Blaster rebuild help information needed :-)

[Parteebhoy]

Recently bought myself a Yamaha blaster 2004 it's got or had a over sized piston (67mm) quad locked up yesterday n I have stripped top end and parts of piston have broke off! So full rebuild is needed can u tell me ways best to buy for top n bottom rebuild Barrel has a score in it so was thinking of gettin vito 240 kit for it! Wat u think? My mate also said something about puttin yz250 head on it cause water cooled will be way better for it! Would a yz barrel also fit on blaster or is that a no go lol
No daft comments Ano am a daft smurf n never checked oil lol live n learn haha
Hope to hear from uz for some help thanks Stephen

 

[Awk08]

the yz cylinder will not fit onto the blaster bottom end, certian years dt200 cylinders will, but seem to be more hassle than there worth, that stock cylinder piped and all ported up will make just as much HP.
just get that cylinder rebored to get rid of the scores and a new matching piston to match, i'm assuming your "across the pond" so finding an engine porter may be troublesome, maybe some other "mates" will chime in with engine builder info for over there ?

that bottom end should be split also, to retrieve/clean them broken piston pieces, some guys try to clean the bearings,
i like to just replace everything since you'll already be in there, and not take any chances of missing any shrapnel and frying it again.

ditch that oil tank/injection system and just pre-mix your fuel/oil and never worry about running out of oil again.
rejet accordingly, there's plenty of jetting threads on here.
use the search button at the top of the page to search for jetting and oil injection delete threads for info on how to do them.

 

[Parteebhoy]

Ye I'm from Scotland mate thanks for fast reply! I'm planning changing everything anyways because there is bits of piston everywhere lol I have bein ore mixing cause mixer pump has a blocker kit on it, why u think piston has fell apart? Wat is biggest size I can go to on standard cylinder?

 

[Awk08]

do not go as big as possible, it adds almost no power, and doesnt allow you anymore bores for future meltdowns.
only have it bored enough to clean the scratches/gouges out, and matched to the piston, any good machine/bike shop will know what to do

 

[Parteebhoy]

Think I will have to get new barrel because there is a 67mm piston in it now n score is bad think id need to put 68.25 in it n that may not be big enough! Is vito kit worth buyin? and a wanna no how to turn engine to water cooled or is that not worth doing?

 

[Awk08]

the dt200 bikes were not sold here in the states, may be more available over there ??
it's alot of work with the wiring for the water pump and power valves, i think it requires a battery added too ??
it'll give you a solid 35hp, but like i said...a stock ported and piped stock cylinder is also capable of that, and will outperform a non ported 240 vito's cylinder.

both vito's 240 cylinder and a ported version are availlable here, someone else from over there just ordered one............

OEM Yamaha Blaster Parts

you should do a larger carb and matching intake boot on those 240's also

 

[Parteebhoy]

Is it only dt200 head that can be used on blaster? Iv found an electric water pump on eBay perfect for it dt200 is hard bike to find lol

 

[Awk08]

Is it only dt200 head that can be used on blaster? Iv found an electric water pump on eBay perfect for it dt200 is hard bike to find lol

no, the whole cylinder and head will swap onto the blaster,
but only a few years, late 80's i believe,
here's full details by mcdizzy..........

Yamaha YFS200/DT200 - Yummie Yami, Upgrade The YFS; To Be The Best

 

[Parteebhoy]

Cheers for your help mate iv looked into n it's goin to cost a good bit to fix so plenty over time at work is needed let u no wat desision I make thanks again but still don't understand how the piston has fell apart lol

 

[Awk08]

Cheers for your help mate iv looked into n it's goin to cost a good bit to fix so plenty over time at work is needed let u no wat desision I make thanks again but still don't understand how the piston has fell apart lol

it's a cast piston, as the bore and piston wear, it allows too much clearence and the piston is trying to come up into the cylinder on an angle, the piston skirt starts hitting the bottom of the cylinder until it shatters the cast metal.
alot of us prefer the much stronger forged wiseco pistons, to eliminate the chance of this ever happening again

 

[Parteebhoy]

Ye that's the piston a got put in ma cr250 thanks again mate

 

[StevieN]

Telfer mate if i was you i would get the rebuild i sugested then when you have the cash get the vitos 240 kit with KOR ported head you can get it delivered to here for £500