Alternative carbs/carb swap

[Yuna_Pup]

Hey all, I have a 2000 baghira 660 and I was thinking of trying to squeeze out a few extra horsepower before changing cams, timing or going with a big bore kit.

Has anybody used a set of carbs from something like a 96-01 TDM850 ?

I know a few people have used the intake manifold from a 660 grizzly and gone with a single carb but it may require cutting a support in the frame, and I cant seem to find any of the intake manifolds easily in the UK.

Any thoughts or advice ?

[breakwellmz]

Hi.

A less restrictive/lighter exhaust system to start, with suitable re-jetting.

I wanted a single carb (A CVK40 `pumper` carb) and started going down that route at one point. I thought the port centre-to-centre distance difference between the Grizzly manifold and the MZ head to be too much for an adaptor plate to accommodate. I also found i didn`t have the space within the frame (Mastiff) for it all to fit!
I ended making my own Heath Robinson version, I`m trying to find a picture of it but here is the RH side -

Cheers.

[breakwellmz]

Here is the image I was looking for. Don`t laugh, it works for me!

Certainly not the `performance` upgrade I think you may be looking for, but the benefits for me are. -

1/ - Far better starting and idle.
2/- Increased low/midrange torque (So much so I had to raise the gearing to make first gear usable!)
4/- Improved fuel economy.
5/- Much quicker off the line.

[DAVID THOMPSON]

what size is the copper elbow i am getting ready to do this
to mine

Dave

[droy]

for true performance your options are a double 35mm to 39mm set of Mikuni or Keihin carbs - new likely worth the same as the motorcycle. Do some searches in this forum for those and you find some info. If you look on ebay (USA) for a Edelbrock Quicksilver Raptor 660 carb you see a 2 to 1 manifold that works on our engine - I have it on a Skorpion but not sure if it hits the Baggy frame.

[Yuna_Pup]

Hey breakwellmz.

Your setup looks really nice !

I didn't know that was the case with the grizzly manifold

I already have a BSM end can on the bike and have changed the main jet on the main (small) carb from a 130 to a 135 with the mixture screw 5 or 6 turns out I cant remember exactly, the bike runs great and can consistently hit 95mph, though I would really like it to pull the front wheel up in 1st and maybe 2nd more.

Basically as much torque as I can get from it without drastically affecting it's reliability.

With your setup, would the missing carb not cause issues with lower air volume entering the engine ? Of course the air now has a much greater velocity which probably outweighs the lower volume especially when the throttle is open. Also, what is the copper tube to the other intake actually doing ? It seems like its at a very odd angle and would struggle to capture much air and fuel from the other intake boot but of course it works for you !

And finally, what kind of jetting are you running ?

I am not very experienced with this kind of thing so if I am talking total rubbish please tell me, just letting my brain run and spitting out the results

[DII]

On my Mastiff with stage 1 cam and 718cc ( stroke 88mm and bore 102mm) I use Mikuni flatslide from Kedo. Wery easy to set up and works like a dream.

[DAVID THOMPSON]

i got spoiled by a BMW 1974 R90s it ran super for 40 years as a daily driver
the original carbs on the mz i an less than pleased
the only time a bike should run bad is it runs out of gas
and that can make you get ran over
BY A BIG TRUCK IN THE USA
dave

[breakwellmz]

what size is the copper elbow i am getting ready to do this
to mine

Dave

Hi David.

It`s a 15mm diameter elbow.

Cheers.

[breakwellmz]

for true performance your options are a double 35mm to 39mm set of Mikuni or Keihin carbs - new likely worth the same as the motorcycle. Do some searches in this forum for those and you find some info. If you look on ebay (USA) for a Edelbrock Quicksilver Raptor 660 carb you see a 2 to 1 manifold that works on our engine - I have it on a Skorpion but not sure if it hits the Baggy frame.

I don`t feel there is any room within a Baghira/Mastiff for any off the various options of 2 into 1 manifolds that have been available, there just isn`t the space compared to a Skorpion frame.

[breakwellmz]

Hey breakwellmz.

Your setup looks really nice !

I didn't know that was the case with the grizzly manifold

I already have a BSM end can on the bike and have changed the main jet on the main (small) carb from a 130 to a 135 with the mixture screw 5 or 6 turns out I cant remember exactly, the bike runs great and can consistently hit 95mph, though I would really like it to pull the front wheel up in 1st and maybe 2nd more.

Basically as much torque as I can get from it without drastically affecting it's reliability.

With your setup, would the missing carb not cause issues with lower air volume entering the engine ? Of course the air now has a much greater velocity which probably outweighs the lower volume especially when the throttle is open. Also, what is the copper tube to the other intake actually doing ? It seems like its at a very odd angle and would struggle to capture much air and fuel from the other intake boot but of course it works for you !

And finally, what kind of jetting are you running ?

I am not very experienced with this kind of thing so if I am talking total rubbish please tell me, just letting my brain run and spitting out the results

The copper elbow supplies the smaller of the two inlet ports.
Increased inlet charge velocity due reduced carb area is exactly the reason the torque is produced at lower revs, I do have slightly less `top end` though I`m sure
What also improves throttle response greatly is the fact the the CVK40 is a CV carb with a "pumper", a good all round sort of carb in my opinion.

I have got all the bits now to proceed with this sort of thing, just need more time! -

[breakwellmz]

On my Mastiff with stage 1 cam and 718cc ( stroke 88mm and bore 102mm) I use Mikuni flatslide from Kedo. Wery easy to set up and works like a dream.

Hi.

I had a look at those, nice. Are both carbs the same size feeding inlet ports of different sizes?
I`m too mean to spend that sort of money on a pair of carbs! I`d love to have a go on your bike though, it must be a beast!

https://www.kedo.com/mikuni-tm34-flat-s ... orked.html

Cheers.