Carb TMS Recommendations
 

first let me say...I don't do carbs!

after my hawk sat for a year with no attention, I thought it would be a good idea to get it rebuilt and freshened up. I took it to a local shop that came with a good recommendation.

The previous owner had done all prior changes to the hawk. those included K&N filter and Staintune high rise exhaust. the bike also has Dr Honda velocity stacks on it.

the mechanic found that the carbs were stock. no jet kit installed and the jets were the same 180 and 180 front and rear. he did research at DynoJet for a new stage one kit and proper jetting. he also set needles as prescribed.

Problem is, there's a surge in the carbs both at idle and cruising around 4k RPM or so.

the mechanic is willing to do some further work on the carbs to try to get it straightened out, but also suggested that the TPS might need to be replaced. I'm looking for some feedback on the idea and what next steps will make good sense to pursue.

if anyone familiar with carbs and considering my specific setup has a baseline suggestion for settings, I can confirm with my mechanic on the current setup.

thanks in advance!

If your mechanic was able to set the needles at the proper hight, well, they weren't stock. Plus, stock jetting is 178 front, and 180 rear. IIRC.


You also have a K&N filter in their, which if you read on it, is not the best filter for this motorcycle. Chances are, the PO installed a jet kit in it, and didn't tell you.


Now, since you're not playing in it, and it's your mechanic, this may make it difficult to help you. But just going on what you're saying, it seems to me you are too rich. Also, just going on the little info we have, perhaps installing OEM filter back in, and stock jetting will be a step in the right direction.


Take the time to read Hawk8451's thread on jetting. It's a sticky. This should help you. There are also dozens of other threads on jetting issues you can catch up on.

thanks for the reply. I did search and read a little on the stock settings, but given my setup, figured it wasn't going to help me. I was just looking for recommendations to tell my mechanic if anyone here had something that worked for them. I'll do some further searching on the K&N issue here too.

thanks

by the way...stock air filter with other setup I have would make sense?

would this be close otherwise? Perhaps 180/182?

178f, 180R
stock needles with one #4 brass washer under each - about .08" thicker than stock
45 pilots
2 1/2 turns out on the fuel screws

I'd start with the 180 and 182 main, and try two shims under the needles instead of just one, and the stock air filter.


Thinking you'll suck a little more air than stock with the velocity stacks and pipes.


Set the pilots depending on where the fuel screws end up - more than three turns out = time for bigger pilots.


My bike on the dyno, stock stacks, TBR mufflers, stock filter was slightly lean on top (14:1 or so) with 178, 180 mains, pretty close in the middle with 1 shim under each needle, and pretty darn good at idle and low rpm with 45 pilots and about 2 1/2 turns on the fuel screws.


Make sure your choke fittings are not broken, and the choke is operating right before running around in circles forever chasing inconsistent results. Best bet would be to just buy jack flash brass choke fittings if you haven't already and then sleep well at night.

thanks. that's helpful. first step is pulling the K&N and replacing with something resembling stock. after that I'll have to figure out how to check the TPS. I found another thread with some helpful info for that part.

Just wanted to say thanks for the advice. the replacement air filter settled it down a lot. I think it still needs some tweeking, but it's MUCH better. Gracias!!!

178 and 180 mains at what altitude??

Stock jetting is 175/178, 45 pilots

Funny hardly anyone ever lists the altitude they are riding at... Kind of important... There are plenty of guys running K&N and BMC race filters with great results, does it take more fiddling? Yes! But fiddling and fettling are fun right.... The downside the VTR fuel tank, and airbox and carbs suck to R&R

The altitude of my front tire is normally 4 feet higher than my rear tire.