I recently acquired my first Blaster which was not running at the time I got it, so of course I start off tring to find out what is the problem. I started by emptying the fuel tank, change the plug and check for spark, and cleaned the air filter. All is good there but still souldn't crank, so I pull the carb and reed cage only to discover there is no gasket at the reed cage and cylinder. So I am thinking first replace the gasket and clean the carb see if that fixes it. But if not, then I am thinking that the rings may be stuck. I dont have a compression gauge but it seems to have compression. If I take the plug out and I can't hold my thumb over the hole while I kick it over so that tells me it has compression but not sure how much. I have done a little reseach on top end rebuild kits. Are K&S gaskets any good? I am thinking of going with Wiseco piston and rings. Is there a better recommendation? I am going to try the reed cage gasket first.
Top End Rebuild
- Thread starter Razberry
- Start date
yeh a compression tester will run ya 20 bucks likely, something every quad owner should have. also get a leakdown tester. if there is an iarleak you will never know where it was if you take it apart
Why spend the money to rebuild top end if you dont even know if it needs to be rebuilt???
Spend the money on a compression tester and a leak down tester.
Spend the money on a compression tester and a leak down tester.
I agree with phrag. Don't buy k&s gaskets they are garbage. you want to get a yamaha oem basegasket and reedcage gasket, headgaskets seem to all be the same to me. weisco is the way to go with pistons. bikebandit is a good place to find oem stuff outside of a dealership.
there has almost been a common concesus on the forum to stick to oem gaskets, ask awk and ken and they will tell you why paper gaskets blow! literally.
i know there are faithfulls in cosmetic gaskets like super noober, i personally am gunna stick with oem
i know there are faithfulls in cosmetic gaskets like super noober, i personally am gunna stick with oem
Thanks for the help. OEM gaskets it is then. I went to the dealership and got the reed cage gasket yesterday but didn't have a chance to put it on yet and I will be buying a compression guage this afternoon. And I'll let ya'll know how it turns out.
Ok I did some checking over the weekend. I have 115psi compression but the coil is only putting out 1.5 Ohmns. Is that enough? It seems like it should be at least 3.
did you hold the throatle wide open and keep kicking til the gauge stoped moving 115 is good to run on just wanted to make sure and im not sure how any Ohmns its spose to put out im no good with eletric stuff
115 is not a lot of compression. There are two possibilities; either it's dry because it's been too long since is has been ran and that number will come back up once you get a little oil and gas flowing or the top end is worn and will need a re-ring soon. Either way not a huge deal, just something to consider.
115, however, is enough to run as long as everything else is in order. There is an electrical troubleshooting section in the factory service manual to walk you through the entire ignition system piece by piece. Once you've stepped through each piece the last thing it tells is to replace the CDI box.
115, however, is enough to run as long as everything else is in order. There is an electrical troubleshooting section in the factory service manual to walk you through the entire ignition system piece by piece. Once you've stepped through each piece the last thing it tells is to replace the CDI box.
Yeah I checked the compression 3 times to make sure it was consistant. I found in the manuel that the secondary resistance is supposed to be 5.28-7.92 ohmns. Mine is only puting out 1.5 ohmns. I am pretty sure that is the problem with mine, which thats an easy fix. I should be back on the trails this weekend.
Alright, need some help. I bought a new coil put it on and It still won't run. If I hold the throttle wide open and spray a little starter fluid in the carb ( I know your not supposed to!) it will crank up for about 2 or 3 seconds then just dies. The reeds look good, the carb is clean, It has good compression and it's getting spark. What is wrong with this thing?
Alright, so we're to the hair pulling out stage, it's time to step back and punt.
Let's go back over the basics. You need fuel, fire, and heat in order to run.
You have fire now because of changed ignition parts.
You have heat because you've done a compression check.
Now you need to worry about fuel. If it'll pop with starting fluid then it can run, you just need to get the fuel mixture right. Check you float level. Clean the pilot system and check the choke circuit.
Let's go back over the basics. You need fuel, fire, and heat in order to run.
You have fire now because of changed ignition parts.
You have heat because you've done a compression check.
Now you need to worry about fuel. If it'll pop with starting fluid then it can run, you just need to get the fuel mixture right. Check you float level. Clean the pilot system and check the choke circuit.
three things you gota have fuel spark and compression you got spark youve got compresion so time for fuel pull your fueline off and turn the petcock to on see how well it flows out if it flows good then move on to the carb clean it spotless check float level like said above then report back
I took the head off my motor after tring everything else. My dad insisted that i take the head off and take a look at the piston and rings just to make sure that wasn't the problem. The piston and rings look fine but it seems a bit loose in the cylinder. how much movement is ok for the piston inside the cylinder. therings seal to the wall fine but the piston moves side to side a little bit. is this normal?
The BOTTOM of the piston should have .002-.004" piston to cylinder clearance. The top of the piston will have bunches more to allow the piston crown to expand when it's heated.
Thanks for that one. I'm taking my head to the machine shop tomorrow and should be ordering new top end kit by the weekend. If I have it bored over .020 do I need to change carbs? currently stock.
no. boring the motor out doesn't require anything else to change. there is virtualy no difference at all besides needing a larger piston.and it's a cylinder you will be boring the head is the part that bolts on top of the cylinder with the spark plug in it.
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