Top end fried, pics, need to know what size to bore

[xj1514]

First off, Ive been searching a ton, brand new to the Blaster, great info here. Got some questions as I need to place an order tonite to get my parts in early in the week with time to have the cylinder bored for riding on the weekend. (Ya ya, we'll see if it happens) This is a 98 Blaster.

Just bought this blaster for 650 bucks, great shape, bad top end. Compression tested at a whopping 45psi, yes guage is accurate, tested my other blaster and got 120 psi. Bike was not running when I got it. Pulled the jug here is what I got...

37F01 is stamped on inside of piston.

Question 1...
Piston measures 65.5mm. Jug measures 65.5 except for one spot on the bottom by the skirting which was 65.8. I measured all over, top to bottom of cylinder. Question is which piston do I buy? I like Wiseco, but open to suggestions. Is pro lite what I want or is there a better bang for the buck or just better quality? Im guessing I need standard 66mm piston, or just to be safe should I go to the 66.5mm piston?

Question 2...
Who do I order from? Rocky mountain atv seems to have alot of parts.

Question 3...
I assume I need a top end kit, Cometic? Tusk? OEM? or Dont buy whole kit just individual gaskets?

Question 4...
Need wristpin bearing, Wiseco?

Question 5...
What did I forget?

Thanks all.

 

[xj1514]

Vito's has good prices. Im looking for a one stop shop. Piston, wristpin, jet kit, high flow airfilter, gasket kit. Does any one know if Vitos Wiseco piston for 84 bucks comes with wristpin, circlips and rings?

 

[Awk08]

just say "no" to vito's !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
the gaskets they supply are worthless and guarenteed to leak

get only cometic or oem yamaha base gasket

only the shop you choose can tell you what size piston it needs, after they see how deep they need to go to get all the gouges out
if you told us where you were from we could recommend one of our builders better.
if you chose one from here, ken oconnor racing being my chioce, he'll get you everything you need, worth the price of shipping it to know it is done correctly,
otherwise i'd look on ebay for the best price of the wiseco, and the last ones i bought came with the piston, rings, wristpin and ciclips

 

[scotj77]

#1 you need to have a shop measure that jug to be sure of piston size.

#2 Rockymountain atv is a good spot

#3 Order oem especialy the base gasket. the other gaskets can be any brand almost.

#4 Make sure wrist pin bearing is name brand the pin should come with the piston. you should be able to get a kit from rockymountain

#5 don't forget the exhaust oring when you get your gaskets. send your jug to ken if you really want to be sure it is done right. or any of the other techs on here. lots of oil durring reassebly, check crank specs while ya got it open.

by the way good questions and format!!!!!!!!!!!!!!!1

 

[xj1514]

Ok, thanks for the help. Guess I was just getting the horses ahead of the cart by trying to buy the piston tonight and get it on its way. If vitos is a no go, looks like rockymountain atv is the best bet. Free shipping. Im trying to find a jet kit thats affordable right now, vitos is 25 bucks while everyone elses is around 50. Any reason I cant just get the right jets the first time rather than buying a whole kit or do I need them to experiment with? If so, who has a more reasonable setup?

 

[scotj77]

list your set up and guys here will tell ya what size jets to buy and you can buy them individually on jet'srus. only buy oem jets

you will have to play around with the jetting to get it right.

 

[Awk08]

exactly, buy the jets seperately from your local dealer, jetrus.com, or cpw.com
let us know what carb and all your mods and we'll get you close on jetting

 

[xj1514]

Depending on what the shop says tomorrow, either a 66mm or 66.5mm Wiseco piston. Stock pipe and silencer unless someone can tell me the best one to get, k and n filter or uni with airbox lid removed, stock carb and are the boyeson super stock carbon reeds worth 37 dollars? If so then I'll grab those too. So, what jets do I need? Thanks a ton.

 

[99LRDblaster]

Question 1...
Piston measures 65.5mm. Jug measures 65.5 except for one spot on the bottom by the skirting which was 65.8. I measured all over, top to bottom of cylinder. Question is which piston do I buy? I like Wiseco, but open to suggestions. Is pro lite what I want or is there a better bang for the buck or just better quality? Im guessing I need standard 66mm piston, or just to be safe should I go to the 66.5mm piston?

Wiseco makes good pistons. The cylinder will need to be measured. 66.0mm is the stock bore size so measuring tool is a bit off. That looks like an aftermarket piston you already pulled out too so it's probably already nursing a rebuild. Try to measure again with another micrometer or vernier. Once you know the cylinder bore, you will know what piston to get for the appropriate bore. Check out Wiseco's site from more specific details. Wiseco Manufactures High Performance Forged Pistons & Performance Parts for Motorcycles, ATVs, Snowmobiles, Marine, and Automobiles

Question 2...
Who do I order from? Rocky mountain atv seems to have alot of parts.

Yes, Rocky Mountain is fine and you get free shipping after $100

Question 3...
I assume I need a top end kit, Cometic? Tusk? OEM? or Dont buy whole kit just individual gaskets?

I've used Cometic and never had any problems. As added safety use some type of gasket sealant like Yamabond and get Copper Head Gasket spray and spray the copper head gasket with it.

Question 4...
Need wristpin bearing, Wiseco?

Yea, just get the wristpin with it

Question 5...
What did I forget?

What does the head look like on the top end? While you have it apart, you should consider porting the cylinder. It will give you a lot more power and you won't kick yourself later after you have it together that you didn't port it then. Even if you don't port it, you need to clean the top end(and bottom end) EXTENSIVELY. You can see bits and pieces everywhere including in the transfer ports there and I'm sure the head chamber doesn't look too happy either with pitting indentations, etc....clean that stuff up really well.

 

[hudack]

i would start with a 260 if your taking the air box lid off no need to rejet for a rebuild only if you went big bore

 

[1995blaster]

Depending on what the shop says tomorrow, either a 66mm or 66.5mm Wiseco piston. Stock pipe and silencer unless someone can tell me the best one to get, k and n filter or uni with airbox lid removed, stock carb and are the boyeson super stock carbon reeds worth 37 dollars? If so then I'll grab those too. So, what jets do I need? Thanks a ton.

and for a pipe if you plan on modding get a right bend like f7 but if you dont get a toomey or fmf

idk bout the reeds ill sell you vforce 2 reeds for 50$

 

[99LRDblaster]

and for a pipe if you plan on modding get a right bend like f7 but if you dont get a toomey or fmf

idk bout the reeds ill sell you vforce 2 reeds for 50$

Personally, I see nothing wrong with using left bend pipes.

 

[UncagedShadow]

i picked up a wiesco topend kit from ebay. It ran me about 90 bucks after shipping. It came with everything except gaskets witch i ordered oem per instruction from this site.

This rebuild was done a year ago and when i knew nothing about blasters. Now a year later, i have a whole engine taken apart in my apartment lol. Be carfeul, the blasters are addicting little SOB's lol.

 

[xj1514]

Question 1...
Piston measures 65.5mm. Jug measures 65.5 except for one spot on the bottom by the skirting which was 65.8. I measured all over, top to bottom of cylinder. Question is which piston do I buy? I like Wiseco, but open to suggestions. Is pro lite what I want or is there a better bang for the buck or just better quality? Im guessing I need standard 66mm piston, or just to be safe should I go to the 66.5mm piston?

Wiseco makes good pistons. The cylinder will need to be measured. 66.0mm is the stock bore size so measuring tool is a bit off. That looks like an aftermarket piston you already pulled out too so it's probably already nursing a rebuild. Try to measure again with another micrometer or vernier. Once you know the cylinder bore, you will know what piston to get for the appropriate bore. Check out Wiseco's site from more specific details. Wiseco Manufactures High Performance Forged Pistons & Performance Parts for Motorcycles, ATVs, Snowmobiles, Marine, and Automobiles

Question 2...
Who do I order from? Rocky mountain atv seems to have alot of parts.

Yes, Rocky Mountain is fine and you get free shipping after $100

Question 3...
I assume I need a top end kit, Cometic? Tusk? OEM? or Dont buy whole kit just individual gaskets?

I've used Cometic and never had any problems. As added safety use some type of gasket sealant like Yamabond and get Copper Head Gasket spray and spray the copper head gasket with it.

Question 4...
Need wristpin bearing, Wiseco?

Yea, just get the wristpin with it

Question 5...
What did I forget?

What does the head look like on the top end? While you have it apart, you should consider porting the cylinder. It will give you a lot more power and you won't kick yourself later after you have it together that you didn't port it then. Even if you don't port it, you need to clean the top end(and bottom end) EXTENSIVELY. You can see bits and pieces everywhere including in the transfer ports there and I'm sure the head chamber doesn't look too happy either with pitting indentations, etc....clean that stuff up really well.

Wow, thanks for the detailed response. You input is much appreciated.

1. Using a digital micrometer, it must be off
2. Rocky mountain seems ok, bit expensive and slow on shipping sometimes
3. I rebuilt my XR600 top to bottom with Cometic with no issues, still have some Honda bond left
4. I really want to port it, along with a ton of other mods, but right now I just need it together to ride. I get laid off everywinter, so that will be the time when the bike really goes under surgery. The head looks really good. Good tips on cleaning extensively though, thanks.

Im trying to basically just fix it for now and upgrade heavily this winter. Its riding season.

 

[xj1514]

Will an FMF Fatty support a big bore kit if I later choose to do so?

 

[roadkill]

Wow, thanks for the detailed response. You input is much appreciated.

1. Using a digital micrometer, it must be off
2. Rocky mountain seems ok, bit expensive and slow on shipping sometimes
3. I rebuilt my XR600 top to bottom with Cometic with no issues, still have some Honda bond left
4. I really want to port it, along with a ton of other mods, but right now I just need it together to ride. I get laid off everywinter, so that will be the time when the bike really goes under surgery. The head looks really good. Good tips on cleaning extensively though, thanks.

Im trying to basically just fix it for now and upgrade heavily this winter. Its riding season.

dont bother buying a separate wristpin or bearing they come with the wiseco kit

 

[xj1514]

i would start with a 260 if your taking the air box lid off no need to rejet for a rebuild only if you went big bore

So 260 Main. What about pilot?

 

[xj1514]

dont bother buying a separate wristpin or bearing they come with the wiseco kit

Weird. Ill have to call in the morning. None of the wiseco kits say they come with the bearing. They do say they come with wristpin.

 

[99LRDblaster]

So 260 Main. What about pilot?

Stock pilot should be fine. Just adjust the gold mixture screw next to the fuel line. In=richer, Out=leaner.

 

[Kgibson]

ive never got a bearing with a kit....always extra