Rebuilding YT125 top end + Boyesen Reeds + ProTec Exhaust = ?

[generallee2005]

Ok, I've got my toped buttoned up on my 81 YT125, I've installed the Boyesen reeds & am getting ready to put the carb & exhaust back on to begin break in. I'm thinking I'll break in the top end with the stock exhaust & then install the ProTec exhaust. What jet changes would I be looking at? I've searched but haven't found any definite ideas, hoping someone chimes in to steer me right.

Thanks

[Bren_downe]

Have you done a leak down test?
You'll probably have to go up 1 or 2 main jets, not sure about mikunis.
You can get then at JetsRus.com

[the great gazoo]

I'd be curious to see your pipe, I can't remember what the ProTec pipe looked like.

[generallee2005]

No leak down yet, its been raining here all week. Hopefully this weekend I can have make some progress. I'll get pictures of the pipe & try to scan the paperwork that came with it this weekend, too.

[generallee2005]

Leak down test was a pass with flying colors, compression test was 115. Fired up on the third pull & once warmed up it purred like a kitten. I did put the Boyesen reeds in already, I'll break it in with them & see where the plug is. Probably next weekend I'll bolt the pipe up, I'd rather had a Bassani all day long, but this is still a neat pipe, I can't wait to try it out. Here's the pictures & flyer. I had scanned it, but it was too big to post. I'm a little anxious about how its going to seal at the stock head pipe, but I figure anything is bound to be an improvement. It did come with two of the neat little stickers, truth told, I like the stickers the best, too bad my YT is a early version I wish I could put the ProTec suspension easy.

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[generallee2005]

Alright, I gotten the top end broken in & installed the exhaust. Went in smooth, looks great, & sounds great! Here's the rub, I feel like my pilot is too rich now, to start it cold I have to hold the throttle wide open & start it like its flooded. Then it simply will not idle unless I rev slightly this improves slightly once warmed but does not go away. Would this be consistent with installing the exhaust? The pamphlet with the reeds says that the reeds will make the pilot slightly lean, but can be adjusted out with the air screw. The pamphlet continues that a smaller main jet may be needed also, 1-3 sizes. Since I cannot get the bike to properly idle I have only rode the bike a few feet to park it in my shed, so no main jet plug chops. What should I expect the main jet changes to be with the new exhaust, smaller or larger? My thinking tells me larger because more exhaust out=more intake needed. Any ideas will be greatly appreciated. Again the only mods I have are the reeds & exhaust, I still run the stock air box with a Uni filter.

[the great gazoo]

That pipe is cool as helll! It's kind of weird that it's not a complete unit, but nothing a little zap zap won't take care of.
And I love those stickers, too! Maybe Blue27 here on the boards could reproduce them, he does great stickers.
As far as your jetting, if it was me it'd be trial & error. I got really lucky with my 175 & the Boyesens, it ran great, just had crazy clutch problems.

[the great gazoo]

I just fully read the Pro-Tec instructions. That's pretty cool ,it slips on and you don't have to weld it