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1
Japanese Bikes / Re: CB400/4 sprockets help
« on: November 02, 2008, 02:45:11 AM »
There is no such thing like a CB400/4 on Honda listing before after 1977 in US. It had 17teeth on the front sproket and 38 on rear sprocket. It uses a standard 530 chain.  Many third party drive chain and sprocket kits are available.

Reducing the number of rear sprocket teeth or increasing the number of teeth on the front could theorically increase top speed at the expense of acceleration power, if there is enough torque left to drive such top speed...  I doubt it. A FOUR is already an acceleration devil but at top RPM, there is only so much you can expect from an engine with two valves by cylinders. You already have SIX speeds on your transmission to extract the best of your available power curve. This bike is rated for max practical speed of 175km/h on sixth speed out of a 37HP engine !

I've got a Honda CM400T 1980 twin engine with 43HP and three valves per cylinders with a five speed transmission. It is said to reach 156km/h. Just follow me...  in 1982 they came up with the CM450 wich had two valves per cylinders and SIX speed transmission. Top speed was NOT improved over CM400.

You are already at very high top speed for a 400cc from the very design of this four cylinders machine. Increasing it would require more than playing with teeth numbers. It would be a shame to ruin such a roarring gem trying to ride it in the red for too long.

Unless you trust a pro mechanic specialized into racing machines, I just would not even try to improve the performance of your CB400F. This is likely a waste of money. You could rather check for foam air intake, modified jet sizes and tuned exhaust. You are talking of big bucks for an expected improvement that is not likely to exceed a few points of percentage, if your engine and driver can survive long enough to test it.  Do you really want to ride a 32 year old motorcycle over 175 km/hour !!!??? This could only be acheived if compression is top shape and nothing is out of optimal adjustment, perfect tires, wheels, etc.

2
Japanese Bikes / Re: What was your first Japanese Motorcycle
« on: March 23, 2008, 07:16:25 AM »
Mine was a 1971 CB175, twin cylinders, twin carb, 95km/h max with no wind, but what a reliable and easy to handle machine. I got it so loaded up with passenger, groceries and all that I had to redo the back wheel spokes after I broke a couple...

The only trouble I ever had was a failure of the oil seal that protected the contact points: nothing major, but I needed a towing to the dealer.

Picture is at http://www.vintagebike.co.uk/Bike%20Directories/Honda%20Bikes/pages/Honda-CB175-71.htm

3
Japanese Bikes / e: Yamaha rd200 running problems
« on: April 21, 2008, 07:34:34 PM »
Hi again,
In addition to our comments so far...
I might add to the basic checkup prior trying to start again:

Make sure you bleed your gas and try with some FRESH gasoline. Don't forget you probably have a RESERVE position to flush too.  Anything older than 3 months without gas stabilizer will make it much harder to start and maintain a regular RPM.

Before you go ahead cleaning and adjusting the carb, cut your gas line and insert a gas filter. Your gas tank is likely contaminated with some rust and else that could ruin your efforts.

Make sure your air filter is clean and in good condition

Make sure you have checked contact points adjustments (ignition). The service manual will provide the specs.

Use the Troubleshooting section of your service manual.

4
Japanese Bikes / Re: Yamaha rd200 running problems
« on: April 21, 2008, 09:06:36 AM »
I too strongly suspect carburator to be gummed up (Be careful to select cleaner that is safe for rubber parts). :-[

Another possibility is ignition problem from a weak battery or choke not operating (unlikely). :-/

Incidentally, you should also perform a COMPRESSION TEST, and make sure your valves are properly adjusted. It is VERY common on such an old motorcycle to see valves guides so dirty thay valves are remaining half shut. No compression, no power, hard to start. ???

I found FOUR service manual at Ebay.co.uk just by searching for "rd200 manual" on Ebay search Engine. :D


5
Japanese Bikes / Re: Workshop Manuals.
« on: February 16, 2008, 12:18:09 PM »
Sorry Mark for mispelling your name. I had just been in touch with Mike Nikon that I quoted on my message to you, his name just came back naturally by accident.

I tought you planned to simply send attachments by Email... much simpler.

"moving the adjuster on it's splines is actually approved Honda procedure" you say ???  interesting... If so, this is precisely what I want to know more about, especially the torque values required when reinstalling the nuts on the  adjuster.  I have not located this information in my Clymer manual.

According to Mike comments, It is quite likely that I can still go more than once on the adjuster, as long as there is remaining teflon on the glider apparently. This was routine maintenance in the 80's he says.

Whenever teflon padding is gone, I will have to change both gliders and balaning chain, remove the crankshaft and reinstall with new bolts on the connecting rod. I already have all required parts to do that, but I definitely prefer to ride for a while without the 12 hours or so of work required to restore with new parts. This might just come whenever the engine is due for complete rebuilding. If the crankshaft is removed, I'm likely going to change all bearings and timing chain too, so this will not only be 12 hours, and I'm not experienced enough to risk working that much on an engine myself.

So whatever accurate information you have on moving the adjuster on it's splines is welcome.

Martin

6
Japanese Bikes / CM400T 1980 crankshaft balancer chain adjustment
« on: February 13, 2008, 11:26:45 AM »
Thanks Mike,
In the meantime I've got in touch with Mike Nixon, who used to be a top Mechanic at American Honda in the 80s. He told me something quite amazing:

" The tensioner can be adjusted further, and at your low miles that is all I would expect would be necessary.  Tell your mechanic to remove the slotted part from its splined shaft and reposition it one spline over to gain more adjusting room. "  Otherwise the adjuster went all the way once only.

This was a very common thing to do back in the 80"s at Honda's dealership he says, but this procedure was never endorsed by Honda.

Have you or anybody on this forum ever heared of such clever shortcut for adjusting the tension on the crankshaft balancer chain ?

Thank you

Martin

7
Japanese Bikes / Re: Workshop Manuals.
« on: February 13, 2008, 07:11:51 AM »
HI,
I've just got my Honda CM400T 1980 top engine restored (valves, cylinders and pistons to factory specs). Unfortunately, as he finished the job, the Honda dealer mechanic told me that the tension on the crankshaft balancer chain is not working anymore. I'm told I should not worry too much about it if noise is not getting worse.

The engine only has 25,000km. I love this bike because it is just the right size for me.  I ride 12,000km /year on my motorcycle.  Part cost to fix the problem is very low (I already found all critical OEM spare parts) but estimate on labour cost is 12 hours. This includes taking engine out of the frame, replacing the balancer chain and guides. I suspect we may also replace a few bits and pieces too as he would have to remove the crankshaft.

I need to figure out by myself if something else can be done or if I can do part of the work by myself. I've got the Clymer manual, but the illustrations and explanations on that topic are diluted between several models.  Do you have more accurate and focused information on :

  • How to adjust this balancer chain
  • How to service this balancer chain and tensionners


Any help would be appreciated

Thanks

Martin

8
Japanese Bikes / Re: Ever changed balancer chain on Honda Twin 400-
« on: April 25, 2008, 08:24:09 AM »
Dear SearchGuru...
I've got the Clymer Service manual and I've read the procedure over and over.

I'm glad you think an estimate of 12 hour is too much, I've got a second estimate a 6-7 hours today, which makes more sense to me. The model I have (CM400 1980) is splitting on the bottom, so sides do not even need to be removed. The balancer tensionner assembly is directly accessible once the case is split.

As for my second question, I still don't feel like removing the engine head, but I may if I have to, because I need to remove the camshaft to change the timing chain. Once Camshaft rockers are removed, there is nothing left to hold the engine together.  If I am working in a clean environment an properly idenfity R an L side parts, I should be OK. I know pistons and rings are fine, I want to keep it that way.

As it is explained in the service manual, the balancer chain must be changed once the wear indicator tells you to. They explain engine vibrations at high RPM are increasing because the balancer are getting out of sync once the chain is stretched beyond the wear indicator mark.  If I try adjusting the tension further, chain noise may stop, but engine vibration will get much worse, as chances of snapping the worn chain into a running engine...  I cannot take such chance, now that compression is restored to specs, engine head is back like new and it is not burning a drop of oil anymore.

Your little story on a similar twin is boosting my confidence and it tells me I can probably do it within a day or two. My main concern is to open and find other damaged parts I must replace and wait for. I've already purchased the rare parts that must be replaced no matter what (such as chains, gliders, new connecting rod bolts). Once the case is split, I will be able to tell and I already located vendors that carry all extra parts I may need, shipped within two weeks to Canada.

To avoir part backorder delays and to risk breaking my engine before I can fix it at the end of season (I'm riding 12,000km/year), I'm planning to buy and install a spare engine and swap it whenever necessary for major repairs.  I know, I will wear them both eventually !!! I'm targeting CM450 or CB450 engines which have an automatic balancer chain instead of CM400 which requires to remove the side cover every second manual adjustment.

You see, I've got my plan, but thanks to you and a comple of buddies I will dare to take my engine apart... knowing I've got a spare one too !

Thanks again

Sono


9
Japanese Bikes / Ever changed balancer chain on Honda Twin 400-450?
« on: April 21, 2008, 09:42:53 AM »
Hi,
I would like to know if any of you ever did perform a balancer chain change on a Honda Twin such as CB400-450, CB450SC Nighthawk, CM400-450.

I've got a CM400T 1980 but I had a bad surprise yesterday: the balancer chain keeps being noisy despite recommended adjustment and it appears to be at service limit (must replace the balancer chain if still noisy when wear indicator on balancer shaft is up to 3 o'clock) it cannot be adjusted any further. The user's manual recommends to adjust it only if noisy and specifies it should be checked after 10,000km. I suspect it has simply never been adjusted and worn out prematurely. Who reads the user's manual ? I do.

The service manual suggest to remove the head and cylinder first, but is it essential ?  Any bearing or worn glider will be changed.

PROBLEM: I'm just reluctant to dismantle the top of the engine because engine head and piston rings have just been restored to specs. DO I ABSOLUTELY NEED TO TAKE IT APART ? It would be cumbersome, but I don't think is it essential. As we say, "If they are not broken, don't fix it !"

I've got all required parts and Service manual. If I'm lucky, only the balancer chain and gliders will need replacement. I may replace timing chain to be on the safe side, as well as any worn bearing and oil seals I may find.

If any of you ever did such repair I would lile to have an opinion on how many hours it represents ?  My mechanic is talking of 12 hour... He was telling me that balancer chain adjustment took 3 hours and I did it in less than two (I'm not a mechanic, but I am quite handy with tools and a manual).

Thanks if you can help to keep my 28years old motorcycle in good health.  

I'm actually considering buying a spare engine or even a spare bike for parts, so that I don't risk to damage my rebuilt engine if the the balancer chain beaks. It is only doing noise at 5-6000rpm, which is my cruising speed (90-100 km/h). I would ride on the spare engine this summer and fix mine in the meantime.

10
Japanese Bikes / Re: Engine gasket sealant
« on: December 20, 2007, 11:25:29 AM »
Be careful with gasket sealant on old honda bikes. I've got a CM400 1980. Soon after I bought it, I noticed that head and bottom cylinder gaskets were both getting wet and I got quite concerned.  >:(

I soon discovered that this was NORMAL if the bike had not been ridden for a while because the Honda gasket material is designed to absorb hot oil and swell to make a tight seal with very little specified pressure applied on engine mounting bolts.  ???

Sure enough, less than 500 km later, the oil stopped leaking as the most experienced mechanics had predicted. I'm not sure Honda gasket material is still designed like that but all Honda motorcycles and scooter engines I ever owned were from that period (mid-70 to mid 80's) and they all use simliar oil swelling material. :)

I later found in the service manual that using any sealant could actually CAUSE more leaks as well as poor cleaning or improper cleaning (using tools harder than aluminum).  :-[

Other brands of motorcycles more recent models and automotive industry may use other type of gaskets designed to used or designed to be replaced by gasket sealer. Lots of mechanics also use sealers because they don't have to wait for new gaskets when they perform repairs on an engine.  

I don't beleive in miracle cures that applies to any engine type. My old Honda motorcycles had accurate service procedures and head gasket installation did NOT include using any kind of sealer. If using a sealer, what would be the correct torque to apply ??? Don't assume that it would be the same.  ;)

Except for rare lemons like the early Honda Magna (see http://en.wikipedia.org/wiki/Honda_Magna) and a few known problems, I would think twice before going against Honda engineers advice.

Doing things the old way is often the best way to go with old bikes ! For instance, just try switching an old bike on synthetic oil (even JASO certified) : gaskets will often start to leak, wet clutch will start slipping, and it may start buring more oil simply because the engine is running too clean (too much detergent additives).
Using mineral oil (which is much better quality that it was in the early 80's) remains the best choice.

Old Honda engines were not as economical in gas and did not run as clean as they now do, but why on earth am-I still driving a 27years old motorcycle ? You must love them as they are intended to be. Also keep in mind that today's replacement gaskets are often better quality than OEM Honda which are often discontinued for ages anyway on a '73 !

I just had my CM400 cylinders and head refurbished to new. One of my valves oil seal failed, too much oil got into that cylinder so piston rings got gummed up and I lost compression on that side. Everything was still within standard specs, but I had to get new rings and have the valves cleaned and readjusted. In retrospect, It is no big surprise to see rubber oil seal fail after nearly 30 years,  but I have a lot of respect for engineers that designed such a reliable engine.

Good luck !

Martin

11
Japanese Bikes / RE: 1980 honda cb750k... worth buying?
« on: March 17, 2008, 10:13:41 AM »
Compression testing is extremely simple to perform and it tells a lot on the engine condition. If compression is uneven or below minimal specs (lower than 7 bars) walk away. Except maybe if only the engine valves require a basic adjustment, it is rarely economical to restore compression on such a four cylinder engine and it is completely nuts to consider rebuiling the whole engine (I mean, you must be maddly in love with it, have a DEEEEP pocket and plenty of time).

I recently had my Honda CM400T 1980 compression restored to specs because the bottom of the engine was in good condition and I had the chance to find for cheap spare cylinders and complete engine head in excellent condition that I got refurbished as new by an old mechanic. A Four cylinder has twice as many parts to change, cylinders to bore and valves to rebuild.

It was a success, but it ended up more than twice the price of a used replacement motor even if the engine did not even need to be taken out of the frame on mine. This is why I consider cost of rebuilding a Four cylinder much to high to be economical.


12
Japanese Bikes / Re: CB500 parts
« on: March 07, 2008, 09:10:06 AM »
There is also http://www.cmsnl.com/honda_model8286/

You may want to contact the vendors too. They might have the parts you are looking for, but they may not have posted on their web site all about early 70's bikes !

What kind of part are you looking for ? Have you done a compression test on all four cylinders ? What kind of problem did you identify ? Has the engine ever been rebuilt ? What total is on the odometer ?

If I'm not mistaken, you are talking about a bike such as this one http://www.cyclechaos.com/wiki/Honda_CB500

Finding new parts will be quite of a challenge considering it is a rare bird, out of production for over 37 years !

Considering the difficulty of finding critical common parts that will eventually require replacement (ignition, gaskets, oil seals, chains and sprockets, all rubber parts) I don't think planning to ride this bike regularly will be an economical experience. Any engine part that fail may be a death sentence. This bike is made to fly ! but you are likely to burn its wings pretty quickly if the engine has not been already rebuilt.

If it is in near pristine condition, a collector may be interested to buy it to restore, otherwise, it is a very risky project for an everyday bike.

I question your will to ride this as a first bike too. This bike is VERY powerfull (50HP) and the engine weight configuration makes it quite heavy to handle in slow traffic. I'm not sure it is going to be very forgiving for a beginner.

Mine is a Honda twin cylinder from 1980. Despite the fact I just had the engine head, cylinders and piston rings rebuilt to specs, I'm considering buying another one just for a complete spare engine and critical parts.  Mine is a very common model and there are still good spare engines to find. I doubt you can do the same, spare bikes and old new parts are long gone for such a rare bird.

In short, because this bike is on the countdown for running out of available essential parts. It is a better candidate for a collector than to be used everyday as a first bike.

13
Japanese Bikes / Re: 1975 cb200t - Should I Buy?
« on: February 20, 2008, 10:24:12 AM »
I would advise you to get a compression test first. If compression is too low, you may have valve problems or your piston rings may need to be replaced.  You have a fairly high mileage bike. Let's say you have to offer a price considering you are likely to do some major work on the engine pretty soon.

Keep in mind that it is quite likely that you may have a hard time to find even common spare parts and make sure you get a Service Manual.

I found quite a few at http://www.davidsilverspares.co.uk/parts/genuine-spares/

and quite a few on http://www.cmsnl.com too

If you can't find it there, I would say good luck on Ebay.

I drive a Honda CM400T 1980. It did look perfect like yours, but after 500km I lost compression on one cylinder because a valve oil seal was defective and piston rings on that site failed.  Rubber parts just don't last that long.  I had to get the engine valves, cylinder and piston rings restored to specs because I was fortunate enough to find all required spare parts.

I don't think it would be wise to assume you will be able to safely ride this 1975 motorcycle for a long time without spending a substantial amount of time and money on finding parts and labour.

My first bike was a 1971 CB 175... I loved it.

I would advise you to consider finding a Honda CM/CMX250: Lower mileage, very reliable, easier to find parts because they were made from 1980-1987.

Good luck


14
Japanese Bikes / Re: HONDA CB1 - 400f
« on: February 08, 2008, 09:41:51 AM »
Warning:
It appears to have been replaced by part number 19200-KAF-010
It is available at http://www.speedsupplies.com/cartdisplay.asp
http://www.bikebandit.com

and probably several other Honda part vendors

15
Japanese Bikes / Re: 15 HP+ for CB400A Hondamatic?
« on: February 05, 2008, 07:04:47 AM »
Incidentally, As I was trying to identify a pair of NOS (new old stock) oversize pistons, it appears as if compression ratio on CM400A is lower than CM400T.

My CM400T pistons (I just had the engine rebuilt) show three depressions on the top to leave clearance for the valves. The picture of the CM400A piston I saw (out of an OEM box with part number) was PLAIN, so it can't go as high in the top position into the cylinder, so compression is probably lower.

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