Author Topic: Restoring 1969 200 MK II HS  (Read 13571 times)

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Offline slawsonb

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Re: Restoring 1969 200 MK II HS
« Reply #20 on: January 01, 2017, 08:42:51 PM »
My guess is that the E817 is the case number stamped on both matching case halves. Is there a similar number on the upper case (or lower since I'm having trouble figuring out which case is pictured). These numbers are to designate cases that were machined simultaneously to assure bore alignment for the shafts and bearing of the crank and transmission.
Maybe Karl or Paul can confirm my hunch. And while your at it guys, where is the engine number stamped on a 200/175? On the rear mount flange on the upper case like a 350?
Probably not advisable to hone the cylinders unless they have minimal damage. A pic or two of the bores would be helpful.
...bert

mqtsteve

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Re: Restoring 1969 200 MK II HS
« Reply #21 on: January 02, 2017, 07:32:33 AM »
Hey rdwilroy,
This is a section from the clymer manual for 50cc-175cc bikes, page 27.  It discusses piston clearance.

On cast iron cylinders, the cylinder can be honed to adjust clearance.
On aluminum cylinders, the piston must be polished to adjust clearance.


Hope this is helpful, Steve
Here's the link.
http://bridgestonemotorcycleparts.com/PDF/BS175ServiceManual.pdf
« Last Edit: January 03, 2017, 06:54:13 AM by mqtsteve »

Offline OldSwartout

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Re: Restoring 1969 200 MK II HS
« Reply #22 on: January 02, 2017, 08:59:22 AM »

Maybe Karl or Paul can confirm my hunch. And while your at it guys, where is the engine number stamped on a 200/175? On the rear mount flange on the upper case like a 350?
The cases did have the machining matching numbers stamped on the case halves, but the engine number was stamped on the clutch cover on a pad  near the kickstarter boss.  Pretty dumb idea IMHO, as damage to that part could cause someone to change it out with another used one with a different number.  My 175 HS was originally from Wisconsin, it is titled using the engine number on the clutch cover. Silly.

Which end of the cylinders did you try to put the pistons into?  Sometimes the skirt portion of the cylinders gets bent slightly, especially if they are difficult to remove and require some prying.  It won't hurt to run a hone through them to remove any burrs, carbon, rough spots, etc.  The chrome is just a couple thousandths thick, so you can't do much, although going through all the chrome would take a lot of time and effort. It cuts very slowly with standard hone.  Run a hone through them, then try the pistons from the top.  Of course, if you have inside mics or a dial bore gauge, just check that way to find the tight spots.
« Last Edit: January 02, 2017, 09:08:27 AM by OldSwartout »
Karl Swartout
Mooresville, IN
BS175 Roadracer. BS200RS, BS350 GTR

Offline bsracer

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Re: Restoring 1969 200 MK II HS
« Reply #23 on: January 02, 2017, 11:44:38 AM »
My guess is that the E817 is the case number stamped on both matching case halves. Is there a similar number on the upper case (or lower since I'm having trouble figuring out which case is pictured). These numbers are to designate cases that were machined simultaneously to assure bore alignment for the shafts and bearing of the crank and transmission.
Maybe Karl or Paul can confirm my hunch. And while your at it guys, where is the engine number stamped on a 200/175? On the rear mount flange on the upper case like a 350?
Probably not advisable to hone the cylinders unless they have minimal damage. A pic or two of the bores would be helpful.
...bert

Looks like the lower case half Bert. The upper and lower cases are stamped with matching numbers on the left rear of the motor. Like Karl said, the engine number is stamped on the clutch cover. For some reason I've noticed that once I've taken apart a 200 the pistons are tight when placed back into the cylinders. I had two sets of 200 cylinders that the bore looked great but the pistons were tight. I don't think I was the initial person who removed the cylinders. What Karl says makes sense about the skirt. I can only guess that wrapping on the cylinder to free it may cause some distortion on the skirt. The one of yours is pretty hammered by the exhaust port and sealing surface. It might not be usable.

Also note that the 175 and 200 heads are slightly different. The 200 head is opened up to the larger diameter of the 200 piston. Don't know if you can run 175 heads on a 200. Again I wouldn't believe it but 175 cylinders will fit on a 200. 200 cylinders will not fit on a 175. The spigot or skirt diameter is larger on the 200 than a 175.

paul

rdwilroy

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Re: Restoring 1969 200 MK II HS
« Reply #24 on: January 02, 2017, 12:06:43 PM »
So the engine# on the clutch cover confirms it's a 200. Evidently someone put 175 cylinders on it.

I ran a hone through both cylinders. Piston drops through the left cylinder now but it has missing chrome at the top. Piston still want go through the right cylinder. Gets hung just above the cylinder skirt. Although the chrome feels smooth, you can see light scoring their on one side and discoloration in the chrome. I might could do some more honing to get it to get through that spot but probably should get it recoated. Any advice?

Thanks for your help!

rdwilroy

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Re: Restoring 1969 200 MK II HS
« Reply #25 on: January 02, 2017, 12:17:57 PM »
Pictures

rdwilroy

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Re: Restoring 1969 200 MK II HS
« Reply #26 on: January 02, 2017, 12:23:21 PM »
Right cylinder skirt

Offline bsracer

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Re: Restoring 1969 200 MK II HS
« Reply #27 on: January 02, 2017, 04:11:01 PM »
Once the chrome starts coming off they are not usable. It pretty much looks like you would have to replate those cylinders. Millennium technologies can plate and probably fix the damaged one. I think they run in the $200-220 per cylinder for plating. They have a minimum fee to repair,  I think around $275. You may want to see if Richard has 200 cylinders or find some that are used and have them plated.

paul

Offline BRT-GTR

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Re: Restoring 1969 200 MK II HS
« Reply #28 on: January 02, 2017, 06:38:18 PM »
          If the bottom picture shows the discoloured area of chrome, it may be that the hammering to the cylinder base on the exhaust side has distorted the cylinder. I agree, have them bored true and replated. It should be possible to weld repair the hammered areas.                    Brian.
« Last Edit: January 02, 2017, 07:39:47 PM by BRT-GTR »
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Offline moonpup

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Re: Restoring 1969 200 MK II HS
« Reply #29 on: January 02, 2017, 06:45:35 PM »
There's a set of used cylinders currently on eBay. Can't tell if the scoring is bad enough to disregard them or not....

http://www.ebay.com/itm/Bridgestone-dual-twin-200-Mach-II-m2-1971-Cylinders-Pistons-L-R-53-08mm-D21-/322124893550?hash=item4b0023cd6e:g:zZ0AAOSwn8FXSNTY&vxp=mtr
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Offline bsracer

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Re: Restoring 1969 200 MK II HS
« Reply #30 on: January 02, 2017, 09:03:53 PM »
There's a set of used cylinders currently on eBay. Can't tell if the scoring is bad enough to disregard them or not....

http://www.ebay.com/itm/Bridgestone-dual-twin-200-Mach-II-m2-1971-Cylinders-Pistons-L-R-53-08mm-D21-/322124893550?hash=item4b0023cd6e:g:zZ0AAOSwn8FXSNTY&vxp=mtr

Might be a better starting point if the minimum to repair is $275 from Millennium Technologies.   

paul

Offline slawsonb

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Re: Restoring 1969 200 MK II HS
« Reply #31 on: January 03, 2017, 10:24:19 AM »
I had a couple of 350 cylinders repaired by Millennium and they quoted the repairs individually. I think the repairs and machining I asked them to do were less than $275 for both cylinders, so it might be worth sending them pics and getting a price. They were very helpful and easy to work with.
...bert

rdwilroy

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Re: Restoring 1969 200 MK II HS
« Reply #32 on: January 29, 2017, 06:11:45 PM »
Got my cylinders back from millennium. Not sure if I. I'm satisfied with them. I pointed out that one had been beaten up pretty good at the base and exhaust by someone before me, I'm guessing trying to get it unstuck. I told millennium that and sent pics before I sent the cylinders. They quoted $210 for one cylinder with no weld repairs and $275 for the other with repairs. Got them back and damage to the base and exhaust is still there. Called and was told one cylinder had a flat spot and that was the repaired one for $275. They didn't fix the base because they were concerned about possible porosity that could require machining cut that would change stack up dimension or could make the cylinder unrepairable. They should have at least called me about it but didn't. They said there is still good base gasket surface area to seal with. I'm not sure if I should send it back and make them fix it or not.

Offline old smokey

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Re: Restoring 1969 200 MK II HS
« Reply #33 on: January 29, 2017, 08:37:26 PM »
Sorry to hear that. It does seem like a phone call before working on it would have been best.  :o
Are they able to say that both the base and exhaust areas are definitely functional as returned?
I had 350 cylinders repaired and plated by them, but that was confined to port repairs.
'67 350 GTR undergoing repairs with a '75 Yamaha TX500 front end

Offline BRT-GTR

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Re: Restoring 1969 200 MK II HS
« Reply #34 on: January 30, 2017, 06:58:56 AM »
G I'm not sure if I should send it back and make them fix it or not.

    So frustrating when a company does this to you, can feel the pain.
    I think it would hinge on, how you worded the original repair (written?) request. If they clearly didn't do what they quoted for, then you may have a case but they do have expert knowledge on their side..(I'm no lawyer)

    If they are unwilling/ unable to put things right, carefully take any burrs off the base flange before refitting, shouldn't be too noticeable on the bike. Whether you could get the exhaust flange welded without distorting the replated cylinder, I don't know.   Again, providing you can make a seal, not too noticeable on the bike, just irritating when you spend all this money and it's not perfect.
« Last Edit: January 30, 2017, 06:39:10 PM by BRT-GTR »
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Offline OldSwartout

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Re: Restoring 1969 200 MK II HS
« Reply #35 on: January 30, 2017, 09:44:24 AM »
I'd suggest filing the base to remove any raised burrs, then if needed to get sufficient sealing surface, use JB Weld to fill in, then file smooth again.  Millenium was probably correct to avoid welding on that area due to the possibility of creating porosity.  Even just filing off any raised burrs, then using a small dab of RTV to fill in indentations when assembling should work.
Karl Swartout
Mooresville, IN
BS175 Roadracer. BS200RS, BS350 GTR

Offline Jeff Bar

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Re: Restoring 1969 200 MK II HS
« Reply #36 on: January 30, 2017, 10:08:14 AM »
these issues and high price is why i said before just buy new cylinders jeff bar
« Last Edit: January 30, 2017, 10:12:52 AM by Jeff Bar »

Offline dcr

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Re: Restoring 1969 200 MK II HS
« Reply #37 on: January 30, 2017, 10:35:51 AM »
Jeff - out of curiosity, how much are new cylinders compared to getting a set re-plated? I paid $400 for plating of an undamaged set. And for the money, the new plating is so much better than the old chrome process.

If a new set of cylinders is available for under $400, then you might have something.

Dan
1966 175 DT and 1968 350 GTR

rdwilroy

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Re: Restoring 1969 200 MK II HS
« Reply #38 on: January 30, 2017, 11:43:16 AM »
I had previously had Richard quote me new cylinders for $529. Based on that, I decided to go with millennium, with a better coating. Probably should have gone with the new jugs.

Millennium has offered to take the cylinder back and repair it under warranty. The down side would be if I end up with them making a machine cut on the base that changes the squash dimension or porosity shows up making it unusable. I'M thinking  I'll just go with the JB Weld and put it together.

Offline dcr

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Re: Restoring 1969 200 MK II HS
« Reply #39 on: January 30, 2017, 12:17:04 PM »
I had previously had Richard quote me new cylinders for $529. Based on that, I decided to go with millennium, with a better coating. Probably should have gone with the new jugs.

Millennium has offered to take the cylinder back and repair it under warranty. The down side would be if I end up with them making a machine cut on the base that changes the squash dimension or porosity shows up making it unusable. I'M thinking  I'll just go with the JB Weld and put it together.

Any chance of finding a used one that needs replating and having them plate it instead of using the damaged one?

Dan
1966 175 DT and 1968 350 GTR

 


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