Triumph Rat Motorcycle Forums banner

Old Cafe Racers new cafe racer.

61K views 165 replies 26 participants last post by  ccs615819 
#1 ·
I started this bike last year to re-create the bike I streeted then later raced in the early '70s.
The original was a 1960 T100A converted to twin points and the later frame mods to the swingarm spindle end brackets.
40 years on and I found a basket case T100T frame (1967) with the original (wrecked) motor and a good T100R (1973) motor on ebay.
There are lots of good restored parts with this buy but most of it will be sold as this bike is pure special build.
So far the frame & swingarm have been enamelled, the engine & gearbox, carbys rebuilt and it's a loosely assembled rolling chassis.
The rear brake is Honda 350 in an 18" flanged alloy rim the front is Grimeca 4L/S in an 18" rim and the forks are brand new from the factory Norton short roadholders just like the original in alloy triple trees.
The oil tank, front mudguard and Dunstall style seat are home made in carbon fiber and the crowning glory is the fuel tank, a perfect replica of the factory race tanks used at Daytona from Glass from the past.
Next post I'll start from the beginning properly with what has been done so far.

.
 

Attachments

See less See more
5
#3 ·
I'll street it for a couple of months to sort things and get a reasonable setup then later in the year down to Lakeside near Brisbane around 1800 km away for a track weekend hopefully.

I suppose I should put some start pictures here as well:
First is the cases after I soda blasted them, second is the carbies after the same.
Can see me running out of photo space real soon here.
It's tropical up here so we don't wear shirts much indoors :)
.
 

Attachments

#4 ·
OCR,

I would like to suggest that you open a Photobucket account. It allows you to share your entire rebuild album with others by simply sending them the link and lets you post full size photos here by posting a link in your post. I did the attachment thing for a while but when I started the restoration thread, I started another PB album. It makes it easier and the photos appear here full size.

Using PB is very easy.

regards,
Rob
 
#5 ·
:)Thanks Rob, I have a website so I'll use that.

First up, the engine.
It was supposed to have been rebuilt but I had doubts so we did a full strip, just as well because the main bearings were new but rusty :eek:
Bottom end:
The crank was unused, polished on size and had been cleaned out ok.
The shells were new as were the conrods & pistons.
The cams were actually timed 180 degrees out :rolleyes: so just as well we did a full strip.
So, blasted the cases, new main bearings, polished & balanced the rods, painted the barrels with VHT light gold header paint, blocked off the tacho drive as we will use an electronic one, blocked the 3 oil feed holes to the primary (BNR belt drive fitted) and reassembled the bottom end.
Sounds easy when you say it fast :)









 
#6 ·
OCR,

Are those 9:1 pistons? There was a thread a week or so ago about a 500 and the owner was trying to determine with CR pistons he had. I thought they looked like 11:1 650 pistons, but realized they would not work in the 500. Mr. Pete said they were std 9:1. If yours are the same, it is a great picture to show the significant difference between the 500 and 650 piston crown shape.

I like the gold jugs.

regards,
Rob
 
#14 ·
Just a few more detail bits from the early stages:

Home made carbon fiber oil tank before the front mounts were fitted and the back bonded in:



New custom made to order rear struts:



Struts first fitting:



Improved all stainless brake adjuster rods with left and right hand thread rod end joints to replace the poor clevises with right hand threads at both ends.



New adjuster rods fitted:



316 stainless head steady:



Custom alloy front engine mounts:



As always, the devil is in the detail.
 
#16 ·
OCR, I actually went back to the beginning of the thread again just to make sure I did not miss anything. Gorgeous bike. I think the right adjective is "svelt". Bike looks like it weighs about 100 lbs. Very clean look and purposeful.

It has to be very rewarding to see and ride the finished product.

So, when it's all done, whattaya gonna do next?:D

regards,
Rob
 
#47 ·
#17 · (Edited)
Thanks for the kind words.
Still plenty to do to it yet, I bought a close ratio gear cluster second hand from the Uk but it had a worn mainshaft 3rd gear, ordered a new shaft complete from the Uk and it arrived today, beautiful...except third gear has 23 teeth instead of 22, so back to the waiting game there :)
Also have a brand new set of Wassel 900 series 28mm carbies on the way too.

I have a Ducati 748 (second love) and a Cagiva Mito (3rd love) to keep me busy, I'm in the middle of building a complete from the ground up new engine and gearbox for the 748, taken to 853cc using special pistons and 916 cylinders.
That should keep me out of mischief for the coming wet season up here in northern Oz.

A few more details:







Belt drive and alternator with custom longer nut and rotor drive pins.


First look at fit up:


 
#18 ·
Well the shakedown period is finally over, 160 miles covered so far now.

Problems?..

First, I replaced the old mis-matched 626/26mm Mk1 concentrics with brand new Wassel 900 series 28mm ones and all the flat spots and irregular idling just went away, she now idles like a sewing machine and pulls strong all through the range. I ended up with 170 mains, 106 needle jets and #3 slides with stay up floats and viton tipped alloy needles.

Second, the oil pressure was too high.. 85psi which turned out to be an incorrect oil pressure relief valve spring (inch and a half long instead of inch and three eights long, easily fixed with a new spring)

Third and quite a tricky one, it slightly wet sumped but only at high speeds and blew heaps of oil out the rocker box breather (around 200cc every 2 miles)
I removed the new Morgo plunger pump and replaced the old stock one but it made no difference.
I finally traced this to an undersized orifice in the carbon fiber oil tank return fitting.
Fitted a bigger bore fitting and the problem simply went away and now it dumps no more than about 3 drops into the breather catch bottle every 20 miles or so at 70-75 mph running and should reduce even further as the new pistons, rings and bores bed right in.

Fourth, I was supplied the wrong pushrod tube O rings so had to remove the head and fit correct ones to stop the leaks.

The Grimeca 4L/S front brake I set up progressive so one shoe comes on, then the second one on the same side, then the other side does the same so it's gentle and progressive, the harder you squeeze the lever the more brake you get, feels a lot like a disc setup with massive controllable power.
I put considerable chamfers on all the shoe leading edges to prevent squeal and grabbing and lubricated the shafts and pivots with high temperature copper grease.

The bike starts first kick every time (love that Tri-Spark ignition)
and according to my 11 yo grandson it sounds mean and nasty! :)
It handles well with the Manx front forks and custom rear units and I haven't even started to dial the suspension in as yet so I'm pleasantly surprised.
It tips in quick and steers fast and holds a line well even over bumps and ripples. (It compares well with the 748 and the Cagiva Mito I also ride, even not taking it's vintage and skinny tyres into consideration)
These little 500's were gems and everytime I ride it I'm back in the late 60's on my old T100A cafe racer.
.
 
#19 · (Edited)
I want to give credit to this bloke (picture attached), Paul Borger who did all the specialised tig welding on this bike for me, gave me all the alloy plate and sheet for brackets and parts and allowed me free use of his metal lathe for many hours along the way.
Paul is a local boat builder here in North Queensland:
http://www.acecomp.com.au/nqborgercats/photos.htm

.
Also a massive thank you to Albert Lord of Bribie Island who made many small intricate parts on his small lathe for me and a big shout out to Ron Stock from California who made stainless shim washers for the rear hub and both of them for giving me support and reasoned advice on a daily basis as the work progressed.
Many thanks guys.

Also The knowledge gleaned from this forum and also the Britbike forum bridged the many huge gaps in my memory of these old 500's and put me on the right path with the many new inovations such as BNR belt drives, Tri-Spark ignitions, and leads to the many parts suppliers I used, not the least of which were BJ's Bikes and Bits in Brisbane (many thanks for your immense patience Preston) and also Chris of Unity Equip in the UK who supplied the front forks, wheel and brake.
Kerry Ellis of Bundaberg bike wreckers supplied the Honda rear brake and hub and who gave excellent service and advice and Ash's spoked wheels in Brisbane who did such a fine job supplying the Morad Akront flanged alloy rim to match the front one and lacing it all together with butted stainless steel spokes for me.
I just had a flick through the 2 inch thick pile of receipts for this bike and will later when time permits compile a complete list of who supplied what as we only used the finest components and materials and that list may come in usefull to others contemplating similar projects.

What a team effort this turned out to be.
 

Attachments

#25 · (Edited)
Put around 500 miles on her since the first start... but... they say life wasn't meant to be easy.

So this is how it went.. first few runs, carburetter problems. sorted them eventually (wrong mixture screws fitted)
Then as the miles went by and it was given more revs, two things started to happen, first it would wet sump again and push 200cc of oil from the rockerbox breather into the catch bottle in 3 miles but only at 4500 RPM plus.
I thought the bores were a little too big (7 thou piston clearance) and blowby was causing the wet sumping so I pulled the jugs bought 10 thou over pistons, had the jugs honed to suit the new pistons by a local engineering shop with a honing machine.
I stuck it all back together and tried again.... still wet sumped and then it started to feel a little tight occasionally and then started a strange bell like noise at low revs in high gear.
I had tried a few different things to solve the high RPM wet sumping.. changed the oil pump back to the stock old one, tried a different grade of oil, increased the size of the oil return fitting at the tank...all to no avail.
Then whilst I had the timing cover off I found the crank had 31 thou end float..
So I whipped the engine out at 250 miles and stripped it to the last nut and bolt.

End float, two reasons, first the crank pinion spacer washer was on back to front with the beveled side towards the bearing (the motor came to me that way) and second, seeing as the crank was free to move in the timing side bearing inner race as the washer wasn't clamping it there was then 31 thou end float which needed a 27 thou shim making to reduce it to an acceptable (to me) 4 thou.

Next I inspected the jugs and found the local engineers had done a lousy hone job, tapered at the top and egg timer shaped down the bottom ( clearance was 3.5 thou)
So I dug out my own tools and re-honed them myself, straight and true with 4 thou piston clearance at the bottom of the skirt.

Whilst I was in there I found the some of the valve springs had taken a set and were well under spec (all checked ok before original install ) so I replaced them as well as fitting imp#011 viton O rings to the stems before reassembly.

Also there was a gearbox oil leak into the primary case which was doing the dry belt no good so we modified the gearbox output shaft and fitted a seal housing to seal down to the clutch shaft to stop the leak.
All the Daytona has to stop gear oil leaking between the input and output shafts is a helical groove cut inside the output shaft bronze bush to push oil back to the gearbox (which doesn't work except with really thick oil)

The Morgo oil pump was refitted and then finally we found the culprit causing the high revs wet sumping... the oil scavenge pickup pipe. The bottom end of it was closed up to around 3mm almost like it had been swaged in with a pipe cutter and not reamed out.
Well ream it out I did making it it's full designed size of almost 7mm thereby increasing it's cross section area by almost 4 times.
Works just fine now, the puzzle was though every time I dropped the sump plug to check after a run there was only 100cc of oil left in there.
What was happening was the pump could scavenge just fine at low revs and clear the sump at the end of a run, but at speed just didn't have the capacity to flow the required amount of oil back with that small suction pipe end and pumped oil up and out the exhaust rocker box breather pipe.

Anyway it all went back together along with a brand new pair of 28mm carbies and now at 500 miles the running in oil has been sucked out and replaced with Penrite 20/60 extra 10 full synthetic oil and she is all run in, sweet as a nut, goes like the wind and leaks absolutely no oil (it lives inside the house in a carpeted room)



 

Attachments

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top