Not ridden one of these modern 450cc 4-strokes, it was all 2-strokes in my day, but we could see the writing on the wall as KTM were just bringing out 4-stroke crosser and enduro bikes.

I had a selection of different sprockets and a couple of wheels for my 465, a 17" which was the original wheel, I had a road orientated tyre on it with higher gearing so it just kept me out of the powerband at 60mph. Then I had an 18" wheel from a YZ490 with usually a sandcross tyre on it, they were quite good in the peat bog we had in Caithness. That was the wheel that I changed the gearing on depending if I was trail riding out in the hills or racing on a track.

Keeping the bike out the powerband and I could get around 60 mpg, use the power and that would drop to about 8mpg, with a 2 gallon tank plus a little in reserve you didn't go far! Oh and on full throttle the original fuel tap could not flow enough petrol to keep the float chamber filled on the carb, I had to drill mine out to 6mm which was the same diameter as the tap on the YZ490.

The big bore, air cooled blue motors are great motors. The WR500 (92-93) is almost the same motor as the YZ465 (80-81). The problem with such a large bore, air cooled engine is that the rider must know how cylinder temp affects carb jetting. I was working in S.Cal at the time of the IT490. We knew the owner would seize the piston in the first 20 minutes of riding if we did not set the main jet to give 8 MPG.

Force10,
You mention track. Are you racing motocross for the first time? If so, remember to pin the throttle if the front wheel is low over a jump. Centrifugal affect of the rear wheel and rebound speed of the suspension are what have the greatest affect for your attitude in mid air (ramp angel being equal). A face plant over the bars hurts more then casing the suspension.

Make sure the stock suspension springs are set for your weight. You have air forks, so find the local guru for those. Once the springs match your weight, take the bike to a trail loop you are familiar with and play with the suspension 'clickers' until you have a feel for how to make the bike feel planted on each type of terrain, whoop, corner, jump.

I spoke with a few IT465 riders and they all had the same problem, 2 seconds of full throttle in 3rd gear and the bike would start to splutter, back off the throttle for a few seconds and you could give it full gas again for about 2 seconds before it started spluttering again.

I spoke with a bike dealer in London that used to race the IT465 in enduros, this is when I was getting the 18" rear wheel, they said that they had the same problem and the simplest cure was to replace the fuel tap with one off a YZ490 but that gave no reserve, so I bored out the main tank section of the IT fuel tap and left the reserve alone that way it forced me to behave when fuel was low

Never had any fuel starvation problems after boring out the tap

Yes...the "panic rev". Also the opposite if you blip the throttle too much on the jump face and are too nose up, step on the brake pedal to bring the nose down. The track I'm going to has what they call a "Vintage track" besides their full blown MX track. The details they give are:

Original Standard MX Track
No Gap Jumps
No Man Made Whoops
No Jumps Over 60'
Prepped every day the tracks are open
No steep Ramp Jumps or Hazardous Landings.
Fun, Safe Environment!

Sounds good for trying out a new bike, I don't think I will venture out onto their large MX track with the dangerous triples etc. for a few trips. I have never been at this place before...I can't ride at my regular OHV places because in California this is a "Red Sticker" bike that can only be ridden October 1st through April.

This track is a private circuit so you don't even need spark arrestors.

Don't ask me why...but the manual states not to make any suspension adjustments during break in. The only thing I'm doing is setting my race sag by adjusting the spring pre-load. It takes 3 people to do it right and my daughter had to leave halfway through the process, so I will finish before I take it out. My race sag is at 115mm so I need to crank the spring down a bit more to get it to that 95-100mm sweet spot.

I weigh 167lbs and I get the feeling this bike is set up at the factory for a rider in the 140 range. I will probably have to stiffen up the forks as well after I test it out. The Tac-Air forks are a bit complicated with the 3 chambers...so I will probably need help from someone setting those up properly.

My first day on the vintage track I'm going to take it easy and work on cornering and small jumps...see how she feels. I plan to run the bike about an hour and half...bring it home and drop the oil and check the oil filter and see how much metal is in there.

I can't tell you how much I appreciate your tips and concern...if you lived close by...beers would be on me! My first planned track day is Thursday the 11th if I can get off work early.

Thanks again Aldo!

Great Bike!

I sure want to try offroading next year, maybe later this year if unexpected money shows up. Coming from circuit racing the tech specs seem not to scary, but then I'm not going over jumps or in between trees. Seems a lot of mechanical work required though...

Let us know how the first outing goes. Video preferable

Sorry for the late reply, I have a bad network cable that some times keeps this computer off line.


That is how they made a 4 stroke almost equal to a same CC 2 stroke. Compare the piston skirt length of a modern 4 stroke piston to an old school 4 stroke or 2 stroke. There is no redundancy built into the modern 4 stroke racer.


The EPA tried to change this a few months ago, but the aftermarket, automotive industry was strong enough to stop them. They proposed rules that it made it illegal to change any component that affects emissions of any mass produced machine, regardless of the use . The EPA is going after your closed course vehicle as hard as others are going after gun rights.

It would be interesting to see a comparison of the environmental impact for the life cycle of a modern 4 stroke vs a 2 stroke using modern, bio-degradable oil. The comparison MUST include pollution created when producing the original engine as well as the replacement parts. A modern, racing 4 stroke has the same 'recommended' replacement interval as a 2 stroke.

Force10,
When you are setting your sag, you need to have all of your gear on. If you are a class A rider, you also need to check the static sag after setting 'race' sag. I should thank you. You are the first person that I have had a discussion about a CRF xxx R where I did not spend the entire conversation pointing out the flaws in that engine. :P one of my CRF customers tell me that he only calls when he is desperate or wants to be kicked in the balls. Have fun, ride safe, and treat her proper or she will make you pay $$.

I live in California so it's pretty strict here. They basically want you to wear a smog device an your face so you're not exhaling poison into the air...lol.

I did put all my gear on when setting my race sag...I got it to 101mm. Free sag is 38mm...it's about 3mm over the guidelines and they recommend possibly using a stiffer spring. I'm coming from a trail bike with only 9 inches of travel on the suspension...this bike having 12 inches of travel will be an improvement so I'm not going to make any radical changes yet. I'm probably a D or C class rider being so new to MX...I will have to see how my years of trail riding convert to the track.

I think the bike's ready. I pulled the air filter and they had it oiled up pretty good with just a few "dryish" spots...so I re-olied inside and out and applied some rim grease to the rim and sealed it up pretty good against the airbox. Checked and snugged up the spokes on both wheels and added 50cc of oil as it was on the low side of the dipstick.

I had to move the shifter up a spline...when I did a quick ride with my boots on I couldn't really get my boot under it. I have Gaerne boots and they're not exactly cheap...they have a hinge to help foot movement but I was still having troubles.

The only thing left to do is set air pressure the day of the ride. For trail riding, I usually go with 12 in front and 13 in the back since I ride on hard pack with rocks...don't want to pinch a tube. The track will be soft...so I will lower it a pound each and go with 11 and 12.

Those are really good boots. Thay take a long time to break in, but they last and give great protection.

A static sag being off by 5 mm is not worth changing the spring rate, or even messing with the spring adjustment. You may find that after a few hours of riding that the springs needs a turn or two. Then it would be worth finding the sweet spot.

Note: I am not an air fork expert, my knowledge is from mechanical springs.

Now that you know the rear spring has the correct preload, check the balance between front and rear. While you are riding slow, stand on the pegs and use your weight to compress or 'pogo' the suspension. The front and rear should move at the same rate. If the suspension is not balanced when moving in one direction, then the clickers are probably the cause. if the suspension is not balanced moving in both directions, then the fork spring rate may need to be changed. We are getting into the realm of B and up riders. Just remember that you have a suspension that allows the bike to adapt to you. You do not have to adapt to the bike.

Last piece of advice (I am sure we are boring the rest).
Two pro riders on the same team will like different suspension clicker settings, once the correct spring rates are used. Write down your starting clicker positions. Go to a trail loop or track you are familiar with. Ride for a bit with the starting settings to get a feel for the ride and wheel traction. Make a major change to one of the suspension clickers (fork or shock, rebound or compression, stiffer or softer, faster or slower) and ride the loop again. Ride with some caution, but get a feel for how the grip of the tires has changed and how the attitude of the bike has changed as it goes into the air.

If you went positive with the clicker from the starting point, do the same 'test' with the clicker set negative the same amount. Do the same for each clicker(set of clickers).

You are tuning your instrument to play the music you like. Your goal to make the machine an extension of yourself.

Don't forget to check the forums dedicated to off road bikes. If there is an inherent problem with a machine you will find out about it there first. But, remember that riders are no different from gamers. Everyone on the net is wrong if they do not agree with you.

Good luck, ride safe, and most of all have fun.

Not boring to me,

just bringing back memories of all tinkering I used to do.

I kept a log of settings for everything based on preference, track, and weather.

Nice looking bike you got there Force10.

Although I would hate to have to put backgrounds and a 3 digit number on those puny number plates, lol

Don't worry about embarrassing yourself, I've done plenty and seen guys do plenty of stupid things that we should have known better than to do. You'll no doubt do your fair share at some point.

One example:

It was a muddy Supercross race, I timed the gate perfectly, had a 10 bike length lead going through the opening sweeper, even bigger lead when I blew through the first turn because I was so excited to get the holeshot that I didn't think to shut off for the turn untill it was too late. LOL I salvaged a qualifying spot but all my freinds we're giving me grief about "goon"ing the start.

Sounds like you have a pretty tame place to start getting used to motocross before you venture out onto the big track.

We had a track like that here called Honda Hills. Very beginner freindly.

And don't worry about being slow, because trust me you're going to be, until you start getting the hang of it. It's not like trail riding.

Just be sure to hold your line when someone is coming up behind you. Nothing worse than trying to pass a slower rider who's all over the place.


Most importantly, above all else, is to make sure you enjoy yourself.

Nooo...it's my thread topic and it's all helpful stuff and on topic!

I survived my fist track day and all went well...didn't dump the bike and had fun! I did make some mistakes...one of them being getting there early and being one of the first one's out. It was sooo muddy. They had been watering it quite a bit and it was thick and deep mud. Really squirrely and I was fish-tailing up some jump faces that were right off the muddy corners.

I would expand more on the day but I'm bummed because there's a problem with my air forks. I got the pump and set the pressures accordingly at the track...and when I checked them today the balance chamber lost over 100lbs. It was
really low when I checked them the night before, but I chalked it up to the dealer not prepping the bike properly.

I have added pressure in the right order...and I just released all pressure from the three chambers in reverse
order and re-filled them. I will check again in the morning but I'm not hopeful.

I will call the dealer in the morning and see what they have to say...and I hope they do good by me. There's no warranty on these race bikes so I hope I'm not screwed.

I bought a brand new bike so I wouldn't have issues with it for awhile.

The sad truth is that you did not buy an XR. You bought a cutting edge racing machine and brand red is not the same after Mr. Honda passed. Plus, air forks are like upside down forks were in the early 90s. All sales hype and years behind the conventional tech for non factory teams.

Stay calm and work with your dealer. I drank the orange cool-aid, but I have to admit that your forks are better then there 4 chamber forks.

You can always try talking to the red customer relations, but that takes calm and skill.

If you have to pay, consider finding the non factory sponsored shops that have a national reputation for air suspension. Don't waste your time on Tech-Care unless it goes to the owners son-inlaw.

Air is much harder to seal then oil. Look at how often dirt caused your oil forks to leak.

Thanks Aldo.

I know to be calm and see what they have to say. I'm not going to get worked up too much if it costs me some. I knew going in that these bikes require quite a bit more financial love. As long as I have it ready before red sticker season officially opens on October 1st.

One guy said he had a stripped rebound adjuster and Honda replaced the lower fork leg and parts as a good will gesture but had to pay the dealer labor. I wonder if I could just get the part from Honda if they're willing to make good, and take it to a mechanic I've used at 650 Racing as his rates are probably more reasonable.

I know about your mechanic chops Aldo...do you still ride? Which flavor of Orange do you have...a 450? Trails or MX?

All this talk about my stuff is probably getting old...lol

No not getting old at all, nor boring

I for one am enjoying reading the tech talk.

Old is the Excelsior 100 I used to take out on the hills when I was 13, the bike was from 1932, or the bit more modern Matchless G80S 500cc from the 1950s that I rode when I was 15.

Last week I saw a Triumph Scrambler, it was a new bike and looked very nice, ( http://www.triumphmotorcycles.co.uk/motorcycles/classics/scrambler/2016/scrambler ) My uncle rode a Triumph 3TA and my father a Tiger 100 both were what we would call trail bikes or scramblers.

Force10,
Your best chance at good will is to have your dealership's service department call there service rep with a valid reason why the fork failure was a manufacturing issue. I have never seen a manufacture good will parts and let the labor go to someone who is not one of there dealers.

I did not get my first bike until I was 15. Someone gave my father a 69 Kawi A1SS. After I got my drivers licence, rather then buy a car, I bought a 73 Triumph Trident. I am now the original owner of a 95 Priller RS250. I still ride her when I can afford the upkeep. She needs new piston and rings every 6K miles and about the same for tyres if it does not see a track day. My body literally locks up if the Gs go less then that of a down elevator, so I stick to asphalt and road course, where it is safe

Good to hear you are still with us Force10, and fingers crossed you get the parts sorted out. "No warranty at all" seems a bit unfair really, even for non-street use bikes...

Oh, that's a nice two-stroke right there Aldo, more my thing We had a racing-converted one at the circuit in June this year, goes like stink and even gave my friend on his old R6 some hell.

Maintenance on two-strokes seems equally taunting as on those off-roads, though. Love my 675 Triple by comparison, all it needs is a bit of oil every few trackdays...

Awesome Force10! Very nice bike. I knew from a previous thread you were thinking about this.



I totally get this. After buying a used 150RB for my son, I learned the hard way what a pain it can be. When I got home and took the seat off, the air filter was literally shredded. I should have driven back and demanded my money back, but took months to rebuild the bike and restore it to good riding condition before I sold it (my son decided he didn't want to ride). I couldn't bring myself to sell a piece of crap to someone, so I worked on it and put more money into it. Ultimately, lost about $500 on the thing, but my conscience is clear. The kid that bought it got a good machine. I learned a lot and am glad to be rid of it.

You saw the picture of my 250X in that other thread.

Here's my new toy:

Sweet ride Goblin!

I considered getting a 2 smoker...but I was looking for a 2002 or earlier so it would be green sticker so I could ride it year round. I imagine you don't have the California type regulations I have so you can ride that year round in PA?

KTM's are pretty expensive...so I'm sure it rides like a dream even though I've never ridden one.

Just an update on my situation:

They more or less identified that the fork is leaking inside the air chamber...as the larger volume outer chamber gains pressure while my balance chamber loses pressure. I was hoping it was just the schrader valve but no luck. The Honda rep is actually paying a visit to my dealer today, and looking into my bike is on his list. They have already spoke to him during this and he suggested checking an O-ring at the bottom of the fork as a possible...but the rep was pretty sure it was leaking into the outer chamber.

The service manager has a "feeling" that the rep is going to cover everything (parts/labor) but is making no promises. It needs an entire fork cartridge at this point and they have one in stock in the southeast but it will take two weeks to ship here.

I can have it expedited for an additional $80-$100...which I might do if they cover parts and labor.

I hope it works out...I get bummed when I look at the empty hole in the garage where my new ride is supposed to be...lol

Yeah, I can ride it year round here. In fact, my 250X came with an emissions control valve that circulated fresh air into the exhaust so it could pass the California regulations. For me, it was just extra weight and I took it off and blocked off the holes with some bling. haha!

Good luck on those forks. I hope they cover the cost for you -- they really should, considering that it's their (Showa) design causing the problem. Did they mention if other bikes were having the same issue?

I've got WP air forks on the KTM, but this is the second year for that fork. The engine has some new design elements and I know I'm taking a risk with the first year on it. So far though, I'm loving it.

Actually the TAC forks (Triple Air Chamber) has been on Honda's 250's starting in the 2015 model and is going to remain unchanged on the 2017's that are coming out soon. All the digging I did online when I noticed the problem...I couldn't find one person that was having the issues I was having. Guess I'm special.

Most of your class A riders swap it out for a traditional spring fork...but it should be good enough for a nub like me.

I sure wish you lived near me...I could use a new riding buddy. My son works all the time so I've been dragging my wife out with me the last couple trips. She rides pretty good but she's pretty slow on the trails. After the day is over...I hop on her bike and do a couple laps so I can
get some fuel through the main jet...not just the pilot...lol.

I love trail riding, but you really need to bring a friend. If you get hurt way out there on 3,000 acre's...it might be awhile before they find ya.