99 KX 144 test (Eric Gorr vs. RPM)

[extreme33]

In 99 my friend and I each purchased 99 KX 125. Since the bike is such a dog, we both decided to get the big bore kits. I decided to use Eric and my friend went with Rick Peterson. When I first received my cylinder back from Eric, I didn't really notice any changes except for the larger bore. My friend’s cylinder was different. RPM turned down the cylinder base and also had a different cut in the head. He also used a two ring piston in his bike. Once we both had a chance to break the motors in, it was time to switch. My friend and I are very similar riders (5'7" ht., 160lbs) with identical riding styles. Both bikes were faster than stock, but had different power. The RPM motor had low and mid power not much better than stock. The top seemed good but had a tendency to over rev. Eric Gorr's motor had more power everywhere. It pulled from bottom to top. It was definitely a noticeable difference. It was a much more useable motor. Even a novice rider could figure this one out. Can anyone explain why this is? What was RPM trying to accomplish by cutting the base down and changing the squish band so dramatically?

Another point I would like to make is the turnaround time and price difference? RPM was twice as much and twice as long. Need I say more?

Eric,
I appreciate the time you take in actually R&D bikes to maximize Hp, instead of just punching out a big bore to create more ponies.

I am considering a 02 YZ 125 (instead of the 02 KX) for next season. I plan on the Eric Gorr 144cc for the bike. Is the YZ 144 better than KX 144? If so, by how much? What is the hp difference between the bikes?

Also as an added note, my friend purchased the 167cc kit from RPM for his 01 KX 125. He didn't learn much from his prior mistake. The bike seems faster than my 01 KX 144 Eric Gorr motor, but only very slight. The $1600 price tag doesn't seem justifiable. He wasn't very happy with the result and now plans on selling the bike to switch to a YZ or KTM. If I purchased the bike (since it has minimal use on it) is there anything I could do to make this engine more useable? It just doesn't seem like the larger displacement is being maximized in terms of power. Is it a porting/timing problem? Why doesn't this bike rip? I can tell you from experience that a 01' RPM 139cc YZ is faster than an 01' RPM 167cc KX. That's a difference of 28cc. It just doesn't make sense. Also, the 167cc seems like too much motor for the 125 crank. The price is right to purchase this bike, but I need to make it run at its max. level. Will porting or anything make a difference? Or should I just scrap the whole idea and purchase a 02 yz 125 and add the Eric Gorr 144cc kit? I would really appreciate some sound advice and input.

 

[marcusgunby]

Thanks for your good write up and time-its unusual to get to test 2 bikes with so much mods back to back.
Steve 125 did have a EG YZ144 and from what i remember it was better than the KX144 he had before.
IMO the 167 is just too much cc for the engine, but i suspect it pleases some riders to have a strong bottom end from a 125 package-too expensive for my tastes i would leave it and go for the YZ.

 

[Pit_Monkey]

i just have one question. i know people are mad at me for my bad write up about the Eric Gorr big bore kit. however i was just voicing my honest opinion. i felt that the engine adn work were excellent. second to none but the turn around time was bad and he was kinda dishonest when i talked to him on the phone and he kept telling me he was going to send it out the next morning. so obviously i was expecting it about a week later but it would never come. i guess i was wrong to be such an ass about complaining about the turn around time but i still feel he was kinda dishonest when he claimed an 8 day turn around not including shippin which is 3 days each way. and he had my engine for a month.:mad:

When I first received my cylinder back from Eric, I didn't really notice any changes except for the larger bore. My friend’s cylinder was different. RPM turned down the cylinder base and also had a different cut in the head

well this confuses me. cuz i had the big bore kit done adn i notice tons of stuff. the porting the head mods the grinding of the cases. it was all very notice able. also how did you only send him the cylinder. i had to send him my whole engine because he said the piston skirt would hit the case because its so large. if what you are saying is true i could have saved my self 80 bucks in shipping and i wouldnt have had to take my whole engine out and i wouldnt have had to wait for the crate to come in. please let me know if im correct in my observation. thanks-Charlie.:think

 

[WorldWideRacer]

PitMonkey,
it is very possible that the KX cases are already open enough to facilitate the larger bore, and your YZ's were not.

On another note, if you are tall enough to ride a 125, you have very little excuse for poor grammer, punctuation, and sentence structure. It makes you look very uneducated and is hard for us to read your posts.:think

 

[extreme33]

What I meant by noticable changes was that RPM had cut the cylinder base dramatically and the squish band looked much different than stock. Both cylinders had noticable porting work, but this is typical. I was attempting to point out the visible changes without the use of a micrometer to check the difference. I didn't have the ability to hold them side by side until after they were bolted on.

In regards to the comment on sending the whole engine, I think it depends on the bike. I had sent EG a 99 and 01 KX 125 cylinder for the 144 kit and only set the head/cylinder/power valve assembly intact. I never sent EG the whole engine. I may be wrong (someone feel free to correct me) but I think on the YZ's (maybe other bike too) you have to send him the whole motor.

By the way, a month turnaround time is nothing. RPM took 9 weeks for my friend and REP took 3 months to port my 98'. If your from CT then you have heard of REP.

I would still appreciate some more input from anyone on the 01' 167cc KX solution. Marcus.... I appreciate your reply

 

[yardpro]

WorldWideRacer-
pitt monkey takes a "creative language " class. glad to see someone flame his communication skills. Taste of his own medicine.
now back to the subject,
i have found that almost every machine shop I have used, lake & shore, rpm, and kustom kraft substantially underestimate their turnaround time. The only exception is US chrome ( I think Eric uses them for plating). They performed the most recent replate job. They told me going in that it would be about a six week turnaround. I received my top end exactly when they said I would. I was very happy with their work.

 

[EricGorr]

Just some observational notes.

The KX cylinder must be turned down .050 inch at the cylinder base because RPM and I both use the same basic piston forging. I did cut the base of the cylinder but it may not of been apparent to the naked eye since I do all the machine work before plating.

I use a single ring and RPM uses a 2 ring piston. I go for the lighter, low friction design. A 2 ring piston is better for longevity, in fact it will probably last 50-100hrs.A 2 ring piston also seals better when using extrememly high compression ratio head designs.

The YZ requires crankcase mods because the 58mm piston would hit the front side of the cases. Yamaha and Suzukis are the only models that require case mods. In fact my web site provides that information up front, and my book has a picture for people who want to try and do it themselves. It's a bummer that RM and YZ owners must pay more but I didn't design those engines in the first place.

Keep in mind that the $1600 RPM engine mods includes bottom end rebuilding and crankshaft stroking, so thats not a bad price.

You guys can criticize me all you want, I don't care and I certainly won't try to censor any of this.

With regards to turnaround time, that varies based on shipping time and backlog at US Chrome. Besides the 98YZ125 engine in question was in my shop in the middle of September and there were a lot of other things going on in the country at that time, and a lot of uncertainty whether air and truck traffic was even possible in those dark days. Yeah I pretty much just chilled out and waited until things settled down before I shipped packages. I learned a hard lesson from the previous years UPS strike, where dozens of my customers packages sat in empty wharehouses for 2 weeks and I was held captive on the phone to their screaming. Recently I lost several hundred dollars worth of books and videos sent through the post office because of security and scrutinization by customs officials in foriegn countries. And just in case some of you guys don't read the newspaper, theres a WAR going on. And nothings normal anymore.


As far as being dishonest goes, thats bovine feices! I try to be as honest as I can but sometimes you just can't keep a schedule in a hectic business.

 

[MX-727]

Originally posted by EricGorr
Just some observational notes.

Yamaha and Suzukis are the only models that require case mods. In fact my web site provides that information up front

Besides the 98YZ125 engine in question was in my shop in the middle of September and there were a lot of other things going on in the country at that time

As far as being dishonest goes, that's bovine feces! I try to be as honest as I can but sometimes you just can't keep a schedule in a hectic business.

I'm glad you responded to these criticisms. I think most of us that have dealt with you knew that there were reasonable explanations.

Pit_Monkey: The September time frame was a critical omission from your flame. I, for one, think you may owe Eric an apology.

 

[Vic]

Pit_Monkey- It's not dishonest to fail to deliver on a promise. It is dishonest to make a promise that you have no intention of keeping. In this case, Eric was clearly a victim of circumstances beyond his control. This kind of thing happens all the time. It's called, "life".

 

[MikeT]

Originally posted by EricGorr
Yeah I pretty much just chilled out and waited until things settled down before I shipped packages.

I think that was very conscientious of you Eric. I think Mr. Monkey might want to reconsider his initial slam.

 

[extreme33]

Thanks Eric for your response. Like always your post are very informative. I am very satisfied with your work, turnaround time and the cost. Furthermore, I also apoligize on the fact that you spent a majority of your post time on defending the 'uniformed'. That wasn't my orginal intent. I know your time is valuable and a large majority of us appreciate your posts.

I think that it would be more benefidal to reduce as much friction (friction equals loss of horsepower) as possibly on 125. I typically replace a piston on the 125 after 10 to 15 hours of use. I not concern about pinching pennies to reach 50 hours of use on a 125. Serious racers have new bikes by then anyways. As I stated before there was a big difference between EG and RPM mods on this particular bike. I was able to have an excellant opportunity of testing two bikes side by side. I hope my experience proved useful to others. Bottom line.... the Eric Gorr bike ripped much better than RPM's. End of story. Maybe other bikes have a different ending.

Another note I would like to make is that this is a 'Mods & Performance Forum'. If you want to complain about something then post it on the 'Flame Board' forum. This is not the place to whine and cry about what things cost or how long. Some of us use this as a very valuable resource. You must remember some of us race for a living and the information found in these forums are the difference between winning and dnf. Winning provides a paycheck. Even a monkey can figure this one out. Sorry to be so rude, but I had a point to make in the beginning so stick with it.

 

[MikeT]

Good job with your posts Mr. extreme. They have been very informative and are good reading. I think you made a good comparison between the two systems.

 

[EricGorr]

Be easy on PitMonkey guys, he's a kid who missed his bike for a while and maybe used some wrong semantics. I admit that during that week in September I was moving a little slow, I was bummed out about the whole thing and just had a tough time working.

I was thinking today about dishonesty in the motorcycle industry and some examples from motorcycle shops or mail order businesses. These are all true stories and some happened to me. Maybe you guys have some horror stories too.

Dishonesty is...

1) Send your perfectly good engine in for a minor service and they tell you it needs a complete rebuild with loads of parts.

2) Send your parts in for service and the tranny gets swapped for a lame one.

3) Buy parts mail order and get a box with a COD tag for cash only and theres only a back-order invoice with a brick that represents the part inside the box.

4) Drop your motorcycle off at a bike shop before opening hours only to have the shop steal and part it out.

5) Bring your bike to a shop for service and go to a riding area to find the mechanics beating on your bike.

6) A mail order company runs a special deal on suspension servicing so a bunch of people send their expensive parts in, and the guy goes out of biz and sells the parts in a foriegn country.

7) You buy a works style aluminum tank one year and the company that sold it to you makes a special offer to you the next year for a new aluminum tank and offers a buy back for a great deal. Then the guy keeps your tank, polishes it up and resells it for brand new.

Sound freaky? I know some way worse stories than that! Anybody else know of any fine examples of bad business practises? Please no names, just general scenarios. Any naming that could be libelous will be censored.
Have at it!

 

[marcusgunby]

A friend sent some forks for a revalve in the UK and later was unhappy with them so had them redone elsewhere-no revalving was performed and we wearnt sure if they were even serviced as every clicker was set the same as when he sent them.

I think suspension servicing is a potential mega money rip off, because all the tech has to do is pour old oil out and put fresh in and alter the clcikers for a different feel-99% of people wont be able to know what was done as if they check- the oils changed and new looking , and they feel different because the clickers have been altered.People cant check the valve stack as if they could they wouldnt be paying for the work to be done.

Eric Ive been thinking about your situation and its very hard for you to do right-heres my reasoning.
A guy phones and asks how long for this job Mr Gorr?
Eric says 4 weeks(this is best case senorio as you dont tell customers the worst case senarios as you will be out of business)-you are at the mercy of US chrome and the post service.
Guy says 'hmm thats a while' i will ring round and get other options
Eric replies sure and if you want to go ahead just give me a bell any time, as you have this amazing service where you will answer all questions at almost any time.
Guy rings round competititors with almost no morals at all and will quote any thing to get the business-he get quoted 3 weeks and goes for it.
What do you do quote times you know you cant meet or quote times you think it will take and loose many customers to the sharks-its a tough balancing act.
Ontop of that your prices are way better than the rest and so some people assume your work cannot be of the same std as the known brand names-so what do you do raise prices? so people think the job is equal to leeser tuners ,
its not easy doing your job and i think you have great heart to not be down on Pitmonkey.:cool: :cool: :cool:

 

[cr-man]

I was getting burned by one of the leaders in the suspension biz they were making me buy new fork bushings every time I had the forks serviced they would give me the old bushings, but they looked great except for slight chafing at the top. Now I knew this did not look right and after reading Eric's book I found out they were not taking the forks apart properly, so I end up paying for their mistakes. That sucks!

 

[larry250]

Forward Motion

Wow wow wow here . After having Eric do work for my on my son’s 95-CR125 cylinder and new piston, I could not be happier, not only with the performance but the service. I was very leery as to sending out a cylinder out of state. If your going to dis Eric and Forward Motion I have a serious problem with that. I’ve been into bikes since the mid 70’s and seen a few things, I would suggest to anyone of my friends to send engine work to Eric any day of the week. And by the way I’ve never met him in my life. Now lets get back to the good stuff, such as how to fix things not take steps backwards. Wining is for those how can solve problems.

 

[yardpro]

I've been lucky. only overdue returns. I have yet to try eric ( he will be doing the big bore on my cr after christmas). I think it was dishonest for Butt monkey not to state the obviously relevant info about the september timeframe. Not telling the whole truth, when it has a relevant effect on the perception of the facts is dishonest, that's why when you are sworn in in court you are under oath ".. to tell the truth, the whole truth..."
Butt monkey would never answer the question of if he had had work done elsewhere. If he had I am willing to bet that he would not have been as critical of eric's work, as "he's the man" ( hey eric, does buttkissing get me a discount on the overbore:) )

 

[P_Taylor]

Annual buddy run thanksgiving weekend , Two employees of the local Yamaha/Kawasaki shop show up with a **** to ride and sink it in a mud bog during the race. It turned out to be a customers machine that was in for service.

Man drops off his bike monday morning at a shop in Evansville , Ind. to be sold on consignment. Wednesday night he goes to an open practice nite at a track about 40 miles away. The bike was there being rode by an employee of the shop that was suppose to be selling it for him. When he confronted the guy riding his bike and said he was taking it back the guy told him he couldn`t have his own bike.

 

[EricGorr]

P_Taylor, yeah thats a beauty but I witnessed one that tops all the consignment stories. When I was a teenager working at a boat shop, a guy brought in a boat for consignment. The salesman moved it fast and the guy paid $18,000 in cash. This dimwit salesman gets the bright idea to take the money with him to Vegas so he could "win a lot more" then pay back the 18K. Well as you can probably guess he lost all the money and the business got sued.
Moral of the story...If you bring your bike to a shop for a consignment sale the odds are that it will get stripped for parts or sold for cash and the big excuse will be "we had a break in and your bike got stolen". Workin in the Chicago motorcycle scene for 20 years as a mechanic, I saw that happen way more times than I care to remember. The funniest one happened at a shop that I worked at in a western suburb that was the notorious home to many mafia guys in the 70s. One time this wise guy's snowmobile got sold and stolen under this scenario and the guy came in with 2 guns and a bad attitude. Guess what happened? He left with his money! Good for him! But there were just as many guys who left down and out.
God I loved the 1970s!:eek:

 

[P_Taylor]

back to the overbore questions

I remember reading something about an aluminum sleeve big bore kit for the YZ250 that was being worked on , is this still in the works to be available???

 

[TONYKX]

I never have any problem with Eric Gorr works and turn around time,I sent two times to him.He done a good jobs.One time it proably my fault which I don't know for sure,the cylinder seized up after 10 hours (sometime you just don't know whose fault) I talked to him,he justed re-do it, just charged what it cost him on parts.I am also in the service bussiness ,so I know this is fair for both.
As far as turn around .,belive me , he wiil do the best he could for you .Everthing can easily happen in between.Eric is a working hard man.Sometime I wonder how many hours he sleep per day?He need to take some time off.Dose he get any vacation like us ?
Tonykx.Magic Imports.

 

[TONYKX]

Worldwideracer,
If you are read my post.Please forgive me,I'm not good at grammar either.
Tonykx

 

[smooth sail]

Eric did a fabulous job on my boys KX-100 cylinder. His professionalism and work ethic are the benchmark that guys like Varner and others strive for but never quite make the mark.Not to say they are bad, but Eric treats the business as a gentleman would- as he would want to be treated. Eric will be getting my boys new KX-125 cylinder and head for some work, and my KX-250 cylinder for the mo better job. :D

 

[Sage]

Originally posted by EricGorr
As far as being dishonest goes, thats bovine feices! I try to be as honest as I can but sometimes you just can't keep a schedule in a hectic business.

Amen! Anybody that dosent understand that needs to have mommy pull the spoon out of their mouth. As far as mail order engines & suspension goes you guys (Eric & Jer) are braver than I. I do it but the hassles mentioned above tend to make a guy real picky on whos stuff gets taken in. Theres nothing like building a hot road race engine and then have some knucklehead slap his carbs back on that were jetted 10 sizes to rich for the stock engine and then say its not any faster than before.

As far as the shop storys, I bought a 89 GSXR 1100 that was way trick for 89, took it to a friends shop to be assembled (bought it all in parts) and 9 months later, after many blow off's, I showed up with a truck to take my parts and was missing my polished wheels, fox shock, 38mm FCR's, half of the body work, the whole front end, sub frame & wire harness!!!

 

[EricGorr]

Thanks for the good words guys, especially Tony. Don't worry about your grammer out in this forum. We've got people from all over the world contributing to this forum and I doubt most of us could comprehend even the simplest words of your native language. I think its great that you've worked hard to learn English and you can call me anytime with your tech questions.