Avanti exhaust options. Advice please.

[Leotech]

I have an Avanti kit I'm building.

I want advice on is which exhaust to use.

Im using a 30 mil carb and hoping to build the kit for touring as opposed to top speed.

I don't want an expansion type exhaust so wanting to know what people are using.

I am a firm believer in using the spec the designer tested so spoken to Ron Moss but his clubman was never made available. I asked about an Ancilloti but he says I need to modify the tail pipe diameter. I've since seen the Gori 50mm and wondered if that would be suitable with my carb.

Any knowledge shared, I would be extremely grateful.

[Adam_Winstone]

No idea about the Gori but I can confirm that the BGM clubman will not fit without a crazy amount of grinding to the barrel and the head. I started grinding and refitting, grinding more, grinding more, etc. and it still wouldn't fit on. NB: This is not to criticize the BGM for not fitting as it was a straight fit onto a standard iron barrel that I tried it on.

Comment made just to make sure that you don't go for the BGM option for your Avanti kit... it really isn't a viable option.

Hopefully someone will be able to confirm whether the Gori fits.

Adam

[Adam_Winstone]

No idea about the Gori but I can confirm that the BGM clubman will not fit without a crazy amount of grinding to the barrel and the head. I started grinding and refitting, grinding more, grinding more, etc. and it still wouldn't fit on. NB: This is not to criticize the BGM for not fitting as it was a straight fit onto a standard iron barrel that I tried it on.

Comment made just to make sure that you don't go for the BGM option for your Avanti kit... it really isn't a viable option.

Hopefully someone will be able to confirm whether the Gori fits.

Adam

[dickie]

Gori tail pipe is the same diameter as ancillotti and bgm.

Af 48mm clubman is larger and the same size as the Ron moss clubman (I think).

I wish someone would make a clubman suitable for these type of kits. I'm building a touring tune ts1 and putting a super tourer on it but only because I can't find a clubman I'm happy with.

I'm sure avanti clubmans would sell like hot cakes if someone would make them.

[rexton270s]

the gori to will not fit straight on to the avanti kit without alot of grinding,i have used a old chiselspeed 48mm clubman on my avanti it was gutless,then a franspeed supertourer but wasnt happy the way the power came on,very peaky,am now testing a jl4 but the kit runs out of revs before the pipe kicks in! not a clue were to go next,fitted a scootopia clubman to my mugello and i love the way the power is spread though a wide rev range,again if i fit one to my avanti the down pipe will need to be bigger or the kit will be restricted and may over heat! (ron moss advise)! no help i know but you may get a little advice from my experience?

[Warkton Tornado No.1]

Why not make your own? Any sporting scooterist had to resort to such measures when the likes of Royspeed & the like folded. We all had to make our own exhausts years ago.

It helps if you have a spare block & preferably similar barrel to use as a jig, but then you need a ‘donor’ standard exhaust & cut it to have a cone to connect the ‘U’ pipe you have sourced or made.

The back end then needs either a cone, preferably, or just a bigger & better tailpipe adding in place of the restrictive original.

You need to be able to weld thin metal, but we all know a tame welder, don’t we?

It’s probably the cheapest, most practicable option to obtain what you want....

[Leotech]

Ron told me the AF big bore tail pipe is too small and it would overheat. I asked about the AF twin pipe but he said that wouldn't work either.

I have toyed with making one. There are parts kits on eBay but I'd prefer a stub manifold and not a full u bend as these tend to come loose easier. It's a lot of messing about making one TBH and if I make it and it's a load of shite I'd be back where I started.

I have an Iron barrel PM pipe lying about but again it will be all Rev and clutch. I don't want that.

[bolzenanker]

That's wierd, my 50mm Gori fitted straight on, no messing.

[steveg]

Ron told me the AF big bore tail pipe is too small and it would overheat. I asked about the AF twin pipe but he said that wouldn't work either.

I have toyed with making one. There are parts kits on eBay but I'd prefer a stub manifold and not a full u bend as these tend to come loose easier. It's a lot of messing about making one TBH and if I make it and it's a load of shite I'd be back where I started.

I have an Iron barrel PM pipe lying about but again it will be all Rev and clutch. I don't want that.

It's a longer story but I have a Ron Moss clubman that was built using a 48mm AF clubman as the doner pipe. Tail pipe on those is definitely big enough. Used it on my 230 Rapido for some years with no issues.

[Blaginit]

I had jl3 Avanti race/tour pipe 30mm dellorto 47 rear 19 front sprocket on a GP 200 gear box set up by chalkie at replay I was doing silly speeds like 65-70 before it would pull in 4 th gear so I put 18 front sprocket back bought bgm exhaust ceramick coated it and fitted it it took 5 minutes to fit. The easyist way to do it is put bgm gasket on bottom of stub measures to bottom of spigot and chop of the rest of the fin each side of exhaust outlet on barrel I used dewalt battery grinder it took minutes and it runs like a dream it totally pulls right through the range and it's really punchy climbs hills in 4th would recommend to any one even the jetting seems ok ps could any one tell me if I fit a sweet breath does it go over the black screw on bell mouth on dellorto cheers for any help .Modification dead easy you just need bottle to do it remember a lot of research as gone into these bgm pipes they take a lot of beating only falt is bare metal finish cost as much to coat it as buy it

[Leotech]

Ron told me the AF big bore tail pipe is too small and it would overheat. I asked about the AF twin pipe but he said that wouldn't work either.

I have toyed with making one. There are parts kits on eBay but I'd prefer a stub manifold and not a full u bend as these tend to come loose easier. It's a lot of messing about making one TBH and if I make it and it's a load of shite I'd be back where I started.

I have an Iron barrel PM pipe lying about but again it will be all Rev and clutch. I don't want that.

It's a longer story but I have a Ron Moss clubman that was built using a 48mm AF clubman as the doner pipe. Tail pipe on those is definitely big enough. Used it on my 230 Rapido for some years with no issues.

How was it made differently then? What was changed?

[steveg]

I don't know because I didn't do it! I know Pete who made the early RM clubmans. He did one for me using a 48mm AF that I provided. He reworked it the same way. I had it from on my engines from 2010 until this year. I've now changed it as it was showing it's age and I didn't want it to fail.

[rossclark]

We've heard a lot about what doesn't fit surely there must be plenty of kits out there with an exhaust on

[Leotech]

I don't know because I didn't do it! I know Pete who made the early RM clubmans. He did one for me using a 48mm AF that I provided. He reworked it the same way. I had it from on my engines from 2010 until this year. I've now changed it as it was showing it's age and I didn't want it to fail.

The pipe you had changed, do you want to sell it?

i could take it apart and have a look at whats changed and modify one similar.

[Psychedelicropcircle]

Can confirm gori does fit. As the Sharks fin is fixed I'd recommend a 58mm crank.

[Leotech]

Is that a GP50 or the earlier ones?

[Leotech]

I'll have to say after much deliberation I bought a GP50 pipe.

The Avanti had me pulling out my hair, It was a wild ride in third at speeds approaching 55 60 mph, but wouldn't pull top gear even when I lowered the gearing to a final drive ratio of 5.38 SX200 14 - 48. It had power to hold the revs but none to accelerate in top.

After much cursing and a million jetting runs I today fitted a BGM pipe. Transformed the beast. Amazing difference. If someone told me it would make such a difference I would not believe them.

Even looking at raising the gearing now back to 5.0 final ratio.

Both pipes fitted easily, but I had to space the BGM away 5mm on the 8mm studs so the shark fin bracket cleared the fins.

[Adam_Winstone]

^... sounds like you are getting somewhere with it, which is good to hear.

Pipes... yes, what a difference a pipe makes! I've played around with lots of pipes on various kits and found that the same kit could behave completely differently because of a change of exhaust, which very frequently required a substantial change to the gearing that the bike would pull. A change of pipe could easily change a 4.6:1 tourer to a 5.6:1 sprinter, with no other changes being made... to the point that you could not believe that it was the same motor (other than change of pipe and gearing)!

For this reason, it is so easy to find that a motor is not quite what you hoped it might be. Many, many motors out there are no more than a couple of setup changes away from being the 'dream ride' that the rider hoped it would be. Sometimes these couple of changes are made and the rider is happy but other times you hear of people losing faith and moving on to a different kit, in the hope that the new motor may deliver what they wanted from the first one.

I'm glad to hear that your development, adjustment and testing is getting you closer to the motor / performance that you wanted from this kit.

Adam

[Blaginit]

The easy solution for bgm clubman is cut 2 fins nearest exhaust manifold in half stub goes straight on less than5 min work with battery grinder does not affect nothing so don't grind fins chop em off

[rumiman]

I have had the same frustrating symptoms as leotech with my avanti with Both piston port and reed valve inlets, with my b-race stealth pipe which pulls like a train on my muggello at 4.7 it will not pull 5.2 on the avanti, I am considering a bit of fin hacking to fit a bgm clubman, so any others with real mile feedback regarding avanti with bgm would be of great interest, I too am not looking for a sprinter, but a reliable mile muncher.