high end noise?

[mudking]

my new blaster (06) is making some noise... not sure.

at higher rpms sometimes I will hear a "slap" or something. at first I thought a tool dropped off the bike or something (was working on carb).

the other day it was raining so I took it out "drifting" on the black top. and I heard a "clack clack clack clack clack" at higher rpms when in the throttle. it was in fast recession (like a machine gun)...

let off and seemed fine and rode it some more and didnt hear it again. but seems I hear something weird like that crack or slap every 5 or 10 minutes when running at higher rpms.

Now the guy before me was running 87 in it. I run 93 in everything. Think maybe the higher octane is making it be stupid? or could my carb cleaning/tunning be off?

I havent rode it much. just down to my parents and back a few times (about a mile total)...

 

[joeak47]

Sounds like possible detonation. Be careful. If its cold outside,Try a larger main jet next. You are possibly on the lean side. You didn't mention any modifications that were done. Yamaha recommends "premium pump fuel"

 

[blasterdemon7]

That's kinda a hard one to call. I would first start out with checking the condition of your engine. Compression test,leak down test and a plug chop. I would take it easy till you find out what's going on. You don't want to snap off a piston skirt and take out the case.

 

[Awk08]

you sure it's coming from the engine ? could be chain slap somewhere ?? chain properly adjusted ? chain rollers good ? swinger skidplate bent up making contact ?

it could be engine detonation your hearing ?, although higher octane fuel can prevent that, it will not over come lean jetting, have you rejetted for the colder temps ? has it been leakdown tested ?

 

[motoman159]

Sounds like detonation to me.

 

[joeak47]

Detonation is unmistakeable. Once you hear it, you'll never forget it. Are you running timing advance/+4 timing key?

 

[motoman159]

Detonation is unmistakeable. Once you hear it, you'll never forget it. Are you running timing advance/+4 timing key?

That is very true. It's like a bad memory.

 

[mudking]

all stock blaster.

that I know of. just got it a month ago.

chain is a little loose, but I dont think bad enough for that. but I will investigate. another interesting thing is that the bike wont run or start on choke. BUT, will start first kick whether cold or hot if no choke... `

wonder if me screwing with the air screw has something off? if you guys are thinking lean. I screwed it all the way in and then backed out 1.5 turns like I saw suggested on here through my searching about tunning. I didnt go far from there.

guess maybe I should recheck that? I did remove the tors. and I did adjust the tors screw a tiny bit to adjust my idle that was just a bit low. and no. its only like 50's and 60's down here in the winter time. not really cold enough that I thought I would have to rejet.

I grew up in norhtern michigan. I road a blaster my whole life. summer/winter. never did anything to it and never had any problems with it... didnt think id have to rejet a stock blaster for anything.

 

[mudking]

ill tighten the chain up tonite, and see where that gets me... I am getting plenty of the 2 stroke smoke out the exaust when riding, but have not paid attention when at high rpms...

I do have a compression gauge and leakage tester on my truck (tool dealer).

I can check that out as well... just dont want to have to rebuild it already.

 

[Awk08]

just dont want to have to rebuild it already.

you doing what is needed to prevent that, hearing/feeling wierd things and checking here for advice, then doing what is needed to check the possible causes I:I

 

[Blaaster]

The first thing I would advise an owner of a second hand 2 stroke is to do a leak test.

Leak tests should be done at least twice a season to predict problems.

If it passes leak test, then plug chop to confirm jetting.

If all ok, now suspect piston slap.

 

[mudking]

what is plug chop?

 

[Durby]

I agree with the detonation theory. I have yet to have a bike detonate on me but last year I got bad gas in my '84 Ranger 375v Bass boat with a Rude 150 two stroke motor on it and at about 5500 RPM it started to detonate. Talk about pucker factor. A blaster motor can be rebuilt for about $200 bucks. Try to find parts for a 1988 evinrude two stroke boat motor......

Also keep in mins that the 2 pokes are prone to cold seize when not properly jetted in the cold weather and always let them warm up before going for a ride.

 

[Reaper26]

it is very possible that its detonation, but being that its used it could also be the cylinder is wearing casing the piston to flop back and forth, it would be worth checking out, you really dont want that skirt to break off, my friends did and instead of spending about 200 dol to rebuild the top end he spent near 500 to build the top end and a new case where the skirt fell under the crank and knocked a hole in it, one easy way to check is to take the tank and pipe off then the head, slide the piston all the way to the top and see how much you can move it around with ur finger, do that all the way down the cylinder, if it moves a good bit replace it, or if you have a leak down tester you can do it that way, but dont just keep riding it, take the time to check it out its worth it trust me. good luck.

 

[Larry's Shee]

Also keep in mins that the 2 pokes are prone to cold seize when not properly jetted in the cold weather and always let them warm up before going for a ride.

what is plug chop?

Not quite true. Jetting and cold seize (aka four point or four corner) are two different things. Cold seize is when the cylinder has not warmed up enough and you're jamming on it and the piston is expanding faster than the cylinder.

Or in my son's case after a slow three mile ride down the road to the lake it seized 6th gear WOT, and jetting was on rich side. 0* F , 50+mph
So if you're running in real cold weather consider putting a sheild to keep the direct blast off engine.

 

[mudking]

again. I grew up in northern michigan. rode my blaster from the time I was 8 till 17 (went to military).

rode it all winter and summer long. we are talking negative degree weather, and I was horrible about letting it warm up.

and I was full throttle everywhere I went. and I rode MILES and miles a day. our property backed up to stateland where I rode every square inch of trail. I NEVER had to do anything to my blaster... never been rebuilt or anything.

 

[Blaaster]

what is plug chop?

Plug chop.

Warm up motor to operating temp.

Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, roll to a stop.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.

If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.

http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/

http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/

This is a good to go plug.

This one is a little rich, but I would run it, I like to be on the safe side.

 

[mudking]

thanks man..........................

 

[mudking]

sorry its taken me longer to do anything.

I got fricken sick this week, and have been just able to go to work and come home and crash.

I did go out last night and peak at it. grabbed the chain and its pretty loose and I shook the heck out of it and heard some similar type noise from it smacking or slapping something... that would be a huge relief.

However, I dont know if I have enough adjustment left to tighten it up to where it needs to be... can you remove links out of these chains?

 

[Larry's Shee]

Yes you can. However when you get to that point it's time to think about a new chain Take chain off, grind the pins at least flush with plate, drive pins thru plate = one link shorter.

Some/most recomend new sprockets with new chain. Myself it would depend on how sprockets look and if it was an economy (cheap) chain, high end chain I'd get new sprockets.

JMHO, your results may, and will vary I:I