Triumph Rat Motorcycle Forums banner

41 - 50 of 50 Posts

·
Registered
Joined
·
7,380 Posts
Your valve seats are already suitable for unleaded fuel when the bike was made. The metal beads are snakeoil product so throw it away. You could run on unleaded cheap fuel as your compression ratio is lower than a T120. I use Shell super unleaded which is higher octane, or the Tesco Momentum version which is 99 octane. These fuels all have E5 in the UK. I would use the Shell higher grade for the safety against any pinking under load. I have 8.5 compression ratio and i can run the lower grade but i suspect it would knock a bit with a pillion and going uphill. Not worth the risk for just a little more money. The battery should not spill if you get a sealed for life type. Halfords, Yuasa range will last around 4 years. I am using Yuasa fire alarm batteries again now at £16 with a life of 5 years. NP7 type. i see no need for paying £40 for a specific battery. I have used these fire alarm batteries for over 20 years without any problems. They can be fitted on their side if you like, but not upside down. They will not leak at all. Spade terminals are fitted.. If you just want a battery now, buy the Halfords product. You might be able to get a Halfords trade card and get 20% off the battery.
 

·
Registered
Joined
·
3,174 Posts
Hi Lee, Regarding the battery sealed AGM batteries are good insurance against leakage. Thing is, the fumes exiting the original vent hose tended to damage chrome & paint, even without droplets of acid coming out.

Rambo's fire alarm batteries may be a good plan. I & all my friends use MotoBatt MB9U battery here is USA. Have proved a very good value & hold charge months while setting with no charger. The MotoBatt is possibly the best battery for these old bikes. Very reliable & very vibration resistant. I've never seen one crack or leak. Not saying it can't happen, but not likely. I've seen several still working good after 7-8 years. I've never heard of one fracturing internal connector bus bars & going open circuit. They have connections on all 4 corners so easy to fit either way round. If you keep bike, I feel they are worth the cost. I wish case was black instead of yellow. That's the only thing I'd change.
Don
 

·
Registered
Joined
·
19 Posts
Discussion Starter #44
Hello again. Happy days! She runs, and oil is circulating. Tickover was high at 2k rpm so I turned the throttle stop on the rhs carb until revs dropped to 1.5 ish. Then took her out for an illegal spin round the block. 1st to 2nd is a knack but we got there after slight panic about slipping clutch issues! But the brakes! They are appalling! Upgrade ideas anyone? I suspect they are par for the course but not exactly safe. I'm trying to ascertain whether it is MOT and or road tax exempt?
 

·
Registered
Joined
·
321 Posts
Well done that man! 1st to second goes via neutral so don't rush it, but IME the 5 spd box is a delight when it's all OK. Well, mine is!

If your Bonnie was first registered 1979, then it is MOT and VED exempt. You still have to 'tax' it on the DVLA website, but there's nothing to pay. I filled in a simple form claiming MOT exemption and sent it off the DVLA with my V5C when I changed the VED class to historic (and hence get the zero VED) but AIUI it can all be done at a post office, instantly. There's a very recent thread on here with the how-to-do-it.

Can't comment on the brakes as I've only got the comical drum at the back and a single disc up front on my TR7RV - but they stop me as fast as I ever need to - I did change the master cylinder, caliper and all the plumbing to get that though up front. I suspect though that yours need an overhaul as the brakes should be good enough. FWIW, I put my TR7RV through the MOT recently, expressing concern to the tester that he needed to consider that the brakes were not exactly of a modern design. His response was that invariably, well maintained Britbike brakes were fine and bike rarely failed the MOT on brakes.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #46
Hi again everyone. Ok, my wife and I took the bonnie out today. She rode while I followed. We did a 20 odd mile round trip without stopping until we got home. There was a substantial engine oil leak of a drip every few secs which I think is from the primary chain case to cover gasket. It's all I could discern from running the bike while checking underneath. The oil was dripping off the frame tube and had gone all over the lhs of the bike including up the exhaust and over the underneath of the engine. I'm hoping it's the gasket which I re-used after degreasing and using a silicone sealant. Do you have any tips for oil tighting this joint? I clearly need a new gasket but it seems to need a bit more to seal properly. Any tips on good sealants? Cheers, Lee
 

·
Premium Member
Joined
·
9,699 Posts
Certainly my mottobat came from my local bike shop.
I run all my bikes on shells power or BP Ultimate..
Even a cub. It just makes life easier- any old fuel left over winter is decanted into a petrol can, then I visit the garage in my car, add the contents of the can, and and at least half fill my car. Then add fresh fuel to the can, putting it into the bike.
 

·
Registered
Joined
·
3,174 Posts
Hi Lee, Great you got it on the road!!

Brakes, front & rear on '79 are good. You should be able to lock either wheel at will at any speed. You need a good grip on front brake lever, but it should stop very well right up to front wheel locking.
. I expect something may be wrong if you feel brakes are weak. Front pads in my '73 Tiger are original from new 34k miles. They still work very well. I've ridden modern Bonnie. I don't know about fade compared to modern Bonnie, but the stopping power is similar, meaning limit of tire traction. You may feel fork flex, but that's another subject.

I don't recall if you changed brake hoses. When aged they can do oddest things especially when inner liner starts collapsing,. deteriorating. Here in USA I find the original steel master cyl tend to rust bad near rod boot end. LF Harris stainless have proven very good for me. For calipers, I'd push pads back say 1/16-3/32" one at a time, then pump handle, foot lever & see how the push back out. Kind of exercise the caliper piston & seals. Be mindful of fluid level in reservoir. Too full & it will hydraulic lock so to speak, or spill out with cap off, Cover tank & painted surfaces well to prevent fluid damage. I just use the original type rubber hoses. Simple & I find they fit & work good, same as originals. Nelson (brand) & date made is printed on hose. It is said years from manufacture date is end of service life. When my original hoses went bad I got both hard lever & poor pressure to pads as well as pads released slowly. New hoses was perfect. I'd replace front master a year or so earlier (LF Harris stainless).

Regarding fuel, all we've had in my area is E10 91 octane. A few states over E10 93 octane. Some states you may find ethanol free, but mostly not. This has been our fuel for many years.

I will say the valves & seats do not suffer even a trace from no lead. Spark plugs never "lead foul" even in hottest weather. E10 might cause more rust in tank. Debatable?? All I can say is original tanks never cleaned don't suffer much rust. Use any type acid cleaner, it rusts fast. Once rusted & cleaned with acids, using tank liner is almost a must.

Octane is huge!! These bikes want old school 99-101. They love that. Use the highest octane you can find. E5-E10 is not a problem overall. Bike tends to work better with jet size about 5% larger with E10. Especially main jet. 100% ethanol from racing days in late 60s-mid 70s we started with twice larger jets & tuned from there. Depending on your bike & fuel moving clip 1 groove lower on needle is good plan. Mark grip & look at tuning guide. You find you almost always run on straight part of needle. The guys melt pistons here above 1/2 throttle. So your better off biased slightly rich than lean with E laced fuels. I tend to back off timing 2 deg. to 36b.

On occasion in the very remote areas we cannot get even 91. Even a few quarts of 87 is just a disaster. Ping comes right on. 100% 87, most Triumphs are almost un ridable in hot weather. Must down shift a few gears & rev motor silly. We have 89 mid grade. almost as bad as 87.

Race gas unleaded (E content unknown) is 100 or 101 octane. It works really well. Off road use 110 leaded race gas is fabulous! Problem is with race fuels you're on 100 mile leash.
Don
 

·
Registered
Joined
·
19 Posts
Discussion Starter #50
Hey Don, great info. The brakes are definitely awful. I'm no gorilla but I think the levers would break before the wheels locked up. I have known this bike for many years and coveted it for ages before the guy agreed to sell it to me for a price I could afford. So I have ridden it before he laid it up and the brakes were terrible then too. Obviously you ride to the limitations but stop in an emergency? Forget it, you're toast. Honestly the brakes on my push bike are better and they are cable operated! So I'm taking a closer look. We have metallic yellow painted AP calipers, one front, one rear, which look about the same size. Discs are undrilled non-floating of course, approx 250mm diameter, again the same front and back. The rear is clean but not scored but the front looks a bit pitted as if it has suffered corrosion which subsequent braking action has not cleaned off. The front master cylinder and reservoir assembly is Tricor which is a UK supplier of spares. The rear has also been replaced and the hoses are braided stainless throughout. Both lever actions are solid, no sponginess, and there is plenty of meat on the pads. If these brakes should provide adequate stopping power, where should I start with diagnosing the problem?
 
41 - 50 of 50 Posts
Top