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Streetfighter, and fighting against engine pulses too!
Hello! My feel is that this forum is better than the Failbook group when it comes to tech stuff... might be wrong, of course :-p
Anyway, I'll try to make it quick. I have a '98 Firestorm with 62k km. It's basically my love, I got a K3 GSX1000 before the summer but got back on the Storm after only 2 months. Basically 'cause I modified it to follow my riding style etc.
The mods:
1) Acerbis Led Vision mask;
2) Oversize front rad;
3) Handmade Ergal subframe with shortest tail and neoprene seat;
4) Fork gaiters and fiberglass front fender;
5) CNC moto risers with low rise 22mm bars;
6) Domino Commando quick action throttle;
7) Discacciati radial master cylinder;
8) Braided hoses for brakes and clutch;
9) Koso DB01RN dash;
10) Urban delinquent gearing, 14-49;
I had the stock headers with two China cans, but didn't like the look. And I've always been a huge fan Buells, always wanted an under-engine exhaust... so made it happen.
As I expected, the new system has a few problems. I basically had the headers cut after the first Y, the one that connects the two pipes, and then instead of going dual again it goes into a bend and then off to just one chinese can.
TO ME it looks great... but of course it's just personal preference.
The problem: the bike with standard carbs setup bogs and hits a wall around 5k rpm. Down low is fine, responsive as usual.
I tried to toy a bit with both needles shims and main jets, and for now I got it better with slightly smaller mains (172 and 170, rear/front). It now bogs but will go over 5k.
A few weeks ago I shipped my TWO extra sets of carbs to a very well known mechanic in the UK, for ultrasonic cleaning etc. - and he gracefully answers my weird questions whenever he can.
He basically said that to make a 2into1 work, I can't only rely on carbs adjustment... he said I should play with cylinders timing and ignition timing, otherwise on the long term I risk to damage the engine, probably 'cause the "wave" created by the engine firing won't find the right way to move down the headers, might partially bounce back and do so with bad timing, basically. So for now my plan is to go back to my welder friend and put the Y back, finding some room for the second can under the engine.
I told him several peoples on forums have a 2into1 and didn't have ill effects, but his opinion is those bikes will probably run badly but owners won't tell. I don't know.
I didn't have much look on Failbook when trying to gather peoples with similar issues, maybe on here it will be easier?
In the years I've been on this forum, I don't think I remember one member being happy with 2 into 1 exhaust. I have seen it done so try searching some. You may find something to make yours better than it is. Good luck, it's one of the deeper rabbit holes with a VTR.
My 1.5 cents on the subject was always that if Honda's AMA Superbike team couldn't get a 2-1 to work right I never understood why people thought they could in their garage. Having said that I'm sure a couple people a lot smarter than me on here have claimed to get their bikes running well with one but it's safe to say more people have failed.
My 1.5 cents on the subject was always that if Honda's AMA Superbike team couldn't get a 2-1 to work right I never understood why people thought they could in their garage. Having said that I'm sure a couple people a lot smarter than me on here have claimed to get their bikes running well with one but it's safe to say more people have failed.
Yeah, I know the 2into1 took TWO YEARS to be developed and to make it work they also had to work on timing and ignition.
I'm not into 2into1 per se, I just want to make the whole exhaust "invisible" (under the engine) and of course finding room for two headers was harder. But it's my plan B... if things go wrong I'll have the second Y piece welded back in place and will add a second pipe to a second can somewhere. Yeah, on the Facebook group a few peoples claim their 2into1 works and they didn't even have to deal with carbs settings... they only say the bike runs a bit rich...
Update: yesterday I was on the phone with the welder. I told him about the fuelling issues and he said "Uhm... but the DB-killer you have on the can is very restrictive... good when you have TWO cans, but you now only have one. Try to remove it and see how it goes". I removed it and BAM! The bog is gone! A slight dip in the torque around 4k rpm but I think it actually got it back a bit higher in the powerband. Very happy as it's now rideable again! A bit lean down low, will have to open the mixture screws a bit (I closed them a few days ago) but I think the mains are right or not too far from right. The only problem is: it's NOISY. It's like 2 Harleys together... it drones in my helmet when off the throttle. At this point I think I should still mod the exhaust but only in the single section, going from the actual 45-48mm to something like 63mm for better flow. Then off to another session of trial and error on the carbs LOL.
Gotta be honest: I owned 3 VTRs, so I'm used to the bike etc. - can't say it's less powerful than usual. I found it's got a slight "dip" in the powerband at 3000 rpm, but I have slightly smaller main jets 'cause I thought it was running rich before removing the db-killer.
I know for sure this configuration is NOT meant to exist, as it's not good for the engine... but I don't like the dual cans with this short tail etc. - and always liked Buell exhaust under the engine. :-(
In pure theory, the only way to make it work AND avoid damage on the long term is to keep it 2into2 and simply change the direction of the pipes while mantaining everything stock (headers length, Y junction between them etc.)
Yep, just the light. Mine is a '98, so has the first type of fuel level sensor, not the float type. Pretty sure you need an extra piece to make it work, Koso obviously has it on the catalog. https://www.digital-speedos.co.uk/ac...so-gauges-p443
I used an extra piece from a second dash I had to make it work, but in the Facebook group I've read posts about making it work without it... no idea how.
Hope this helps!
Is that opening of the exhaust facing forward ? So that when you ride the bike, you have ram air into the muffler, raising back pressure ?
So you not only have reduced muffler volume with your 2 into 1, but you're restricting exhaust flow with cramming air into the muffler from the front.
Find a U bent tip that directs exhaust towards the rear and see what happens.
Unless what I'm seeing is an optical illusion...
