Help XT600E big bore piston kit
 

hey guys...I'm about to get a new piston kit for my 1990 Yamaha XT600E...

I've searched and found Wiseco 2MM over bore (97MM) 11.5:1 compression ratio.... ain't that too much compression?

The rest of the engine is still stock besides the kickstart I've assembled..... The bike has only a little less than 17000KM so it's "NEW" considering it's age but since it has to have some work done because it ain't got any compression I'll put in a higher compression piston :cool4: althou 1mm might be what i need which I prefer than having to over bore 1mm more :cool4:

Help :rolleyes2:

I also found a JE PISTON KIT with the same specs...which one is better?

whoa there!
 

Dude, if you re-bore 2mm overbore your 'using up' the room for a re-bore, sureley?
and your not gonna notice any power difference as it will only increase the capacity by maybe 1 or 2 cc at the most ( I may be wrong at 1 or 2 but it wont be a LOT, OK? )

if its power difference your after i dont think your gonna notice much.

go for the WISECO

Hi,

I cannot answer your questions, sorry, but if you are worried about the compression then there are a number of alternatives offered by Wiseco.

Take a look at the last page on this link (page 10):-
http://www.wiseco.co.uk/_private/07/YamahaCycleDirt.pdf

One other aspect that you may want to checkout and consider with the higher compression is the engine oil and fuel needed. Do you need to upgrade from semi-synthetic to fully synthetic oil? Do you need to upgrade the octane of the fuel (e.g. use Shell Optimax instead of ordinary unleaded)? I think you may well have to do something to help the higher compression engine?

Hope this helps,
Geoff

Hi Geoffe...as a matter of the oil...I don't know if I'll have to put full synthetic or semi... I use 10W40 as it's mentioned on my user manual...
As for the fuel I use unleaded fuel..I know it has less octanes but it says it should use only unleaded fuel but their is a lil product to add octanes which has to be =) I think it says unleaded because of the cataly or whatever it's called in english, I think......

I'm thinking of going for the 11.5 : 1 ratio =) 1 mm overbore

Why
 

don't you just buy the Yamaha oversize, in steps of 0,5 mm. No fiddling with the compression, just oversize piston to match the bored and honed cilinder.

Auke

Hi =) because I can get something a tiddy better that will give me more power and performance and it'll cost a little less for the same as OEM parts..

they are lighter, stronger, give me more power even tho a lil more fuel might it need to run efficient =)

Which I think it'll make it even more fun to ride =)

Get the Yamaha Piston reliability quality and you can get 2mm oversize if you really want to.
how much lighter is the Yamaha piston compared to the Wiseco piston.
It is possible to put the XT660 piston into the 600 motor.

I have a ProX 97mm,same as a Yamaha piston but cheaper.The Wiseco is 100g lighter,and mine had a broken skirt,hence the ProX replacement.You can fit a 101mm,but need to use another sleeve.

Hi =)

Motu you said: "The Wiseco is 100g lighter,and mine had a broken skirt" was it the OEM that broke or you already had placed a Wiseco piston?
Is the piston you have stock compression? I'm probably going to that 96MM from Wiseco with 11.5 : 1 compression ratio

Brian E what is that piston reliability thing? I've never heard anything about it =)

The Wiseco broke - it was running well and there was no wear or marks on the bore.I replaced with the ProX,which is identical to OE,standard comp,the Wiseco was standard comp too.The Wiseco is a slipper type piston with a very small skirt,I don't think it's very strong.I didn't fit the Wiseco,but found the damage when I pulled the barrel to fit rings.

Slipper pistons are sensitive to worn barrels(sleeves) They start to "wobble" very easely and crack. I used them in a Husaberg I had some years ago,good stuff for competition or race purpuse.But don´t expect much milage out of them if you plan to use them in a daily comuter/travel bike.

Hi.

The barrel will be ovebored... so it won't be worn right?

The thing is I ride it strong most of the time...how much milage do they normally hold average of course? I ride it everyday when I'm back home and in 2 years of riding it I've done less than 6000 miles on it... now I'm away from home studyng in college and only go there for a week or two on holidays so it'll take alot more now to do 6000 miles again :cool4:

When I said I ride strong is I like the acceleration but I don't keep the high revs because there just aren't roads for that where I live, for speeding that is.. so I keep medium, medium-high revs........

I 90% of the time ride below 80mph but still mostly around 65mph..

If the Wiseco last 15000 miles that'll give me alot of years on it :D


What's the difference between Prox and Wiseco? :innocent:

Thanks:cool4:

ProX is a cast OE copy - Wiseco is a forged piston.The forged piston is supposed to be stronger....it is heavier than cast,and that is why the Wiseco is cut down to a slipper piston.They are also run with more clearance because they expand more with the thicker material.

Hi. What do you mean by it runs with more clearance? [it's more "loose" in the cylinder] ??