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8/16/2006
Location
Sacramento, CA, USA
Edited Date/Time
1/26/2012 9:26pm
At some point in this year I will probably move the youngest off his BBR kitted Xr100 to a little smoker to ride, not race. In Calif that means targeting an 02 or little earlier to catch the green sticker for all-year riding (no KTM 85/105 
" title="Sad"> )
My understanding is that the CR's and YZ hit are less smooth because they lack a power valve. We had a cr at one point for the oldest and it definately had a hit. The Zooks and KX are a bit smoother off the bottom.
So, questions:
1) Is that summary pretty much true?
2) Have there been any major changes to any of the big four 80's bikes since 2000?
" title="Sad"> )My understanding is that the CR's and YZ hit are less smooth because they lack a power valve. We had a cr at one point for the oldest and it definately had a hit. The Zooks and KX are a bit smoother off the bottom.
So, questions:
1) Is that summary pretty much true?
2) Have there been any major changes to any of the big four 80's bikes since 2000?
The kawi does have very manageable power, but will run as fast as you need to go if you want it to. Plenty of really fast kids race kawis and do great on them
The biggest thing I can point out is that the Kawi's (KX85 and KX100) are flat out as reliable of a bike you will ever find.
Our riding is less track and more trail and desert. I do like that you can get a bigger tank on the Kawi.
The Shop
Luxon 4-Post Bar Mounts
$189.95 - $239.95
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
For me, for what we would do, I would want an 02 for the green sticker. That's a no go for the KTM.
Our riding is less track and more trail and desert. I do like that you can get a bigger tank on the Kawi.[/quote:jbinalrl]
Yes the bottom ends are interchangeable from the KX85 to the KX100. The swingarm is longer as well as the frame. Look in front of the gas tank on the 100, there is a bracket that is not on the 85. The tank sits about an inch farther back away from the steering head on the 100. Overall the frame on the 100 is about an inch longer than the 85. Also, all plastics, seat, forks, shock are all the same. If you look at an 85 the forks sit way up in the clamps, on the 100 they are farther down, this is to accomodate the longer wheelbase.
As I understand it, the Honda made some pretty good changes within the last couple years that brought about some semblance of low-end (only helpful if you can put the new cylinder on an older machine). Yamaha has done almost nothing to a very stout package that's absolutely devoid of any bottom-end. The KX has had minimal changes for several years, but as you noted, it doesn't require you to rev the snot out of it just to get up a small hill and guys like Eric Gorr can get some really impressive low-end out of the KX. I believe that Suzuki has been the best about actually making little changes to improve the bike, most of the mfg's are really into bng's for the mini's.
http://www.thracing.com/performance85.htm
CR-Honda quality that we expect, but no power valve so not as much bottom end power.
RM- Good power from bottom up but breaks frames.
YZ- No power valve, but still has plenty of bottom if jetted right and seems to fit kids coming off 65 perfectly.
My personal opinion is to stay away from the KX and either go with the RM or YZ with the Yamaha being my personal choice.
He has been riding his RM85 on SX and MX layouts, 100+ motos last year and lots of practice time with absolutely no frame issues. I do know that the RM has a slightly bigger frame size which works for him as he is tall.
I don't know where the "breaking frames" deal comes from as I have never really heard about that barring some freak huge jumping.
He rode an 04 RM85 two years ago and last year we got a new 07 both bikes have been excellent right of the floor.
We don't do anything to them besides different bars, a little jetting as we race in humid conditions sometimes and Factory Connection suspension as he is too big for the stock.
The RM definitely has more grunt off the bottom and a smooth hit into the power.
Just my .02
Hope your kid has a blast whatever bike you get him.
He has been riding his RM85 on SX and MX layouts, 100+ motos last year and lots of practice time with absolutely no frame issues. I do know that the RM has a slightly bigger frame size which works for him as he is tall.
I don't know where the "breaking frames" deal comes from as I have never really heard about that barring some freak huge jumping.
He rode an 04 RM85 two years ago and last year we got a new 07 both bikes have been excellent right of the floor.
We don't do anything to them besides different bars, a little jetting as we race in humid conditions sometimes and Factory Connection suspension as he is too big for the stock.
The RM definitely has more grunt off the bottom and a smooth hit into the power.
Just my .02
Hope your kid has a blast whatever bike you get him.[/quote:302ibodz]
Good to hear you have never had the displeasure of breaking a RM frame, but it does has happen often. I know of around 6 just within the groups we race with. Each of these bikes had the suspension set up correctly for the rider weight and they still broke. My son broke his this past year, multiple cracks around the steering head and the small tube that the coil mounts to was broke off the main frame and pulled back about 1/4". You may never have a problem, but keep an eye on it. It does happen.
Not much has changed since 2000.
Finding a mini in the year span well maintained is going to be your biggest challenge.
Wish ya well FTE and son.
Good to hear you have never had the displeasure of breaking a RM frame, but it does has happen often. I know of around 6 just within the groups we race with. Each of these bikes had the suspension set up correctly for the rider weight and they still broke. My son broke his this past year, multiple cracks around the steering head and the small tube that the coil mounts to was broke off the main frame and pulled back about 1/4". You may never have a problem, but keep an eye on it. It does happen.[/quote:36jojmse]
Wow.
Yeah I will have to make sure to keep an eye on it, that would certainly suck to find out in the middle of a moto.
I usually give it an eye inspection after every race weekend, now I will have to be a little more careful looking there.
This should be his last year on the 85 anyway, we are 125 bound.
Have you guys heard similiar issues with the big bike frames?
RM - The Suzuki makes great power, maybe the best of the bunch but........ they have a tendency to break frames and other things you really don't want to have to mess with. The biggest thing for me is, the parts cost. Suzuki parts costs to rebuild an engine, including a crank, are outrageous. If I remember correctly the OE crank for an RM85 is around $400. You can get a hotrod for most others for half that, maybe less. Fro me the parts cost on the Zook is a deal breaker.
KX - If I absolutely had to have a bike with a powervalve this is the one I'd choose. Parts are very reasonable and available almost anywhere. Kawi is very good at getting their parts out to the dealers as well. The engines are good although the cylinder coating doesn't hold up long. Making 100's are easy for the 85 since the engine exists in OE form. For a kid that's going to ride for a long time, I'm not sure the powervalve thing is that important.
CR - I'm a Honda man, their build quality is second to none. Fit and finish makes working on bikes a lot easier. The engine is dead simple. No powervalves to worry about. It's pretty much unchanged for the last decade, although they did go from 80 to 85. In 2006 they changed the carb and pipe to produce more bottom end. I don't know of any real nagging problems with the CR other than they aren't as stout as the others without a little tuning.
YZ - This is currently my bike of choice for the young teen. The engines make great power. Parts are cheap and so are the bikes compared to the RM and KX. The engine is easy to work on. It has no powervalve but you can tune around that for more bottom. Teach a kid to ride one correctly and they won't miss a powervalve. More importantly, they haven't changed this bike since like '96. Plastic and stuff has changed a little and the bore dia changed somewhere along the way. The bike fits smaller riders great and can ge made into a big wheel pretty easily. There are big wheels and swing arms all over that you can find very reasonable. My biggest complaint is, that the clutch inner hubs from '06 and up (including replacement OE parts) are junk. If you have an older one with a good inner hub, cherish it. I have a buddy that had a 2000 model for his daughter and put a washer in the exhuast to tone it down. He then rejetted it to run properly and it was a great bike for her. Almost like a souped up PW80 with good suspension.
I've not been in the KTM but it sounds like you aren't in the market for one of those either.
Pit Row
Fair enough, like I said, I don't remember the cost of the parts but I do remember that doing a crank, cylinder, and full top end job on an RM was like 40-50% more than that of the others. Hot Rods didn't make one for the RM at that time.
Part Suz cost Kaw cost
Piston 46.34 46.09
Cylinder 382.46 322.52
Rear Brake Lever 33.69 34.91
Crank Ass'y 237.17 186.75
It looks like the major difference could be on major engine components. This is the area where I spend most of my time. It's also the area one worries most about when considering maintenance costs for motocross bikes. Maybe you've just got a really good Suzuki dealer in your area.
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