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Old 09-29-2010, 11:37 PM   #1
Palak OP
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Joined: Dec 2009
Oddometer: 93
TransAlp Valve Clearance Adjustment Procedure

I own a 1990 Honda Trans Alp XL600V. I checked and adjusted the valve clearances for the first time a month back. Thought I would post the procedure, together with my thoughts, recommendations, and experiences, for others out there that have this or a similar bike. I know I use search engines a lot to find out how to work on my bike, and advrider comes up pretty often on the searches. Hopefully someone out there will find this helpful.

I combined the instructions shown in the Honda Service Manual with the Haynes Manual, for what should be a complete and thorough description of the procedure. I have also added my and others’ comments in italics, and have posted a few pictures below.


Valve Clearance Procedure for TransAlp Motorcycle

Equipment needed:
  • Wrench 10x12mm for turning the lock nuts. An offset spanner or boxwrench is helpful, but is not required.
  • Valve clearance adjusting wrench to adjust and hold the adjusting screw. A crescent, spanner, box wrench, or even needle nose pliers may also be used. I used needle nose pliers, and they worked serviceably. A really handy DIY tool would be an adjusting wrench made out of 1/8” strap steel, and with the right size slot cut into it. Holding the adjusting screw is probably the most fiddly task involved in adjusting valve clearances. The clearances are very sensitive to minute movements in the adjusting screw. If you can’t hold the adjusting screw perfectly immobile while tightening the lock nut down, you will have to redo the procedure.
  • 17mm socket for turning the flywheel. A normal depth socket worked fine for me.
  • 10mm allen wrench for opening the crankcase hole cap.
  • 24mm box/spanner wrench. This was also a very critical item. I thought I could get away with using a crescent wrench. However, the front exhaust valve port has very restricted access, and you almost have to have a 24mm wrench. Luckily, the neighbor came through for me here and saved me a trip to the autoparts store.
  • Feeler gauges. At a minimum, need 0.15mm (clearance for intake valves), and 0.20mm (clearance for exhaust valves.) I got two cheap sets at Harbor Freight (about $2.50 per set.) I confirmed with a micrometer that the gauges read true to their stampings (they did). Using a bench vise, I bent the ends into ells (see picture), which helps greatly in the procedure. I also used the next largest size (0.18mm, and 0.23mm) for both valves, to make a kind of go-nogo two-gauge set for each valve (e.g., if 0.15mm drags, and 0.18mm doesn’t fit, then the intake valves are adjusted correctly.)
Procedure:
  • The engine must be completely cool before checking valve clearances, so let the engine sit overnight.
  • Remove the fuel tank. It will also help to remove the air duct. Because I was also doing some work on my carb, I had them out as well, so I had lots of room. Carb removal is nice, but probably not worth the trouble if you don’t need them out for some other reason.
  • Remove the right-hand radiator mounting bolts and either remove or displace the radiator. I was able to get just enough clearance by displacing the radiator, and using a strap to keep it out of the way. Sure beats draining the system.
  • Remove the crankcase hole cap and timing hole cap. Make certain the 10mm allen wrench you use to remove the large center plug is a tight fit. It's very easy to round off the hex hole in this cover since it's only aluminum. If you find you can't get the plug to budge - sometimes CAREFUL heating of the cover around the plug with a plumbers torch will help things separate. You could also try icing the plug to maximize the expansion difference between the plug and the cover....DO NOT OVERHEAT ! You might also try to break this plug loose with the bike warmed to operating temps before you tackle the job (if you do this, then make sure you allow the bike to completely cool down before adjusting the valves). Many have stated that these plugs can be very frustrating. I used penetrating oil on mine, and let them sit for about 30 minutes. They came off relatively easy.
  • Remove the valve adjusting covers from the cylinder head covers. These are the long oval cover with two 8mm bolts holding it in place, and a round cover with a large 24mm bolt-head on top. The long oval cover covers the two intake valves, and the round cover is over the one exhaust valve.
  • For the inspection and adjustment of the front cylinder head, rotate the flywheel counterclockwise to align the “FT” mark with the index notch on the left crankcase cover. It is easier to turn the engine over if you remove one or both sparkplugs (as for me, no way am I going to the hassle of removing the front-fore and the rear-aft sparkplugs). However, if it is about time to change the sparkplugs, now would be a very convenient time. Also, have a strong ligh to shine through the timing hole, and make sure you are stopping at the correct mark. In addition to “FT” and “RT” marks, there are other labeled marks on the flywheel that could potentially confuse you.
  • Make sure the piston is at TDC (Top Dead Center) on the compression stroke. The service manual assumes everybody already knows how to do this. I didn’t, but here’s how. When the piston is at TDC, both the intake and exhaust valves will be closed. There will be some free movement between each rocker arm and the valve in all three valves (both intake and exhaust). If there is not, then the piston is not at TDC. If at FT mark and not TDC, rotate flywheel CCW through one full turn (360 degs) to get to TDC. Confirm that there is now freeplay in all rocker arms indicating that the engine is correctly positioned.
  • Inspect the clearance of all three valves by inserting a feeler gauge between the adjusting screw and the valve. Intake valve inspection and adjustment requires two feeler gauges, one inserted between each adjusting screw and intake valve, because these valves share a common rocker arm. Proper clearance is indicated by a slight drag on the appropriate feeler gauge(s). Others have written that using the “slight drag” feeling can be overly dependent on prior experience or judgment, and can lead to leaving the clearances too loose. They recommend using a go – nogo technique, whereby if the proper size feeler gauge fits, but the next larger feeler gauge does not fit, then the valves are properly adjusted. I did this, and it was a good confirmation over the feel method. Also, I feel that you could get away with only having one set of gauges, and doing each intake valve separately.
  • The Valve Clearance specs are: Intake – 0.15mm, Exhaust – 0.20mm. The Service Manual does not list tolerances.
  • As mentioned above, a set of angled feeler gauges makes this job easier and much more accurate. You can't get the feeler gauge to fit exactly perpendicular to the gap with a standard straight gauge. The gauge gets bent and goes in on an angle. Normally this yields measurements a bit on the loose side. No bad thing. If you err at all....err on the "loose" side. The gauges look like this ( _/ ) in cross-section.
  • Adjust by loosening the lock nut and turning the adjusting screw until there is a slight drag on the feeler gauge, or until the next larger feeler gauge will not fit between the screw and the valve.
  • When the screw is adjusted to spec, hold the adjusting screw and tighten the lock nut. The service manual says to torque the locknut to 17 ft-lbs, but most won’t have a torque wrench that allows an open-ended wrench fitting (top access to the locknut is blocked by the need to hold the adjusting screw), so guesstimate as best you can.
  • Expect the gap to change when you tighten down the lock nut. So...., RECHECK the gap after you've tightened the lock nut. If it got smaller you may have to set the gap a bit on the loose side, then tighten the lock nut and have the clearance close up to spec. Not all the adjusters will do this since it depends on how the parts are machined. Be ready for a bit of inconsistency here. Just recheck after the lock nut is tight. You may find you have to "play" with a certain adjuster multiple times before the locked-down gap is just right. In all, I had to adjust four out of my six valve clearances. The front exhaust valve took me nearly an hour. I just could not keep the adjusting screw from moving when tightening the lock screw. Part of this was due to the awkward and limited access to the valve. The other valves took only 5-10 minutes each to adjust, working carefully. A good tip is to hold the adjusting screw as firmly as you can when tightening the lock nuts. The barest movement may put your clearance out of spec.
  • After adjusting all three valves on one cylinder, turn the engine CCW two full turns (720 degs), align the marks to TDC, and recheck the clearances. (Re)Adjust as necessary.
  • Rear cylinder valve inspection and adjustment is done in the same way as the front. Rotate the flywheel CCW to align the “RT” mark with the index notch on the left crankcase cover. Make sure the piston is at TDC on the compression stroke. Access to these valves is better than the front cylinder (especially the exhaust valve.)
  • Inspect and adjust the valve clearances.
  • Check the o-rings of the valve adjusting covers for damage and replace if necessary. Install the front and rear valve adjusting covers.
  • The manuals say to apply MoS2 paste grease (containing 40% or more moly) to the timing and crankcase hole caps. Install and tighten them. Others have indicated that other greases/pastes may work as well, such as antiseize grease. I used antiseize. Won’t have confirmation for how well that worked until the next valve job.

All in all, not an overly difficult procedure, just a lot of prep work to get access to the ports. The hardest part: definitely working on the front exhaust valve. Access is a bit of a trial here. Also, you have the engine minorly open here, so make sure you keep ports plugged or covered when not working on it, and keep dust, debris, etc. away from the bike if you don’t want uglies to make their way into the cylinders.

This is one of these jobs that I feel I can do better than the dealer. Sole reason is, the access can be limited, and the adjustment finicky, and I won't be (as) tempted to cut corners. Many shop mechanics, after having the adjusting screw move for the fifth time after tightening the nuts, will probably say F*** it, good enough, resulting in maybe having a valve or two marginally out of spec. When it’s your bike, you take the extra time to do it right.


Here's a set of my "homemade" feeler gauges.







Here's an example of the flywheel just past the FT mark.






Here's a picture of the front exhaust valve, showing the adjusting screw, lock nut, and a strange glob of white substance that I have no idea what it is or how it got there. I was able to rub most of it off with alcohol.

Palak screwed with this post 09-29-2010 at 11:52 PM Reason: Photos confound me.
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Old 09-30-2010, 06:05 AM   #2
BOBaloo22
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Palak, Thank you for taking the time to post this. I've been planning to check mine this winter and your notes will make my job easier.
Thanks again,
Bob
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Old 09-30-2010, 09:29 AM   #3
KilgoreTrout
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Valve adjustment

Palak thanks for posting this. I have a new to me 87 Alp with 27000klms on it. It runs smooth now so I not going to fudge with it yet but I am wondering how much mileage you have on your bike so I will have an idea as to when I should be doing this procedure.
Thanks again for posting this info.
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Old 09-30-2010, 10:22 PM   #4
Palak OP
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Quote:
Originally Posted by KilgoreTrout
Palak thanks for posting this. I have a new to me 87 Alp with 27000klms on it. It runs smooth now so I not going to fudge with it yet but I am wondering how much mileage you have on your bike so I will have an idea as to when I should be doing this procedure.
Thanks again for posting this info.
You have an '87 TA? Didn't realize Canada got them two years before the States. Or is it a Euro transplant?

Service manual says that the valve clearances should be checked every 8000 miles.
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Old 10-01-2010, 01:39 AM   #5
NordicRider
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Thanks for the detailed description...

...I have been holding off on checking valves because of the access difficulties you describe, but am now ready to give it a go!
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Old 10-02-2010, 09:56 PM   #6
KilgoreTrout
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Quote:
Originally Posted by Palak
You have an '87 TA? Didn't realize Canada got them two years before the States. Or is it a Euro transplant?

Service manual says that the valve clearances should be checked every 8000 miles.
Thanks for the info on the clearances, they were available here for two years 87,88 but very hard to find although not as rare as the Africa Twin which I do not believe was ever available here. Thanks again for the info.
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Old 10-04-2010, 10:18 PM   #7
Palak OP
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Quote:
Originally Posted by NordicRider
...I have been holding off on checking valves because of the access difficulties you describe, but am now ready to give it a go!
Don't let it put you off. It's a bit of a pain, but hurts a lot less than paying the dealer!

I think I've done nearly every procedure in the Maintenance section of the Service Manual (plus a bunch of other stuff.) Thus far, the biggest pain in the necks, for me, have been changing the foremost front cylinder spark plug (zero visibility and limited access) and pulling the carbs off the bike after who knows how long they had been last pulled.
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Old 06-09-2013, 11:22 AM   #8
jwb
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Hey, I am about to tackle this job on my '89 (50k miles, or maybe 150k; nobody knows, and none of the maintenance has ever been done, as far as I can tell). I have all the tools, even the 24mm, except I don't have an offset 10x12mm box wrench. Is the one in the toolkit good enough? Also, which end is it? 10mm or 12mm?

Thanks in advance,
jwb
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Old 06-15-2013, 09:20 AM   #9
jwb
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Quote:
Originally Posted by jwb View Post
Hey, I am about to tackle this job on my '89 (50k miles, or maybe 150k; nobody knows, and none of the maintenance has ever been done, as far as I can tell). I have all the tools, even the 24mm, except I don't have an offset 10x12mm box wrench. Is the one in the toolkit good enough? Also, which end is it? 10mm or 12mm?

Thanks in advance,
jwb
So anyway, it's the 10mm, and the offset wrench in the toolkit is adequate. On the other hand, you really need a low-profile 24mm to get the cover off the front cylinder exhaust valve adjuster without whanging the frame. Also "displace the right radiator" is full of lulz.

I think next time I need to do this I am going to fabricate a little wrench with 8 points for turning the adjusters. Turning them with plier, especially on the front cylinder with all the coolant hoses and the carbs in the way, is stupid.
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Old 06-15-2013, 10:58 AM   #10
MookieBlaylock
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Quote:
Originally Posted by Palak View Post

I think I've done nearly every procedure in the Maintenance section of the Service Manual (plus a bunch of other stuff.) .
I was intimidated but no longer, i will give this a go as i had planned to do plugs and jetting anyway. One question is when synching the carbs and plugging into the vacuume line that operates the petcock, does the bike still get fuel without this connected?
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Old 06-15-2013, 11:35 AM   #11
R_Rick
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Quote:
Originally Posted by MookieBlaylock View Post
I was intimidated but no longer, i will give this a go as i had planned to do plugs and jetting anyway. One question is when synching the carbs and plugging into the vacuume line that operates the petcock, does the bike still get fuel without this connected?
You will need to either rig up a fuel supply or make your petcock gravity flow and install a much longer fuel line .... the first doesn't require stripping the petcock apart.
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Old 06-15-2013, 01:43 PM   #12
Santa
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Motion pro makes a great tool for this.
I was able to locate just the one for the Honda. It works very well and is extremely simple to use.

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Old 06-17-2013, 04:22 PM   #13
MookieBlaylock
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Quote:
Originally Posted by Palak View Post
I had to adjust four out of my six valve clearances.
I ended up taking the cyl head covers off, but i got it measured and adjusted. They were all off by around .8, as in the .8 feeler wouldnt go in the intakes and .13 was stopped by the exhausts. Is that bad? I guess the indy mechanic who supposedly adjusted the valves a thousand miles ago ripped me off pretty good,oops.
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Old 06-18-2013, 04:33 AM   #14
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Quote:
Originally Posted by Santa View Post
Motion pro makes a great tool for this.
I was able to locate just the one for the Honda. It works very well and is extremely simple to use.

That's a great looking tool! I wish I'd seen it before I did mine. I used a little 4mm wrench from Craftsman (the one that only comes in a kit of tiny wrenches for which I have no use). It was very hard to hold with its tiny handle. I didn't have much confidence I was getting the clearances right so I checked them three times.
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Old 06-18-2013, 07:13 AM   #15
jwb
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Originally Posted by MookieBlaylock View Post
I ended up taking the cyl head covers off, but i got it measured and adjusted. They were all off by around .8, as in the .8 feeler wouldnt go in the intakes and .13 was stopped by the exhausts. Is that bad? I guess the indy mechanic who supposedly adjusted the valves a thousand miles ago ripped me off pretty good,oops.
Mine didn't have any clearance on any of the six valves, and that's with the engine cold. No wonder it didn't have any power.

Runs like a top now, though.
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