OzVMX Forum

Marque Remarks => Yamaha => Topic started by: caps 999 on April 30, 2008, 09:44:46 pm

Title: top end swap
Post by: caps 999 on April 30, 2008, 09:44:46 pm: question will a it175j top end bolt onto a yz100j bottom end
Title: Re: top end swap
Post by: Nathan S on April 30, 2008, 10:26:04 pm: Pretty sure the 100s have a shorter stroke, which will bring you undone.

An IT175 top end will bolt onto a YZ125G bottom end (and presumably a YZ125H one too, if you can deal with the un-used water pump).
Title: Re: top end swap
Post by: caps 999 on April 30, 2008, 10:31:38 pm: according to climer the 125j 100j and it175 have the same stroke and use the same rod kit
Title: Re: top end swap
Post by: cyclegod on April 30, 2008, 10:37:32 pm: Quote from: caps 999 on April 30, 2008, 09:44:46 pm
question will a it175j top end bolt onto a yz100j bottom end

YES YES YES , but you have to change the rod as the pin size is different at the piston end or change the YZ100J crank for a YZ125G crank as they use the exact same crank parts (as YZ100J) but have the correct 175 rod for the conversion. If you look at a 175 barrel and compare it to the 100 you see that they are the same but that the 100 is massively sleeved down.

100J rod is 4V2-11651-00-00
175J rod is 3R2-11651-01-00

Both those part numbers are for 100cc bike 4V2 is YZ100H and 3R2 is YZ100G

Heres what you need....
http://cgi.ebay.com/ebaymotors/Yamaha-YZ100-YZ125-MX125-YT175-Connecting-Rod-Kit-76-79_W0QQcmdZViewItemQQcategoryZ34284QQihZ004QQitemZ140221671536QQrdZ1QQsspagenameZWDVW
Title: Re: top end swap
Post by: caps 999 on April 30, 2008, 10:41:21 pm: in this case has any one got a it175 head and barrel ang a good 125g crank
Title: Re: top end swap
Post by: Tim754 on April 30, 2008, 10:54:08 pm: Check ebay item number 220228807615 Cheers Tim
Title: Re: top end swap
Post by: cyclegod on April 30, 2008, 10:57:49 pm: If you're checking with the wreckers ask for prefix 5X8
Title: Re: top end swap
Post by: TT5 Matt on May 01, 2008, 03:17:15 am: beware of cut back gears [not full width gear teeth] just the differences i noticed between dt/it 175 gearboxes of the same era,could be abit much grunt for the box to handle

TT5 Matt
Title: Re: top end swap
Post by: caps 999 on May 01, 2008, 10:52:03 am: should be rite i checked ypic and according to it the centre cases are the same part# for the yz and it
Title: Re: top end swap
Post by: cyclegod on May 01, 2008, 11:04:20 am: Quote from: caps 999 on May 01, 2008, 10:52:03 am
should be rite i checked ypic and according to it the centre cases are the same part# for the yz and it

Don't forget to post pics of the finished product (and your grin) after its ready
Title: Re: top end swap
Post by: caps 999 on May 01, 2008, 01:21:04 pm: wiil do ill post a before pic when i get home from work (shhhh) ::)
Title: Re: top end swap
Post by: evo550 on May 01, 2008, 02:54:49 pm: Why stop there, why not just bolt a complete it200 motor into it.
Title: Re: top end swap
Post by: Hoony on May 01, 2008, 03:04:04 pm: or just go and get a 500cc 2 stroke and be done with it. :D
Title: Re: top end swap
Post by: caps 999 on May 01, 2008, 03:09:03 pm: i still wanna keep it lookin like a 100 ::)
Title: Re: top end swap
Post by: Tim754 on May 01, 2008, 05:30:19 pm: Hey Caps while your the little screamer was here at my place I did happen to measure it re fitting a real engine. Failures Honda 754, Honda XL350, Yamaha XS650, Kawasaki W1/2 650 Ducati 860 ::).. Kawasaki H2 750 and H1 500 triples. Possibles with a bit of work Kawasaki S2 350 triple, Yamaha RZ 250/350 (Mmmm 8)) , Honda 500/550 4, Ossa 250, Victa 160cc . Easy fit Yamaha IT175/200 and easiest of Yamaha all YZ100. ;)