[Cristado]

Hello everyone,
I’m looking for a little bit of help identifying this engine.
not sure if it is a mix match
Numbers start with “PG” does this mean it is a 1972?
It is also stamped tr6r which makes me think it could be obviously different parts put together
I am wondering because I came across a 68?basket case kind of. The frame etc are kind of together. Nice parts etc.
anyway.
Frame is pre oif cannot see numbers as it was powder coated over. Apparently it is ‘68. Also looks like rocker cover is on backwards?
It does not have the inspection holes on the side like my 71 and I thought after 72 the inspection caps changed to the oval style?

Nothing is fastened tight together but looks taken care of.
attached is a picture. Is it a complete engine from a oif bike ? Anyone have any thoughts?apparently was all together running good before taken apart for storage

 

[rambo]

72 cases with pre 71 rocker boxes fitted the wrong way around. TR6R would have been a single carb 650. I would also check the numbers under the cases to see the cases are a matched pair.

 

[StuartMac]

Hi,

help identifying this engine
Numbers start with “PG” does this mean it is a 1972?

check the numbers under the cases to see the cases are a matched pair

Pending the result of following @rambo Geoff's advice - specifically the code stamped on each case at the lower engine mounting - all that can be deduced from "PG" is the drive-side crankcase was part of a '72 model year ("G") engine built in November ("P"). Btw, that means the original engine was actually built in November 1971, Meriden switched to building '72 model-year bikes during calendar July 1971.

If the code stamped on each case at the lower engine mounting is the same, the two case halves were machined together at Meriden.

stamped tr6r which makes me think it could be obviously different parts put together

Correct; the major difference between the engine in your photo. and the engine as built at Meriden is the engine as built would've had a single-carb. cylinder head.

rocker cover is on backwards?

pre 71 rocker boxes fitted the wrong way around

While the rocker-boxes are fitted the wrong way 'round - protruding threaded shaft end should be on the timing side - oval inspection cover first appears in the '73 parts book (although I have it in mind they were fitted from part-way through '72? @KADUTZ will know).

Oval-cover 'boxes don't have the "inspection holes" and plugs in the sides.

Also be aware rocker shaft threads could be 3/8"-26 Cycle or 3/8"-24 UNF.

not sure if it is a mix match

It is.

Hth.

Regards,

 

[Snakeoil]

Somebody spent a lot of time and effort polishing all those aluminum bits. My guess is this was in somebody's choppa. Hopefully, it will go back to being put back in service as a real bike.

All together and running good and then taken apart for storage?? Who the Hell does that?!!! More like put together quick to sell. No kickstarter, no shifter shaft. Might not have been in a choppa. Might have been the start of a living room lamp project. If you have not already purchased it, I'd want to see inside it before I gave someone cash. Without seeing inside, the value to me would be the sidecovers and little else. Jugs and head could be very pretty scrap.

 

[speedrattle]

that motor wasnt running anytime recently. it looks like he bought a lot of new parts to make a motor and then just screwed them togethrr so he wouldnt lose anything while in storage

it may be a set of empty cases, or whats inside may not be overhauled.

 

[thefledgling]

Can't see frame number? Have to ask seller to sand it back in this area. Otherwise how to you know what you are buying?
I like the polished engine.

 

[StuartMac]

Hi,

Frame is pre oif cannot see numbers as it was powder coated over. Apparently it is ‘68.

Hmmm ... powder-coat has to very thick to obscure frame stamping completely ...

The frame number should be on the steering head drive-side, running down the front downtube. If there are any indentations in the powder-coating suggesting the frame number, before "ask[ing] seller to sand it", try rubbing over the area with a finger with some some talcum powder, chalk dust, etc. on it; if the white dust goes into the indentations, it might show the frame number.

Two other differentiations between '69/'70 dry frames and pre-'69:-

. '69/'70 have a raised flat area on the drive-side of the steering head casting for the frame number. Pre-'69 doesn't, number was just stamped on the downtube.

. Pre-'69 number will always be immediately preceded by "DU"; very early '69 numbers are too but the number will be higher than 85903.

Hth.

Regards,

 

[Cristado]

Hello everyone. I decided to make a deal and purchase this as a project.
So the frame etc is a 68

The engine cases are are matching 72. Cylinder head is a 68.
Everything is all there.
I have ordered most things I need and will be slowly working on It this winter.
I have torn the engine completely down. New sludge trap, bearings, big end bearings.
As I put it back together crank moves nice and freely.
Once I tighten the bolts it seems to bind.
The right side main bearing had some trouble going on with the case but it did go on. I am wondering if that got moved a bit and is not properly seated.
Camshafts move and spin when case bolts are tightened.
I am hoping someone has an idea on what it could be , or possibly something similar has happened to someone?
Thanks.

 

[Tritn Thrashr]

Heat the cases until spit bounces off, then whack them around the bearing housings with a mallet.

Or part the cases and take a good look.

 

[Mick Barratt]

Hello everyone. I decided to make a deal and purchase this as a project.
So the frame etc is a 68

The engine cases are are matching 72. Cylinder head is a 68.
Everything is all there.
I have ordered most things I need and will be slowly working on It this winter.
I have torn the engine completely down. New sludge trap, bearings, big end bearings.
As I put it back together crank moves nice and freely.
Once I tighten the bolts it seems to bind.
The right side main bearing had some trouble going on with the case but it did go on. I am wondering if that got moved a bit and is not properly seated.
Camshafts move and spin when case bolts are tightened.
I am hoping someone has an idea on what it could be , or possibly something similar has happened to someone?
Thanks.

It seems that some timing side crank mainshafts are very tight in their bearings, but if you assemble the clamping washer, crank pinion and nut and really tighen, it should pull the crank all the way into the bearing, dont go hammering the bearing onto the shaft. You can get the shaft part way into the bearing using a spacer behind the crank nut to geting started. That's assuming the bearing outer is fully home in the case a la Tritn Thrashr.

 

[StuartMac]

Hi,

engine cases are are matching 72. Cylinder head is a 68.

Be aware you'll need to ascertain the year of the tappet guide blocks in the cylinder block - pre-'69 and '69-on tappet guide blocks, pushrod tubes and PRT seals between guide blocks and head are completely different and not interchangeable.

Hth.

Regards,

 

[Cristado]

I just heated and tapped with a mallet. Helped a tiny bit but I don’t want to hit it any harder . Maybe a tiny bit.
Looking in at the crankshaft I’m the bearing there is a little gap. Hard to see but looks maybe 1/16” or so probably less. Should the bearing be riding right up against the “lip/groove “ on the crank on the inside ?
I will assemble crank pinion and hopefully this pulls it just the amount it needs.
Should the clamping washer be right up against the metal when set in place?should the crank be coming out more than it is on this side. Picture attached.

 

[Mick Barratt]

The short answer is that there should be no gap behind the bearing to the shoulder that the bearing fits , (not against the crank cheek). The washer once fitted should be just shy of the step in the crank against where the pinion sits. You need to have that pinion etc fitted and TIGHT, other methods may well damage the bearing, I promise you, it will be fine!

 

[Cristado]

It worked! Tightening it sucked it in. And it felt a lot better than beating on it.
thanks so much.
when I run into other obstacles on this build, would it be ok to post questions on this post?
Also,
Pushrods, tappet blocks etc are for ‘68 and rocker so should work.

 

[Cristado]

Another tight fit…..
I have a new gearbox sprocket(20 tooth. Changed from 19.) when trying to slide on Main shaft 4th gear it will not go. I can force it on with a mallet but I don’t see how I will be able to get it on while gear is in bearing and case. I tried the old sprocket and it is just as tight. I sanded/ used wires brush but it did not make a difference. I figured it should just slide on? It only slides to the edge of the threads.
attached are pictures.
does anyone know if these are usually such a tight fit?

 

[tridentt150v]

They are usually a light tap on fit. No force needed.

 

[rambo]

My 20 tooth sprocket also went on without any problem. I suppose it is down to the manufacturer. I just trusted a good spares company at the time and he had always supplied good items.
Maybe another sprocket from a different supplier would fit.

 

[speedrattle]

we re going to see a lot more of that sort of thing as fewer and fewer of us are around to merit expensive tooling

 

[Cristado]

If is strange as the old sprocket is just as tight.

 

[Cristado]

I managed to get the sprocket in place tapping lightly with a socket on the sprocket side. Now torqued to 80 ft/lbs.
as I am waiting on partsI I am working on forks/ front end.
There is play when I hold the front tire between my legs and move the handle bars side to side. With the front fender in place it makes a slight difference but still more movement than I feel comfortable with. Checking my 71 tr6r it feels very solid.
Could this be the steering stem nut is not as tight as it should be? New tapered bearings installed.
Thanks.