PDA

View Full Version : TRX90 questions and some help.....



fastlx
01-02-2006, 02:16 PM
Ok, where do I start.... I have a 2003 TRX90 that is ridden by my 9 year old daughter. We ride mostly in the dunes, but do some trails riding. Here is what I am looking for. I would like to buy a BOLT on big bore KIT, yes KIT for it. I own a CRF50 and it has a big bore kit on it that was purchased as a complete bolt on kit. That is what I am looking for. Does anyone have such a beast? I want to get a bit more power to help turn the paddles and go up some of the bigger hills. Right now it is totally stock, and it did ok last summer when we went, but when we go back to the dunes in April, I want to have a major improvment for her. Here is the kicker, I dont want to spend a million bucks. Any help would be great. Thanks!!!

badvox
01-02-2006, 02:19 PM
http://www.powroll.com/P_HONDA_TRX90.htm

fastlx
01-02-2006, 03:16 PM
Not exactly what I am looking for. I dont want to have to bore the cases. I would like a new cylinder, piston, intake, carb, etc..... all in one happy kit, like I can buy for my 50. Anyone know if this will work.....

http://www.hondatrailbikes.com/catalog/product_info.php?cPath=56&products_id=779

The cylinder is 69mm tall. Thanks for all your help.

3-D Racing Dad
01-02-2006, 03:23 PM
http://www.icracing.com

Give Eric or Mike a call and see what they have...

fastlx
01-02-2006, 03:52 PM
3-D, I see that you have a TRX90. What have you done to yours?

3-D Racing Dad
01-02-2006, 04:53 PM
Well it's a long list... but here are a few of the high points.

ICRacing suspension:

Dual A-arms
Hydralic brakes front and rear
ICRacing swingarm
Titanium Axle
Works shocks

ICRacing motor

124cc Stroker
26mm Kehien carb

She will be a full race ready quad when it's done..

3-D Racing Dad
01-02-2006, 04:54 PM
Pappy is a good one to talk to as well..

fastlx
01-02-2006, 06:21 PM
Ok, I will do that, thanks! Calling Pappy, where are you?

Pappy
01-02-2006, 06:33 PM
why me:p

ill lay it out the way it has been explained to me by builders and those that have run big bore 90's.


Once you break the threshold of some magical cc number (noone has yet to tell me exactly what that is) there seems to be a disagreement between folks. Builders and those running big bore kits have gone both ways on what im about to tell you, so in all honesty i have no idea on who is correct....


Almost every person ive chatted with that is running a stroker or a big bore 90 has complained that power goes away due to overheating. riders complain of lack of power near the end of a 45 minute XC race etc. Some builders have agreed with this while others call horse hockey to it. The builders who disagree claim that cylinder wall thickness is the same as a stock engine so how could overheating be an issue.

Now, I am abslutley no expert on engines. i know enough to usually keep our stuff together and running good, but thats about it. Add in the fact that relaying info correctly over the net is an art and im no artists:p

We have been running a true 90cc TRX90 for competing in the GNCC 90CC Production class . Ported head and intake, 11-1 Powroll Piston and Cam, and a 20mm carb. This engine produced 7hp at the rear wheels on a dyno, while a similairly built 90cc 2 stroke will push 11hp. We have been pretty happy with our power output, but with new rules in place this season, the 125cc is an option for us.

Plans are for now to run a 124cc stroker built to the hilt in hopes of gaining every bit of power we can. How this holds together is still up in the air, and thankfully I have a few weeks yet to investigate more options.

I probably added to your confusion, but thats all I know. I do not know of anyone producing a bolt on big bore for the TRX90 like they do for the mini bike engines.

I would also love for some of the builders that visit this site to jump in here and inform those of us scratching our heads as to what will work best for power and for longevity.

fastlx
01-02-2006, 09:05 PM
Pappy, thanks for the info, I think:) I will do somemore looking around and report what I find. Thanks again. I am going to put a call into Rob tomorrow and see what he has too say.

Pappy
01-02-2006, 09:07 PM
robb seems like a pretty smart cat. i chatted with him about this awhile back and he had some good info. i know he is running an aluminum cylinder and they have ZERO problems with heat, and his son flat rips that 90 up!

fastlx
01-03-2006, 09:23 AM
I just got off the phone with Rob, hell of a guy. I think I'm going to use his 111cc kit. I will let you know what I decide and go from there. Thanks again for all the help, I appreciate it.

Birddogg
01-05-2006, 01:13 PM
The prices are outrageous. I realize that there are only a few companies selling these kits and they overcharge because they can. You can build a 117 stroker out of a CRF50 for around $500 complete with carb, cam, head, cylinder, and piston.

pappawiz
01-06-2006, 03:58 PM
dratv.com i've seen some bolt on's on that site....

ROBBSRACING
01-07-2006, 12:40 AM
Birddog please tell me where i can get those parts for that price. The cylinder heads alone that I use are over 800.

212racing
01-07-2006, 01:48 AM
not to mention amount of money spent on r&d

Pappy
01-07-2006, 04:46 AM
Originally posted by Pappy


I would also love for some of the builders that visit this site to jump in here and inform those of us scratching our heads as to what will work best for power and for longevity.


anyone:D

we dont expect secrets, just some basics on these big bore engines and some remarks about reliability.

212racing
01-08-2006, 04:48 AM
cant help you pappy with the amount of time you will be running your trx. we only had 1 overheat issue. and it was because of some new things we were trying at lorettas, boy did that screw up bite us in the points. you can talk with johny and monica on this site. i believe they ran a big bore kit and ran xc.

mcvay20
01-09-2006, 02:40 PM
Hi Pappy
I haven't been on this site for sometime but I wanted to reply to the big bore setup if it will help anybody.
My son, 130lbs. ran a 125 trx90 setup last year at the nationals and we never had a problem with the motor overheating and losing power.I used an aluminum cylinder just like Robb did and know he never had a problem either.
I do all the machine work on my motors, stroker cranks,cylinder sleeving and boring, whatever needs done.I run my motors almost square ( 54mm bore x 54.5mm stroke = 124.817 )
The stock cylinder skirt is .105 thousands or 2.66mm thick.If your building a 125cc setup and use a 54mm piston the cylinder skirt would only be .040 thousands or 1 mm thick give or take a little.I bore the motor cases out for a 54mm cylinder and you can't go much bigger because you will hit the studs that hold on the cylinder and head. What i'm trying to say is it's almost impossible to have a cylinder skirt ( sleeve ) .105 or 2.66mm thick on a 125 setup unless you run a longer stroke and smaller piston which can run into a lot of other problems,oil pump shaft is #1 and I could go on but I don't want to where out my welcome.
Pappy, hope this will be some help to you and anyone who needs it.
I want to say hi to Robb and Keith !!!!

Charlie McVay
Mcvay Racing

Pappy
01-09-2006, 02:43 PM
THANK YOU MCVAY!

i knew there was a reason why some builders claim thicker wall thickness or something along those lines, and you are correct from what i can tell

how well will one of your engines do in GNCC style racing where we race 45+ in some serious mud? id love to find out!

mcvay20
01-09-2006, 02:53 PM
Pappy,
They hold up extremely well.I finally figured out what works and don't work thousands of $$$ later.
I did Devon Dalucca's motor for the GNCC last year and I'm building him a 125 for this year.
I have to get back to work or my wife is going to fire me, so if I don't get back with you on this site you'll know why.
Charlie

Pappy
01-09-2006, 02:59 PM
take care charlie, we appreciate the time out of your schedule!

deluccas quad ran damn strong in the gncc's.

if you do get a chance, pm me a cost for a full on 125cc, id be interested in seeing what it takes!

Birddogg
02-18-2006, 12:47 PM
Originally posted by ROBBSRACING
Birddog please tell me where i can get those parts for that price. The cylinder heads alone that I use are over 800.


Trail bikes.