How to restrict a 850 t3

hi all,this is my first post or Question so I am not sure if I am asking in the right place or not. please advise if i am in the wrong place.I have a 1980 850 T-3 and after many years i finally have a date to take my full driving test. it is 10/02/2014 so i dont have much time to sort out my question I need to restrict my bike to under 35 kw and with a power/ weight ratio not exceeding 0.2kw/kg. I am not excatally sure what kw my bike was when newand I know it will have fallen by now. I was told there is a reducer kir/ spacers or washers that I can install into the carbs to reduce the kw.Can anyone confirm this or advise me on how best to restrict my bike to under 35 kwand if so where to buy the necessary parts and at what cost to expect.I look forward to hearing from someone very soon ,Till then,Martin Smith

Hi as far as I have read in the past the restrictor kit needs to be a fully authorised KIT and not some diy home unit
So I think you might be clutching at straws
If its required for test it would be easier with time restraints to hire a bike for test purposes

good luck on the day and nice to see you have a Guzzi

Why not get a V50 to learn on then put the T3 on the road once you have passed your test and sell the V50.

These list them but dont have stock

Hi all
Thanks for your suggestions and please feel free to. Give me any more ideas. Like everything else it is down to money and it is a shame to spend unnecessary when I already Have a bike and if there is a quick fix then well and good.

Some people were telling me if I put spacers/ washers into the carbs and got a dyno test done that would give me a certificate stating the kw


Martin Smith

now this part of it is intresting you would need to work it outSince the law was introduced there is a lot of confusion with regards to what your allowed to ride.
It is not the size of the bike which is restricted, it is the power
of the engine or the power to weight ratio, putting it simply as an
example, most cruiser style bikes like Harley Davidson’s do not need
restrictor kits fitted because they are heavy bikes which produce low
down power so a bike that weighs 260kg and produces 50bhp will not need
a restrictor even though its above the 33bhp limit. A lot of manufacturers
have realised that there is a demand for restricted bikes, manufacturer
restricted models are usually cheaper to insure. Aftermarket or shop
restrictor kits are rarely recognised by the insurer.

rather than restrict the carbs with washers how about restricting it at the twist grip? the max BHP figures are quoted at 7000 rpm…

fortunately not something i’ve had to get involved in, but it does seem a bit of a minefield…

Might have this wrong but weight of bike 210 kilo power of bike 53 Hp 53 Hp = 38.98 Kwso 39.98 Kw Divided by weight of 210 kilo = 01856 kw per kilo so i make it that you are below thew power to weight limit i think 210 was dry weight so fully fueled and ready to go the weight will be more so that will put you further in the safety margin you need to check this before turning up on the day

Ex smokingbiker2014-01-10 11:51:01

  1. Contact a GOOD rider training school OR the DVLA and ask

  2. Ask a real good dealer Corsa italiana would be my first phone call and speak to Paul

Failing THAT cheapest option IF you cannot use the Guzzi is hire the bike from the training school.

[QUOTE=Ex smokingbiker]These list them but dont have stock

Ah they appear to be throttle slide limiters? But £180, strewth

Could have dreamt this but didnt MCN publish a list when they did an article a bit back.
With an old bike how are they going to be able to prove or dissprove it qualifies ?
As Ray says, a copy of manufacturers quoted specs for the model, the formula and a calculator ( sh*te at Maths) is the way to go in the first instance I would have thought…

The rules changed early last year and are now a complicated combination of power - weight - riders age and type of test taken. Restriction if needed has to be by an approved method not by a Dyno reading. It really is so complicated and open to interpretation that it would be best to speak to someone like Corsa and go from there.I hope you are able to use your T3

Assuming you are taking one or more modules for the A2 test, and not the full test, here’s what the DSA say:
Sub-category A2 motorcycles used for tests must:

be a solo motorcycle
be at least 395cc
be between 25kW and 35kW engine power
have a power to weight ratio no more than 0.2kW/kg
If the engine power of the motorcycle has been restricted to fit sub-category A2, the normal unrestricted power can’t be more than double its new restricted power.
If you have an A2 restricted motorcycle, you must bring proof of the restriction to your test, or it will be cancelled. It must be on headed notepaper from a main dealer, official importer or recognised specialist, and must show the motorcycle’s registration number.

A dyno test certificate will not be accepted as proof of the restriction.

ExampleIf the original unrestricted power of your motorcycle was 60kW, you can’t restrict it to less than 30kW.
I assume, if the link below is correct, the T3 was 43.1kW, with a kerb weight of 240 kilos. By my calculation, power to weight ratio of original bike 0.18kW/kg. (Is the bike’s power printed on the V5?)
If your many years of waiting mean you are over 24, and are happy to ride a 200 kilo bike, you could consider hiring a 595+cc/40kW bike + instructor and taking the same modules for a full A licence. If you pass, you would never need to restrict the T3, and you would be able to insure it more easily.

guzzibear2014-01-11 18:39:05

Surely those four requirements above are inclusive, not either/or, so the bike must have a power output of not more than 35kw AND must have a power to weight ratio of not more than 0.2kW/kg.

Yes, Brian, I agree. So, in fact, big heavy cruisers cannot be used.


As I said the CHEAPEST option is to use an instructors bike …the sheer cost of restricting, getting proof ect is well over £200.

The new bike test is a nightmare, they sure must be trying to put youngsters off from getting into biking. I just wonder what will happen in the future, there will be so few riders to keep all these wonderful bikes that we have now going.

Don-Spada2014-01-11 18:51:19

**** me glad I grew up in a time when just bought a superdream collected it having never sat on a bike before and put in for the test that involved the instructor standing on a corner and it was 4 left circuit and 4 right circuits

The cost will put off many potential riders. For an absolute beginner obtaining an A2 licence at 19 by direct access or a full licence at 24 can cost £900 in instruction and fees alone. That assumes both parts of the practical modules are passed, probably on the same day. If you put a foot down in the figure of eight or U-turn, you you will not be allowed to go on to take the road test…you lose the fee for the second module, and have to wait a minimum 3 days to retake the first. If you fail the independent riding test, you must wait a further 10 days to take it again - for a new fee (£75 or £88.50 evenings and weekends).e.g. Prices
EasyTiger2014-01-11 19:21:59