Single carb on Mastiff AGAIN!

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[breakwellmz]

Hi.

Only in order to modify it to fit an appropriate air filter.

[breakwellmz]

A mate turned up an adaptor to match my K n N filter to the carb for the price of a packet of fags and i put in the three attachment holes.
Pulled out the vent passage cap on the side, tapped it M8, and screwed in a modified brake bleed nipple to which a rubber pipe is pushed on to.
Rusty enrichener cable is only a temporary one!

Air box modified and now await a 60mm ID silicon coupling hose -

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[breakwellmz]

Hi.

It makes me wonder how it used to breathe at all to be honest, just between the top edges of the box and the underside of the seat and that (the air box)
used to have a vinyl lip filling most of that gap!
The K n N was off my old 580 BSA/CCM and it appears to be the right sort of size, i also have a bottle of K n N filter oil!
The CV40 pumper can rotate in situ for easy access to float bowl and slide needle for jetting changes which has made me go ahead with fitting an alternative exhaust system as well.

Cheers

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[breakwellmz]

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It`s not like trying to run up hill with your hand clamped over your mouth then?

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[breakwellmz]

Hi
That looks interesting.
That double the original power output and a lot less weight, tell me more!
I had a GN400 which used the same engine. It was quite quick off the line but could be a pig to start and i soon wanted to go round corners faster that it did!
So why did Suzuki drop it and replace it with another (slightly smaller) air cooled single in the DR350?

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All clear now!

My Beta Alp 4.0 (DR350 engine) - Love it! The Mastiff may end up being lighter than the Beta!

[breakwellmz]

Well i`m so pleased with the way this runs i`m going to keep to this setup and not bother with the manifold and other inlet port, so thank`s to STANIMAL for the inspiration! viewtopic.php?f=3&t=7357
It`s more prompt to start and idle (especially from cold) and power is stronger and more linear right from idle up.
There was no numbering on the pilot jet but best idle was about 2 1/2 turns out so it must be in the right ballpark.
I`ve raised the needle with one M4 washer but i think i`ll add another.
I must add that i replaced the original silencer with a regular looking, road legal silencer and baffle and opened up the airbox at the same time as fitting the carb, so i`m not exactly comparing like with like.

[jpmsteadi]

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Well i`m so pleased with the way this runs i`m going to keep to this setup and not bother with the manifold and other inlet port, so thank`s to STANIMAL for the inspiration! viewtopic.php?f=3&t=7357
It`s more prompt to start and idle (especially from cold) and power is stronger and more linear right from idle up.
There was no numbering on the pilot jet but best idle was about 2 1/2 turns out so it must be in the right ballpark.
I`ve raised the needle with one M4 washer but i think i`ll add another.
I must add that i replaced the original silencer with a regular looking, road legal silencer and baffle and opened up the airbox at the same time as fitting the carb, so i`m not exactly comparing like with like.

It is a very interesting proposition youve done. I'm sure it runs very well at most RPMs. Id be curious to hear about how it feels right up to redline. thats the place I'm thinking this setup could be problematic. But, with the carb so close to the intake valves and with the cross over you might be getting more swirl going into the cylinder and a more responsive throttle by not having a runner. I think the best solution is to have two smaller carbs opening sequentially, but the added complexity and cost aren't worth it for me. I just got an FCR39 (https://www.keihin-na.com/aftermarket/f ... arburetor/) off of a WR450 to install on my skorpion. I am going to design an intake manifold, partly cause of the size of the carb and the fuel tank means it wont go directly onto the intake port.

I love to see people experimenting!!

[breakwellmz]

Hi jpmsteadi

Well i`m very pleased and not a little surprised at how well it runs to be honest!
I`ve been up to the red line a couple of times and it doesn`t seem to be an issue despite having less overall total carb inlet area compared to what it has replaced but then it has (i feel ) a less restrictive exhaust and an opened up air filter box as i said, perhaps that compensates.
The new carb is no closer to the valves than the original ways by the way, in fact it is further away from the LH valve than original.
I do know that it suits me and the sort of roads and conditions that i ride and the throttle response is really good throughout the rev range without any downside that i have yet come across.
I started off with the intention of making up a manifold and adaptor etc to supply both inlet ports and it seems i`ve come up lucky by using a cheap and cheerful carb combined with a simple installation to get the results i wanted.
Keep us updated on your project.

Cheers

[jpmsteadi]

Thats great. I'm glad to hear it is doing well. Super interesting. It makes me very excited to fit my pumper carb. The bike is already great; can't wait to see how good it is with a better carb.