'07 Scrambler - Need Advice On Re-jetting For New Exhaust.

Hello Group,

EDIT: Just found that the pipes I have are from 'British Customs' and called simply 'High Pipes'!

New to this forum so please forgive me for any potential oversights. I'm also relatively unfamiliar with my '07 Carbureted Triumph 'Scrambler'..... other than having owned it for a few years and ridden it very little. On the 'up' side, I'm really quite familiar with the basics of 'tuning'.....and have tuned more Harley's and Yamaha XS650s in the past 20 years than people have fingers and toes....like 10X that! So, my purpose here is learn some specifics, and make sure my bike is running correctly.

As I said, I've not spent much time with my 'Scrambler'..... but I LOVE the bike! Unfortunately, it's ride height was a bit 'tall' for me, and..... with other bikes around to ride, the Triumph just didn't get the love it deserved. BUT, it's getting it now! As of yesterday I replaced the rear shocks which lowered the rear by about 1.5". I also dropped the front forks about 0.75 inches in the triple trees. Results: Ride height is now perfect for me! I'm a LOT happier with that part of it. AND, since I had to take the exhaust system off to change the shocks, it was a perfect time for me to swap out the exhaust system as well. The former OE system might have been replaced prior to my purchasing the bike. Of that I am not sure. My local Triumph dealer seemed to think it had been replaced....but I'm now doing it again. I've never been really happy with the what was on there, so I went shopping for something different. And, I managed to find a really nice set of true-duals.....one on each side, all stainless, and with some nice little megaphone mufflers on each side. This was a 'used' set off Facebook Market place....and unfortunately I don't know the brand. I'll try to put up a picture and maybe someone can help me with what I've not got.

Anyway.....the plan is to now do some plug chops and see how it's running. As this is a Carb bike, I'm looking for any suggestions on things to watch out for, things that might be important to do, and where one might get jets for this carb? With that.........many thanks!!

Tom D.

 

This is quickly turning into quite a project! Prior to responding to you both I have read through the files you both sent......and 'wow'!!...... some very interesting stuff! Many thanks for the references! GREAT info! I guess I need to make a decision here as to whether or not I'm going to go 'all out' on this.......and really dial it in by perhaps enlisting the services of a good dyno shop....... OR..... just do it by the old 'seat of the pants' method and get it to the 'it runs OK for me' stage. I do think I'll address the air box issue.......and perhaps just go with some unipod filters. I've used them on my XS650 bikes and I'm generally quite happy with them. I've always been a bit discouraged that the folks at UNI haven't ever addressed the aesthetic aspect of these things......by perhaps making just a 'dress' cover of some kind that maybe complimented the bike while obscuring the foam some. But..... hey..... it is what it is, right? Anyway... because this is more an exercise meant to protect the bike by assuring it's 'not' running in any dangerous 'overly lean' condition, my objective isn't necessarily to extract every bit of HP and torque from the motor as those tuning sheets might permit me to do. I won't race the bike, and in truth it probably won't see much more than the infrequent 50 mile ride. BUT, I don't want to cook the valves or seats.....or melt a spark plug. So, I'm going to pull the carbs and at least make sure that I'm running a 115 main and 40 pilot jet, and just 'adjust' some from there. If I put the Unipods on it I may go with the 120 main jet. Also I noted some 'popping' on decel with this new exhaust. (I should mention that the 'air flow' mod has already been done to this bike). I may have to increase that pilot to like a 42 or so to help ride that symptom as well. But, I'll have at it.......and in the end she'll run well and be 'safe' to operate under most any conditions!

 

Another quick update: The seller from whom I purchased the pipes just gave me a call in response to my 'text' message to him. I texted him to ask if he could give me the info on the type of pipes and he responded with a text containing the info in the 'edit' above. But, he just called me as he was about to send me the brochure or 'instruction' sheet that came from British Customs with the pipes, and on it is written that the correct Jet size for use here in this area is a 135 main and a 42 pilot jet, along with removal of the 'stock' air intake and replacing with a K&N system. I'll have to see what K&N has to offer, as their stuff is usually pretty good too....and I'm guessing they offer a 'replica' of the old Bonneville 'Pancake' type intake filters. I think I'll probably still stick with the Unipods, but I feel obliged to at least check my options! Anyway, 'progress'!! Thanks again! Tom D.