:
 

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HAHAHA sucks lost race time and all that but what ya gonna do
I think this is a lost year I'm gonna have to come back strong next year.

My knee is still all trashed from the hamstring ACL graph (racing on a torn ACL is bad). They think they're going to have to go back in now that the screws and staples are holding, they need to completely replace the medial miniscus that's three knee surgeries in less then a year. :banghead::banghead::banghead:

If the quad isn't broken I am:thumbsdown:
its allways something mike.. pretty much how my year endend last year.. you will be up and goin strong soon man.. hang in there..
 

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its allways something mike.. pretty much how my year endend last year.. you will be up and goin strong soon man.. hang in there..
I have a 2007 Yamaha raptor 700 it will start immediately and run perfect then it will stop immediately as if somethings stopped the piston dead in its tracks then immediately after it’s a little tough to start but it will fire back up pretty quick seems like it hesitates but if you let it sit a minute if Iris right back up please help
 
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