Donít Ask: Your Dirt Bike Tech Questions Answered

Sep. 05, 2012 By Rick Sieman
If you choose to email a question to this forum, then you must conduct yourself accordingly. Therefore, the following rules are in order:

1. Do not write your email to me IN CAPS. If you do so, I will print out your question and do terrible things to it.

2. Do not request a personal e-mail response. Since I get thousands of questions each month, trying to answer them all would cut deeply into my leisure time, which I value more than your current state of confusion.

3. Try to spell at least in a semi-correct fashion. If you choose to mangle the English language, expect no mercy from this quarter. You might be mocked severely.

4. Do not ask for me to send you copies of my many manuals and literature. I am not in the library business, nor do I want to spend the bulk of my day at the copy machine just because you're too lazy to ask your dealer,  or look around a bit.

5. Don't bother me with truly stupid questions, like how to get 50 more horsepower for a buck and a half

6. Now that you know the rules, think carefully and have at it!

Oh yes Ö Iíll leave your e-mail unedited, for what itís worth.
Have a question for Rick ďSuper HunkyĒ Sieman? E-mail questions to, Attn: Donít Ask.

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For some reason, I keep finding odd Maico photos around the web. I am the same jackass that sent the Maico thumper photo awhile back.

This time I dredged up a photo of a Maico trials bike. Perhaps just a random bike with Maico stickers? The web site is in Italian, and google translate sucks, so I wasn't able to glean much info from that. Thought you may like a look, or a laugh. Maybe you folks know something of this?

Daryl Salek

Actually, what you have is yet another one of the Italian frames with a Maico motor in it. The Italian have literally dozens of very small factories, usually in the back of garages, which produce an almost bewildering variety of motorcycles.


I have a yamaha pw80 and up until just 2 weeks ago has been running great.  All of a sudden it wants to bog down and die as soon as I lean it over to the left side.  The right side leaned over nothing happens, but the left is NOT good.  Any ideas?
Thanks so much

This is a simple straightforward problem. In the float bowl of your carburetor, you have either water, or dirt, or both. When you lean the motorcycle to one side as you described, the crud blocks the jet and the motorcycle momentarily runs out of fuel. The cure? Take the carburetor completely apart and clean out everything properly.


hi Rick
hope all is well with you. i just picked up a 72 kawasaki f9 bighorn.....the only one i have ever seen up here, and was thinking of rebuilding it at a later date. i was wondering what your thoughts on this bike were because i'm sure you tested it back in the day.

We did a project on the Kawasaki 350 Big Horn back in 1973 while I was at Dirt Bike Magazine. The bike was such an erratic runner that we took it to Kawasaki to have it checked out. They told us that to ensure a modified Big Horn ran properly, we would have to go through the bike and thoroughly check all the specs to make sure they were within tolerances. Kawasaki did that and found out the bike we had was horribly off on what it was supposed to be like. After they blueprinted the bike, it was a super runner. So what does that mean to you? It means that you might have a good running Big Horn, or you might have one that is very disappointing. I hate to be the bearer of bad or confusing news, but those are the facts.

I picked up a 1977 Suzuki RM370 that is in need of a set a shocks/tires.

Does anyone have a set of good working used shocks that they would want to sell? I believe the 1977 RM370 used a 15.25" rear shock but 15.50" would be fine too.

Also who has the best prices for a new set of Progressive shocks with springs in case I have to go that route?

Who has the best prices for new tires, I need about 3 or 4 21" fronts for this and various projects.

Tires like all oil-based products have gone up quite a bit since I have purchased a set. The Maxxis tires that were once a deal and worked well are priced near the same as the big guys.

Thank You

The 1977 RM 370 was a great bike with the weak point being a set of shocks that would fade after about a half hour of hard running. I don't have much experience with Progressive Shocks, but I can tell you what worked back then and what works now is Works Performance shocks.  When I put them on my 370 back in 1977, it made a world of difference.  Today, you would expect even more Ö and you would get that with the Works Performance shocks. Call up Gil the owner at 818-701-1010 and get a price. You won't be disappointed with how they work. As for the tires, I've seen the Maxxis tires still going for a fairly good price, but you have to be very careful where you shop.


i have a bunch of 90s wr 250 parts im trying to get rid og hmu

And og hmu to you. What in the plu-perfect hell kind of e-mail is that?  And what exactly does og hmu mean? I'm not in the business of selling parts, but if you want to get rid of them, try eBay. And please don't tell them that your username is og hmu. Now go away.


HELP!!! I have a 98 wr 400 that has recently had a full top end rebuild ($3,500 worth) then spat the balance shaft gear (on the end of the crankshaft) clean through the casing...I replaced all damaged parts n had the hole fixed, but when I tried to fire her up all I got was an awful grinding noise in the bottom end n she won't start......any suggestions please before I launch her onto the bonfire???
Blue Girl

In many cases, people would be wise to get rid of a bike that would put them into the poor house. This seems to be such a case. Consider the fact that you got one of the early four-strokes built. At most, the bike is probably worth $1500 bucks if it's in clean condition. To spend $3500 on it boggles the mind. Letís face the facts: Most of the new four-stroke racers are hand grenades and were built to blow up on a daily basis. $3000 is just about the norm for a typical rebuild. Your bike is 14 years old and even the most optimistic rider in the world will tell you that it's a lost cause.


Hi Rick.
Big, big fan since the early Ď80s. I have always love your honesty. It's unusual and refreshing.

I cleaned out my buddy's shed, and came away with two interesting bikes. They were stored since the mid 70's in Pueblo, Colorado. That means no rust.

The first one is a 1969 Yamaha AT1 Enduro. 1300 miles. It came with the owners manual which states on the E model, do not premix the fuel. Mix 30:1 on the M. Any reason behind that other than racing is harder on the little 125 than street riding? Also, do you know the point gap or is a matchbook cover close enough?

The second bike is related to one of my favorite bikes to read your writings on. 1972 TS 400. What differences are there between the TS and the feared TM, besides street legal stuff? This bike has 1200 miles.

One more question for you. While I know that these are not old Porsches or Jaguars, what is your feeling on restored versus original? The tires are dry rotted, the need fuel lines and fork seals, etc. Modify slightly to make road worthy or leave as is for a collector? I really want to ride them before I sell them since he really needs the money.

Thanks for everything and glad to hear you are healthy.
Eddie Memphis

Yamaha always advised to add premix to an injected MX Yamaha in case of a pump failure, or air in the lines from a big jump or a long set of whoops. Most of us just took the pump off and bought the Yamaha accessory plate to cover the hole in the case and mixed a good-quality two-stroke oil at 32.1.

The TS400 was kind of a failure compared to the 360 Yamaha Enduro. They didn't sell that many, and it was kind of a portly, bad handling faux dirt bike. The only thing it was good for was the magneto, that fit on the TM and made it a lot better MX bike. You don't see too many TS400s, making it a rare bike if it's in good shape.

You can put some WP shocks on the back, and have Noleen Racing re-drill the damper rods, put some better fork springs in it, and you can have a decent handling reliable vintage enduro. Also have a shop clean up the ports, raise the exhaust port 1mm, take 1mm off the head, hog out the transfer ports, knife edge the bottom of the transfers, and put a reed valve kit in it. Then you will have a fast TS400. Also get a nice up-pipe expansion chamber from any of the retro dirt bike shops off the net that will build you a pipe for around $200.00.


Re: History of Honda Dirt Bikes, PT 1
My father and Jaques Tougas, were in the Guiness book of world records for testing the new Elsinore, in a 24-hour endurance test...David Cunningham, r.i.p.
Alastair Cunningham

The first Elsinore from Honda set a new standard as to what a production motocrosser should be like. It was truly a breakthrough machine and the fact that you witnessed the first 24-hour test of the bike is quite remarkable.


I have a frame number cs3-200887. is it possible to get the year, style and engine size here. Its pretty hard to do anything with out that.
Andy Anderson

While it would be possible for me to look up every motorcycle ever made to find out what type and year ID you have, it's truly bad manners to request an ID without even telling me what kind of a motorcycle it is. You, sir, should go to a corner of the room and bang your head against the wall for quite a while.


Re: Penton Sixday 125
just pu same 1971 125 penton great shape runs great what would the value be on this bike
Guy Thurston

A 125 Penton in restorable condition would go for about $800. That's assuming everything is there and the bike does run.  If the bike is in real good condition, the value it could be as much as $2500 or so. A lot of the price is going to depend on cosmetics; how the bike looks.


i have a HONDA XR200R its a 1982 and it wont idle right does any one know whats wrong with it. i tried to turn the idle up & down but i will get i right on the dot and it will rise again

There are two likely conditions that can cause the idle to be weird.  The first is that you have something partially clogging the pilot jet, or the other is that you have an air leak. Check for both these things and chances are your problem will be cured.


Re: Yamaha Vintage Dirt Bike Guide
can anyone help me id a yamaha yz 80 or maybe 85,its air cooled and mono shock,with drum brakes front and rear,the number on the headstock is 3r1-000235

You have a 1980 YZ 80G and cheers back at you.


I was looking at "Don't Ask!" for June of 2010. Some guy was having plug sooting/flooding problems with his XT500. One of the possible problems you mentioned was the "home made" air filter set up.

If it helps...and it should, there are 2 kinds of foam. "Open cell" and "closed cell". This guy could have closed cell foam for his filter. The difference is easy to determine. One way is by sight. The other is putting your mouth on it and blowing. Closed cell foam will pass little, if any air. Closed cell is the foam used in furniture so your 400 pound Aunt Bertha won't sink to the floor when she flops down on it.

His flooding problem sounds like incorrect foam. I know it's too late, but a quick troubleshoot would be run it w/o foam filter and see what happens.
I get this all the time at work. Guy will tilt lawn mower the wrong way to remove his neighbors dead cat from the blade area and the oil will run through the breather into the paper air filter. They can't figure out why it ran, then all of a sudden sputters and smokes black.

I'll ask them, "did you tilt it?"
I then remove the filter which now weighs triple and fire it up. Runs great. I place filter against housing while running and engine immidiately sputters/smokes.
"That'll be $5.50 for a new filter."

Customers are always thrilled. Sometimes I even get a tip for not charging the $15 minimum labor charge.
David Fruhling

Once again, Dave to the rescue. This guy knows more about TT 500s and XT 500s that should be legally allowed by law. Thanks for the tips, Dave.


The reason the quads came out is: When Japan stopped making 3 wheelers, they thought, "Man, we were making a killing selling these 3 wheelers to all those squids. We are losing our asses, now. What do we do?"

Well, they thought and thought and finally a dim Christmas bulb flickered in someones head and he goes, "Let's just add another front wheel!"

The bike gets one That's why there are now squids breaking their necks, limbs and backs again. A 3 wheeler with another wheel on the front. I've ridden a couple and they are more ill mannered at handling than any 3 wheeler I've ridden. Quads handle like a wheelbarrow full of pumpkins with a flat tire.
David Fruhling

I agree with you completely about the three-wheelers. Whoever came up that idea is responsible for more injuries than we can count in a month of Sundays. Four-wheelers, I think, have an incredible number of squids piloting them. When you learn to ride off road on a dirt bike, the first time the bike gets wobbly you get frightened and realize that a mistake could cost you a lump, or a bruise or even worse. You get respect for the bike.

On a four-wheeler, a beginning rider has no fear for what is happening.  His initial riding experiences are at relatively low speeds where nothing much happens. It's only later on when the speeds progress and the quad gets into trouble, the new rider doesn't know what to do. The quad will crash and the rider will get hit in the back of the head with about 600 pounds.  It is my opinion that the average quad rider out there is completely unprepared for what the machine can and will eventually do.


I bought a 50 cc valor Sr who makes it and from where can I get info on them ? I also have a 2003 Suzuki Jr 50 cc how do I beef up suspension and also how can I make it faster without spending too much anyway to.adjust throttle cable ? very much appreciate your time thanks Kevin
Kevin King

SR50 R Factory

Manufacturer Aprilia

Parent company

Production 1992 Ė Current

49.38 cc (several different engines used)
Top speed 45-50 km/h restricted, up to 85-90 km/h derestricted. Optional gear up kits available, they can lift the maximum speed up to 110 km/h.
Front telescopic fork, rear hydraulic monoshock
190mm disks front and rear
13" wheels 130/60 tyres
1290 mm
Dimensions L 1860 mm
W 705 mm
Seat height 765 mm
Weight 108 kg (wet)
Fuel capacity 7.45 L
Oil capacity 1.2 L
Fuel consumption 90-120 mpg

The Aprilia SR50 is a scooter built by Aprilia. Introduced in 1992, more than 800,000 units have been sold, bucking the trend for less use of two-stroke engines. Aprilia claims several firsts for the SR50 in the scooter market, including 13-inch wheels, liquid cooling, double disc braking, and a direct injection engine.

The performance-oriented suspension, tires, and engine are consistent with its styling. Colours and graphics vary by country. The digital instrument panel gives readings for speed, clock, odometer, trip counter, fuel level, coolant temperature and battery voltage.

The SR50 has used a variety of engines, sourced from Morini, Piaggio and Minarelli. It conforms to EURO 3 emission standards. The DiTech model used an injection engine, with technology from Orbital. The engines allow reaching very high speeds for a scooter, the SR50 can reach 90 km/h in its standard configuration after being derestricted.


This article was really helpful. Just took the head off of my '77 CB750 4K. Turned out to be the big end bearing. A sad day.

I don't know how much the article would help you when you're riding a four-cylinder Honda 750. But thanks for the pleasant words.

i have a cr85 2002 with no spark , have checked all comon faults and checked all resistances on the ignition system ,and all came in spec. could the pick up on the inside of the fly wheel?
You have to do all the basic stuff when trying to find out why you have lost spark. The first thing you should do is pop in a brand new spark plug. Then you should check the spark plug cap and the wire leading to the coil from the cap. Then check every connection and wire in the entire system for corrosion, or shorting out, metal on metal. Most problems are usually solved by doing basic stuff first.


Rick ``the man`` the 71 MC400 Maico decent for VMX?  what
would a 7 out of 10 be worth?..runs good,has a Mikuni and the beat up
OE pipe,the frame on the bike now is said to be a Wheelsmith with
forward mount shocks,Wheelsmith airbox,a different looking swingarm and
a brace around the lower stem area,original fiberglass is rattle can
painted,nice seat,alloy wheels with a later front hub..and includes the
original frame,airbox and swingarm...?...Thanks

Ken Faro

The older Maico motorcycles have really shot up in value over the last two or three years. A decent running 1971 400 can go for $3000 or more. A pristine Ď71 400 could cost $5000 or $6000. As far as being competitive in vintage racing, the bike is excellent. The fact that you have a Mikuni on it makes it even more desirable. It will run cleaner down low and start easier with a Mikuni than the stock Bing carburetor. If you get the bike dialed in with good shocks on the back, Iíd give it a solid 10.


My new book, THE LAST RIDE, is at now out. It's fiction and starts in 1969, when an 18-year-old kid just out of high school gets a chance to ride his Yamaha 250 DT1 from Pennsylvania to Los Angeles Ö all off-road.  His adventures are truly amazing.

The book then jumps 40+ years where the same person, now in his 60s, wants to get that old Yamaha back in his possession and return it home by riding it all off-road across the country again.  The book is $15 plus $2.75 for mail anywhere in the US (or $5 for Priority Rush mail) and for more information, the email is:

Have a question for Rick ďSuper HunkyĒ Sieman? E-mail questions to, Attn: Donít Ask.

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