At least that's what my mechanic says.....I've got a Forcewinder high-flow filter and a set of Thunderheaders and re-jetting was not required. As long as the CV is properly tuned, all is well.

So, I guess if I start running lean, I could always re-jet later.....my only concern is damaging the motor between now and then.

Any thoughts?

 

If you got a high flow filter and a Thunderheader, I don't see any way that you are not running lean without a re-jet. These bikes are extremely lean from the factory, and as much as you opened it up with a Forcewinder and a Thunderheader, you are going to be leaner yet.

Your mechanic said there was no need to re-jet if the carb was properly tuned?? Re-jetting is a part of proper tuning. How else do you tune a carb. other than idle adjustment and re-jetting? With as much extra air as you have coming in and going out, you have to give it some more fuel. The only way that I know of to do that is with bigger jets.

I predict that if you run very long like you are, your Thunderheader is going to be a nice blue or gold instead of chrome.

I'm not a mechanic, so this is just an opinion. Check your plugs and see what they are telling you.

Regards,

Bill

 

I thought you could tune the carb by opening it up and fine tuning the mixture screw? When the mix is right, supposedly there is no need to re-jet.

 

The only mixture screw I know about on a CV carb. is the idle mixture. It is under a little plug that has to be removed on the bottom of the carb. This is only for idle, and just off idle. It will do nothing for normal running RPMs. The slow jet, or needle jet is the one of most concern. It is the one that gives you fuel as the needle picks up. It is also sometimes referred to as a midrange jet..

Again, I would encourage you to check your plugs. Here's how. Run for about 5 minutes at 60 or 70 MPH, pull in the clutch, shut off the engine and coast to a stop. Pull the plugs and see what color they are.

Black and sooty=rich. Tan to near grey=OK. Very light grey to near white=lean. Brown Glazed=too hot/lean

Hope this helps.

Regards,

Bill

 

My mechanics did that yesterday and found the plugs to be fine. Two different mechanics at my shop test drove my scooter and it ran fine.

I think this weekend I'll try what you suggested and check the plugs.

Thanks for the info!

BTW, the bike runs like a champ with the Thunderheaders. They sound mean as hell and I noticed a lot more top-end torque. I can also maximize the entire power band. The response off the line is great too.

 

After my trip to Myrtle Beach bike week, I'm sold on dyno tuning. The crew from Speed's Performance Plus installed a new K&N kit that removed all stock intake hardware and then dyno'd and tuned it. I did have the stock backer plate drilled and a K&N filter inside the stock housing, but the new setup is no comparison. Ran it for a day with the new intake and then went with their suggestion to add a 2 into 1 Hooker pipe. Then they dyno'd and tuned again. End result: 14 HP increase, great mid range power, great sound and MUCH smoother running bike.
It sucks that now I'm home I'll have to travel a little for dyno work. But the plan is to run it for a year and take it back to Myrtle next year and have Wayne, Jimbo and the boys look her over again and compare to this years results and tune it again.

 

After my trip to Myrtle Beach bike week, I'm sold on dyno tuning. The crew from Speed's Performance Plus installed a new K&N kit that removed all stock intake hardware and then dyno'd and tuned it. I did have the stock backer plate drilled and a K&N filter inside the stock housing, but the new setup is no comparison. Ran if for a day with the new intake and then went with their suggestion to add a 2 into 1 Hooker pipe. Then they dyno'd and tuned again. End result: 14 HP increase, great mid range power, great sound and MUCH smoother running bike.
The V&H Big Shots that were on the bike came home in back of the truck. The crew from Speed's as well as a few other sources tell me that those pipes actually rob HP from the TC 88.
It sucks that now I'm home I'll have to travel a little for dyno work. But the plan is to run it for a year and take it back to Myrtle next year and have Wayne, Jimbo and the boys look her over again and compare to this years results and tune it again.

 

I would seriously doubt your mechanic. Don't know of any bike that had low restriction intake and exhaust on it that didn't need rejetting. The idle mixture screw is just that , idle mixture and doesn't extend even to 1/4 throttle settings , and you are leaning out the mixture above idle with your mods where the idle mixture will not help much at all. The enclosed attachment will show you the functioning areas of the circuits in the carb. I would suggest with your combination to run a #46 slow jet, a #190 main jet and shim up the jet needle with 2 - #4 brass washers, then readjust the idle mixture warmed up to the highest and steadiest idle mixture, readjust your idle speed to specs and HOLD ON TIGHT

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I recently had Supertrapp 2:1 exhaust installed on my '05 HD Sportster XL1200R to replace the HD SE II mufflers that were installed at Stage I. I also have a ****** Racing Hurricane Flow breather system. The original factory jets were 42 pilot & 180 main. At stage I, installed 45 pilot & 185 main. After 2:1 exhaust and dyno tuned, back to 42 pilot and down to 175 main. I now have 72.15 HP and 71.44 torque peak at 3,500 rpms, right where I want it. Pulls like a champ and sounds great! No change in gas mileage...still get 50 mpg. However, the muffler end cap and the 18 discs are black and sooty which suggests a rich condition. Haven't been back to the dealer yet and I'm waiting for a call back from Supertrapp. Bottom line...every bike is different!

 

Sounds pretty close to what I got, Phil. K&N breather that looks pretty much like a Forcewinder and a two into one Hooker got me from 57 up to 71 HP.