Rejetting for new exhausts Dragstar 650 classic

[stockie]

Alrite all, I took the first step and got a set of loud pipes for the dragstar. I didnt realise that they were straight throughs (highwayhawk slashcuts) until I picked em up, but the louder the better as far as im concerned!! Only thing is I dont want the hassle of re-jetting now because I intend puttin a hypercharger on after the summer and i'll do it then. The guy in the bike shop- got em 2nd hand- said I would'nt need to re-jet but ive read in a couple of places that I should.

I suppose what im asking is whether i'll get away without having to re-jet for the summer at least??

[DirtyDT]

Moved to Customs section.

[Toutsuite]

You might be able to. Ride around for a while and see how it performs. I expect you'll get a lot of popping on deceleration. But if you get any popping on acceleration, you need to rejet stat. In any case bear in mind you'll be running the engine too lean for 3 or 4 months. When you do rejet, I'd suggest changing the plugs as well.

[EazyDuz]

The HH slashcuts usually say they dont require rejetting.

The drag is a very underpowered, low tuned engine, you would struggle to ever damage it if it ran a tad lean on wide open throttle.

[Toutsuite]

Ok, I've had a look at the HH slash cuts on youtube: they're not really straight-through pipes, nor that particularly loud. Should be fine without rejetting.

[gizmo666]

the hh slashcuts have got rivetted baffles in them

and as toutsuite said not very loud

this my hh slashcuts after the removal of said baffles

and now as loud as hell lol

still to test it yet to see how it runs

but it ticks over and freely revs with no popping

[Grave]

while planning shortshot pipes for my XVS1100 i read up on the vstar knowledge base about re-jetting. this was the one time i regretted pre-planning.

have since learned that to get it right (if you do need to re-jet) you should put the pipes on first.

this is all 1100 stuff so not sure if it'll help, but for what its worth:

VStar 1100 Knowledge Base (Carb Jetting)

https://sites.google.com/site/vstar1100kb/home/tuning/carb-jetting

[Ttaskmaster]

You do not NEED to re-jet, but every mechanic I've ever known strongly suggests you do. Take from that what you will...

Personally - if you do not re-jet, your fuel consuption will go down (which is good), your power and performance will fall (bike will be notably slower) and you may find your pipes burn up by the headers, resulting in a heavy bluey-black patina.

[Noise]

You need to re jet them as Tasky said. If you dont then the bike WILL run like a bag of wet shit. I have short ram air filters on my 650's carbs and straight through pipes and ive had to put my Needle jets on the highest notch and have gone from 92 main jets up to 122.5 main jets just so that she runs ok. It took me 5 goes at stripping the carbs re-building them and the bike to get her perfect.

Also a top tip, the screws that you need to remove from the carbs are a bag of wank and are like plaster-seen so take care taking them out as i bet you a bacon butty you will round them off, so place them in a vice with soft grips, have a hack saw blade ready to cut a groove in the head to fit a flat head screw driver in (best way to get them out) and replace them with stainless steel Allen head screws, this will help with the re-strip down and re-build due to the whole process being trial and error.

Things to look our for are:

If she goes to cut out when you pull away, pull choke out and if you can pull away better then you need bigger main jets.

if she pops & farts like a gooden then you need smaller jets

If your spark plugs are white then your too weak and need to go bigger.

If your spark plugs are really black your too rich thus need to go smaller

I still get popping and flames out my pipes on over run when i give her a fist full but she now runs like a dream and the bangs and light show is her way of telling the folk behind me to stop tail gating

Here's mine spitting flames

http://www.youtube.com/embed/OmSh5G033sI

[gizmo666]

nice video

[Noise]

That was the first time i started her up after the first build. she sounds a little better now.

[stockie]

Cheers lads, some great advice there. I rekon il give them a few runs and see how she performs, if im getting too pissed off with the drop in performance then il most likely get the intake sorted aswell. Im a few weeks away from getting anything done but il let yis all know how I get on. Thanks again

[Noise]

Just a quicky, if your changing the intake system too then you will def need to re-jet. and im more than possitive you will get pissed off with the drop in performance

Here is a video of when i didn't re-jet. You can here the bike loose power with i opened here up right near the end of the video.

PS im not fat it was just a very cold day

And of course the back fire!!