3 wheels on my wagon

[Andrew C]

I have now done about 50 miles in my R4 based trike since it passed its MSVA test, and nothing major has fallen off yet, so a result so far!!

It seems to ride OK, and goes round corners reasonably well.

Performance is a bit sluggish as yet, but from some other symptoms (stutters when accelearting on light throttle and stalls occaisonally on a trailing throttle), I'm tentatively diagnosing weak mixture.

The carb is a 'direct' replacement for the Zenith 28IF sold to me by the Carb. Hospital. It took some filing to fit, and purports to be a Solex 32SE1A on the invoice, although it has Zenith cast into the body. There appears to be just the same mixture adjustment screw as on the 28IF, so I'll open it out until it feels a bit happier. If that fails I'll either borrow my dad's colourtune or investigate a Gunson gas analyser.

Do you feel I'm on the right track?

 

[Steve Hennessey]

I also went to the Carb Hospital to buy a replacement for the 28IF when I first got my R4GTL. I also had to file the holes out to make it fit. It was expensive and it performed in exactly the way that you describe. After some research I found out that it was originally for a Mk1 Vauxhall Viva. Nothing I did to it made it work properly and the Carb Hospital were less than helpful in suggesting remedies. I refitted the 28IF, and although it's not a good carb in my opinion, at least it worked. The Vauxhall Viva carb has been chucked in a box to gather dust forever. An expensive mistake on my part and I will never deal with those cowboys again.

The carb you need to fit is a 32IF from a Mk1 1100cc R5. I have already posted details about this carb on this forum so do a search and get all the info.

Sorry to hear that you've been conned as well.

Steve

 

[Andrew C]

Thanks for the reply

I wish I'd know about this website before I bought the carb, but unfortunately that was back in 2003. Now I have spent the money (you're right, it wasn't cheap), I'm inclined to persevre, particularly as I just built the trike for pottering about in on B roads and its not a daily driver.

My latest work this weekend has been fitting new points, rotor arm and distributor cap. The trike uses a 'self-build' Vellman electronic ignition kit I bought from Maplin. This retains the points, along the lines of the Boyer and Pazen sysems I've seen posts about. The kit only cost about a tenner, but you have to solder it up yourself. I had to have a go at this, becasue my dad, who's an electronics engineer by trade, designed and built an electronic ignition for his 'M' reg 850 Renault 4 back in the 1970's.

Other changes from standard are a 'cut and shut' exhaust pipe to route straight outside the bonnet, and a fairly simple exhaust system that uses stainless steel pipe and a single 'cherry bomb' silencer. I'll try and attach a photo.

After retiming the ignition to Clementines recommendation of 'between the timing' marks, I went for a run this afternoon and the performance seems a bit better. Still a very slight hesitation on light throttle, but a fair degree of acceleration once its past that point. Mind you, there should be, the thing only weighs about 440kg unladen. If I can get my confidence up, I should be more than capable of giving the 2CV trikes a run for their money.

 

[Steve Hennessey]

This carb is exactly the one they supplied to me and you have made it fit in exactly the same way I did. I even bought the pancake filter from them as well. I can see that, because of the bonnet line, you can't fit the R5 IF32 set-up so you have lot's of playing around to do. You could try replacing the main jet with a larger size as it will run weak with that filter, or by fitting an air filter that is more restrictive. Good luck!

 

[Andrew C]

Carburettor type

Hello Steve,

I think this 'mystery' carb has appeared in a number of posts on the site now, and I think I can identify it. It seems to be a Zenith 30IZ, and was original equipment on Viva 1100, Reliant Rebel, Ford Escort 1100 and possibly others in the late 1960's / early 1970's. There are a number on ebay at the moment, both new and second hand. I've found an exploded view image which I'll attach below, but unfortunately the item no. list isn't there.

Regarding your comments on the air filter, I was wondering if the problem might be that it was too restrictive. Its a lot smaller than the original filter, and very close to the bonnet as you point out. I've also found the plugs to be quite black and sooty, and it seems better now I've screwed in the mixture screw slightly. Is there an infallible test for mixture strength that doesn't involve a gas analyser because I've never had much look with Colourtunes? With regard to the airfilter, in the past on kitcars I've always used K&N filters, which are supposed to flow more air than the chrome pancake foam type. I'm struggling finding a K&N that will go under the bonnet however.

In case I'm wrong about being too rich, I've also picked up from a reliant website that the main jet was originally 100 - 105 and was reduced to 92 - 95 for emissions. I might contact the Carb. Hospital and ask what jet it was originally supplied with, and whether a 105 jet is available in case I am to weak

Finally, when you tried this carb, did you modify the pancake filter case to take the oil vapour breather pipe?. I've done this so it feeds back into the filter case.

I'll keep updating this thread in case anyone else wants to try this carb out as a replacement or alternative for the 28IF. The second hand 30IZs on ebay start at around a fiver.

 

[Steve Hennessey]

Hello Andrew,

In theory there is no reason why this carb should not work, it just didn't work with me! I have never found those pancake filters to be restrictive enough and I'm surprised that the plugs are sooty. However, there needs to be a fine balance between the filter and the jetting so one compliments the other. To get a true picture of what's going on it may be worth going to a friendly garage or MOT station and ask them to hook up their professional analyser to look at the readings throughout the rev range.

I did modify the pancake filter to fit the engine breather pipe.

If you do manage to sort it out then I'm sure others may be interested, but for me, I would always recommend and use the 32IF with the water heated base. If someone was to use this Vauxhall carb on their R4 the air must be heated in cold conditions via the exhaust pipe otherwise the carb will ice up. You can't do this with the pancake filter, but I take it that you won't be using the car in winter??

 

[Andrew C]

Hello Steve,

I have taxed for 12 months (its cheap for a trike!) and fully intend to use all year round, becasue the major advantage a R4 based tike has over a 2CV based trike is not the extra 500cc capacity, but the fact that I've kept the heater!!. I speak from experience as my dads 2CV based trike can be decidedly cool at this time of year, and he generally only taxes between May and October.

I will however only be using it when its not raining, so that might limit my mileage for the next 6 months, as anyone who's seen the pictures in the gallery will understand.

On a serious note, I'll watch out for carb icing, although I think it will be warmer under my bonnet due to the reduced volume, and the fact that the radiator core is somewhat narrower than the original R4. A local radiator factor made it up as a special using the plastic R4 panniers and a new, narrowed matrix. This was easier than fitting a Mini unit or similar, becasue the inlet and outlet pipes still line up. Cooling capacity in summer hasn't been tested yet however.

 

[Andrew C]

Update on Zenith 30IZ carb

An update on the Zenith 30IZ carb. I didn't use the trike much last year (work etc.), but when I did use it the stuttering was still present. I splashed out on a second hand gunsons gas analyser from ebay, and after a careful afternoon it was maybe a little bit better.

However, a couple of months ago I was searching the forum for clues and decided to investigate what Haynes calls the 'oil vapour reintake' system. On blowing through the pipe, it was clear there was a blockage, and investigation revealed the 1.5mm dia hole in the 'bung' nearest the carb was blocked, so I carefully cleared it. Unfortunately I haven't driven the car after this until tonight, but a quick pre MOT run around seemed to indicate a transformation, with no stuttering or fluffing, and a lot better acceleration.

Speaking of MOT's, can anyone beat my appointments for tomorrow morning
08:00 T reg MX-5 (bought off ebay just before Xmas)
10:00 Marlin Cabrio kitcar, built by me 1994, 31000miles, but only 500 in the last 2 years
12:00 R4 based 3 wheeler, again only a couple of 100 miles since retest

Why is it where cars are concerned logic goes out the window?

 

[angel]

A question from me: Did you fit the 30mm carburettor on a manifold made to accept a 28mm carb? Did you enlarge the inlet bore? If not, this may well be the problem. Also I think that 95 is too small a size for a main jet for 30mm throttle. What venturi size do you have?

 

[iancr900]

you could get it dyno tested.thats what most of the mags recommend when its a carb problem.