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Discussion Starter · #1 ·
Took my PRV apart.
Automotive tire Auto part Gas Technology Audio equipment


Yesterday, this mod possibly saved my engine from exploding.
Best £5 mod, if I may be so im-mod-est...
I'll get my coat

Sunny day yesterday, all's well for 30 miles, minding my own business. Then, oil light brightly comes on at 2500 revs. Then 3000. Then 3500. Rode home mostly at 4000 revs. Less at slow speeds, hoping for the best.

PRV has 1½" spring, it turns out. Although 1⅜" is supposedly correct, same 1½" in my all original '77 bike.
Took a 1⅜" spring out of an all-orginal '79 bike I have.

After 5 mile Light still comes at 2000 revs. Then at 2500... No ignoring that light...

Longer spring must mean more pressure? Maybe damaged crankshaft seal...

Anyway, Slo
I am sooo jealous! :love:
I look upon it as the New Normal. Being off the road. It's actually old New Normal for me. That's why this thread is good. Ride someone else's ride.

Edit
I know the PRV has a damaged mesh. It was crushed, then split when I prodded it. Fitted a new body as well as spring.
 

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1978 T140E EX
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I know the PRV has a damaged mesh. It was crushed, then split when I prodded it. Fitted a new body as well as spring.
After my engine is heat soaked I get the red light blinkety-blink even at a high idle so checking my PRV is on the list to look at.
How did the piston and bore look? Anything else look out of the norm other than the spring length?
 

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mine used to blink at hot idle. when i blocked the oil feed to the tappet guide block the light went out and i never see it any more when the engine is running.
 

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Discussion Starter · #4 ·
After my engine is heat soaked I get the red light blinkety-blink even at a high idle so checking my PRV is on the list to look at.
How did the piston and bore look? Anything else look out of the norm other than the spring length?
Piston and bore fine. Replaced them anyway with original Triumph PRV body, only 10,000 miles of use.

Exactly same thing. Start of ride light goes off even when idling, at very beginning. Then light comes on at idle, after a few miles. Then a bit later at 2,000 revs ... presumably as oil things, pressure drops.

Not hot here. Oil only 600 miles old.

Think it's normal to blink at idle though, when oil is hot, don't think you have a problem?
 

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The oil light shouldnt be on at all when the engine is running, even idling. Never seen that on my T140E (owned 42 years as of a couple of days ago). When the oil light did come on a few weeks ago, checking the oil pump found that the feed side plunger / ball valve were not working properly. Time to get into the timing chest and check the operation of the oil pump. PRV spring length; the Haynes manual suggests one length, the Triumph workshop manual - downloadable from various websites - suggests 1.375" / 35mm.
 

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Hi,
oil light brightly comes on at 2500 revs.
red light blinkety-blink even at a high idle
The oil light shouldnt be on at all when the engine is running
This.

Top of any "list" should be, "Obtain/fit oil pressure gauge in place of mickey-mouse switch. Ride around 'til engine is good 'n' hot. Does oil pressure match Triumph workshop manual? If yes, throw away mickey-mouse switch. If no, throw away mickey-mouse switch and strip engine."

The OP switch closes (and the lamp lights) at around 3 psi. As you should know from looking in your Triumph workshop manual, idle pressure is at least 20 psi and "Normal running" (3,500 rpm +) is 65 psi. Even if you dream that 10 psi per 1000 rpm is OK, it's still nowhere near 3 psi.

17-62 psi is not in 1/8" of OPRV spring. Agonising over it is a triumph of hope over reality.

Many years ago, one of my T160's was doing similar things. Less-experienced, I believed the folk remedies of 'experts' who told me I just had to change the switch. Even though it's getting on for forty years ago, the bill to rebuild that engine is still :eek:

Hth.

Regards,
 

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Discussion Starter · #7 ·
Top of any "list" should be, "Obtain/fit oil pressure gauge in place of mickey-mouse switch
I've been toying with that. Then saw price. £150

However,

Many years ago, one of my T160's was doing similar things. Less-experienced, I believed the folk remedies of 'experts' who told me I just had to change the switch. Even though it's getting on for forty years ago, the bill to rebuild that engine is still :eek:
I'm too old for such a shock 😀

I'll start toying with the idea again.
 

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you can buy an inexpensive oil pressure gauge from any industrustrial supply house, plus a few fittings. the difficulty is matching the threads on the gauge to the threads in the timing cover. even with the correct TPI, the cover threads can be straight or tapered, and tightening the wrong threads can crack the cover.

however, even a fitting with the wrong taper can be gently screwed into the cover temporarily, just tightly enough to test oil pressure. ive done that. just be careful.
 

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Discussion Starter · #9 ·
however, even a fitting with the wrong taper can be gently screwed into the cover temporarily, just tightly enough to test oil pressure. ive done that. just be careful.
Thanks. I'll pass on that, Speedy. Need to consider neighbours. When it turns out I wasn't careful enough 🤠.

Maybe someone knows a correct fitting? I'd mount it permanently, as a problem could arise on the next ride. Or one of the following.

I like the solution below. Although has distinct disadvantage of not being visible whilst riding with ones head in normal position.

Automotive lighting Automotive tire Vehicle Motorcycle Motor vehicle
 

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Discussion Starter · #11 ·

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Hi,
Can't really wait as purpose is to check before using bike again.
inexpensive oil pressure gauge from any industrustrial supply house
Friend has a sideline working on Triumphs. As many bikes don't have a pressure gauge, he cobbled up a second-hand car one from Ebay mounted on a spare clutch lever pivot casting/clamp so it could be mounted temporarily on any bike.

Otoh, if you want a new gauge, e.g. WIKA?

Maybe someone knows a correct fitting?
Any Triumph twin with a date code in the engine number originally had a timing cover with 1/8"NPS (US National Pipe Straight) thread, likely still does.

Nevertheless, over half-a-century on from when the first were fitted, there is an outside chance any twin can have been fitted with a very early '69 timing cover, at least some of which had 1/8"NPT (US National Pipe Tapered) thread.

For clarity, as they're pipe threads, the 1/8" is a notional inside diameter, both threads are over 3/8" OD.

The ideal way to check any timing cover is to have two oil pressure switches, one of each thread, and try them in turn, fitting them using thumb 'n' finger only. However, if you only have a NPS switch:-

. NPS cover thread, switch should screw all the way into the cover using thumb 'n' finger only;

. NPT cover thread, NPS switch'll screw in only a few threads;

. NPT cover thread and NPT switch, it used to be the switch'd also screw all the way into the cover; modern shonky switches, no guarantee. :(

Gauge bought in GB will most-likely have a 1/8"BSP (British Standard Pipe) thread. Be aware, while BSP looks similar to either NP thread, it isn't, BSP is both a smaller OD and 1 tpi (thread per inch) different.

I'd mount it permanently
My preference too. My T160's have L.P. Williams kits, my T100 has:-
Three Gauge Brackets for Triumph Motorcycle (triplesrule.com)
... however, if you want something quick to discover whether your bike has an actual pressure problem, neither of these'll be quick. :( The potential problems are:-

. LPW gauge mounting isn't suitable for a pre-'79 twin. Also, while the eponymous Les fitted his '79-on twin-based "Buccaneer" with the gauge and therefore an engine connection, LPW's current owners don't offer the engine connection bits. :(

. OIF fork yokes are closer together than dry-frame; only a 1/4" but that brings the fitting on the end of the Triples Rule OPG either very close to or actually contacting the headlamp shell; :( this has caused problems for both @triumpt120rv and @TR7RVMan. '73-on fork shrouds, ime the Co-op was somewhat cavalier about the exact vertical positioning of the threads for the headlamp brackets so, if one pair causes the headlamp shell to contact the OPG fitting, another pair might not?

. Another problem with the TR OPG is it doesn't have built-in illumination. :(

. At the engine end, on a twin, the only possible OPG connection without major work is the oil pressure switch port in the timing cover, then you bump into the thread problem detailed above ... @triumpt120rv has encountered problems with the hose fittings TR supply so likely the best solution is something from Morgo, either the "Multi Point" thingy you found or a version of this with a NPS- or NPT-thread banjo bolt as required.

Hth.

Regards,
 

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Discussion Starter · #14 ·
best solution is something from Morgo, either the "Multi Point" thingy
Been looking hours. The thingy ( Morgo multi point pressure switch adaptor) is all I've found that has NPS to BSP adaptor. The BSP end can then be fitted with BSP to oil line fitting


I not exactly au fait with all these pipe abbreviations, so getting the above will at least mean it fits (🤞 bar what Stuart points out; can't say whether anyone has swapped the case for an older one).

So I might get that, and a ⅜ BSP run-of-the-mill guage and two ⅜ BSP fittings. This works out no cheaper than buying the Morgo guage kit, so it's a pain it's not in stock.

I'll see if anyone posts anything here...
 

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Discussion Starter · #15 ·
Friend of has a sideline working on Triumphs. As many bikes don't have a pressure gauge, he cobbled up a second-hand car one from Ebay mounted on a spare clutch lever pivot casting/clamp so it could be mounted easily on any bike
Read that. Went in garden.
Wood Twig Plant Metal Natural material


Rescued this Triumph lever that was rusting away. Might be able to bodge a handlebar mount.
👍
 

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Discussion Starter · #16 ·
Going back to an earlier picture posted.
Automotive lighting Automotive tire Vehicle Motorcycle Motor vehicle


Appears to have a single (not multi) NPS connection. Might have retapped cover?

Maybe someone knows of such a NPS connection? Morgo don't sell them separately, maybe for obvious reasons.

I prefer it to the Morgo multi, not as bulky. And don't think I'd need a light anyway, with a guage fitted?
 

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Hi,
not exactly au fait with all these pipe abbreviations
⅜ BSP
Uh-uh, none are 3/8", all are 1/8":-
For clarity, as they're pipe threads, the 1/8" is a notional inside diameter
Then:-
1/8" NPS (US National Pipe Straight) thread
... most likely in your bike's timing cover;

1/8"NPT (US National Pipe Tapered)
... outside possibility in your bike's timing cover;

1/8"BSP (British Standard Pipe) thread
... most likely on any gauge you buy.

Rescued this Triumph lever that was rusting away. Might be able to bodge a handlebar mount.
Risking labouring the point, the existing clamp will fit around the handlebar, discard the lever and pivot bolt, mount whatever gauge your find/buy on the remainder of the lever pivot clamped to the handlebar.

Morgo multi point pressure switch adaptor
might get that, and a ⅜ BSP run-of-the-mill guage and two ⅜ BSP fittings.
As above, they'd be 1/8"BSP.

works out no cheaper than buying the Morgo guage kit, so it's a pain it's not in stock.
Afaict, the "kit" is "Out of stock" only because the gauge itself is out? If yes, while you can obviously order all the bits separately, have you considered asking Morgo if they'd just supply a "kit" without the gauge, you'll source the gauge elsewhere? As I say, most-likely any gauge will have a 1/8"BSP connection, their normal kit gauge does and they supply a hose-gauge adapter.

Going back to an earlier picture posted.
Might have retapped cover?
Unlikely - remove the switch from your bike's timing cover and look at the wall thickness of the cover, no material to drill out for another thread, any pressure (even just screwing in a switch too hard) splits that outer wall. (n) Really crap by Triumph, they should've added material to '69-on covers, they did it on other castings where it was more difficult. :(

someone knows of such a NPS connection?
Ime, off-the-shelf NPS-thread connectors have been difficult for years, NPT is more common even in the US. :( The connection in your photo. could be NPT or it's simply been turned from bar - easy to thread if the turner either has the necessary die or can screw-cut the thread.

don't think I'd need a light anyway, with a guage fitted?
If you never ride in the dark ... :cool: fwiw, I've retained the warning lamp on all my Triumphs.

Hth.

Regards,
 

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1978 T140E EX
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I came across an ad for this in Vintage Bike Magazine
Three Gauge Brackets for Triumph Motorcycle (triplesrule.com)
@Flicker - This is interesting and looks well made. I emailed them to see if it is in stock. A gauge is provided but no fittings. Wonder if the bracket gauge bore is specific to their gauge - will ask if they reply.
@Rioja John this looks to be the same manufacturer as your 2 gauge bracket. Was there a reason you installed the 2 gauge bracket and then the handle bar mounted Morgo?
These folks in Texas offer the Morgo OPG setup Sealy Cycle Service but it states it comes with a 1/8 BSP fitting. They also have some very fine cycle gallery photos! I sent them an email to check stock.
 

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Hi Ricky,
(y) The bracket is a work of art (I've had one on my T100 for something like 25 years).

gauge is provided but no fittings.
Uh-uh. From the webpage:-
Includes Oil Gauge, Oil Line, & Fittings
... however, @triumpt120rv has reported problems with the supplied mixture of Imperial fittings and metric hose. I avoided any similar problems by accident - first my original gauge, hose and fittings came from a British supplier (long story, posted previously but I can relate again if desired), now because I use Goodridge braided hose and end fittings.

Wonder if the bracket gauge bore is specific to their gauge
No, standard size, I'll measure my T100's if it's important.

Sealy Cycle Service
offer the Morgo OPG setup
states it comes with a 1/8 BSP fitting.
(y) The gauge fitting is 1/8"BSP (I suspect it's pretty-much standard as BSP is an ISO threadform). If you look at images of the contents of the Morgo OPG kit, one part is https://www.morgo.co.uk/product/morgo-4mm-female-push-fit/:-
4mm x 1/8″ BSP female push fit pipe fitting designed to fit our pressure gauge kit. Gauge end.
... i.e. connects the 4 mm. plastic hose to a gauge's 1/8"BSP male thread.

Hth.

Regards,
 

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You can get NPT to BSP adapters pretty easily.
You could convert the NPT thread to NPS using an NPS die.
You could maybe run a single hose direct from the timing cover then add a T piece hidden higher up, maybe behind the headlight, for the switch.
None of this is particularly quick though.
There are cheap electric gauges (£15?) with a pressure sensor at the engine and a wire to the gauge, need 12v power to the gauge and might not work on positive earth unless isolated, probably ok just to do a quick oil pressure check at home.
 
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