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Beginners Guide to Base Gasket Replacement

74K views 54 replies 10 participants last post by  B-dub 
#1 ·
I had to replace the base gasket on my TW recently, and have noticed that a few others are facing the same issue. So, I thought I would post up a guide to give you an idea of what's involved, and a reference if you decide to give it a shot.



So, here goes:



Service manuals here (for specifications and additional insight) Thanks Petrus!
 
#2 · (Edited)
Intro - If you have some experience working on your TW, just use the TW200 main manual. It provides enough detail you should be fine. If you have little or no experience you may want more detail, thus the purpose of this guide. The guide may look a little daunting, but none of this work is difficult. Like eating an elephant you just need to approach it one step at a time. I would encourage you to read through the instructions and maybe watch the videos to get an overview, then dive in. Read one set of instructions, then do that particular task and move on to the next and repeat.



If you're concerned you won't be able to remember where everything goes take pictures with your digital camera, or better yet get an accomplice to do so.



I've done the base gasket twice, now. The second time was because I didn't verify I had the correct base gasket the first time. Yeah, I know, kind of dumb of me. The parts person assured me the newer part number would supersede the older one. It didn't. You can avoid my mistake by simply ordering parts for a 2010 TW.



The first time I did the guide I took pictures and wrote up the description. I described how to retain cam timing. In revising the guide I filmed video, and demonstrated how to restore cam timing. So this aspect of the video description and written instructions is different.



After viewing the videos it has caused me some anguish to recognize that I made some mistakes. Each time I saw a mistake, I went to the written guide and revised it to reflect the better way. So, you'll see some differences between the video and written instructions. You can choose which way to go with cam timing, otherwise I would follow the written guide. I just included the video because it's helpful for some people to see it done. I wish I could do it again to clean up the videos, but it's impractical for me to do so, and I think it's beneficial for you to see the mistakes I made so you can avoid them. So, recognize the videos aren't completely accurate, the written guide is much better.

 
#3 · (Edited)
Obtain the parts - At the minimum you will need a base gasket and head gasket. Some base gaskets have been defective from the factory. The new improved version is # 5VC-11351-10-00 (part # supplied by Qwerty). Be sure to get this one or you may be doing the job again. Just tell the parts person you want a base gasket for a 2010 TW. The manual says you shouldn't reuse the piston pin circlip. Since the associated o rings are low cost it would be wise to replace them also. This engine can build a lot of heat which degrades o-rings over time. I recommend rockymountainatvmc.com. They normally have parts in stock, ship quickly, and parts are priced competitively. They also have a good online parts catalog. You can look at the exploded views to see what you need, then go ahead and place the order or go to your local dealer with a little better understanding of what you need to get.



Thanks to bogey 72 and others for providing guidance and encouragement, and to jwashkau for compiling a list of parts, including diagrams that I've included here for your reference.



jwashkau said:
UPDATE for anyone else wanting to do the same thing and not knowing exactly what to buy: (I hope this is all correct, someone please let me know if it is not!)



My parts list (that I had my local dealer pricematch to partzilla)



5VC-11351-10-00, GASKET, CYLINDER (Qty. 1) @ $8.96 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-5VC-11351-10-00.html) FYI: My TW is a 2007, but I am using the 2010+ gasket as others have noted, NOT the 5VC-11351-01-00 which the dealer recommends



1NU-11181-00-00, GASKET, CYLINDER HEAD (Qty. 1) @ $18.73 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-1NU-11181-00-00.html)



93210-72529-00, O-RING (Qty. 1) @ $3.23 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-93210-72529-00.html)



93210-13361-00, O-RING (Qty.1) @ $1.55 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-93210-13361-00.html)



90430-14131-00, GASKET (Qty. 1) @ $2.19 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-90430-14131-00.html)



93450-17044-00, CIRCLIP (Qty. 2) @ $1.53 -- (Pricematch link: http://www.partzilla.com/parts/detail/yamaha/YP-93450-17044-00.html)



Head Gasket Parts:





Base Gasket Parts:





Piston Circlips:

 
#4 · (Edited)
Clean everything - Begin by thoroughly cleaning your motorcycle. If you've ridden it very long with the leak it's collected quite a bit of oily grit. You can learn from my mistake. After washing my TW it looked clean, but when I started removing parts I realized it was still quite dirty. Be sure to clean your bike thoroughly so as to avoid getting dirt in the engine. On this page there is some insight from Lizrdbrth and Qwerty how to get your engine spotlessly clean.
 
#5 · (Edited)




Gain Access



Remove the Seat - There are two bolts easily seen by looking under the rear of the seat, above the rear tire. Remove them with a 1/4" drive ratchet and 10mm socket or equivalent. Sorry for the mess!!!
 
#7 · (Edited)


Remove the Gas Tank - Remove the bolt at the back of the tank. Turn the petcock to off. Get something to plug the fuel line with in case your petcock doesn't seal completely, then remove the line from the carburetor and plug it. Pull up on the back of the tank and to the rear to remove the tank.
 
#8 ·


Remove the Exhaust head pipe - Remove the two bolts securing the head pipe to the head, and loosen the clamp securing the head pipe to the muffler. Then just pull foward to remove the head pipe.
 
#9 · (Edited)


Remove the Carburetor - On the left side of the bike loosen the two clamps that secure the carburetor to the boots. Rotate the top of the carburetor toward you. This will allow you room to remove the two bolts holding the intake boot to the head. Pivot the front of the carburetor away from you and it will slip out of the rear boot. Position the carburetor out of the way and secure it to the frame. I didn't find it necessary to remove the cables.



Remove the spark plug -
 
#12 · (Edited)
Verify Cam Timing



Important- Cam timing ensures the valves open at the appropriate time. Getting the cam retimed correctly upon reassembly is probably the most critical part of this whole operation. So make sure the engine is in time before you disassemble it, and take pictures and/or make notes/drawings to make sure you understand where the various marks should be.



Rotate the engine so it is on the compression stroke - Put a finger over the spark plug hole then bump the engine over with the kick starter until you feel the air pressure from the rising piston push your finger off the hole. If you don't have a kick starter you can turn it over with a socket on the crankshaft bolt. If you turn the engine with a socket on the crankshaft bolt be sure to turn the engine counterclockwise when looking at the engine from the left side. It's fairly easy to position yourself on the left side of the bike looking back, reach your left hand around the front of the engine, put your thumb on the spark plug hole, and rotate the socket with your right hand.
 
#13 ·


Rotate the engine until the timing marks line up - With a socket on the flywheel bolt (middle of left crankcase cover) turn the engine until the mark on the timing sprocket lines up with the pointer at the top of the timing sprocket opening. It should be fairly close from the previous step, if not you may want to repeat it.
 
#14 · (Edited)


Verify the timing marks line up on the flywheel. Look inside the small hole near the top of the left crankcase cover and check to see if the flywheel timing marks line up. By rotating the flywheel slightly one way or the other you should see there are actually three marks. With the marks on the timing sprocket lined up you should see that the flywheel mark furthest to the right lines up with the pointer at the top of the hole. If you look more closely (may need a flashlight) you'll see there is a cross at the top of the mark to form a T, for Top Dead Center. In the picture I'm not quite lined up. When the marks are lined up, put the transmission in gear to prevent movement of the crankshaft.



Engine Disassembly







Remove the triangular brace that attaches the head of the engine to the frame. You'lll need to use a 14mm wrench to hold the nut on the back side of the bottom bolt.
 
#16 ·


Remove tension on the timing chain - At the left rear of the cylinder there is a tapered piece extending out from the cylinder. This is where you adjust the tension on the timing chain. Remove the cover, then loosen the locknut.
 
#17 ·


Now, turn the whole assembly counter clockwise until it is removed. Take care not to lose any of the pieces, and pay attention to the orientation of the pieces. Page 144 of the manual shows the parts and their orientation if you need to review. On '01 and newer bikes the tensioner is different, but will still need to be removed to release tension on the timing chain.
 
#18 · (Edited)
Remove timing sprocket - There are two lines of thinking in removing the timing sprocket. One is to keep the chain on the sprockets and keep tension on the chain so when the engine is reassembled the sprocket will slip back on the cam and still be in time. The other line of thinking is to not worry about keeping it in time, and just retime the cam when reassembling the engine. I think if you have a helper it's worth trying to retain the timing. If you're doing it by yourself it's probably just as easy to retime the cam when you reassemble. I'll describe both ways:
 
#19 · (Edited)


Retaining the timing - For this you will need a zip tie and a light bungee a couple of feet long. With everything in time put the zip tie around the chain and sprocket near the timing mark. Cinch it down to hold the chain on the sprocket. This idea was contributed by a member of the forum, sorry I don't remember who. Remove the bolt through the center of the timing sprocket. Keeping tension on the timing chain slip the sprocket off the cam.
 
#20 · (Edited)


Hook one end of the bungee through a hole in the sprocket, then loop the bungee up over the handlebars and hook on something to keep tension on the chain. When removing the head and cylinder you'll have to unhook the bungee and keep tension on the chain until the part is removed, then hook up the bungee again to hold tension on the chain. The tension is necessary to ensure the chain doesn't change position on the crank sprocket.
 
#21 · (Edited)
Retiming the cam - If you're going to retime the cam upon reassembly you can forget the zip tie and bungee, but you will need a piece of safety wire (thin, durable wire) to attach to the chain. The wire needs to be a couple of feet long so if the chain falls into the crankcase it can be easily retrieved. Secure the wire to the chain wherever convenient. Remove the sprocket and lay the chain aside. Wrap the end of the wire around something to keep it from going inside the engine.
 
#22 · (Edited)


Remove head bolts - Turn each head bolt (including the allen head fasteners) 1/8 turn counterclockwise. Repeat 1/8 of a turn at a time until the bolts are loose. Work in a criss cross pattern to remove the pressure evenly. On page 142 of the TW200 main manual it shows the head bolt tightening sequence. Just use the sequence in reverse to loosen and remove the head bolts.
 
#23 · (Edited)


Remove the head - With all the bolts removed you should just be able to pick up on the head and remove it. You will have to remove the bungee and keep tension on the timing chain while you do so. You may have to wiggle the head around to clear the frame and timing chain guides, but it shouldn't be too difficult. With the head out of the way hook the bungee back up to the timing sprocket. Be sure the head locating dowel pins stay in place on the cylinder. If not, put them back where they belong.
 
#25 · (Edited)




Remove piston and cylinder - Unless your TW has a lot of miles you shouldn't have to replace the piston rings. My TW has well over 9,000 miles and the compression is still near the top of specifications, and the cylinder looked great. So, we want to remove the piston and cylinder together as a unit, keeping the rings in the cylinder if at all possible. You will need a 10mm deep socket or similar to push the piston pin out with, a small screwdriver to remove the piston pin circlip, and a helper if one is available.
 
#26 · (Edited)


With the tools at hand unhook the bungee and while keeping tension on the timing chain slowly and carefully move the cylinder up the piston until the piston pin is exposed. Be aware the piston rings are very close to the top of the hole for the piston pin, so be careful you don't go too far. It's not a bad idea to put rags in the hole as you pull the cylinder up. Once the piston pin is exposed have your helper hold the piston and cylinder while you remove the piston pin. Use the small screwdriver to remove the circlip. There is a small recess in the pin area of the piston to allow you to access the clip. Just pry it out of the groove and remove it. Be very careful the clip doesn't fall into the engine or go zinging off into space. With the clip removed use the deep socket to push the pin out of the piston and connecting rod. It shouldn't be difficult to push out. With the TW on the side stand I worked on the right side of the bike to remove the clip and pin while my brother (thanks Mike!) held the piston and cylinder from the left side. With the pin out remove the cylinder.
 
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