1967/1969 Bonnie Rebuild Desert Sled Project - Any Advice

So . . . with my set-up, being an older one with the holes in the ball ends, the thackery washers go next to the rocker arms and the flat washers are on the outside? I'm pretty sure this is correct but . . .

 

I am planning to purchase some new engine case fasteners as well as engine to frame fasteners. It seems that there is a difference in the fasteners kits I see for engine to frame, like on thebonnevilleshop web site. There is a kit for up to 1968 engine to frame, then a kit that is 1969/1970. So my frame is a 1967 and the engine is 1969. Have any of you had this issue before? I’m trying to determine what might be the best kit/solution for my 1969 engine going into my 1967 frame? Thanks again.

 

Yes, I will be going with the 67 fastener kit. Thanks.

 

Since I got my new cams, I thought I would do a dry run assembly making sure they had enough clearance in my bushings - as I had to to some trimming of the timing side bushes. So, the exhaust side was fine, however the intake side could rotate but I could tell it was binding, I believe on the inside part of the bushing on the timing side. So, I am going to need to remove this bushing. I think I know the answer to this, but is it possible to reuse the bushing even though it has been installed once? I would think it is not worth the risk of having a bushing spin so I’d need to get a new one and trim it as needed. Thank for your comments.

 

ok, thanks for the advice. I’ll try. I’m pretty sure it is binding on the inside however. When I try the cam with the case open it seems the shoulder of the cam doesn’t extend enough for the cam gear shoulder to seat with clearance.

 

Yes, the whetstone. Do you think I can re-use the bushing - or would need a new one since this one had already been installed and it might be a looser fit? Not sure if anyone has done this.

 

Yes, I am pretty certain it is the timing side intake bush. I tapped it out and I can see where the cam was rubbing against the inside (top hat side) of the bushing. It did tap out quite easily, that is why I wondered if it was a good idea or not to re-use it. I could take the whetstone to it to remove more material and then re-install it - or get another virgin bush.

 

Looking for Help with Pushrod Tubes. I’ve taken a good look at the 69 parts book regarding this, as well as the page on JRC Engineering that has a great description (https://www.jrcengineering.com/tech...ding-triumph-tappet-blocks-and-pushrod-tubes/) . However I am still a bit uncertain how to proceed with my rebuild.

My pushrod tubes align with the one in the 69 parts book, it is castellated at the top (part number E9349). When disassembling it had an O ring inside a cutout on the bottom of the tube, as well as an O ring at the top (E7310), fitting over the castellated part (just like in the parts book). It also had a white rubber washer that was sealing the bottom of the tube - however this is not represented in the parts book. So I suppose what this means, from what I’ve read, is you use whatever size of washer(s) you need on the base of the tube to insure a good seal when assembling.

When looking at the JRC Engineering diagram for 69-73 650 Twins, it seems to identify another component of this assembly (that was not found when I disassembled my motor). So I am wondering if this is the “wedding band” part that I have heard mentioned at times? This being the case, would it be good for me to include this wedding band when I put my engine together? - Seems so if it will fit.

The length of my tubes from the top shoulder to the base is about 4.87 inches. The diameter of the base of my pushrod tube is about 1.24 inches, and the diameter of the cut out on the base of my new Aerco Cylinder for the rod tube base is 1.36 inches. So it seems there is some room for something here around the base of the tube - like the wedding band item.

I see the wedding band listed on the JRC Engineering site as part numbers 71-1707, 71-1707C, and 17-7107S (also on thebonnevilleshop site). So it this is a good idea to fit this band, how does one determine which pf the 71-1707’s to use? I would imagine it depends on the clearances, however I have not been able to find the measurements of any of these bands.

OK - well while writing this I found Service Bulletin No. 324, which seems to indicate the wedding band was a fix, and that it is something I can add to my re-build. Again, if this is the case, which band is the correct one? Are they different sizes? Once again further looking I find that the size must be the same, the C version being chromed and the S version being stainless.

So I think I may have answered my own question while writing this - but if there are any comments that might assist me I will greatly appreciate it!

Thanks.

 

Yes, thanks. Great to have!

 

Well, I’m quite busy today on the forum - result of finally getting the flu. So here goes some more questions.

Regarding tappets. Those from my bike need replacement, There was some chipping on the edges of a couple and uneven wearing so I need 4 more. I’ve been advised to beware of those manufactured in China as they have had some failures.

My bike had the oil driveway plugged for the exhaust tappets - The Routt barrel that was on it wasn’t drilled. The new Aerco barrel I have is drilled, however I am going to keep the case plugged as I’ll be having new tappets and cams (nitrided).

Please take a look at the photo of my cams, they all look the same, with a smaller diameter section in the middle of the tappet rod So, do I need to find tappets with the same smaller diameter middle section? For example see the photo from thebonnevilleshop of intake R tappets that are the same diameter the whole length of the shaft. Would there be any problem with these? Also, since I am not running with an open oilway for the lube to the exhaust cam, is it OK, fine, advisable to use 4 tappets which are the same - as was in my old motor. So could I just purchase 4 of these R inlet tappets and be good? The other tappets I see for sale that are exhaust tappets have the oil hole, is there any benefit running those on the exhaust side when the oil driveway is plugged?

Thanks again

 

I also note that the exhaust tappets I see for sale have the oil hole in the rod, an oil hole on the tappet bearing surface, and the head of the tappet has 2 cutouts on either side. I am curious how this affects the engine in view of my previous query?

 

OK, so my old cams from megacycle had the recommendation for the R's. My new cams are LF Harris, 70-3134 and 70-9989. I guess I should check with LF Harris about tappet recommendations. Good idea.