FAQ about BB kits, Pistons, Cylinders, Head Rebuild, ETC

J

japdeathtrap

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Jan 3, 2016
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2005 Blaster, stock head, carburetor, gearing etc.
- has a DMC Header, DG muffler
- deleted oil injection, so pre-mix fuel only
- no lid on air box and aftermarket foam filter
- new boysen reeds
- TORS delete & new throttle
So in one of my last threads, I had a no-start issue, and then I rebuilt the carb, got the float level, and proper jetting for my mods set up. the bike will now crank and run and poorly idle, but after 3/4 throttle there is bogging and dying.

Here is a link to he other thread, please bare with me...then I didn't understand half the stuff I have learned now.
http://www.blasterforum.com/threads/somthing-horribly-wrong-engine-died-help.64826/

My most recent compression test only gave me 50-60 psi, leak down test was fine. and there is a little bit of wiggle on the piston, and i can feel a un-even ridge about right at the top of the cylinder above the exhaust port.

I am trying to figure out what I should by to fix my top end.

there are these kits on ebay, that are all the same products, but at different prices, ranging from 190$ to less than 100$ and most being exactly the same if not only having like minor differences...like the upper head gasket being copper, or some including the upper rod bearing.

There is this kit on ebay. It is 90$ for a new head, cylinder, all the gaskets, etc..
http://www.ebay.com/itm/Yamaha-Blas...ash=item58cf66194e:g:lxgAAOSwSdZWcdzX&vxp=mtr
I have seen that the piston for this kit is less than acceptable in most of our users opinions.

This is why I am considering buying a big bore kit. Why not just go ahead and get the cylinder that i have now bored and then get a piston kit that will make my bike a 240cc?

There is a LAPC piston?
http://www.ebay.com/itm/YAMAHA-BLASTER-200-TO-240cc-BIG-BORE-PISTON-KIT-72MM-ALL-YEARS-/391540233762?fits=Make:Yamaha&hash=item5b299dd622:g:VlUAAOSwGIRXZHVh&vxp=mtr

and these Namura pistons...
http://www.ebay.com/itm/Namura-040-Over-Bore-Piston-Kit-1988-2006-Yamaha-Blaster-
200-YFS200-67-00mm-/251125931226?hash=item3a78459cda:g:TfcAAOSwEK9TyCkR&vxp=mtr

I just need some advice. I am not spending 500+ on a 700$ quad. and I wouldn't mind going ahead and boring over, especially when I can buy new cylinders for so cheap.

If I go this route, do I buy the piston first, and then take the piston, W/ Rings and head to the machine shop? Does the head cover (top plate of the head) need to be bored out too?

also even on the stock bore replacement kits, i could just buy one of the cheap ones and get a better piston (stock 66mm), but they say that chamfering is needed. how do I do that?
 
Last edited:
forget those chi-wanese $90 cylinders, they're garbage.

japdeathtrap said:
Why not just go ahead and get the cylinder that i have now bored and then get a piston kit that will make my bike a 240cc?
Click to expand...

NO, it'll need resleeved to accept a big bore 72mm+ piston

if you go big bore kit, you should ugrade your carb and pipe also = more $


best bang for your buck...... call Ken monday morning after 9am. (860) 230 - 5003
check out his website until then http://kenoconnorracing.com
to get an idea of pricing of new piston/bore & top end gasket set.
porting and head mod if you want real power.
send your cylinder and head in, Ken will do the rest
 
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Great advice above!!! /\ /\ /\

Get your "stock oem" cylinder matched to a piston of your choice.
Get it done properly the first time. The stock oem cylinders are the only way to go, because they're quality. If you have the extra money to invest in porting AND a head "Re-chambering", do it.
You can run this set up with a stock carb and double your HP (almost). Stock is right at 16-17HP. After porting and head re-chambering, you'll be knocking on the door of 30 HP... reliably! You can always experiment with a larger carb later ,... if you actually feel the need.
I would also install new crank seals while your at it and leak test it without question. I would also add one of those inexpensive digital hour meters (about $10). Good luck on your build. Get it done correctly. Call the number above.
 
joeak47 said:
Walmart, Target, Amazon, ebay? Wtf???
Click to expand...
The link I added takes you to an add, and at the top it says "continue to ebay" I dont know why, it did that automatically and I couldn't change it.

best said:
I Have a Vito's bbk and 3mm stroker on a Blaster and it doesn't make the torque of a stock cylinder Joe ported years ago.
Click to expand...
That is great info, but I am not going to go that route as I said in the first post. I'm going to buy the vito's super-stock kit which comes with:

- 1 forged weisco piston (ported)
- upper rod bearing, wrist pin, & circlips
- piston rings
- base gasket, head gasket & header gasket

What I need to find out now is what size I need.
I was getting ~67mm diameter in the cylinder and 66mm diameter on the piston.

the Vito's superstock kit comes in 67, 67.5, and 68+
 
It should say what size the piston is on top of the piston like this
Measure the bore on the bottom of the cylinder to get a more accurate measurement
please do yourself a favor and dont put a new piston in a old bore do it right the first time and send your cylinder to a reputable builder like ken oconnor
20141224_204512.jpg
 
Awk08 said:
let whoever is going to bore your cylinder measure and tell you what size to get.
measure first, then buy piston, not the other way around.
Click to expand...

So yesterday I dropped off my cylinder and head along with my vitos superstock piston at Iron horse motorcycles out here in monroe, NC. they are a honda/yamaha/harley ATV, UTV and motorcycle dealership with a nice parts shop and service facility that has been here for over 15 years....they will be boring/honing and chamfering my cylinder to fit my piston.

I am going to be doing Ken O'conner's DIY port job and I will also try to advance my timing DIY.

I wont try the timing advance until I actually have the bike idling again so that I can rule out the basics if there is an issue.

AWK, what jets do you think I would need for this superstock piston, DMC exhaust, no lid airbox, no oil injection, and the stock mikuni carb?

what about with the timing advanced? I do still have that 290# main, and the carb has been freshly rebuild with all new bits and a fresh gasket. The floats are original and last time i checked were set at 21mm. the needle clip is in the middle

Is it safe to heat cycle, and break in the new rebuild with that 290 main? Ken said to stay off Wide open throttle pulls for the first tank of gas. and from what I have seen the main is the final circuit so that is 75% - 100% throttle
 
You have to have the ports champhered after porting a cylinder. ...its better for someone with experience do it so you don't snag a ring and mess up your new top end
 
japdeathtrap said:
what jets do you think I would need for this superstock piston, DMC exhaust, no lid airbox, no oil injection, and the stock mikuni carb?
Click to expand...

if that's the mods you had before the bore/piston ? you should run the same jets you were before, (DMC's supposedly like the 2nd clip position from bottom ?)

airflow into and out of (exhaust pipe and intake/air filter) are the biggest determining factor in jetting, switching from injection to mix = +1-2 main jet. over bore/piston won't require a jetting change.
tune the airscrew per the DIY in carb section, drop needle clip until it stutters then back up one till it pulls hard, and plug chop for main jetting

btw...if you're using that novelty piston, skip the porting on the exhaust port if you do porting, since that piston provides a pie cut to mimic raising the exhaust port,
if you do both it'll raise the exhaust port too much, (possibly not even close at all)
and most likely loose low end, and have nothing but a short, all top end, power band.
I'd only widen the exhaust port with that piston and not raise it at all.
 
What do you guys think of the wiseco piston kits that include the stock bore cylinder? Does that still go with what you mentioned previously about the aftermarket cylinders being junk? I'm just wondering for future reference? Or even if I was to go with the BBk say vitos for example would you recommend getting the stock jug bored or just buying the complete kit from vitos?
https://www.ebay.com/itm/Yamaha-Bla...-Rebuild-Kit/191914438275?hash=item2caefdee83
 
Joewaldr said:
What do you guys think of the wiseco piston kits that include the stock bore cylinder? Does that still go with what you mentioned previously about the aftermarket cylinders being junk? I'm just wondering for future reference? Or even if I was to go with the BBk say vitos for example would you recommend getting the stock jug bored or just buying the complete kit from vitos?
https://www.ebay.com/itm/Yamaha-Bla...-Rebuild-Kit/191914438275?hash=item2caefdee83
Click to expand...
Probably should have started your own thread. I don't see where your question has much to do with this topic.

With that being said, those cheap after market cylinders have VERY poor quality !! I would do ANYTHING including resleeving your cylinder before I gave my money to the chicoms.
 
Larry's Shee said:
Probably should have started your own thread. I don't see where your question has much to do with this topic.

With that being said, those cheap after market cylinders have VERY poor quality !! I would do ANYTHING including resleeving your cylinder before I gave my money to the chicoms.
Click to expand...
The first post on this thread asked essentially the same question just about the Chinese kits... but I was wondering specifically about the wiseco kit if that was still considered to be a junk cylinder
 
https://www.blasterforum.com/threads/niche-industries-top-end-kit.61580/page-3#post-810326

The only thing"Wiseco" about that kit is the piston. The cylinder is still made by the Chinese Communists .

You get what you pay for (if lucky)
Quality doesn't cost it pays.

Apologies, I only read the title which didn't mention the kits.
There has been so many problems with those kits. Some were lucky to get a couple hours before failure.

If I linked the right thread it will show the voids in the casting which would be hot spots.
 
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