1100E with V&H 4into1 - runs great without rejet

[Guest]

Just put a V&H 4into1 on my 82 1100E, I have a brand new Dynojet kit stage 1&3 on it's way but the bike seems to run perfect without rejetting the carbs.. Starts right up, idles perfect, throttle response is INSTANT and revs clean right to 10,000..

I haven't done a plug chop since I just put the exhaust on but being around bikes all my life i can tell a lean running bike.. This does not seem lean at all..

I often wondered with these 4into1 Street exhausts with baffles if all these rejets are really necessary in the first place.. The Primary header tubes aren't any larger than the the factory exhaust.. the only restriction I would see is that the V&H muffler might be less restrictive BUT then again we are making 4 cylinders breath through a single opening as opposed the factory exhaust which is 2 cylinders per side.. I just can't see why a 4into1 with the same tube O.D would need to be rejetted if it's a street exhaust with baffles.. There is a noticeable sound difference over stock, it sounds great..

The ONLY thing I can think of is that all cylinders help each other vent out which might speed up exhaust pulses??

Any ideas or opinions on this??

[trevor]

Let me know how it works out. I am ordering a V&H for mine too. I'm araid not to re-jet though. Got any video of the new sound?

[Agemax]

some bikes run just fine with just a 4 into 1 fitted, with standard airbox. when i first got my GS1000 it was stock apart from a Harris 4 into 1 with race baffles. stock airbox and filter and jets. ran perfect as yours does, revved out clean with no flat spots or hiccups.
some bikes do need a slight upjet, or a Dyna stage 1 with a pipe, others dont.
stage 3 is usually only required when you fit pods as well as the pipe.

[evh]

Let me know how it works out. I am ordering a V&H for mine too. I'm araid not to re-jet though. Got any video of the new sound?

trevor the sound is much more racey than stock and it's louder, sounds sort of like newer sport bikes..

[Katarat]

The stock V&H is as restrictive as the factory exhaust is why you dont need to rejet. Dont run any better either.

[posplayr]

Just put a V&H 4into1 on my 82 1100E, I have a brand new Dynojet kit stage 1&3 on it's way but the bike seems to run perfect without rejetting the carbs.. Starts right up, idles perfect, throttle response is INSTANT and revs clean right to 10,000..

I haven't done a plug chop since I just put the exhaust on but being around bikes all my life i can tell a lean running bike.. This does not seem lean at all..

I often wondered with these 4into1 Street exhausts with baffles if all these rejets are really necessary in the first place.. The Primary header tubes aren't any larger than the the factory exhaust.. the only restriction I would see is that the V&H muffler might be less restrictive BUT then again we are making 4 cylinders breath through a single opening as opposed the factory exhaust which is 2 cylinders per side.. I just can't see why a 4into1 with the same tube O.D would need to be rejetted if it's a street exhaust with baffles.. There is a noticeable sound difference over stock, it sounds great..

The ONLY thing I can think of is that all cylinders help each other vent out which might speed up exhaust pulses??

Any ideas or opinions on this??

The 4:1 collector makes for a peak in airflow at 8000-10000 and a lull at 1/2 the values. So the needle and jet are necessary to feed the flow. Of course ifyou did not do pods then it will have less effect.

The stock exhaust with the cross overs is more like a 4:2:1 which does not have the peaking at max RPM.

If you are at altitude it maybe running richer than at sea level to start with.

Also remember you are using a "seat of the pants" meter to measure performance not AFR.

[chef1366]

I have a V&H pipe and run 150 Mikuni mains.

[mrbill5491]

Slip in a K&N air filter to replace the stock element, then you will have to rejet. Would like to see a pic of the V&H baffle. Far as I know my ole RC 4-1 is way less restrictive (has original baffle and newer packing) then the stock pipes. Take the V&H/RC emblems off the megaphone, you can't tell the difference. They look alike.

[KEITH KRAUSE]

The V&H pipe will flow better at higher rpm's. A stock intake will greatly reduce the new pipes ability to flow better. But it will still flow better at higher rpm's so more fuel is needed to correct the mixture.
Most of my experience is with both intake and exhaust changes, so a poor match (stock intake and freer flowing pipe) makes it hard to guess what jetting changes are needed. I'm thinking a full size (5) larger on the mains may work for the main circuit which regulates fuel at 3/4 to full open throttle. Leaving the stock mains in means it will be lean for sure at 3/4 to full throttle. Not dangerously lean, but lean.
If the larger mains create any momentary bog while opening (3/4 to full throttle) it up at lower/moderate rpm's but it runs a little faster at top end then you know the bog is there because at lower rpm's the engine is flowing much like stock and can't handle that larger main until rpm's are higher and the added flow of the new pipe can take advantage of the extra fuel. Poor intake and exhaust matches often create a situation where performance improves at one point but a problem comes up at another point.
Besides the main jet, you will run a little leaner while operating on the jet needle (throttle position about 1/5 to 3/4). Not near as much as compared with the main circuit, but still a bit leaner. Shimming the jet needle will be needed, but only if you want to make the fuel/air ratio spot on.
As always, you have to test to see what works best. Good chance you can get away with just a main jet change. Depends on how the bike is used. If you ride it hard then re-jetting is much more important. If you don't run hard very often then you may be OK with doing nothing. But for sure do a full throttle run, chop off, and check the plugs. If on the white side, then a larger main is needed.

[gs11ezrydr]

Like you are experiencing I also have had pretty good luck without rejetting at times with the V+H megaphones.They use to make what they called a race baffle for that pipe which I can't find any more with a 1/4" larger dia. outlet and still wasn't that loud that seemed to need a little jetting for sure.The only other jetting I found was needed at times was raising the needle and the main jet as posted earlier.With out taking off the air box lid, removing the little snorkle,and installing a high flow filter seemed to be ok.Getting a little off base here since you said you have a jet kit coming.I have also tryed leaving on the air box plenum which has the rubber velocity stacks inside it and on the back of the carbs.Then completly removing the air filter case itself and installing a large oval K+N (part# RU0960)directly onto the plenum instead of "pod"type filters.Which "personally" I don't like with CV carbs.I drilled the slide lift holes,installed the DJ needles, richened the pilot air jet (smaller)and installed the smaller of the stage 3 main jets and the bike screamed from idle to redline not a flat spot to be had with the "race" baffle installed.I just purchaced a set of 36mm CV's and had the head ported by Star Racing. I am going to see how that same set up works in conjunction with these new modifications also.A tip for new pipes I use while new out of the box is to coat the inside of them with ceramic header paint before installing seems to help the discoloring "bluing"that happens a little and helps transfers more heat out the end of the system.