YZ100 - IT175 cylinder conversion

DrGreg
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DrGreg
Edited Date/Time 4/18/2019 8:36pm
With the renewed interest in the YZ100's, I'm wondering if anyone has actually done the conversion of putting a 1982/83 IT175 cylinder on a 1982/83 YZ100 ?

I have spent time researching this online and have found some opinions that this can be done, but no one who has actually done it.
What I have learned so far is that an IT175 connecting rod would need to be used, but I have not found any information about fitting the 175 pipe and carb on the 100. I would assume for the "175" engine to run well, the 175 pipe and the larger 175 carb would absolutely be required.

Has any one attempted this conversion? Or have any other well informed information on doing this conversion?
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A.j._Stevens 6/29/2014 4:52pm
6/29/2014 4:52pm
A friend of mine did this on one I am going to buy from him. He actually used the 100 pipe and had to section it at the bottom and he did use the 175 carb
DrGreg
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DrGreg 6/29/2014 7:40pm
6/29/2014 7:40pm
Thanks.
Have you ridden the bike yet? Can you comment on just how much more/different the power is with this conversion?
A.j._Stevens 6/29/2014 7:50pm
6/29/2014 7:50pm Edited Date/Time 6/29/2014 7:50pm
I never had a chance to ride it in stock form but to compare it to anything it has a smooth power band that I wouldnt be afraid to put up against my 03 kx125 if it was in a modern chassis
A.j._Stevens 6/29/2014 8:18pm
6/29/2014 8:18pm
One other thing he did use was the 175 intake boot and boost bottle as well he said it made a significant difference

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DrGreg
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DrGreg 6/30/2014 7:23am
6/30/2014 7:23am
Thanks!
Post some pics when you bring her home!
CamP
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CamP 6/30/2014 9:42am
6/30/2014 9:42am
Hey Greg, a former pro, #73, buddy of mine was looking for a 82/83 YZ100 to race at Diamond Don's next spring. Would you be interested in sponsoring him with your bike? It wouldn't be legal as a 175, but the 100 can scream with a little work.
DrGreg
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DrGreg 7/1/2014 6:21pm
7/1/2014 6:21pm
Hey Cam we can certainly talk about that, I have ALOT of work to do on it. (it is this summers project)
Yeah, the 175 conversion would disqualify it, I didn't know that. I thought it was "anything goes" based on the way some of those bikes looked at Don's this year.
The cylinder is maxed out, so I have been watching ebay for one, unsuccessfully. I guess I will have to send it out to get sleeved. Cooksey should be doing the crank next week, so progress is being made. Give me a call
CamP
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CamP 7/1/2014 8:52pm
7/1/2014 8:52pm
Greg, I think Wiseco makes a 2mm overbore piston for the YZ100. Is your cylinder already bored to 52mm?
vetmotoxer34
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vetmotoxer34 4/10/2018 3:21pm
4/10/2018 3:21pm
I know this is an old thread but curious about the details on this conversion. My little 83 one-hunny's crank went out so I was wanting to bring her back to life as a 175. Any help is appreciated. I have found on ebay a 83 it175 cylinder head. I've heard I might need a 175 connecting rod. Was curious what year connecting rod? What about the intake or boost bottle?

Thanks in advance. Email is vetmotoxer34@yahoo.com
DrGreg
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DrGreg 4/17/2018 1:55pm
4/17/2018 1:55pm








I finished the YZ100/175 conversion. This was the final result.
1
PJSMAN
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PJSMAN 5/21/2018 10:29am
5/21/2018 10:29am
DrGreg wrote:
[img]https://p.vitalmx.com/photos/forums/2018/04/17/256035/s1200_IMG_1808.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256036/s1200_IMG_1807.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256037/s1200_IMG_1805.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256038/s1200_IMG_1811.jpg[/img] I finished the YZ100/175 conversion. This was the final result.








I finished the YZ100/175 conversion. This was the final result.
Is the 175 motor better everywhere compared to the 125 motor?
Did you use the 100 close ratio transmission?
Is that the IT175 pipe? with which DG silencer?
thanks
vetmotoxer34
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vetmotoxer34 11/11/2018 8:02pm
11/11/2018 8:02pm
DrGreg wrote:
[img]https://p.vitalmx.com/photos/forums/2018/04/17/256035/s1200_IMG_1808.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256036/s1200_IMG_1807.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256037/s1200_IMG_1805.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256038/s1200_IMG_1811.jpg[/img] I finished the YZ100/175 conversion. This was the final result.








I finished the YZ100/175 conversion. This was the final result.
Hey Greg,

Your buddy Charlie hooked me up with modifying a 1985 IT200 pipe and silencer to fit my 100/175 conversion.





wfoyz250
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wfoyz250 1/2/2019 4:54am
1/2/2019 4:54am
Ahh HA!!! I'll keep an eye on those "ringers" at Diamond Don's......PROTEST! lol
pakala
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pakala 1/7/2019 8:15pm
1/7/2019 8:15pm
In ? revenge class air cooled two stroke 100cc with over bore to 52mm. 100cc air-cooled four stroke 2 valve head, 150cc max bore / stroke.
vetmotoxer34
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vetmotoxer34 1/18/2019 5:44am
1/18/2019 5:44am
wfoyz250 wrote:
Ahh HA!!! I'll keep an eye on those "ringers" at Diamond Don's......PROTEST! lol
Hahaha... that’s my TVRC 0-200 cc weapon. I’ve got a “legal yz100 for Desoto, Diamond Dons, and Rio.

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DrGreg
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DrGreg 4/11/2019 6:02pm
4/11/2019 6:02pm
Hey Vetmotoxer34-

Man I've been away from Vital for a while. Glad I could be of help on your build! Your bike turned out great and from the reports I've heard from my TVRC buddies it rips. I'm glad you went to Charlie, he's the "man" with stuff like this. As you saw his work is better than the factory's !
It's only a 50/50 chance I can make DD this weekend, but if I do I'll try to find you.
vetmotoxer34
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vetmotoxer34 4/11/2019 8:40pm
4/11/2019 8:40pm
DrGreg wrote:
Hey Vetmotoxer34- Man I've been away from Vital for a while. Glad I could be of help on your build! Your bike turned out great and...
Hey Vetmotoxer34-

Man I've been away from Vital for a while. Glad I could be of help on your build! Your bike turned out great and from the reports I've heard from my TVRC buddies it rips. I'm glad you went to Charlie, he's the "man" with stuff like this. As you saw his work is better than the factory's !
It's only a 50/50 chance I can make DD this weekend, but if I do I'll try to find you.
Hope to catchup with you soon. ???. Let’s do connect if you make it to DD’s
A.j._Stevens 4/16/2019 11:59am
4/16/2019 11:59am
DrGreg wrote:
[img]https://p.vitalmx.com/photos/forums/2018/04/17/256035/s1200_IMG_1808.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256036/s1200_IMG_1807.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256037/s1200_IMG_1805.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/04/17/256038/s1200_IMG_1811.jpg[/img] I finished the YZ100/175 conversion. This was the final result.








I finished the YZ100/175 conversion. This was the final result.
vetmotoxer34 wrote:
Hey Greg, Your buddy Charlie hooked me up with modifying a 1985 IT200 pipe and silencer to fit my 100/175 conversion. [img]https://p.vitalmx.com/photos/forums/2018/11/11/301832/s1200_5B64A3ED_B604_405B_9FD9_CC271D7F1867.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/11/11/301830/s1200_163C29CE_6239_42DF_9860_CFB1EF3C25ED.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/11/11/301831/s1200_C5AF5129_9C0E_4B62_AD07_D6FE9BCD916D.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/11/11/301833/s1200_963097E4_6494_41E4_871C_BACC2CE4971B.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2018/11/11/301834/s1200_F9822858_A568_4D69_942F_ABCBD5C46F72.jpg[/img]...
Hey Greg,

Your buddy Charlie hooked me up with modifying a 1985 IT200 pipe and silencer to fit my 100/175 conversion.





Did he have to shorten the back end of the pipe up? I currently have a modified yz125 pipe on mine but like this setup way better
DrGreg
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DrGreg 4/18/2019 6:02am
4/18/2019 6:02am
I put a 1985 IT200 pipe and silencer on mine to really let it "breath". Fit was actually pretty darn close. Charlie St. John definitely had to rework the pipe/silencer junction and modify the pipe mount to the frame somewhat but it all fit perfectly after he was done. Bike had such a unique bad ass tone/sound to it people in the pits would come up to me about it. It was an "ass beating" Charlie said to do it, but he has figured out a better/easier way for VetMotoExr34's bike.





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