engine issues part 2

giantvt104

giantvt104

New Member
Jan 6, 2012
261
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0
deer park, ny
Hey my original thread was here:

http://www.blasterforum.com/general-support-17/no-start-bad-noise-46551/
Thought i could get more in the engine section then in gen support.

After yesterday issue. today i pulled my whole top end off to see what was going on. first i removed just the head and pumped the piston up and down. seemed perfect. i could hear good suction as the piston went through the motions. i then pulled the cylinder off to inspect everything. the piston and cylinder looks perfect. there doesnt feel like there is any excessive side to side connecting rod play beyond the spec of 1mm. no up and down play at all. the crank feels good to me no side to side or up and down play at all. on the clutch side underneath the kick start gear mount the is a square hole open to the tranny gears. it is a little rough looking some i am wondering if it is a normal port. might have been just like that from casting. i also noticed some black speckles on the cylinder head in the comustion chamber and in the exhaust ports. looks to me like carbon but its weird how its speckled and not coated evenly like the top of the piston. i posted some pics and a vid of what i did here:

Pictures by giantvt104 - Photobucket


i any more pics or video are needed im ready and got the cam in hand. thanks guys
 
Last edited by a moderator:
That hole is same on mine, just checked I:I Check kicker idler closely. Check counter balance gear and bearing, even if you have to pull clutch. Don't know which went first, gear or bearing but the carnage chunked the case good X( there's only three little rivits that hold the gear together. My son's friend was driving when it let loose so I have no clue if it gave any warning :eek:
Also check for slop between gear and clutch basket
 
my .02, leave the clutch cover off, put the cylinder back on w/o the head or the carb or exhaust, put the bike up in the air and put it into gear, then spin the rear tires so you will be turning all the gears, clutch, crank etc., go through all the gears, this will eliminate them being a problem and any clutch side noise;. if there is some noise then most likely you need to split the cases, chances are from what you had apart there will be none, it sounds like the kick start gear is not properly engaging, from the first video. also things to look at when you do it is how the clutch basket spins, i have bent the main shaft the the clutch sits on b4, never seen it anywhere else but it was causing a similar sound. post up with any findings...hope this helps
 
quadboy22p said:
my .02, leave the clutch cover off, put the cylinder back on w/o the head or the carb or exhaust, put the bike up in the air and put it into gear, then spin the rear tires so you will be turning all the gears, clutch, crank etc., go through all the gears, this will eliminate them being a problem and any clutch side noise;. if there is some noise then most likely you need to split the cases, chances are from what you had apart there will be none, it sounds like the kick start gear is not properly engaging, from the first video. also things to look at when you do it is how the clutch basket spins, i have bent the main shaft the the clutch sits on b4, never seen it anywhere else but it was causing a similar sound. post up with any findings...hope this helps
Click to expand...

haha thats awesome thats exactly what i just did I:I. i think i elimanted anything on the clutch side. so i think i figured out my issue. i went on the flywheel side and i removed the flywheel bolt and the flywheel came right off. no puller needed? the key on the crank for the flywheel is completely shaved off!!! that would cause a noise like that and make it shut off right? heres some pics:

there is a little bit of damage to the shaft and the inside of the flywheel seat. can i just clean it up and put a new key in? whats the best way to get that piece of leftover key out. prob just a chisel and a little elbow grease but i dont want to do any more damage.
 

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just use a pick or small screwdriver and hit it out, you shouldn't need alot of force, and yest that will cause it to not run and stop since the spark will not be at the right timing
 
Thats it!!!! the flywheel nut backed off and sheared off the key and was flopping around on the crank. went up to home depot got a matching key installed it and put loc tite on the nut threads. put all the crap back together that i tore appart. started right back up and runs great.

hey at least i know now my topend and crank is perfect!!! i can still see the circular machining in the cylinder from the factory!! i went a little over board but i think it was worth it. at the ended i leakdown tested it at 7psi 4 times with the piston at all phases of stroke at it holds perfect. now i just have to warm it up good and go back and retorque all head and cylinder bolts.

thanks everyone for the help. much appreciated... I:I
 
good to hear, hope you used an impact on that nut you gotta tighten the hell outta the flywheel
 
Larry's Shee said:
Banshee is only 58 ft/lbs
Click to expand...

blaster is 53 ft.lbs.
before reassembling, that flywheel should have been "lapped" to the shaft with valve grinding compound to improve the interference fit of the 2 tapers (shaft/flywheel)
as thats what holds in in place, the key just alings the timing, and the nut holds it on, the interference fit of the taper keeps it from spinning/moving
 
Last edited:
giantvt104 said:
haha thats awesome thats exactly what i just did I:I. i think i elimanted anything on the clutch side. so i think i figured out my issue. i went on the flywheel side and i removed the flywheel bolt and the flywheel came right off. no puller needed? the key on the crank for the flywheel is completely shaved off!!! that would cause a noise like that and make it shut off right? heres some pics:

there is a little bit of damage to the shaft and the inside of the flywheel seat. can i just clean it up and put a new key in? whats the best way to get that piece of leftover key out. prob just a chisel and a little elbow grease but i dont want to do any more damage.
Click to expand...

UHHHH yeah, that would cause noise and it to shut off! LMAO!

Awk's absolutely right. Now that you know what your problem was you should consider yanking it back off and lapping that damage down with valve lapping compound.
 
Cool thanks guys. yeah thats what im gonna do. im gonna take it all back off and get some lapping compound and clean it up cause the old key def left some metal fused on to there. should i go with the really fine grit? can i use loctite on the crank threads for the flywheel nut? ill bust out the torque wrenchs and go to 53ft lbs and i still have to go over all the engine bolts that i took off and put back on. post heat cycle.

Is the wooddruff key that goes in there supposed to be metric cause the ones that i got were standard one at 3/32 was to thin and the other i got was 1/8 which was too thick so i used the 1/8 but shaved it down till it fit snug? im just wondering cause im gonna get the factory woodruff from yamaha so i can sleep better.
 
yep, get a factory woodruff key, and fine grit lapping compound will work, may just take a little longer, but prolly end up with a better job
some blue loc-tite won't hurt anything
do you have the tusk flywheel/clutch holding tool to hold the flywheel while torqueing it ???
 
giantvt104 said:
Cool thanks guys. yeah thats what im gonna do. im gonna take it all back off and get some lapping compound and clean it up cause the old key def left some metal fused on to there. should i go with the really fine grit? can i use loctite on the crank threads for the flywheel nut? ill bust out the torque wrenchs and go to 53ft lbs and i still have to go over all the engine bolts that i took off and put back on. post heat cycle.

Is the wooddruff key that goes in there supposed to be metric cause the ones that i got were standard one at 3/32 was to thin and the other i got was 1/8 which was too thick so i used the 1/8 but shaved it down till it fit snug? im just wondering cause im gonna get the factory woodruff from yamaha so i can sleep better.
Click to expand...

I bought standard Permetex valve lapping compound from an auto parts store. Creates a nice fine "scratch" pattern kinda like a fresh hone job. You can really feel when the flywheel and stator are matched again. The flywheel goes from moving easily to grabbing. Remember to spin for about 20 seconds and then pull the flywheel off and wipe the compound down onto the taper again. I wants to congregate in the flywheel's keyway and get much less effective upon doing so.

I did the same thing with my yellow blaster. I needed a key so I got the 1/8" key from Ace hardware and carefully held it with pliers against my sander. I had a crank right beside me to keep a check on it and stopped when it was a snug fit. The interference fit between the two tapers is what actually keeps the flywheel from "spinning", the key is only there for alignment purposes Obviously, if you have a stock key it would be nice to use one you didn't have to sand down to fit but the sanded down key will work well too.
 
giantvt104 said:
Great thanks guys. so i coat the flywheel and crank with the compound and install the nut loosely and spin it around by hand about 20 times?

no awk i dont have that. i was just using a large rubber strap wrench. but i def will get that. it works to hold the clutch too?

this one?

Tusk Clutch Holding Tool | ATV | Rocky Mountain ATV/MC

should i get this puller too?

Tusk Flywheel Puller | ATV | Rocky Mountain ATV/MC
Click to expand...


You don't even put the nut on. You just apply lapping compound to the crankshaft and spin it over and over. It acts like sand paper slowly polishing the two tapers together.

That's the flywheel/clutch holding tool if you want to buy one. That's also a good flywheel remover if you want to get them at the same time and save on shipping.
 
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ok perfect i can even get the compound from rm. i like spending a hundred bucks min on there at a time cause of free 3 day shipping. i think im gonna get a new oem head gasket and cylinder gasket. when i took my engine apart i didnt have new gaskets so i used the old ones which passed the leakdown perfect but id feel better with new ones. ill get some tools. also when i had the carb and intake boot off with the reed still in place i noticed when i was turning the motor over when going through the compression stroke the reed petals were bubbling a little cause there must not be sealing great. the boyesen pros are the top ones from boyesen right?

these ones:
Boyesen Pro Series Reeds | ATV | Rocky Mountain ATV/MC
 
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