Crank won´t rotate at all! ..

lassek

lassek

New Member
Feb 23, 2009
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Sweden, Denmark is my native
Hi guys.
I have some bad news..
Yesterday i where putting the freshly bored cylinder (68mm) and a Wiseco piston on my quad due to engine failure some weeks ago. But something happend.....

It all started a few weeks ago....:

The problem was a terrible grinding metal sound and the engine stopped.. When i disassemled the engine the piston and head where badly damaged.... It seemed like some metal pieces / shards? had found its way to the top of the piston and completly destroyed the top of the piston and made a lot of scrathes /damage to the head.. some of the metal pieces where actually pressed in the top of the piston.

So the solution was to bore the cylinder and get a new piston.. the head dont look beautiful anymore but has been grinded smooth again..

I then tried to clean the crankcase as good as possible without opening the engine but with compressed air, oil, gasoline it tried to clean it.... (now dont punk me, i know its not good to do it without completly tearing the engine apart) .... BUT, i then mounted the new cylinder and piston etc... finally the time was here to try the first start..

The first thing i did notice was how hard the kickstarter was?! I couldnt believe it was the compression... i then tried a few times, the kickstarter got harder and harder to kick... and then suddenly i jammed/ locked completly... i could stand on it without movement! (95kg!!!) ... I disassembled everything and the piston and cylinder was completly unharmed.. i took the cylinder and head and piston apart.. then i noticed it is the entire crank that i locked up or jammed inside the engine case. ....

What can it be? metal pieces? faulty bearing? It is currently impossible to turn the crank around one revolution..

Please advice... I know now I have to take the entire engine off the frame (which I already did) but is it possible for me to open and maybe change the bearings by myself ? Or does it require special tools and what not.. Could it be something completly diffrent? .. What should i do from from this point ? ..

Thanks in advance!
 
.. the head dont look beautiful anymore but has been grinded smooth again..


-first mistake*



I then tried to clean the crankcase as good as possible without opening the engine

-second mistake*


... finally the time was here to try the first start..


-third mistake*
 
ive never torn down the engine in a blaster. But it sounds like the rod bearing is shot. I had the same problem with a suzuki 230 after a rebuild. Im not saying this is a definite thing but it sounds like it to me. Metal shavings would break lose. So it sounds like the bearing has most likely gone bad.
 
yeah most likely your lower rod bearing on the crank is shot but also could be your crank side bearings . your going to have to get a new crank and bearings. You could just buy a new rod and bearing but the price it takes to get it pressed out and new one installed would be about the same as just dropping in a new crank.
 
FLOTEK: Always some good advice and hints huh?. . . I can tell you that IF the head should look beautiful again then the entire head needs to be grinded 1mm at least deeper everywhere! .. now its smooth and even again.. but many marks go deep into the metal so i would require to remove a lot of metal to remove.. but if you take your fingeres and touch around its smooth and even to go.. besides a mechanic said it would NOT impact performance.. as long as it is smooth


244blackblastard : I have looked into this kit, is Wiseco crank kit any good ? I mean they make great pistons !..

eBay Motors: Yamaha Blaster Crankshaft Gaskets Seals Bearings Wiseco (item 270378045728 end time Apr-24-09 04:59:35 PDT)
 
Last edited by a moderator:
I bought that exact same kit for mine about 3 weeks ago from Koons Powersports and have had no problems with it. I was suprised that it came with some good Koyo crank bearings. They were also fast shippers.
 
244blackbastard:

IF im gonna replace my crank please explain what this +3mm crank is? Is it a crank with a longer rod 3mm? That makes a stroker engine?

IF so.. Can i use that with stock cylinder bored to 68mm with a Wiseco pro piston then head has been milled .035" ... Will any of that be a problem???? Also can you run a +3mm with theese mod with a stock carb 26mm ..
 
a +3 would be a stroker crank. the rod gets moved further out from what the stock rod position would be so it's not the rod being longer it's just moved farther out on the crank to have a longer travel. you would have a longer stroke by using the spacer plate supplied in the kit to keep everything else you have the same regarding your intake and exhaust ports. stroker crank will just give you more torgue/power because it moves more of the power towards outside of crank. getting the head milled to .O35 from stock increases your compression and could still run pump gas. it wouldn't matter what carb or crank you use for getting the head milled. and everything would work together. some cases would have to have a minor trench done to them because the rod is moved further out and could make contact with either side of case because of factory case being misaligned.
 
you could upgrade your carb bigger from stock to help a little like maybe 28-30 but if your not increasing your bore/piston size or port/polish there's no need for a bigger carb and also since a motor is an air engine you wouldn't see increases that much unless you put on a better flowing exhaust and some airbox mods to increase your total engine flow. everything goes together as a whole.
 
Sorry i forgot to mention i have the complete tommey B1 kit.. and made a cleanup port and ported the intake and have a V3 Force reed cage.. My concern was if the piston would hit the head if milled.. ?

Also where exactly would this grind be in the engine block if needed with the stroker crank?
 
Bump:

My concern was if the piston would hit the head if milled.. ? ex. 0.0035".. (If milled AND stroker crank 3mm)

Also where exactly would this grind be in the engine block if needed with the stroker crank? Because im taking my engine totally apart.. and maybe i can "pre-grind" to be sure.. any pictures would be nice..
 
You won't have a prob with a 3 mill and a shaved head, that's the setup I run. Just run the spacer plate that comes with the crank. As far as grinding, I wouldn't grind anything until you get the crank installed to see if there is a clearance issue. I had to grind mine a bit, but I've heard that most people don't have to grind anything. The area you have to grind, if any, is at the front and rear of the case by the crank where the rod goes by when it rotates. You'll see what I mean when you get it in. Install the piston and rings, mock up the cylinder and spin it by hand to see if the rod hits. If it doesn't, you're good to go.
 
Ok that sound really nice! .. I would definally buy a 3mm+ instead of stock..

But wouldnt it be better to grind before the crank goes in? I mean with metalpieces and dust that needs grind afterwards? .. the reason im asking is my engine is being disassemled because there are metal pieces allover in the crank... so i dont wanna try that aging specially with new parts....
 
heres some pics of where i had to grind the case for my +3 stroker

100_2745.jpg


100_2746.jpg
 
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