Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 175 & 200 Talk => Topic started by: BeerGeek on June 10, 2015, 10:07:26 PM

Title: 1969 HS Motor Rebuild
Post by: BeerGeek on June 10, 2015, 10:07:26 PM
 OK.  I finally removed and tore down my 175 HS motor tonight.  I have a buddy with more experience t this than I do so he helped.

I need a seal kit (the right side was smoking/spitting oil) so i'll need the gasket kit and seals.

And the kickstarter wasn't always turning over the motor.  Looks like it may be the dog/pawl? 

Any other suggestions on what to replace now that I have it like this?

https://scontent.xx.fbcdn.net/hphotos-xtf1/v/t1.0-9/11252859_10206779562037067_7891139468099746089_n.jpg?oh=31f3c9ad6403d10e182fc1f5c7e5fff3&oe=55FC4299

Thanks!
Title: Re: 1969 HS Motor Rebuild
Post by: dcr on June 11, 2015, 09:33:56 AM
This link will take you to a current Ebay item that Richard Clark (provider of this site) has for sale - Its a full 175 engine gasket set. He also has the original seals you will need. Email him with the part numbers you need.

http://www.ebay.com/itm/Bridgestone-175-DT-HS-Full-engine-Gasket-set-NEW-/141665489201?hash=item20fbebd131&vxp=mtr (http://www.ebay.com/itm/Bridgestone-175-DT-HS-Full-engine-Gasket-set-NEW-/141665489201?hash=item20fbebd131&vxp=mtr)

It doesn't appear from your pictures that you split the motor cases, but since you have the side covers off, you should remove the rotary valve covers and replace the 100mm O rings - part #09066-103. The rest depends on the condition of the oil seals and if you have any oil leaks.

Im in the middle of a complete rebuild of a 175DT motor. The crank has a bad center bearing and seal so it is out getting pressed apart and rebuilt.

Dan
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 12, 2015, 08:34:13 AM
I did split the case.  To get a look at the kickstarter shaft.  Not sure what needs to be replaced here:  The kickstarter rarely engages.
Title: Re: 1969 HS Motor Rebuild
Post by: OldSwartout on June 12, 2015, 08:48:21 AM
There isn't much to to wrong with the kickstarter, either the corner of the pawl is rounded, the spring is broken or missing or the notches in the outer gear are worn.  It looks like the spring is there, so finish taking it apart and check the pawl and internal gear. It's most likely the pawl.
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 14, 2015, 01:40:49 PM
We found this roll pin laying in the bottom of the case when we opened it up.  Anybody recognize it?
Title: Re: 1969 HS Motor Rebuild
Post by: OldSwartout on June 14, 2015, 05:07:28 PM
It looks like the locator pin for the rotary valve drive hub. Maybe someone dropped one, couldn't find it and put in a replacement.  Anyone else have a guess?
Title: Re: 1969 HS Motor Rebuild
Post by: dcr on June 14, 2015, 05:42:21 PM
If it measures 3mm X 10mm, it goes in the end of the crank and is the locator pin for the rotary valve as OldSwartout has stated.
Title: Re: 1969 HS Motor Rebuild
Post by: disc_valve on June 16, 2015, 06:37:12 AM
Was the pin found sitting in the transmission cover? If so, it is hard to imagine it came from the rotary valve since that is inside yet  another cover once the engine is assembled. There is another possibility - a 6 * 10mm roller fits in the end of the clutch actuating thread and pushes against the centre of the pressure plate. It's possible that someone dislodged that roller when assembling the case and never bothered to retrieve it.

Graham.
Title: Re: 1969 HS Motor Rebuild
Post by: OldSwartout on June 16, 2015, 05:37:33 PM
I just took a closer look at your photo.  That's a split roll pin, not a dowel. so it isn't the rotary valve drive dowel nor the clutch push rod dowel.  The rotary valve cover and oil pump locating pins are also solid dowels. Measure it to be sure, but it appears to be 3 x10mm. There are only a couple 3mm pins in the whole engine. Look through the parts catalog and see if you can find one that matches your pin size.  It likely that it was a part that was dropped, lost, and replaced at a previous disassembly.  We've all done that, just gave up trying to find a part, then just replaced it.
Title: Re: 1969 HS Motor Rebuild
Post by: coxy on June 17, 2015, 04:14:53 PM
oil pump return spring stopper? (control arm),there does not appear to be a part # for this.
Title: Re: 1969 HS Motor Rebuild
Post by: coxy on June 17, 2015, 05:20:31 PM
This is just pushed in with thumb nail
Title: Re: 1969 HS Motor Rebuild
Post by: coxy on June 17, 2015, 05:23:28 PM
Sorry about the camera work
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 18, 2015, 07:01:21 AM
Coxy-
I'll check that!  I didn't notice if it was missing upon disassembly, but I wasn't looking for it either. 
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 19, 2015, 07:12:50 AM
That's exactly what it was!  My pump was missing one, and the one I found fit perfectly.

Thanks!

Attached is a picture of the ratchet and ratchet gear.  The ratchet looks a bit worn.
Does that look like enough to cause a problem?  Does the gear look OK?
Title: Re: 1969 HS Motor Rebuild
Post by: dcr on June 19, 2015, 09:52:47 AM
Coxy - very impressive work by you.
Title: Re: 1969 HS Motor Rebuild
Post by: slawsonb on June 19, 2015, 11:22:03 AM
dcr, I agree. The sleuthing prowess of this group is really amazing. The latest example is coxy's nail of the roll pin. Very Nice!
...bert
Title: Re: 1969 HS Motor Rebuild
Post by: OldSwartout on June 19, 2015, 12:31:49 PM
Attached is a picture of the ratchet and ratchet gear.  The ratchet looks a bit worn.
Does that look like enough to cause a problem?  Does the gear look OK?

The gear looks OK to me and the ratchet is a little worn, maybe enough to cause a problem.  I'm assuming the spring and pin were intact although not in your photo.
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 19, 2015, 12:35:38 PM
Yes.  The spring and pin seem fine.
Title: Re: 1969 HS Motor Rebuild
Post by: BeerGeek on June 22, 2015, 08:00:50 AM
Is the pawl reversible?  Is it possible to put it back in reversed?
Title: Re: 1969 HS Motor Rebuild
Post by: BRT-GTR on June 22, 2015, 02:29:44 PM
 Hi,
     I can't answer your question directly without taking one apart and only on a 350 which has a similar, if not identical ratchet arrangement. The end of the pawl is not machined square, it slopes slightly, the corner/side with the angle above 90 deg should face the ratchet gear.
        Strange one this  ??? The pin springs do give trouble, I have one that is jammed but you say yours is ok. Another thought, is the correct thickness washer fitted at the back of the pawl. If it was too thin it may allow the pawl to pick up on the step at the back of the pawl gear and not engage fully.
Hope this helps , Brian.
Title: Re: 1969 HS Motor Rebuild
Post by: OldSwartout on June 22, 2015, 07:21:14 PM
This picture is in the 350 Service manual:
Title: Re: 1969 HS Motor Rebuild
Post by: BRT-GTR on June 23, 2015, 07:06:28 AM
Thanks Karl,
                  That explains the pawl orientation better.                Brian.