Triumphrat

czycat · 11-09-2009, 09:08 PM

Hey Guys,

New to the forum - but been reading a bit over the last week or two - great resource here! I picked up a '70 Bonneville last month - first Brit bike - and am putting a to-do list together for the winter, and want to order some parts for it now in preparation - any and all advice will be genuinely appreciated!

First a little about the bike. P/O (Harley mechanic) rebuilt it from boxes and his wife ran it for a while. Apparently they originally had a Tiger head on it, but replaced it with a Bonnie head later. As it sits & what I know/was told: stock bottom end, but tall c/s sprocket for the highway, head was ground down and supposedly fitted w/ racing cams & oversized valves, stock carbs, 2" TT pipes with baffles inserted. Rewired for negative ground, Boyer ignition, Single dual-output Dyna coil, MSD wires & NGK B7ES plugs. Halogen headlight which only switches on in the right position, ammeter seems to be wired directly to the battery (is that correct?), but otherwise everything seems okay. Also has a fram filter hiding behind the oil tank, blown out fork seals, and leaks like a sieve from the sides (less from the tappet tubes & head/valve covers).

It ran pretty poorly when I picked it up - since I've fiddled with the carbs. The right pilot appears to have been clogged, and she's running much better now. In the beginning she occasionally wouldn't start and was missing spark, so I was looking over the ignition, but over the last 8-10 tries I've had no issues with spark...

So here is where I'm sitting; I can't afford to redo the whole bike - for now I want to get it reliable, quiet enough not to scare the neighbor kids, and generally looking respectable. Down the road, I'd love to buff out the motor, hop it up a little, renew/repaint it so she's really sharp, but for now, get her reliable and enjoyable.

So some questions:

Exhaust. I'm pulling the 2" TT pipes (fun, but loud). Any comments about running 1.75" pipes & mufflers as opposed to the original spec 1.5"? Is it worth the extra $200 to do it? Planning to put K&N filters in the cute little round filter holders as well...

Top end. Planning to pull it apart to get a better idea of what is going on in there. Want to clean it up, maybe new rings, valve guides and put it back together. What else would you recommend? Any feedback on gaskets, techniques, etc? What's the word on bumping up the compression a bit? Definitely want to liven the motor up at some point...

Front End. Forks need new seals. I imagine there is a whole bunch of stuff to look at in there - bushings and stuff? I've been trying to figure out the springs - are there just the little ones on the outside? I'd like to put on new ones - recommendations there? Aftermarket? Caught the beta on SAE 20 to 30 for for the forks. Any recommendations for improving the suspension is greatly appreciated!

Back end. Plan to clean things up as best I can. P/O recommended either replacing or rebuilding the speedo sending unit. Beta on that would be great! Will likely hold off on new shocks, but apparently Hagon is a good route?

Electrical system. Knowing that the bike has been re-wired makes me nervous - I plan to go through it and tidy things up a bit, but will leave it negative ground. I haven't checked the Dyna coil yet to see what ohm rating it is, but as of now with the bike running well, I'm also leary of changing it (though it would be nice to get the coil (s) back under the tank). Pulled a pretty Negative Ground Triumph Wiring Diagram from the Rask Cycle website which should help sort things out, but it doesn't get into specifics of how the headlight should be wired, or where the ammeter fits in, horn, etc., so give a shout if you have some ideas there.

Well, that appears to be a good start. Sorry for the long winded questionnaire!

Cheers,
Jeff

GrandPaulZ · 11-10-2009, 09:54 AM

Welcome to the forum!

Slow down and do a lot more searching, you've got all winter.

Too many good answers to EACH of your many questions, so you'll need to prioritize, budget and weigh your options in an orderly manner.

You're doing 2 things right - getting it running as good as it can AS IT IS NOW, and installing quieter pipes with mufflers (even if they are the original straight-through type).

I don't think the difference in price for big-bore pipes is worth it, if that's what you've been quoted, but they do LOOK good!

Total flush and re-fill with known good quality lubricants is always a good step. (front to back, top to bottom)

All the photos you care to post will be appreciated by everyone here.

czycat · 11-10-2009, 08:25 PM

Thanks GPZ - just trying to get some ideas from folks so I can get some parts coming. Being a noob with the Triumph keeps me scratching my head - too many options. Neat bike though! I'll be sure to post some pics when tear into her.

GrandPaulZ · 11-11-2009, 12:17 AM

"Shop manual and parts book"

"Shop manual and parts book"

"Shop manual and parts book"

"Shop manual and parts book"

I think you get the drift...

"Kim the CD Man" 2 disc set is the best resource out there.

czycat · 04-22-2010, 04:40 PM

Back again, thought I'd give an update. Working on the bike has been a constant struggle, at least in my head. The PO did a poor enough job with almost every avenue, the bike sits like a siren, begging me to take her all the way apart and rebuild her properly. Still, I'm holding true to trying to get her running well for summer, and to stop (read: slow) all the leaks. The rebuild will have to wait until I can afford to do it right.

Since about half the oil was coming out of the top end, apart she came. NEVER in my life have ever seen so much RTV squished out around the gaskets. Bit of a junk show. The rockers look fine otherwise, but the head is #71-2360 ('71-'72?) - only noticeable difference I can tell is the rocker boxes don't quite match up; looks like the proper ones were a little thicker in one spot and had some pins to hold them in place. Until I can afford a full rebuild, she'll have to work...

Before I pulled the heads I ran a cold comp. test, which brought back 110 psi in both cylinders. Pretty disappointing, but once I pulled the head, I felt a little better when I noticed that a fair bit of oil I used to prime the bore had blown past the gasket, not to mention the center was black with blow-by. Pretty rough shave job on the top of the cylinders I think led to that, plus it didn't feel torqued at all. I'v put together a piece of plate glass with wet/dry 220 on it to lap out all the rough surfaces, especially the poorly shave cylinder. More RTV all over the pushrod seals, which were heavily deformed. I'm guessing that the shave job required thinner push rod seals to get it to seal right.

Question: Looking at the parts book, I only see two o-rings on the push rod tubes (diff. #'s top and bottom, yet it seems while not shown, that the white square ring is pretty standard in forum discussions. Is it correct to have a top and bottom o-ring, and then the white sq. ring on the bottom as well? That's the best I can figure looking at it...

With the top of the cylinders needing lapping, off they go as well. .040 over bore is to be expected, bore are looking reasonable and are just barely in spec, but the ring gaps are over spec. (.025+). To keep the project in budget, a hone and new rings are in the works. Inspecting the tappets/followers catches my attention, one of the exhaust tappets is clogged. Hopefully I can clear it out - can't be good for the cam... But if anyone has a decent used exhaust tappet to spare, I'd be happy to swap it out.

That's where the project sits at the moment. The chassis and electrical are a whole different can of worms, and I haven't started with the fork rebuild yet. At least it is warmer in the garage now!

Cheers & happy wrenching,
Jeff

jimmy bush · 04-23-2010, 12:11 AM

czycat. You say it has a 71 head and there appears to be a mismatch with the rocker boxes. When Triumph went to the OIF frames in 71, they had to change the head bolts and rocker boxes. If you are running the original 70 head bolts and stays, you would need to run the 70 or earlier rocker boxes to get proper clamping on the head. They didn't have dowel pins to locate them, the head bolts took care of that. The 71 and later engines had shorter head bolts that fit inside the rocker boxes and were torqued before the rocker boxes were installed. They applied the clamping pressure directly to the head and would sometimes leave an indentation in the head. If yours has the indentations, you wont be getting proper clamping when you torque the earlier style head bolts that applies the clamping pressure through the rocker box.

czycat · 04-24-2010, 12:46 AM

Thanks for the heads up, JB. Thankfully it has the earlier rocker boxes, and surprisingly, the mating surface with the head looks resurfaced (though with obvious milling marks as the cylinder had...). That should allow the four head bolts that go through the rockers to get even torque on the head. As for the others, only the center head bolt looks significantly wallowed out. Any suggestions as to how to even up that surface?

Unfortunately the clogged exhaust tappet oil feed hole still looms. I can't find a bit in town smaller then 1/16" to try to get in there. If anyone knows what size of a bit would work, or has another suggestion as to how to clean the metal from the hole, I'm all ears!

shrugger · 04-24-2010, 01:42 AM

Yikes!
Anyway, lets see. The pushrod tubes would have upper and lower 'O'
rings as well as the squared ring at the bottom. Roll the top one on
like a rubber.

The exhaust cam followers (or tappets) don't absolutely need the oil
passages. They were actually deleted in later years. And the Morgo
big bore kit has no oil passage for them. But if you really feel the need
then soak them in solvent and use a Guitar string to clean em out.

110 while not optimal isn't horribly bad. Was this wet or dry?

jimmy bush · 04-24-2010, 11:51 AM

as for the push rod tube seals; if the head has been changed, the combination of seals required up to any one's guess. there were a few combinations of heads, tappet blocks and push rod tubes that required different seals. Some heads had a deeper recess where the top of the tube rested, some tubes were a bit longer. some tappet blocks requried the flat seal, some the flat seal and an o ring inside, some just had o rings top and bottom. If the head has been milled, a different flat seal may be required. I usually install the cylinder on the engine and just set the head gasket, push rod tubes and and head on the cylinder and check the gap between the head and gasket with different combinations of tube seals until I get the right fit. I try for .040" to .060" gap between the head and gasket before snugging the head bolts.

shrugger · 04-25-2010, 02:17 AM

Just read through again. Owned by a Harley mechanic you say.
Certainly not giving me any confidence in ever buying one of those
monstrosity's. If that's the level of quality to expect.

If all the mod's were done that you stated. then you should
already have a kick ass bike. I'm of a mind that you should offer that
head to ebay and and find the correct one with correct rocker boxes.