1991 Yamaha YZ125

Harm_Van de Bunte
Edited Date/Time 10/9/2022 10:30pm
My 1991 YZinger still going strong in 2022..anymore magenta's out there?

11
|
Glen
Profile picture for user Glen
Posts
273
Joined
11/26/2010
Location
Rockaway, NJ US
Glen 9/27/2022 3:46pm
9/27/2022 3:46pm
damn that is nice!
1
Tyrone lavelle 9/29/2022 6:17am
9/29/2022 6:17am
Team hot pink! Looks cherry. Is it a statue or a rider?

The Shop

See All »
profeshenal125 9/29/2022 7:28pm
9/29/2022 7:28pm
I hit 1 of them so hard in the back of the swingarm that the rider flew off on my 87 cr125. I really didn’t mean to hit him that hard. But that bike was super slow. A Yamaha dealer offered a new 1 to me I declined the offer to ride my 87. They say it’s the slowest 125 ever made. Sorry I,m not picking on it. I think it’s a rad bike and would Love to find 1 in similar condition to yours. Super rare bike . Emig 91 yz125 had extreme mods his mechanic tuned it without using a pilot jet. I saw Jeff race at 91 Millville it sounded really unique.
1
profeshenal125 9/29/2022 7:31pm
9/29/2022 7:31pm
Doug Henry holeshot a moto on a DGY 91 yz125 at Millville. The race is on yt.
2
Harm_Van de Bunte 9/29/2022 11:11pm
9/29/2022 11:11pm
profeshenal125 wrote:
Doug Henry holeshot a moto on a DGY 91 yz125 at Millville. The race is on yt.
I saw many races and supercross with the 91 yz in front. The DGY team was also flying.
And Emig offcoarse on the factory 91,92,93 YZ125, it was reported as the fastest 125 back then.
SmokinJoe439 9/30/2022 10:18am
9/30/2022 10:18am
It was slow came from those who A never rode one B never bothered to set it up properly. They did come factory with some minor issues that hindered performance.

Mostly the power valve stop was machined wrong and it didn't let it open fully. Weak reed petals. Bad squish clearance stock. So places like dgy would do some mild engine work and it was much better. It had decent bottom good mid okay top. Those gen ypvs drum engines didn't rev out high.

The last bit was media bias at the time still hung up on the cr125's ability to rev out high. Similar to how last gen rm125's where known for. So it was the "fastest" best engine of the time. Yamaha would come along in 96 and change that ideology. That a broad power band was better after all.

3
Harm_Van de Bunte 9/30/2022 11:06am
9/30/2022 11:06am
SmokinJoe439 wrote:
It was slow came from those who A never rode one B never bothered to set it up properly. They did come factory with some minor...
It was slow came from those who A never rode one B never bothered to set it up properly. They did come factory with some minor issues that hindered performance.

Mostly the power valve stop was machined wrong and it didn't let it open fully. Weak reed petals. Bad squish clearance stock. So places like dgy would do some mild engine work and it was much better. It had decent bottom good mid okay top. Those gen ypvs drum engines didn't rev out high.

The last bit was media bias at the time still hung up on the cr125's ability to rev out high. Similar to how last gen rm125's where known for. So it was the "fastest" best engine of the time. Yamaha would come along in 96 and change that ideology. That a broad power band was better after all.

Finally somebody with a good comment! Most people said that indeed. I raced the 91,92 and the 93 YZ125 those years and they were properly tuned and very competive,no problem! The 91 had a boyesen rad valve,a aftermarket Dutch exhaust system and good jetting,I remember my mechanic did some adjusting with the powervalve but no barrel porting in 91 junior class,just perfect jetting every race and I was always in front with the starts.I love that bike!! The 92 and 93 were more serious tuned as I raced the higher class those years and they were serious fast and competive at National level. This 91 bike on the photo is my spare bike from that year and is still like new as it is abouth four hours old.
1
Harm_Van de Bunte 9/30/2022 11:11am
9/30/2022 11:11am
SmokinJoe439 wrote:
It was slow came from those who A never rode one B never bothered to set it up properly. They did come factory with some minor...
It was slow came from those who A never rode one B never bothered to set it up properly. They did come factory with some minor issues that hindered performance.

Mostly the power valve stop was machined wrong and it didn't let it open fully. Weak reed petals. Bad squish clearance stock. So places like dgy would do some mild engine work and it was much better. It had decent bottom good mid okay top. Those gen ypvs drum engines didn't rev out high.

The last bit was media bias at the time still hung up on the cr125's ability to rev out high. Similar to how last gen rm125's where known for. So it was the "fastest" best engine of the time. Yamaha would come along in 96 and change that ideology. That a broad power band was better after all.

I do remember mine 91 had a very broad midrange and low end also. The 92 and 93 were tuned for top end power and were serious competive those years.
SmokinJoe439 9/30/2022 1:09pm
9/30/2022 1:09pm Edited Date/Time 8/20/2023 9:09pm

My friends had those bikes back then brand new. None of them were prefect stock.
I have a 92 Yamaha 😁 I have acquired most of the parts 
 

5
Harm_Van de Bunte 9/30/2022 1:37pm
9/30/2022 1:37pm
SmokinJoe439 wrote:
My friends had those bikes back then brand new. None of them were prefect stock. I have a 92 Yamaha 😁 I have acquired most of...

My friends had those bikes back then brand new. None of them were prefect stock.
I have a 92 Yamaha 😁 I have acquired most of the parts 
 

They needed fine tuning back then like Smokinjoe439 explained. Then they were actually pretty good..my friend Who raced in the same class back then,we swapped bikes in training session(91 KX125) and he liked my YZ125 more and I noticed my YZ125 was a bit better with power
450exc115
Profile picture for user 450exc115
Posts
708
Joined
11/6/2014
Location
Hebron, CT US
450exc115 10/4/2022 7:33am
10/4/2022 7:33am
I have a 98 YZ250 the last of the drum power valve 250s. I had Noleen port the cylinder in 99 for motocross and the biggest changes I saw were they modified the stops on the drum for more closed and open and they shaped it to match. That bike still to this day had the broad spread of power I've ridden. Pulled way down low and ran hard all the way till it ran out of RPM. Now if I could only find a matching Noleen pipe for it (mine I smashed racing hare scrambles).

My 86 YZ250 has no stops on the PV so I often wonder how open it goes, it's a strong motor also with the ports cleaned up and the second Boyesen port added.
1
sandman768
Profile picture for user sandman768
Posts
7978
Joined
3/21/2014
Location
Saratoga Springs, NY US
sandman768 10/4/2022 8:44am
10/4/2022 8:44am
450exc115 wrote:
I have a 98 YZ250 the last of the drum power valve 250s. I had Noleen port the cylinder in 99 for motocross and the biggest...
I have a 98 YZ250 the last of the drum power valve 250s. I had Noleen port the cylinder in 99 for motocross and the biggest changes I saw were they modified the stops on the drum for more closed and open and they shaped it to match. That bike still to this day had the broad spread of power I've ridden. Pulled way down low and ran hard all the way till it ran out of RPM. Now if I could only find a matching Noleen pipe for it (mine I smashed racing hare scrambles).

My 86 YZ250 has no stops on the PV so I often wonder how open it goes, it's a strong motor also with the ports cleaned up and the second Boyesen port added.
Many seized due to worn drum & stopper, allowing the drum to over rotate into the exhaust port, and impacting the piston.Definitely have to relieve the drum if you allow for more rotation. I was impressed with the simplicity of the design when I rebuilt my 92 250. One of my riding buddies loved his 89 & 91 Yz125”s, he was not big on maintenance and the bikes lasted a long time….
1
MaxPower
Profile picture for user MaxPower
Posts
2697
Joined
8/15/2006
Location
NJ US
MaxPower 10/4/2022 5:34pm
10/4/2022 5:34pm
Harm_Van de Bunte wrote:
It's orriginal to the bone...not riding it😅
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with a spray can on Facebook Market after you pass don't you?
2
Harm_Van de Bunte 10/4/2022 11:13pm
10/4/2022 11:13pm
Harm_Van de Bunte wrote:
It's orriginal to the bone...not riding it😅
MaxPower wrote:
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with...
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with a spray can on Facebook Market after you pass don't you?
Ahhhhhnoo,don't put the idea in my head😅😅

Pit Row

See All »
SmokinJoe439 10/7/2022 8:59am
10/7/2022 8:59am
Harm_Van de Bunte wrote:
It's orriginal to the bone...not riding it😅
MaxPower wrote:
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with...
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with a spray can on Facebook Market after you pass don't you?
Harm_Van de Bunte wrote:
Ahhhhhnoo,don't put the idea in my head😅😅
You can just send them to me where they would continue living the posh garage queen life.
Always wondered how the 91 vs 92 vs 93 was like engine performance wise.
I believe the 92 had the better forks over 91.
Harm_Van de Bunte 10/7/2022 10:32am
10/7/2022 10:32am
SmokinJoe439 wrote:
You can just send them to me where they would continue living the posh garage queen life. Always wondered how the 91 vs 92 vs 93...
You can just send them to me where they would continue living the posh garage queen life.
Always wondered how the 91 vs 92 vs 93 was like engine performance wise.
I believe the 92 had the better forks over 91.
I do remember I liked the 91/92 handling better tho than the 93.Here are all 3 of my 125's
9
cvm
Profile picture for user cvm
Posts
150
Joined
9/7/2016
Location
Monrovia, MD US
cvm 10/8/2022 9:10am
10/8/2022 9:10am



This was basket case, 1st resto, built rider, no where near Harm's beautys. But had to chime in cause their rare.
Has 2000 front end adapted, New spare top end w/ pwr valve, lots of spares, and is for sale. I cant ride anymore.
Harm they are beautiful.
6
cvm
Profile picture for user cvm
Posts
150
Joined
9/7/2016
Location
Monrovia, MD US
cvm 10/8/2022 9:16am
10/8/2022 9:16am
MaxPower wrote:
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with...
You know your kids are going to be selling a fresh YZ125 for 500 dollars to some thug that's going to paint it BBQ black with a spray can on Facebook Market after you pass don't you?
I have a 40 yr old vette, top level certified original, 11k mile garage queen, made 567 in that color, and your comment scares me, cause could be true Sad
MaxPower
Profile picture for user MaxPower
Posts
2697
Joined
8/15/2006
Location
NJ US
MaxPower 10/9/2022 10:30pm
10/9/2022 10:30pm
cvm wrote:
I have a 40 yr old vette, top level certified original, 11k mile garage queen, made 567 in that color, and your comment scares me, cause...
I have a 40 yr old vette, top level certified original, 11k mile garage queen, made 567 in that color, and your comment scares me, cause could be true Sad
I said in jest kind of. I've had to clean out more than a few of loved ones possessions that ment so much to them and it is all but junk to me. Yes I could sell it for what I think it's worth, but I don't want to deal with douchebags coming over my house to beat me up on a price. I either give them to someone that is close or it hits the dumpster. So for me I'd rather build a bike,ride the wheels off it and let the next guy worry about rebuilding it. Chances are the next guy won't love vintage mx like I do anyway. If you like my Aunts China set I'd be glad to give it to you
profeshenal125 10/13/2022 6:51pm
10/13/2022 6:51pm
SmokinJoe439 wrote:
[img]https://p.vitalmx.com/photos/forums/2022/10/02/571759/s1200_00399.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2022/10/02/571760/s1200_s1200_image1.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2022/10/02/571761/s1200_s1200_Jeff_Emig_1991.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2022/10/02/571762/s1200_1c5b6bd474d37fad427cccc25fea0744.jpg[/img]




Remember Emig,s 125 that had a square welded on the side of the cylinder . I always wondered what they did there. Cut a transfer out and reshape double boost port maybe ? Haha I drop that a lot talking about my 04 cr125. I,m very surprised no one ever caught that. It’s from the pre production 91 rm125 . All the talk of a secret double boost port. When the bike was released it wasn’t there. Haha ps you forgot Jimmy Button he won some sx races on the 91 or 2 yz.

Post a reply to: 1991 Yamaha YZ125