Honda Twins banner
1 - 14 of 14 Posts

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #1 ·
New member, been watching this forum for about a year or so now and am surprised as always how the online forum communities pool knowledge and resources. Currently have my 81 cm200 in an unassembled state due to a non fireing/stalling/low power issue that left me stranded on the side of the road 1200 miles from “home”. Bike has around 7k miles and apart from some nuts and bolts, fuel petcock, some fuel line, the taillight lense, a flasher relay, battery and a brake handle it is original in its entirety(also minus gaskets... why don’t they make quality like this anymore??? Sigh) Had an after market carb on it that did a so so job but the sale to me came with the original witch just needed a little sea foam and some gaskets. It has an odd spot around 1/4 to 1/3 throttle that I’ll have to work on.
I’ve just finished restoring normalcy to the head and pistons (wish I had before pictures to show you how much carbon and crap I’ve greases off these pieces),

0E7F8A56-0AA1-4546-B954-22EB09A9FE18.jpeg
1290E2E0-6251-40FA-A3E4-94136754D218.jpeg



need to lap valves better
A6928CA4-99CB-4127-BABA-66F2D2EC8BDD.jpeg



and then it’s on to reassembly. Have some new piston rings coming in, new crank seal, output seal, kick start seal and shifter seals coming in as well as other odds and end on deck to order.

Have one buggered bolt hole in the case for the head bolt to deal with.
2479F0DB-7999-4F49-BB43-57436CF02377.jpeg

Is that “plug” looking circle a place to add a tach?? Anyone familiar with

hone the jugs,
022605A9-5732-4651-96F2-5E2C26E39B53.jpeg

find and add on center stand (luxury I know) and then I do believe I’m back to putting it all together. The bearings all feel immaculate.
Never had a clutch apart in my life but the friction looks and feel adequate and the steels could use some scuffing
55FE2811-EE04-4E31-B98A-6414BF52FAE1.jpeg

“cleaned” with brake clean and I’ll be taking some 120 grit to the steels (open to suggestions on grit as I’m shooting from the hip. I notice that one side of the steels are somewhat rounded and smooth around the edges and the other side has somewhat of a bur or edge so I plan on reinstalling them facing the same direction.

Got the engine out before the snow mostly
B192028F-8A3B-4838-9400-0AD1EC39FCCA.jpeg


Crank seems to be immaculate shape, I noticed the piston arms seem to have some hot spot coloring which I assume is somewhat normal
8C78F665-2B8D-402D-BA26-DFB9D5E82009.jpeg

The cam chain guides have these groves running in them where the chain follows and at first it concerned me until I looked at some pictures of new guides and it seems to be manufactured that way??

also have that pesky carb heat shield issue (being broken that is)
3A4AE563-A293-4802-AD1C-02B3ACAECB25.jpeg


I saw one gentleman used a mud flap cut out to replace it and thought that was brilliant. If I have a spare flap around I’ll do the same but adhere it to the remaining shield as opposed to grinding down the thickness of the flap. But then I thought I’d fabricate one out of wood because... just because (tell me it’s a bad idea and I should abandon it)
4C27F909-70D6-4A37-B66A-EDEB5DC93CD8.jpeg

even if I do go a different route this will remain my “avatar” in memorium to the outlandish idea.
My nephew just polished my tank foooo free!!! Didnt even ask! (At pic limit or I would post)

will be installing 16 tooth front sprocket to increase top speed. It seem if I was cruising in 4th I could only reach about 55~60 even though there was plenty of throttle... thoughts?

parts acquired so far
  • gasket git
  • carb rebuild kit
  • stainless Allen bolt replacement kit
  • fuel petcock
  • brake lever (twice...)
Parts in transit
  • piston rings
  • crank seal
Parts to order
  • shifter seal
  • kick start seal
  • output shaft seal
  • 16t front sprockey
Parts to find still
  • 6mmx134 headbolt x2
  • intake manifold O rings (26x 2.7 I do believe)
  • centerstand
  • front forks, triple tree, steering knuckle if possible,

I think that’s all

howdy again

also located in western pa,verrrrry novice wrencher, intimidated working on vehicles that lose 50% of their stability when you remove a wheel
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #2 ·
Here is the polished tank
314154

Got some rings in her but still works. I’ve come to find the hard way,having to walk the bike a few miles to refill, that fuel doesn’t seem to make its way to the reserve level position adequately. It is either that or I have too much fuel line “looped” so to speak from the petcock to the carb. The line I used to replace with is rather stiff and doesn’t bend the in the most efficient way for direct delivery so something I need to play around with
 

·
Registered
'75 CB500T
Joined
·
20 Posts
Looks like a fun project bike.

Not sure if anybody on here has made an intake manifold insulator out of wood before, but I suppose it might work as long as it won't start to burn up. As for clutch metal disks, I don't think you need to sand them down. Any sanding necessary will probably happen while in use.

Looking at the picture of the bottom cylinder, do you have a rust spot? If the spot I think in the picture is indeed a gouge due to rust, you probably want to fix that before you begin engine assembly.
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #4 ·
Thanks!

Looking at the picture of the bottom cylinder, do you have a rust spot? If the spot I think in the picture is indeed a gouge due to rust, you probably want to fix that before you begin engine assembly.
]

I had to scour the pictures for about 5 minutes trying to see what you saw then decided to look at the real thing hahaha. No rust no gouge, musta been the light but am honing this week. If the you are referring to to the divot in the cylinder head gasket mating area, been working on it but am afraid of removing to much material to get to it. Sand it down polish it up?
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #5 ·
I’m now understanding that when soon (probably tomorrow) my piston rings will arrive and shortly after some seals and I will have to place the cylinder body onto the crank. I’ve read about using a mythical holding device and/or towels to brace the pistons so they don’t bang around on the case when lining them up. Any suggestions out there as to a method?
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #6 ·
314174

314173

The cylinders need bored and over sized rings and pistons installed but it may be outside my buying power currently. There are some vertices marks that I can only attribute to starting the engine after sitting for a while and not enough lubrication on the cylinder walls. I have learned to crank the engine with the kill switch engaged a few seconds before starting the engine after a few days of sitting. Rookie mistake. Also, shall I be posting updates here or start a “build” thread in the applro
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #7 ·
Valves lapped and back into place. News seals from a 4into1 gasket kit. Make shift spring compression tool perched on the valve cover; made from washers. It was tedious and took longer than it should have. The spring tool I had was too large to compress without jacking the spring to the side or slipping off. The hold downs were a pain to shimmy and shake into place. Starting to reassemble crank case. Wd40, MMO or motor oil to prelude before reassembly?
314175
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #8 ·
New piston rings shipped today
314182


new drive seal as well
314183


would have had the case back together today but forgot I am awaiting other seals before reassembly.

I was looking in my clymers And Haynesand it appears the 4(200) and 5(250) speed share most of the same transmission components and an added gear may be a possibility. Will be researching if part#s are a match. It seems that it would only require two gears, one for the main and one for the lay shaft, a shift drum and possibly a selector head for the drum to turn this into a five speed. Will let you know what I find out and if anyone has any input on the subject please feel free to add it
314184
314185

Won’t be able to get much done except cleaning till Monday or Tuesday.
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #9 ·
It appears that components on the output shaft share many a similar characteristics. Some odd dimensions listed on common shared pieces like thrust washer and collars bushing diameters but for the most part it all looks the same (output shaft so far, will be looking at the main shaft next). Major difference include 2nd gear on the 5 speed being integral to the shaft and with lug tooth notchs where as the 4 speed the gear is removable and without the notches. 5th on the output looks to just take up the mostly empty space between 4the and 2nd on the 4 speed. Also the assembly of the first gear bushing appears to be opposite of the 4 speed where the 4 speed has the bushing inserted from the right side of the crank case and the 5 speed it is inserted from the left. Finding dimensions of the pieces I don’t have is a challenge as I’m relying only on the sales websites which excludes most cept for tooth count and front sprocket dimensions on aftermarket parts. Also noted is that some of the center three digit codes don’t match up to any model from the numbers lists I gathered from this forum. No parts today so just working on the carb heat shield and soaking friction plates
314201
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #10 ·
News seals today
314311


and theheat shield is in spec
314312


reassembling
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #11 ·
Almost back together

314315


I had used a dowel and wood to secure the crank when removing the rotor crank bolt and opposite crank nut but had the luxury have a wrench on both when reinstalling. The cam sprocket is just set up like that so I can rotate the engine without losing the chain falling into the case. I had to destroy most of the case case cover screws to get them out and replaced most with hex sockets for easier removal.
314316

Clutch back together after soaking. Took me a while to find a Jaso ma rated oil but I did at a reasonable price. I played with that clutch for a solid hour or so as it was the first one I had apart and it is a pretty ingenious design. While putting the case back together I noticed some binding in the transmission. Once inspected it appears that the kick starter, being only retained by 2nd gear on the output shaft and its hole in the left side of the case, binds to the transmission. Slight pressure towards the rear of the engine and then mocking on the right side cover reassured me it was just needing to be back together and the binding had stopped. Was about to have the jugs back on the pistons and then found I had two extra dowels and had to stop to figure out where they went and it appears they just go in the cam holders on top so it should be almost back together tonight or tomorrow. New 16 t front sprocket installed. Note for anyone else possibly doing this in the future that doesn’t know; at minimum loosen the rotor bolt and crank nut while still in the frame as this little engine becomes a bear to wrestle around due to its small size on the work bench trying to lock the crank while breaking those two loose.
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #12 ·
head on
314324


cam shaft in. Took a lot of time to get the sprocket lined up for proper timing. Although I appreciate the design I am sure there is a better way that would facilitate easier timing. It seemed like there was one way and one way only in which that gear could meet the links of the chain and in the tight confines it was a burden to rotate gear to have it sit perfectly but it is done now.

314325
314326


carriers and arms on
314327


torqued. I didn’t notice this in disassemble but the two rear head bolts are of differing length and the cast head receiving holes for those Bolts are offset in height which corresponds to the receiving threads in the crank case being differing heights also... weird...

then the intake manifold and sketchy custom heat shield. Lookin at the carb next.
1BEA27B4-D823-45FC-BABD-BAA9A5DF594F.jpeg

314328
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #13 ·
Finally finished and back together. Kiki pro carb back in place instead of the factory, has some minor intermittent sticking but seems to level out pretty quick. Adjusted idle to a shy under 1100 rpm and took it for a few spins locally. Currently illegal but soon rectified. May be looking into an after market carb, center stand and front forks as well lighting hardware in the future. This bike is a tank. Would still be interested in trying the 5 speed mod once I secure the funds as the top speed on this bike (scooter) is lacking and I do a fair amount of highway driving. Haven’t yet had it out on the highway to see a difference in the front sprocket change; will report findings in the future.

315882


may not be the prettiest or shiniest but she goes pretty darn well.

Completed
 

·
Registered
81 cm200t Twinstar minor rebuild
Joined
·
16 Posts
Discussion Starter · #14 ·
and JUST when I thought I was done for a while lo and behold an 82 5 speed transmission shift drum forks and hardware comes on eBay all for less than a Franklin including shipping.

316061


Third is pretty worn on the input

316062


and the output shafts

316063


will be trying to source these new or second hand if necessary (82 cm 250 if anyone is interested in adding a gear to their 200).

will be cleaning all with marvel and wire brush. Won’t be tearing it back apart until the weather forbids me from riding (which will probably be close to December cause I’m an idiot).
Also plan to bore out +.5 and new pistons to get the tiniest little extra umph out of her. The larger front sprocket made my mid range feel a little boosted and made higher speed cruising easier to reach though not completely the gains I was looking for. 65 uphill is still impossible but on a flat I can push 70~73 now.
Also picked up the center stand, spring and C shaped bracket off an 83 cm250.

316065


its just a hair wide to fit on the brake pedal spindle so some meat was ground off. Not enough to accommodate though. Will be having the inside welded so I can chop more off and hopefully have a center stand which for some odd reason I so much desire.

316066


If anyone has any knowledge about the hows and the wheres of how this was originally attached to the 82 cm250 I would greatly appreciate the insight as I am at a loss on exactly how to rig up the ‘C’ shaped plate and where exactly the spring attaches to the stand it self.

will update on the stand within the week, the transmission and oversized pistons will have to wait for the weather to change. Hope you enjoy following the progress of this scooter; it’s been somewhat entertaining tearing this thing apart and putting her back together. Incredibly simple yet complex piece of engineering and fun to ride too.
 

Attachments

1 - 14 of 14 Posts
Top