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What are the Chances? (good story) Yoshimura 450 Power Kit

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So this story starts back about 5 years ago... way before i got into drz's

i was looking through the want ads and came across a 2000 DRZ400E with a title/S frame for $800. at the time i was looking for an enduro to covert to a Street Legal 3 wheeler, so this was perfect and cheap.

so i show up to look at the bike. the bike was not running, the kid didn't know why, he only had it for 6 months. it cranked over but didn't start. it had some nice aftermarket parts, that i could see or knew to look for anyway, like radiator guards, exhaust, scotts top clamp w/damper mount, ohlins rear shock, e-line side covers. so i bought the bike, got my title and went on my way.

worked on it for like a week, got the bike running, just needed to be reshimed and the carb cleaned, found yoshi cams in it as well, and started the 3-wheeler conversion. the project got put on hold while looking for parts, and before you know it 4 years had past with the 3-wheeler just sitting in my cousins garage. last year i ended up buying my 06 DRZ400SM, which got me thinking about the 3 wheeler again. did some more work on, actually got it going and moving, but there was still much needed to be worked out before it was ready.

After reading the forums about all the good mods for my SM, i went back to the 3 wheeler and grabbed all the mods on it. and quickly installed everything on my SM. i also started a thread asking about my head being ported, it also had stamp marks on it, but didn't have good pics at the time or a stock head to compare, so didn't get much info.

SSPX0065.jpg

SSPX0070.jpg

So Present time now, Reading the posts from the thread i started, "Has anyone ever ported there Head?" Someone mentioned something about a Yoshimura Power up kit, i heard it before but never thought anything of it, until today. i started thinking back to when i bought the original E model... The kid didn't know anything about bikes, he just kept saying it's a race bike, it's a race bike... that's what the previous owner told him when he bought it.

So i started putting all the cluesl together today, yoshi cams, yoshi exhaust, yoshi carb throttle cam, all the extra stuff like the ohlins, e-line covers, scotts clamp, rad guards, MCCT, engraved numbers on the head, i thought it was ported, etc it just clicked, i probably have the whole yoshi power kit... so i threw on some dirty clothes and went straight over there and started taking the motor out of the 3-wheeler. threw it on the bench and took off the head and cylinder, and this is what i found...

081.jpg

077.jpg

093.jpg

SSPX0527.jpg

SSPX0526.jpg

065.jpg

095.jpg

103.jpg

071.jpg

its 95.5mm bore, its stamped with numbers on the cylinder, aftermarket retainers, i'm assuming springs also, oversized valves, head is slightly ported and stamped with some numbers, nice piston that probably needs to be replaced, it has had contact with a valve, also has had a valve replaced that is definitely not the right size, different clutch springs. needless to say i am pretty excited right now!!! Who knew, i had this sitting here for the last 5 years...

though the crank does not look like a stocker i have kicking around, although the rod does have the same part #, so i am not sure on what i have exactly, maybe a offset on the crank pin with a stock rod? i thought the yoshi kit was a +5 crank and 92mm bore. maybe i don't have the yoshi power kit, just most of the parts... but if it does have a the crank and a 95.5 bore what would that make this motor, a 480? i can't wait to try it out, but the head needs to be sent off to be repaired, probably get a new piston and gaskets and go from there. and i just ordered a cylinder works BB kit too!

here is a link to the 3 wheeler thread

https://thumpertalk.com/forum/showthread.php?t=798538

and the old ported Head thread

https://thumpertalk.com/forum/showthread.php?t=822008&highlight=turbophein

What do you think???👍:banana:🤣:banana:🙂

Edited by Turbophein

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Looks like the stock crank to me.

The yoshi kit has a 92mm 2 ring piston.

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Shame that it looks to have died an early death..Piston is real clean. If the crank was reworked by Yosh you should notice some grinding on the balancer to provide clearance for the crank.

92mm and 2 ring piston is correct.

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Looks like the stock crank to me.

The yoshi kit has a 92mm 2 ring piston.

so who would of made this 95.5mm kit over 6 years ago? also what about the valves, springs and retainers, i need to take it apart and verify what i have so i can change whats needed and get this motor up and running again.

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so who would of made this 95.5mm kit over 6 years ago? also what about the valves, springs and retainers, i need to take it apart and verify what i have so i can change whats needed and get this motor up and running again.

Not 100% certain..Ed would know but if I had to guess its a 450cc by Maxpower.

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will check this out...

If you find shims under the valve springs that would be another indication its Yosh stuff..

this will be the next thing i do!

Wiseco has been making that piston for longer than 6 years.

eddie did you get my pm about repairing this head, i would need the matching oversized exhaust valve, and what ever repairs needed.

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Wiseco has been making that piston for longer than 6 years.

i know you frown on anything bigger than 95.5 because of the headgasket issues, so i am assuming since this kit is old, that this is probably one of the problem kit's, no?

not sure what to do here, wonder if the piston is still usable if i clean up any potential hot spots

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not sure what to do here, wonder if the piston is still usable if i clean up any potential hot spots

Um....no. That piston is nto usable

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Um....no. That piston is nto usable

it ran fine, as for longevity, i think iwhat would matter most is the thickness of the material where the indents are, i think if there is plenty of material and no hot spots it would be ok, if there was not much material i would be worried. i will make a decision after looking at it tomorrow. this will be a spare motor, maybe a ticking time bomb!!👍

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ive been out of town all week end using my phone to post on a very limited basis.

i will look at the pm when i get a chance.

just so you know,the fact you are even considering using that piston makes be very very leary to be involved in anything you are doing on any level.

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ive been out of town all week end using my phone to post on a very limited basis.

i will look at the pm when i get a chance.

just so you know,the fact you are even considering using that piston makes be very very leary to be involved in anything you are doing on any level.

this would be the first time i've seen a thumper piston with this damage, which isn't all that bad compared to what happens with interference car motors, people reuse these car pistons all the time, you have to remove any potential hotspots, they don't even pull the block most times, its all done in car. replace the head and keep boosting to 7.5k daily... and those pistons are not near the quality of this piston...

but thumpers are a different ballgame and they rev to 10k also, but explain what you think would happen to this piston, just out of curiosity. what would fail and why? since you just confirmed the kibblewhite stuff in the head, this motor reallymeans nothing much to me at this point... i willing to bet it would take quite a bit of abuse like this though... from my experiences

i'm not saying this is right but, i am not planning on putting money into this motor either, new gaskets and valve, clean up the head a little and call it a day. nothing leary about that. do you want to see my other builds?

EDIT: I found the piston with a gasket kit for a great price on ebay that i couldn't refuse, so i picked it up $110 shipped. so no more flaming please. i will use the old piston for a wall ornament!!! http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=140393682388

here is a motor with valve damage, that has been reused after cleaning it up,

downsized_0825091154a.jpg

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no one is flaming you. you just gotta rethink about the ways you tend to go about things if you want any one to take you serious.

do i really need to explain what could happen if the 95.5mm piston comes apart?

using the car motor analogy isnt helping. ive seen very scary things from the "car motor builder" world that the real car motor guys would be way less understanding than we are being about this.

there is a right way to do things and a wrong way.i wont accept that you dont know the difference.

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can i stack E base gaskets to reduce compression? 13:5:1 is a little much no? is race gas needed for 13:5:1? i want to set it up for pump 93

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