1989 CR125 project

Jim in VA
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Jim in VA 7/4/2019 10:03am
7/4/2019 10:03am
Looking great! I finally got my 88 all together and rode it last weekend, great time. Yours is going to be sweet when finished!
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MaxPower
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MaxPower 7/6/2019 6:53pm
7/6/2019 6:53pm
I'm confused by your thinking Lucky Nino. I get you don't like black rims on old bikes because they weren't from the era. But you say to use a Vforce reed block. They weren't used back in the day yet that doesn't bother you. I'm not busting balls, I don't understand what is different. If anything the VForce I would think may bother you more as it provides a performance increase and black rims are cosmetic
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billyslad
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billyslad 7/7/2019 11:49pm
7/7/2019 11:49pm
It’s a fine line Max I wonder how many bikes would not be on the start line at Farleigh if the modern upgrades were taken off some visible some not
jesselm68
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jesselm68 7/25/2020 4:47pm
7/25/2020 4:47pm
luckynino wrote:
On such bikes you need to do a full disassembly to inspect and rebuilt basically everything! I have rebuilt 3 such bikes from scratch. One was...
On such bikes you need to do a full disassembly to inspect and rebuilt basically everything!

I have rebuilt 3 such bikes from scratch. One was my '89 VRP full aluminium custom bike. You can check my builds in my Flickr-Albums here
Nino's '89 VRP: https://www.flickr.com/photos/ottospeed/albums/72157657243148579
Nino's '89 Racebike: https://www.flickr.com/photos/ottospeed/albums/72157668784699162
Nino's '89 Practice Bike: https://www.flickr.com/photos/ottospeed/albums/72157682317899484

Also parts that from the outside seem ok won't be ! Usually seals got hard over time and don't do their job anymore. Swingarm bearings , leverages, steerer, wheels, also inside the engine...everything needs to be replaced with new bearings & seals! During the 1st ride even my seemingly perfect chainrollers would disintegrate...the rubber was so hard they simply fell into pieces...all ruber is hard and dry and won't work anymore!

Important also that you take off the waterhoses to check the state of the cases underneath! The stock cases were Magnesium and corroded badly. My bike looked great as well but taking off the hoses revealed severely corroded cases...



On vintage bikes don't go with black rims! Black is all the hype NOW but wasn't back in the day. If you want some coloured rims go with gold but stay clear of black. That's my opinion. Vintage bikes need to be vintage still and black just doesn't go with a vintage bike. If you do a rebuild do it right!

Ufo has all plastics.Good quality. New plastics get your bike that new look.

Footpegs: the stock footpegs are just too thin.There you definitely want to upgrade to something with a larger platform. I found YZ/YZF footpegs fit great with only minimal modifications. I had to file just like 0,5mm on mine to allow them to fold up more.Otherwise they fit great and offer a much, much better platform!

The engine needs some extra care. 30 years of use show wear. Especially the ATAC exhaust system needs to be taken care of as those parts developed some play and the simple & basic exhaust system really needs to be free of any possible freeplay to offer decent performance. Most probably you'll need to take the governor apart and replace that bearing in it. There is a lot of play in the governor alone, then there is the levers&joints that connect the governor with the actual valve...the valve itself sometimes also is worn or it's bore in the cylinder. If you have slop/freeplay in the system it will never run as it should! I have done a whole thread on the rebuild of the HPP & ATAC exhaust system on Thumpertalk where i show how it's done:
https://thumpertalk.com/forums/topic/1207620-honda-125-hpp-setup-tips-t…



I have very good results using a bigger 38mm PJ carburetor and VForce reedblock. It adds a healthy dose of power mid-top. For slightly more low-end i made these spacers for the ATAC chamber:




BEST upgrade to the engine is a italian MESSICO exhaust. DON'T, i can only repeat: DON'T put a Pro Circuit exhaust as it's definitely one of the weakest. I can only laugh when i put my PC on (yes - me too i bought one thinking they must be the best). But both, the PC and the stock exhaust feel like having a rag in the airbox. The PC makes some more revs up top when compared to the stocker but it offers NO torque at all. They are so weak it's hard to believe. True story. The Messico is on a whole other level. No comparison! Bottom to top...that's the single best upgrade on the little CR !!


In the end such a bike is still offering great performance and is a lot of fun. Mine are rocketships and definiotely faster than a stock 2019 YZ 125 !

Here's a video of a couple weeks ago riding my '89 Mugen equipped "practice" bike during a vintage-day in Italy:
https://www.youtube.com/watch?v=_XwdhrLwhiE


I'm new to this post and dirt bike world and I too have been working on a 89 cr125 but need a little help with the power valve linkage. Is there a certain position it needs to be when attaching it to the govenor? And does the piston need to be in a certain position as well. My manual I have doesn't give me a good breakdown just only the linkage bolt hole needs to line up up. Hope this makes sense. Bike wont start now after removing the right cover to seal a look leak.

The Shop

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_X_
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_X_ 7/25/2020 5:40pm
7/25/2020 5:40pm
I'm beginning to wonder if anyone actually rides/races these bikes?
Jim in VA
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Jim in VA 7/25/2020 5:43pm
7/25/2020 5:43pm
_X_ wrote:
I'm beginning to wonder if anyone actually rides/races these bikes?
I do!
2
Jim in VA
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Jim in VA 7/25/2020 5:46pm
7/25/2020 5:46pm
luckynino wrote:
On such bikes you need to do a full disassembly to inspect and rebuilt basically everything! I have rebuilt 3 such bikes from scratch. One was...
On such bikes you need to do a full disassembly to inspect and rebuilt basically everything!

I have rebuilt 3 such bikes from scratch. One was my '89 VRP full aluminium custom bike. You can check my builds in my Flickr-Albums here
Nino's '89 VRP: https://www.flickr.com/photos/ottospeed/albums/72157657243148579
Nino's '89 Racebike: https://www.flickr.com/photos/ottospeed/albums/72157668784699162
Nino's '89 Practice Bike: https://www.flickr.com/photos/ottospeed/albums/72157682317899484

Also parts that from the outside seem ok won't be ! Usually seals got hard over time and don't do their job anymore. Swingarm bearings , leverages, steerer, wheels, also inside the engine...everything needs to be replaced with new bearings & seals! During the 1st ride even my seemingly perfect chainrollers would disintegrate...the rubber was so hard they simply fell into pieces...all ruber is hard and dry and won't work anymore!

Important also that you take off the waterhoses to check the state of the cases underneath! The stock cases were Magnesium and corroded badly. My bike looked great as well but taking off the hoses revealed severely corroded cases...



On vintage bikes don't go with black rims! Black is all the hype NOW but wasn't back in the day. If you want some coloured rims go with gold but stay clear of black. That's my opinion. Vintage bikes need to be vintage still and black just doesn't go with a vintage bike. If you do a rebuild do it right!

Ufo has all plastics.Good quality. New plastics get your bike that new look.

Footpegs: the stock footpegs are just too thin.There you definitely want to upgrade to something with a larger platform. I found YZ/YZF footpegs fit great with only minimal modifications. I had to file just like 0,5mm on mine to allow them to fold up more.Otherwise they fit great and offer a much, much better platform!

The engine needs some extra care. 30 years of use show wear. Especially the ATAC exhaust system needs to be taken care of as those parts developed some play and the simple & basic exhaust system really needs to be free of any possible freeplay to offer decent performance. Most probably you'll need to take the governor apart and replace that bearing in it. There is a lot of play in the governor alone, then there is the levers&joints that connect the governor with the actual valve...the valve itself sometimes also is worn or it's bore in the cylinder. If you have slop/freeplay in the system it will never run as it should! I have done a whole thread on the rebuild of the HPP & ATAC exhaust system on Thumpertalk where i show how it's done:
https://thumpertalk.com/forums/topic/1207620-honda-125-hpp-setup-tips-t…



I have very good results using a bigger 38mm PJ carburetor and VForce reedblock. It adds a healthy dose of power mid-top. For slightly more low-end i made these spacers for the ATAC chamber:




BEST upgrade to the engine is a italian MESSICO exhaust. DON'T, i can only repeat: DON'T put a Pro Circuit exhaust as it's definitely one of the weakest. I can only laugh when i put my PC on (yes - me too i bought one thinking they must be the best). But both, the PC and the stock exhaust feel like having a rag in the airbox. The PC makes some more revs up top when compared to the stocker but it offers NO torque at all. They are so weak it's hard to believe. True story. The Messico is on a whole other level. No comparison! Bottom to top...that's the single best upgrade on the little CR !!


In the end such a bike is still offering great performance and is a lot of fun. Mine are rocketships and definiotely faster than a stock 2019 YZ 125 !

Here's a video of a couple weeks ago riding my '89 Mugen equipped "practice" bike during a vintage-day in Italy:
https://www.youtube.com/watch?v=_XwdhrLwhiE


jesselm68 wrote:
I'm new to this post and dirt bike world and I too have been working on a 89 cr125 but need a little help with the...
I'm new to this post and dirt bike world and I too have been working on a 89 cr125 but need a little help with the power valve linkage. Is there a certain position it needs to be when attaching it to the govenor? And does the piston need to be in a certain position as well. My manual I have doesn't give me a good breakdown just only the linkage bolt hole needs to line up up. Hope this makes sense. Bike wont start now after removing the right cover to seal a look leak.
Piston position has no influence on this. Also, it’s a coincidence that it won’t start, nothing with the powervalve will keep it from running. What manual are you referencing? I might be able to send you a few pics from my Honda service manual tomorrow if you need them
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mark_swart
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mark_swart 9/13/2020 9:11am
9/13/2020 9:11am
Some great looking bikes in this post!! I'm starting an 87 build now, just curious if anyone has any extra powervalve linkage/spring pieces or if there is a workaround? All I have on mine is the powervalve itself and the actuator rod / linkage that comes out of the case. Thanks!
ricaze
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ricaze 6/29/2022 8:42pm
6/29/2022 8:42pm Edited Date/Time 7/22/2022 5:42pm
I got my project bike after looking for awhile, 1989 Honda CR125R, it’s in “fair” shape but I already had few surprises… I appreciate some input !









2
ricaze
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ricaze 6/29/2022 8:49pm
6/29/2022 8:49pm
Anyone knows the meaning of the B and C on the cylinder?
1
sandman768
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sandman768 6/30/2022 6:47am
6/30/2022 6:47am Edited Date/Time 6/30/2022 6:48am
Turn cylinder upside down, look at his port work👍 Aside from the rotten water pump case, Bike looks pretty decent…
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ricaze
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ricaze 7/4/2022 11:46am
7/4/2022 11:46am

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ricaze
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ricaze 7/14/2022 10:05pm
7/14/2022 10:05pm
Transmission was junk, bought a used one in good shape, right crankcase was also bad, new piston, new rod and all bearings replaced. Swing arm polished and frame powder coated.

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ricaze
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ricaze 7/22/2022 5:51pm
7/22/2022 5:51pm
Long process…





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ricaze
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ricaze 8/4/2022 2:30pm
8/4/2022 2:30pm Edited Date/Time 8/4/2022 2:32pm


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ricaze
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ricaze 8/4/2022 2:37pm
8/4/2022 2:37pm

GnccDE
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GnccDE 8/7/2022 6:21pm
8/7/2022 6:21pm
ricaze wrote:
Anyone knows the meaning of the B and C on the cylinder? [img]https://p.vitalmx.com/photos/forums/2022/06/29/557261/s1200_09B30087_5FD6_457C_9327_2F7A9F06D6CE.jpg[/img]
Anyone knows the meaning of the B and C on the cylinder?
Barrs competition from NC?
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ricaze
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ricaze 8/9/2022 6:44am
8/9/2022 6:44am
Thanks for letting me know!

Pit Row

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ricaze
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ricaze 8/21/2022 3:43pm
8/21/2022 3:43pm

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CR-Dude4
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CR-Dude4 8/23/2022 7:38pm
8/23/2022 7:38pm
Jim in VA wrote:
Nice 89 Nino, I love the Mugen cylinder, that HRC cover is awesome as well. I’m restoring my childhood 88 CR125 currently after 20 years of...
Nice 89 Nino, I love the Mugen cylinder, that HRC cover is awesome as well. I’m restoring my childhood 88 CR125 currently after 20 years of neglect. Are you selling the ATAC chamber spacers, or would you have a dxf file for me to cut out my own? Please let me know, thanks!
Black Diesel Bomber wrote:
Make sure to post some photos of your '88 when it's done. I took Nino's advice to use a Messico exhaust system and ATAC spacer on...
Make sure to post some photos of your '88 when it's done. I took Nino's advice to use a Messico exhaust system and ATAC spacer on my '89. If Nino doesn't have any spacers for sale you should be able to find them on eBay. You can also find the Honda Racing clutch/ignition covers on eBay.

If you're going to powder coat your frame and want to match UFO plastics, I would suggest using RAL 3020. This is the color swatch on the left next to the fender. This frame was done with bengal red, which is not the ideal color to match the plastics:




I think the 89's color is called "Fighting Red" It looks like a blood red to me. Hard to match. I use napa to mix up a can of real automotive paint and I use an old plastic fender that I saved. 88 and 89 were the only 2 years that were blood red.
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ricaze
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ricaze 10/14/2022 9:14am
10/14/2022 9:14am
Getting close!

6
ricaze
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ricaze 12/12/2022 2:01pm
12/12/2022 2:01pm

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luckynino
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luckynino 12/23/2022 2:18am
12/23/2022 2:18am Edited Date/Time 12/23/2022 2:21am
ricaze wrote:
Getting close! [img]https://p.vitalmx.com/photos/forums/2022/10/14/573059/s1200_21D58934_F0DB_4B44_9A1B_3FF06C5EB341.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2022/10/14/573058/s1200_AB420FF8_7AD9_4CD0_9FD9_513C94E3834C.jpg[/img]
Getting close!

Nice-well done!

However i'm absolutely no fan of the allen bolts you chose. Those don't belong on a offroad machine let alone a Honda.

Pro-Bolt or Specbolt offer bolt-kits with all lenghts you need. Specbolt does a kit just for the engine which includes all the needed bolts. Get rid of those ugly bolts!

 

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luckynino
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luckynino 12/23/2022 1:48pm
12/23/2022 1:48pm Edited Date/Time 12/23/2022 1:50pm

It is all correct BUT you have waaaaay too much freeplay/slop in the mechanism! That's normal on a bike which is soon 34 years old...you have to get rid of this play and i did a whole topic on that on Thumpertalk. It is about the HPP system but it is valid for the ATAC as well!

 

It is the part abou the governor. That bearing inside which wears out and needs to be replaced. NO added preload on the ATAC though! This is needed just on the ATAC when using the bigger carburetor.

By the way: i use the 38mm carb also on the '89....it makes for huge gains!

https://www.thumpertalk.com/forums/topic/1207620-honda-125-hpp-setup-ti…

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ricaze
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ricaze 8/2/2023 11:10pm
8/2/2023 11:10pm

IMG 6326 2

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luckynino
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luckynino 8/3/2023 12:37am
8/3/2023 12:37am

Looking great - congrats!

ricaze
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ricaze 8/3/2023 1:13am
8/3/2023 1:13am

Thank you! Still having a hard time to make it idle.

ricaze
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ricaze 8/3/2023 1:03pm
8/3/2023 1:03pm

IMG 6332

ricaze
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ricaze 8/3/2023 1:04pm
8/3/2023 1:04pm

IMG 6329.jpeg?VersionId=aIPU4FhMzMhzjn79EtoHiK2 kO

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