New blaster owner!

[Rugerdude]

Hey guys, new blaster owners here!!!!

Little info on me, i used to race mx on a honda 250x in the youth quad class back in 02-04 and switched to a east coast atv/ gibson yfz450 in the B class locally and gnc nationals from 05-07 untill i got ranover 4 times in a local race. Sold everything a few years later.

I was a certified stihl mechanic for 8 years so I have a pretty good mechanical background.

Now im getting riding again and have a xr100 with 120 bigbore, a 1978 ct70 and a 1998 bayou 300 2x4 ive managed to collect the past few years.

i just picked up a 01 blaster from my neighbor for 150$ its clearly been apart before with blue rtv on the cases and intake. The engine is clearly blown up and theres oily gunk all over the lower engine and skid plate, hopefully from a leaking seal or gasket ...Currently have her stripped down and am fighting the swing arm bolt.

Im missing the rear brake caliper too, should go i go stock or some sort of swap ?

Any useful info or mods i should know of about these bikes?

 

[Slydog]

Hey guys, new blaster owners here!!!!

Little info on me, i used to race mx on a honda 250x in the youth quad class back in 02-04 and switched to a east coast atv/ gibson yfz450 in the B class locally and gnc nationals from 05-07 untill i got ranover 4 times in a local race. Sold everything a few years later.

I was a certified stihl mechanic for 8 years so I have a pretty good mechanical background.

Now im getting riding again and have a xr100 with 120 bigbore, a 1978 ct70 and a 1998 bayou 300 2x4 ive managed to collect the past few years.

i just picked up a 01 blaster from my neighbor for 150$ its clearly been apart before with blue rtv on the cases and intake. The engine is clearly blown up and theres oily gunk all over the lower engine and skid plate, hopefully from a leaking seal or gasket ...Currently have her stripped down and am fighting the swing arm bolt.

Im missing the rear brake caliper too, should go i go stock or some sort of swap ?

Any useful info or mods i should know of about these bikes?

Welcome.
Sounds like a fun project.
Useful info would be don't buy a $80 Chinese top end kit. Bore original cylinder.
Got any pics of the blaster? You may have to resize them to post them

 

[Rugerdude]

 

[Rugerdude]

Got the engine pulled yesturday and de greased it. Im going to pull it apart today and see what the damage is like. Ill take some pictures of what i find

 

[Rugerdude]

So upon futher inspection the bottom end ran dry and seized up along with some piston damage. The lower con rod is pretty stiff. The expansion chamber must have taken a hit and someone cut it pulled the dent out and welded it back up, with pin holes and gaps still there.

So this needs a full rebuild top and bottom. Anything else you guys think i should look for or take apart before ordering parts?

 

[Slydog]

So upon futher inspection the bottom end ran dry and seized up along with some piston damage. The lower con rod is pretty stiff. The expansion chamber must have taken a hit and someone cut it pulled the dent out and welded it back up, with pin holes and gaps still there.

So this needs a full rebuild top and bottom. Anything else you guys think i should look for or take apart before ordering parts?[/QUOTE
Need to figure out what happened. So it doesn't happen again on your new build.
Is the oil injection still hooked up? Or are you premixing? Bad airleaks. Wrong jetting?Also the exhaust needs to be sealed up tight. No leaks anywhere.
You rebuilding the stock crank or getting a new one.? Definitely crank bearings and seals. A tube of yamabond 4. For sealing case halves together. Or 3 bond also works well.
Check the number on top of the piston to see the size.
Sounds like a bore and hone is in order?

 

[Slydog]

Look into why this happened. Can you do a 2t leakdown test before disassembly?
Bad airleaks. Jetting. Oil injection not working if still using. Wrong oil ratio if premixing? 32:1 is what most run
On these with a quality 2t oil. No chainsaw oil.
New crank bearings and seals.
Are you rebuilding stock crank or buying new. Check piston size. Sounds like a bore and hone is in order.

Gaskets. Wristpin bearing

 

[Rugerdude]

Look into why this happened. Can you do a 2t leakdown test before disassembly?
Bad airleaks. Jetting. Oil injection not working if still using. Wrong oil ratio if premixing? 32:1 is what most run
On these with a quality 2t oil. No chainsaw oil.
New crank bearings and seals.
Are you rebuilding stock crank or buying new. Check piston size. Sounds like a bore and hone is in order.

Gaskets. Wristpin bearing

I did not do a pressure / vacume test before i tore it apart. There is blue rtv on every surface the previous owner could put it on.
The bottom of the engine and skid plate are COVERED in oily muddy gunk.
The cylinder could be honed and re used, i think its aftermarket cylinder with "niche" markings.

Im not sure if the crank is a oem or a aftermerket unit.

Thinking about sending it off to KOR to have the crank rebuilt. Ive read people buy new cranks and have ken rebalance them so im not sure what brands to look into

Im open to any input on this.

Thanks guys ill get some pictures today
I did notice the quad has prm skid plates , both belly and a arms

 

[Slydog]

Cylinder needs to be bored and new piston.
Kor can do the crank and bore for you. Or he can get you a new crank. And all parts. Crank bearings and seals. Ect