Posts
47
Joined
12/25/2014
Location
Princeton, MN
US
Edited Date/Time
11/15/2020 8:50pm
Hi everyone,
I have been riding motocross for fun for the las 8 or so years. I am an average B rider who typically only rides tracks.
I am looking to send my 07 cr125 engine to get modded to a 144. I have heard good and bad things about Eric Gorr, same with Tom Morgan. Does anyone have any input for me? I plan on keeping it running with pump gas (non oxy).
I have been riding motocross for fun for the las 8 or so years. I am an average B rider who typically only rides tracks.
I am looking to send my 07 cr125 engine to get modded to a 144. I have heard good and bad things about Eric Gorr, same with Tom Morgan. Does anyone have any input for me? I plan on keeping it running with pump gas (non oxy).
IMO if you need more power you are better off looking for a different bike. Any money you put into the engine you will not get back if you decide to sell. Reliability and parts availability will be reduced, not a good combo. There is a mixed bag of reviews, some love 144's, some don't. Is it worth risking $600+ on engine mods you "might" like? Put that money towards a different bike, you will be much better off in the long run.
The Shop
My 03's are my indoor bikes (MN winter) and my 07 and 06 are for the outdoors so I can go through the bikes on its off season. I bought the 05 as an extra 125 to have some fun playing with mods. I know the ktm 150sx is still going to be faster all around but I am a die hard honda person until I can't find parts any longer. I have been tempted to switch to ktm just haven't yet and want to continue to ride red for now. I also know that it really comes down to the rider skill vs engine size. I just wanted to have some fun trying things out and learning. I haven't really been one to want modded out engines but lately I have had an interest in it.
I have a few extra oem cylinders and heads (bought them when it took over a year to get one for my 03cr250 because I was concerned that they will stop producing them soon). With that being said I can always return it back to stock.
I haven't gone to ktm for a few reasons. I don't want to deal with air forks ( i know you can switch them to cone valves but it isn't cheap) I love the reliability of the bikes I own and have seen even new bikes have issues no matter the brand. I also really like the way my bikes handle and have been on them for years. I am not trying to go pro or anything just out hitting track with my friends and occasionally racing nothing serious. To me with the bikes I have, I would rather invest $600 in modding an engine just for the fun of it then buying a new ktm for $7-8k when all of my bikes are paid off and I have tons and tons of extra parts. My friends joke with me saying I run a factory honda shop.
I mean did you watch red bull straight rhythm last time they had it? The old Honda did fairly well against the new ktms haha they may be slow but it is also enjoyable being out there passing people on a 15 year old bike when they have the newest and the greatest. Its all about having fun for me and my Hondas let me do that without dropping $7k. The modding was just going to be for a little fun project
When tuned, the 144 is much easier to keep on the pipe than stock bore. Mimics the OE powerband, still not much over-rev, but with more go. Hopefully you have the TMX dialed in or have a 38mm PWK on it already as well. Running 13-50 gearing, so much different than the 13-52 stock. For video reference/sound, I'm 200lbs. and still enjoy riding mine: https://youtu.be/xcb746vup9s
Had HP Racing do mine years ago: Loved the work, but Mr. Harris missed the delivery window by over four months...#WouldNotRecommend
In a nutshell, it's still slower than a modern 150SX/TC with a narrower operating window, but the best handling bike on any track with solid build quality all these years later. BTW, this one was a stock bore and didn't sound too bad for a Gen3 Fun25: https://youtu.be/w5G7s3dKu1I
It started as a garage find with a crankcase full of sand but an immaculate chassis back in 2013.
I paid $900 for it. New bottom end bearings/crank/clutch + Eric gorr 144 kit. It never ran right - rode it a bit then put it on display for 5 years.
I was in about $5k at this point
Bike $900
Rebuild bottom end + 144 kit $1500
Clamps/plastic/graphics/wheels $1500
A kit shock + b kit forks $1000
When we decided to race RBSR we spoke with Varner and he was all about it. Dyno showed the Gorr 144 kit was actually worse than stock. Not anywhere in the rev range was it better.
Terry suggested a 134 and had a spec. Another $2k in engine parts and $2k in Terry’s time and we ended with right around 38hp. Not a KTM beater by any means, but 7 more than the Eric gorr 144 had and it’s noticeable.
The moral of this story is: anyone can buy a bike off CL, build it to stock, scotch brite a frame and bolt on new plastics, pipe and stickers. It’s an entirely different world to get an old bike to run at its peak performance. You’ll turn a $5k project into a $10k project. More than a 2021 crf450.
For the performance, if you have the budget I wouldn’t get anyone other than Terry to do your bike. I also didn’t see my $10k cr125 from RBSR last year until world 2 stroke this year. Almost 12 months. After reading threads in here i thought I may never see it again. Spoke to Terry Thursday before 2 stroke race and he assured me it would be ready to ride Friday morning and it was.
Side note: best mod you can get for this bike would be a factory transmission - or develop your own with a taller 2nd gear or shorter 3rd gear.
That’s the best info you will ever get on a last gen CR125. I’ll probably take it to Pala tomorrow so if you’re local come check it out.
If this bike was an 05+ do you think that Varner would have made it a 144 vs a 134? From my understanding only the 05+ cr125's can be a 144.
I really don't want to spend $4k in engine mods for this bike, I am more looking at the $5k plan haha. For the skill level I am at and not trying to compete at the highest level (sure I wish I had the skills and experience to do that). I am too old and just enjoy riding as a hobby.
It was awesome watching that bike compete against the 150s at RBSR! I was pumped for you. Are you Micheal Leib? Or did you buy the bike from him? Or loan him the bike?
I would love to come check it out, but I actually live in MN and am deployed across the pond at the moment.
Pit Row
I forget now, was 2000 the last year you could run the old HPP cylinders on the bottom end? Everyone seems to agree one of the best mods was adapting the older HPP cylinders to the newer engines, where it was applicable.
Here's another builder name that will cause a stir on here.. Derek Harris. You can search the posts and draw your own conclusion. Not recommending him one way or the other, as I only know what I've read on here, but he always seemed pretty knowledgeable and experienced as far as engine performance was concerned.
I narrowed my search down to Tom morgan, watts, Varner and a local tuner ( Haeseker racing). I chose Varner, but there wasn't a 15 page bash thread at the time either lol. I looked at who was building the bikes for the two stroke national, and from talking to people at local tracks with their crs and his name kept coming up.
I would call Tom and talk with him. Honestly, you would think since Varner knows about the thread, he would make a business change when it comes to customer service and logistics, but you never know. Tom seems like a safe bet from the research I did a few years ago.
What we found is simply boring out doesn’t really get results. The results were found in the dyno time testing pipes, carbs, jetting, timing etc.
Yes most people are not looking to race when they build a 20 year old 125. Having an extra 20% over stock certainly makes it a lot more fun to ride even if your just ripping up the vet track with your kids.
I appreciate all of the info. I'll be doing the same just wanted a few little mods done without spending a fortune. I can ride my 250 if I really am in need of more HP vs spending thousands to squeeze it out of my 125s.
Im enjoying every bit of it.
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