[shashank.nk]

Sir Alec, great work to clean the carb and post a thread on it. We also have a very old Maruti 800 (1988 model) and the minute i noticed the thread i thought i'll try it on our own 'bakra'. Its a lot more complicated than i thought, so i'll stay away from what will end up in a 'mis'adventure.

Out of curiosity, will my car also have the same carb as your 12 year old model ?

[techkarl]

Originally Posted by SirAlec

Sorry! I don't have it. I used this manual only as a reference to everything.


PS:I am also searching for the same.

Is there any special tool by which you can unscrew the carburetor nuts more easily? As they are in an awkward position, Thanks.

[techkarl]

Originally Posted by SS-Traveller

The complete carburettor assembly and part numbers...

Attachment 931475

Attachment 931476

Attachment 931477

Is this a mikuni carburetor?

[SirAlec]

Originally Posted by techkarl

Is there any special tool by which you can unscrew the carburetor nuts more easily? As they are in an awkward position, Thanks.

normal open 13/14 spanner does the job well. You have to turn it in small steps.

Originally Posted by techkarl

Is this a mikuni carburetor?

Don't remember the part number but Its indeed a mikuni.

[SS-Traveller]

Originally Posted by techkarl

Is this a mikuni carburetor?

Yes indeed, Karl, it's a Mikuni. Afraid I don't have the technical specs and how-to manual. But as SirAlec said, it's not too different from a Solex, so you'll be able to open and reassemble without messing up (if you've got previous DIY experience with carbs of any type, though).

Wish you all the best in your project...

[techkarl]

Originally Posted by SS-Traveller

Yes indeed, Karl, it's a Mikuni. Afraid I don't have the technical specs and how-to manual. But as SirAlec said, it's not too different from a Solex, so you'll be able to open and reassemble without messing up (if you've got previous DIY experience with carbs of any type, though).

Wish you all the best in your project...

thanks, do you have a picture of higher quality so as to print it in larg format ? Thanks.

[SS-Traveller]

Originally Posted by techkarl

...do you have a picture of higher quality...

Sorry Karl, but I only have low-res scans - have lost the original paper version (hard copy).

[fighterace]

Originally Posted by SirAlec

...

About the brake system, the Booster assembly was found by a friend with a kabadi. So i checked for any leaks and it was perfectly all right. All the markings are worn out. Its a possibility its a Kalyani one.

I make use of a T that i found and use the vacuum supply from input manifold. Yeah the same place the input is given to miniature AC pump.
...

Dear SirAlec,

I am interested in attaching a booster to my '99 M-800 carb. The braking is good with 1-2 passengers, bit with a full load it is a little... inadequate. I'd be grateful if you please share the post booster experience, and also let me know how to get clearance between the fluid resevoir and the air filter housing.

Regards

Fighterace

[SirAlec]

Originally Posted by fighterace

Dear SirAlec,

I am interested in attaching a booster to my '99 M-800 carb. The braking is good with 1-2 passengers, bit with a full load it is a little... inadequate. I'd be grateful if you please share the post booster experience, and also let me know how to get clearance between the fluid resevoir and the air filter housing.

Regards

Fighterace

i have installed booster of old zen. There is no need for any clearance. Brake is adequate for stock 800. its just that i keep experimenting on this car as this is not my daily drive. Its my first car so will keep it till eternity.

If its not adequate please bleed the line. and make it proper before trying anything new.

[sanyal779]

Good day Sirs,

this is a wonderful thread and enjoyed all the posts. excellent pictorial guidelines for DYI.

The reason for my response is I would like to pass on a suggestion which might interest some M800 owners.

I had bought a 1989 model Maruti 800 sometime in 2003, a few months after our first new Zen mpi 2000, only to learn about the carburettor! I had opened and reassebled the carburettor many times and tried all sorts of repairs including re-building the butterfly flaps in a ' Lathe".[ Please note Lathe here in this post does not mean a Lathe machine, in Kolkata mechanic circles, a workshop carrying out machining jos is called a Lathe !, funny but true].

There were endless experiments and settings to try including A/F ratio variations and altering the spark timing {Adv/Ret} and testing the flywheel speed with a stroboscopic torch I had borrowed from my friend. I had used the passage cleaning sprays to clear out blockages in the inaccessible parts in addition to cleaning by petrol. I had also taken help from mechanics , both from road side garrages and from maruti autuorised workshops, to the point where these people too kind of gave up me! No doubt the performance improved a lot, but refinement and smoothness of a new car was never achieved. I tried in vain to eliminate the vibration felt on the steering during idle, it never went away fully. Recommended speed setting in idle is about 800 rpm, but in my tuning, at any setting below 940 rpm steering vibration would persist. But tuning a M00 at any speed above 820 is not accepted as a good job by the professionals! And lowering to 800 rpm , the steering vibrations would relapse! Of course I had the engine re-built in between using the maruti authorised 'half-engine' [ meaning upwards of the crankshaft]. All engine mountings were renewed by MGP new spares. Etc. The car was an excellent performer , city and highway both at maxm 120 kmph steady [ above this I did not feel safe as the car used to feel very light] The only problem that intrigued was how to remove this steering vibration at idle.

I reasoned out that the fine measurement internal passages are gradually eroded by the flow of air fuel mixture, this is something that no one can restore. Even the butterfly flaps can never be made perfect. So why not try a complete new carburettor? Mechanics including those from Maruti Authorised worskop would not agree with me, saying that nothing better can be done to an old car. But I went ahead and boght a new carburettor for maruti 800 from an indepndent spare part shop- it was not a so called Delhi made part but a MGP spare [ I had believed the shop guy].

I came home with new complete unit and dismantled it to check. Visibly there were no much difference from in-use one, except the butterfy valves looked better. Re-assembled and fiited onto the engine. Was a very very soothing experience to do it myself - the same memories when I saw the photos in this thread!

My engine worked nice and smooth. I lowered the idle speed to 850 , still no vibration in the steering. I was too happy with my job. But still not perfect. For more fine tuning took it to my friend who owns the Maruti Authoriised Service centre and is an automobile engineer himself. He too was happy that my doggednes finally paid. He did the final tuning and the advance/retard adjustment himself. Now we had it smooth and perfect at 810 rpm and the electrical timing about 5 degress os so retarded.

The full carburettor unit had cost me Rs 3500 in mid-90's. I am sure some units will still be available in BS-III towns. I would encourage all old M800 owners to try this and enjoy a complete new engine feel.

warm regards
SSanyal

[fighterace]

Originally Posted by SirAlec

i have installed booster of old zen. There is no need for any clearance. Brake is adequate for stock 800. its just that i keep experimenting on this car as this is not my daily drive. Its my first car so will keep it till eternity.

If its not adequate please bleed the line. and make it proper before trying anything new.

Thanks SirAlec. I'll keep youe advice in mind. The 800 is a different beast from a diggerent era, and I guess is best left as such. My 800 is my dad's car in which I learn to drive :-), and is in my poesession at the moment, along with my own used B-Zen (B for battered). I

[fighterace]

Originally Posted by sanyal779

... I tried in vain to eliminate the vibration felt on the steering during idle, it never went away fully. Recommended speed setting in idle is about 800 rpm, but in my tuning, at any setting below 940 rpm steering vibration would persist. But tuning a M00 at any speed above 820 is not accepted as a good job by the professionals! And lowering to 800 rpm , the steering vibrations would relapse!...

Dear Mr Sanyal,

I too am a Zen MPI and 800 Carb user, and was using the 800 before I got the Zen. Both were used cars with approx 10 years and 65000 kms before they came to me. I'd like to say that they are very different machines, and the vibrations at idle that you talk about are a very 800 experiene, esp. after a cold start. In fact my FNG (a skilled one i must add) uses the vibrations to set the idle rpm, much like a doctor checks the pulse. The 800 is to be enjoyed upto a speed of 70 kmph, and the bottom end torque is to be relished- I can accelerate from almost near standstill in 2nd gear with two passengers, and in average city traffic the 3rd gear is like an auto transmission, which'll be a boon in Cal traffic. Quite opposed to the Zen which feels best when the engine is almost near redline, but low end torque is almost absent- i have to rev the engine to mid rpms to get the car rolling, or the engine starts to protest.

regards,

Fighterace

[Doc Maanava]

Installed purfectly
Attachment 910496

Secondary jet pump
Attachment 910497

Dear SirAlex and other experts, Today i asked my MASS to perform a carb overhaul. They did and in the end they said that it failed and they have to replace the entire carb. This costs Rs.7000 without the labor costs.

My question is there is a brass like thing in the picture with legend "Installed purfectly". Could you please tell me what that is. The mechanics are saying that it is not pumping enough fuel, when acceleration is required all of a suden and hence when we accelerate there is a jerk. Moreover, this cannot be corrected and hence we have to buy a new carb. However, driven sedately it can be managed but with stoppages and jerks.

1. Can a carb overhaul fail so badly that we need to change the carb?
2. What is the name and function of the brass coloured stuff in the pic. I have attached a pic to this post and i have placed a red coloured arrow to point to the (jet?) thing i am talking about.

Could any of the experts please help? I report back to the garage tomorrow morning and i need to make a call on whether what the mechs are saying is true?

Does my maruti really require a new carb or are they taking me for a ride.

Looking forward to your replies. SOS. You can reach me on 919141855109 as i really need to be at the service centre early tomorrow morning and i might not be able to see your posts.

Please help. A million thanks!

[Sankar]

Originally Posted by Doc Maanava

My question is there is a brass like thing in the picture with legend "Installed purfectly". Could you please tell me what that is.

Thats the accelerator pump squirter. There is an accelerator pump circuit in that carburetor in the pic. When the throttle is stomped on in a hurry (for quick overtaking for example) the accelerator pump will squirt some petrol into the venturi. This is to compensate the lean condition that arises during the sudden opening of the primary throttle butterfly. When the throttle is opened gradually the accelerator pump doesn't squirt fuel into the venturi. If this doesn't work the engine may hesitate during quick acceleration.

The carb overhaul kit should come with all gaskets and O rings including the one thats required for the accelerator pump, so i'm not sure why it can't be set right? Mostly all A.S.S.es operate in replace mode rather than repair mode since that saves time. But if you find the right person he will make that carb as good as new, probably some one in your area can help you out.

[CrackedHead]

Originally Posted by Doc Maanava

Dear SirAlex and other experts, Today i asked my MASS to perform a carb overhaul. They did and in the end they said that it failed and they have to replace the entire carb. This costs Rs.7000 without the labor costs.

Do get a second opinion at Suraksha on hosur road. They are highly recommended.

It is likely that something is clogged and your current MASS is unable to sort it out.