Motorcycle Club » MB Do It Yourself Mods

Slip-ons and jetting

14 posts from 12 voices
About This Topic
  1. lferk
    #

    Hello all,
    I am a total motorcycle virgin! My wife and I bought a '09 V Star 1100 Silverado last week and I LOVE it! I want more bad ass sound but my budget is about $300. I was looking at some Cobra Slip-On Drag pipes. I found some for about $260. What happens if I do not do the re-jet thing? Does anyone have any other suggestions? Thanks guys

  2. zhatovofzelf
    #

    No need to rejet with slipons, only on full exhausts. The worst is it could need PMS adjusted. No big deal either way.

    Enjoy your new ride!!

    Dan

  3. vgink18054
    #

    I put vance and hines slipons on my 07 1100 and no need to rejet.

  4. Vzdar18
    #

    I added Roadhouse Motoclassic slip-ons without rejetting. No problems.

  5. micg10
    #

    what about the 4 hole mod some of us have done on our 650's, can that be done on the 1100? and that will only cost you the price of a 1/2 inch drill bit.

  6. targwzdar
    #

    ok so what about slip ons with no baffles, do you have to rejet then if your bike is already re jetted?

  7. retzdaret
    #

    You do not have to rejet for slip ons regardless of the baffle being in or out. Though you may loose some low end torque with the baffle out.

  8. targwzdar
    #

    So keep the baffle in,,, makes sense. Thanks.

  9. ruzdjtok8
    #

    Will just the slip ons do anything for performance,or would it only give you a better sound?

  10. MigejCojode
    #

    Most slip-ons don't need rejetting. Some will require tweeking with the baffle removed. However it's always a good idea to read your plugs or do a choke test and roll off test (more practical on the 1100). If you come up with issues during either the plug read or the tests then you can correct a lean condition.

    Motors like to run a little bit lean but I tend to jet them a tiny bit rich. Rich burns extra fuel, too rich causes carbon build up. A tiny bit lean ensures peak performance and reduced Hydro carbon emissions, but too lean causes pre-ignition (pinging), hot spots, and then piston burn through. By jetting just a touch rich I can ensure that the engine doesn't end up in a lean condition, regardless of the altitude it runs in. A lean engine will backfire on decel (the occasional burp is normal) and the double wall head pipes will yellow or blue (single wall pipes almost always turn colour).

    Keep in mind an engine in it's simplest form is an air pump. Freer flowing pipes tend to lean the bike out just a touch, but with Yamaha's tendancy to reduce intake flow to compensate for emission controls slip ons don't usually require rejetting. If you've modified the intake at all then slip ons will require a change in your carb setup. And yes, with intake mods, slip-ons can increase your net hp and torque.

    Here's a few links for the checks:

    Roll off test and lots of great info: mikuni.com

    Choke and roll off on a 650 same for any carb engine: 650ccnd.com They say the spark plug test is a waste of time, I don't completely agree with that although they do have a point WRT additives, super lean will still show up as very white and really rich still shows up as black. As always use your own judgment.

    The best plug read. http://www.ymhmotoboard.com/ Yes I wrote it but I used info that Rawhide had given me. Now that is a man that knows his bikes. Again use your judgment, if the above tests don't indicate a problem then, with how hard the plugs can be to get at on the 1100, I'd avoid this one. If you have to rejet I wouldn't dispense with this one, the only better way ensure proper jetting is on a dyno with a sniffer.

    Again you probably won't have to rejet, but I would definitely do the choke and roll off just to be sure.

  11. retzdaret
    #

    If there is a performance gain, it would be minimal until you upgraded your air intake and rejeted.

  12. Merlin595
    #

    Most slip-ons don't need rejetting. Some will require tweeking with the baffle removed. However it's always a good idea to read your plugs or do a choke test and roll off test (more practical on the 1100). If you come up with issues during either the plug read or the tests then you can correct a lean condition. Motors like to run a little bit lean but I tend to jet them a tiny bit rich. Rich burns extra fuel, too rich causes carbon build up. A tiny bit lean ensures peak performance and reduced Hydro carbon emissions, but too lean causes pre-ignition (pinging), hot spots, and then piston burn through. By jetting just a touch rich I can ensure that the engine doesn't end up in a lean condition, regardless of the altitude it runs in. A lean engine will backfire on decel (the occasional burp is normal) and the double wall head pipes will yellow or blue (single wall pipes almost always turn colour). Keep in mind an engine in it's simplest form is an air pump. Freer flowing pipes tend to lean the bike out just a touch, but with Yamaha's tendancy to reduce intake flow to compensate for emission controls slip ons don't usually require rejetting. If you've modified the intake at all then slip ons will require a change in your carb setup. And yes, with intake mods, slip-ons can increase your net hp and torque. Here's a few links for the checks: Roll off test and lots of great info: http://www.mikuni.com/fs-tuning_guide.html Choke and roll off on a 650 same for any carb engine: http://www.650ccnd.com/trouble.htm They say the spark plug test is a waste of time, I don't completely agree with that although they do have a point WRT additives, super lean will still show up as very white and really rich still shows up as black. As always use your own judgment. The best plug read. http://www.yamahamotorcycleforum.com...19&postcount=5 Yes I wrote it but I used info that Rawhide had given me. Now that is a man that knows his bikes. Again use your judgment, if the above tests don't indicate a problem then, with how hard the plugs can be to get at on the 1100, I'd avoid this one. If you have to rejet I wouldn't dispense with this one, the only better way ensure proper jetting is on a dyno with a sniffer. Again you probably won't have to rejet, but I would definitely do the choke and roll off just to be sure.
    This is an excellent post!

    I agree with MigejCojode on almost everything. Others who have stated that slip on changes don't require rejetting are incorrect. It is totally dependent on the machine and how it was calibrated out of the factory.

    For example;

    My 1997 Magna. Sorta lean out of the factory and in completely stock form has a flat midrange. Most common modification is to install Cobra or Jardine 4-into-4 drag slip-ons (both are baffled slip ons). The result is a strongly pronounced surging at part throttle and loud deceleration popping. Changing air screw settings does not improve the performance or running condition. Then some owners go a step further and install the K+N filter which makes the bike virtually unrideable between 3K and 6K rpm. With these bikes, even just the addition of slip on exhaust will seriously affect running condition and performance. The cure is to upsize the main and pilot jets and shim the carb needles, which cures 99% of the issues.

    My V-Star 650 (1999) came to me with V+H slip ons already on it, bike ran "okay" but very sluggish. The addition of a Kuryakn Hypercharger with jets made all the difference in the world.

    Basically, exhaust or intake modifications will often times require changes to the jetting, but how much or significant it is depends on the machine and how you are starting out. It's a mistake to assume that just the addition of slip-ons is okay on any bike with no changes in the fuel.

  13. bkman
    #

    I agree that this depends largely on the make and model of the bike, but Mikey was referring specifically to Yamaha, and even more specifically the 1100. Even though my 1100 is a later model, I found that it was not all that lean from the factory, and the OEM intake is more than a little bit restrictive. I could easily see how slip-on mufflers might warrant removing the AIS, but I'd be suprised if they would need a change in the carbs. I dare say that you might even get away with SOME aftermarket pipes without rejetting if you didn't mess with the intake.

  14. quicgmicg
    #

    I agree that this depends largely on the make and model of the bike, but Mikey was referring specifically to Yamaha, and even more specifically the 1100. Even though my 1100 is a later model, I found that it was not all that lean from the factory, and the OEM intake is more than a little bit restrictive. I could easily see how slip-on mufflers might warrant removing the AIS, but I'd be suprised if they would need a change in the carbs. I dare say that you might even get away with SOME aftermarket pipes without rejetting if you didn't mess with the intake.
    bkman....As usual, I agree with you all the way. It's the intake side that has the most restriction..working on that end will usually always require rejetting. Not so much so on the exhaust end...at least it's not usually as drastic of change to require immediate rejetting. I guess that is why so many people to intake and exhaust modifications together.

    ........good thread guys...some great info here.

Reply

You must log in to post.