Trike Problem

[Yoda]

After making the trip from birmingham to scotland my reliant trike showed up a problem that needs sorting ...TORQUE
it will pull healthily to about 65 mph in 3rd gear but when putting it in fourth the revs drop right down and there aint sufficient torque to bring it back up to a reasonable speed (Reliant 850cc recondititioned/unleaded engine mated to a rebuilt reliant box and rialto axle)

any idea's as to 'serious' mods to increase torque and maybe a little more BHP
but not being an expert or even have a clue as to serious mods to an engine i need idea's as to where to start..and as economical as possible to...

i also think that if i cannot get the power i need i may have to convert it to a sshaft drive bike engine (but this will cost me a lot more ... so is a last option realy)

i am waiting for a company company called M & T Race Developments (just outside warwick) to get back to me they are going to have a look and see if they can increase the torque and BHP in my engine and solve my hilly problems...if there aint a realistic solution the i think that i may have to shoehorn a bike engine in it, although after quite a long chat with the bloke, things seem promising......Hopefully (but i would like some ammo to go with first so i dont get whooshed or ripped off)

any help or advice appreciated
and before anyone say sell it and buy another, i cant as it was built around my disability so selling is just not an option
piccies here
http://www.bikerlifestyle.co.uk/Trike/trikes.htm

Yoda

[Pennywise]

i can give you a solution that you have already considered...and that nitrous:)

I got a reliant thingy here...and my father was looking at it the other day, and he said it was a triumph engine....it looks like a trumpet engine. and it bolts to the gear box in the same way with loads od 13mm nuts.....might be worth looking into seeing how close the design is to the trumpet engine, and possibly fit the 13/1500 spitfire engine in there?

failing that...as you say.....shaft drive bike engine

one more thought....why not do a search for these rebel racers, and the reliant banger racer boys, surly they would be the people to get speed and power out of your lump?

[Reliantman]

Yoda.
There was a site somewhere with 1/3 scale racing cars, using piggy engines. I am sure the company that makes them is up in your area.
I know they use a 4-2-1, long centre branch exaust, along with the other mods we have already found. They seal the engines for racing, but If I remeber correctly they get around 70bhp out of them.

[Pennywise]

yip 1/3 scale...thats rebel racers

[Teasy]

Hey Yoda try looking at this earlier thread it has some info on getting more from your Reliant motor.Hope this helps.
Reliant 850cc needs some GRUNT (http://www.100-biker.co.uk/forums/showthread.php?t=167)

[Yoda]

i have spoken to a few people now and the process seems to be as follows
1, Twin choke weber of mk1 fiesta
2, high lift cam
3, electric fan (thanks odie)
4, electric fuel pump
5, porting

and if all this isn't sufficient then
5, engine re-bore

the four branch manifold would have been ideal exept that there is now way i would have enough depth to accomodate one

i am awaiting a call back from an engineer tomorrow as to the cost
but if anyone has a mk1 fiesta twin choke webber for sale? then let me know

Cheers

[Pennywise]

have you considered a set of bike carbs?

if some one can give me a set of carbs and rubbers, ill happily make you a manifold to bolt onto your engine.

[Blackjack]

the Reliant engine has more in common with the Austin Seven engine from the 20's and 30's.

Before you start spending money, you are sure the thing is set up properly? No air leaks, timing set correctly (auto advance not sticking, vacuum advance working), valve clearances set correctly and so on.

A bigger carb and a higher lift cam can quite easily REDUCE the peak torque by the way..........

[Yoda]

the Reliant engine has more in common with the Austin Seven engine from the 20's and 30's.
A bigger carb and a higher lift cam can quite easily REDUCE the peak torque by the way..........

being a bit of an engine internal numpty, what exactly does a high lift cam..or any other cam for that matter do and how does it increase power?

are there any other mods (no not the Fishtail Parka type :D ) you would recommend?

Yoda

[Alik Windrush]

Before You Go Spending Loads Of Dosh Borrow A Set Of Std Reliant Wheels & Tyres... You're Overgeared M'dear...
If The Pig Wheels Help, Then Try 12" (old) Mini Wheels, Then Try 13" Vauxhall Wheels....

[Mad Dog]

I was gonna ask what size wheels are you running? But Alik got there first.

Guy in our club reckons his Reliant is quicker with smaller wheels, he has been able to keep up with club runs and it does 80mph, and flies up hills with little problem.

[Yoda]

14" wheels, but dropping wheelsizes will cause clearence problems....

[Blackjack]

Then you need to look at a lower ratio for the axle. Height of the wheel (including tyre) times Pi will give the distance it travels for one revolution of the wheel. Ball park figure with out any actual data I would expect something like a 25% increase in overall gearing (depending on tyre profiles and so on). Which is a lot.

If you divide the rolling diameter of the standard wheel by the big number in the axle ratio you get the distance travelled for one turn of the propshaft. Divide the rolling diameter of the new wheels by this figure and you get the diff ratio you need to acheive standard overall gearing. This isn't necessarily what you want as that will depend on stuff like the weight difference and the drag coefficent difference between a stock Reliant and your trike, but it should be a lot better than what you've got now.

If you know the height of the standard wheel, the height of your current wheels and the diff ratio you've got I can run the numbers through for you if you want.

[Mad Dog]

What clearance problems?

May be cheaper and easier to address them.

[Yoda]

if i where to loose 2 or 3 inch of the back would leave my sump and exhaust uncomfortably close to the ground and as the engine is mid mounted and we have loads of speed bumps around here then i fear at the very least the sump would ground out (as the trike is quite long)

and i have just priced up the bike engine option (although i would prefer this option as i am realy struggling with the clutch and gear change and if i keep the reliant engine then i am stuck with the gearchange)
and it seems very expensive if i go that route (unless i could get an engine real cheap)
as i would need the following (engine 900cc ish) reveerse gearbox and clicktronik and so far the quote comes to
£650 for quaife reverse gearbox
£500ish for klicktronic
£1200 engine (although shoping around could reduce this somewhat)
£100 ish on parts to move clutch to hand in fitting

and this is without all the frame adaptions of fitting costs

i have just contacted NABD to see what sort of help is available and have to ring the adaptions bloke after 6 tonight

Yoda

[Pennywise]

or just get a 3 cylinder dihatsu engine or simmilar and pay about £120 to have an adapter made

[Yoda]

If you can fit a russian Dnepr or ural reverse gearbox to the Reliant engine (Takes a bit of expertise but can be done) you could then have a klicktronic fitted and use the standard handlebar clutch lever. New g/box mountings would be needed.The propshaft can be a bit of a pig to mate up but you could do the whole job for not a lot of money. The gearboxes are about £50 ish S/H. Use the russian clutch and a pre 69 BMW plate. They will comfortably handle 50 bhp so they are well over the capabilities of the engine. If you got a spare engine, most of the job could be done with your trike still on the road.

As if my tuppenceworth is actually worth owt

i have no prop shaft
my gearbox is mated straight onto the diff (mid mounted)
but tell me more of this russian box i am assuming it is a motorcycle gearbox?
what sort of size is it and have you any links to pictures of it?

i have just spoken to NABD and i can apply for a grant of £1200 which would go a bike way to solving both the gearchange issue and the torque as if i get it i think i could afford to go along this route.


Yoda

[Reliantman]

Yoda.
I have a Cossack flywheel which has been drilled out to fit a reliant crankshaft. I was going to use it with the Reliant flywheel, to keep the electric start. Also have the adapted backplate to fit the gear box. It has been cut out of plate with a torch, needs tidying up, and it only has pilot holes drilled in it so far, which means the holes need enlarging and threads tapped into them.
The Cossack gearboxs are a bit shorter than the piggy one you have, so the length should not be a problem.
Give me a shout if you are interested.

Doug

[Reliantman]

Happy biker.
I had been saving the flywheel and gubbins for a solo piggy-engined project, but it is low priority as I have other stuff to do first. I do not have the clutch though, just the modified flywheel.

[Reliantman]

I will let the stuff go, as I mentioned above, I have quite a bit else to do first and I can't see the bike being built any time soon.

[dracken1]

reliants are not my forte, i perfer vw's air cooled goldwing engine. but..

i believe a 1984 on rialto diff is 2.89:1. where as a robin or early rialto is 3.323:1
if you have the late rialto then changing to an earlier diff would lower your gearing making it a bit more rev happy :)

[odie]

I was led to believe (by my local reliant dealer) that the "rialto 2" (high comp engine, yellow rocker box) has a ratio of 2.78:1 ( i have such an axle ) and that all the rest of the reliants have a ratio of 3.2:1 other than van variants that have a ratio of 3.7:1 and of coarse the regal that has an even lower ratio (cannot remember what) and an axle that comes in 3 parts (good for chain drive trikes).
Your idea is good though draken.
Yoda: your trike is over geared, you could try lower profile tyres or get your engine rebuilt, it would be cheaper than the other options you have put forward, standard reliant with 10 inch wheels , straight out the crate should be good for the ton (just) as they get older and the engine wears out they get slower, any reliant engine that wont do 80mph with 13 inch wheels needs rebuilding.
If you do go for a rebuilt engine get them to do a "lead free" conversion as reliants dont have hardened valve seats.

[Yoda]

my engine is a brand new unleaded unit as is the gearbox rad,starter etc....
i have just put about 1000 miles on the new lump (i think that the overgeared problem is the most likely as the wheels are 14" with high tyres on them.
but having contacted nabd
i have applied for a grant to get the disabled adaptions (klicktronic, reverse control and getting rid of those damn foot controls..woo hoo..no more struggling) done at the same time as i have a motorcyle engine fitted.

just waiting for a quote from GLF in swindon (i have a feeling that this is gunna cost me)

Yoda