I haven't had any issues whatsoever with the heat on my rear fender from the exhaust tip. I don't have the 2" tip, mine is only 1- 5/8" wide opening but nevertheless the plastic is still there with no heat marks or melting on the plastic. The 2" is only 3/8" difference from my tip so I don't know if that would make a huge difference heat wise. Have you ran it since you put the tip on? If so and it didn't do anything I would think you should be ok.
The only way I can see that changing the diameter of the exhaust pipe would cause more heat is by inlarging the exhuast you lean the mixture of fuel to air and cause the machine to run hotter. If this is the case I would HIGHLY suggest re-jetting your carborator to make the machine perform better and last longer. A good way to check if you are running lean is to get rolling, with a load (ie. not sitting in netural) to a moderate speed (20-40MPH) hit the kill switch and then imediatly pull the plug and see what the coloring is. If the plug is white or a VERY light brown you need to change your jets to a larger size (lets more gas into the carb). If its black (not going to be your case) then its to rich and you need to lean it out slightly (smaller jet and less gas).
The reason yours will probably be lean is that you have changed the air intake with a different less restrictive air filter, and you have changed the flow of air out of the engine (larger pipe with no baffeling). This causes the air/fuel ratio to change and causes there to be to much more air. simply re-jet the carborator to give more fuel to go with the more air and restore the appropriate air/fuel ratio and therefore causing less heat and better performance...
You don't have to purchase the whole Jet kit...just go to yamaha dealer and ask for a larger than stock main jet...you can also clip the spring down to a shorter spring and cause there to be better initial response but I don't recommend this as its 1) irreversable and 2.) might cause the throttle to get stuck open at higher elevations or off camber situations (this is due to less downward pressure on the needle that lets the gas into the carb because of a shorter spring).
I hope this was helpful!!
P.S. I did most all of these mods to my rincon and hated the results because I was not good at "adjusting" the stupid carb...its takes talent I presume to be able to set the thing up in its sweet spot...I would either take it to pro with a dynojet or have a mechanic buddy with a REALLY good ear/touch...
I have only taken it out on a short ride (+/- 45 minutes in light rain) so I really do not know if it will burn the plastic yet. My initial concern was after I read on ebay (Power Tip for Yamaha Grizzly 660 and Rhino 660 Exhaust) the seller says...Our tip directs the exhaust flow down and away from the rear fender. Beware of other tips out there on the market that come straight out. They will melt your fender!
So I went to look at the back of my Grizzly again, and I noticed that the edge of the fender, and a whole chunk of the overfender, seems to be in the LINE OF FIRE of the exhaust.
I dont think the exhaust is running hotter (as Marine agrees) but the original tip points downward and the 2" billet tip points straight back! Therefore it may melt the fender and overfender!
Anyway last night I took Alunimun Foil (Ovenliner) and Electricians Glass Tape, and i made a sheet with 2 layers of each, I then used contact adhesive and lined the inside of the fender and about 2cm of the lip. I hope this will prevent any damage. I will test it out this weekend!
Hey Marine, thanks for the advice again! it is always "spot on" and appreciated. I will check my plug after a day or two of riding to see if I am running lean.
I also run two airbox valves which lets in more air and that along with my exhaust tip you would think the fender and overfenders would melt/burn, but so far so good. I did a plug chop when I first installed the valves and the plug looked right on the money. I wouldn't take much into consideration as for the seller on ebay suggests(sales pitch). The tip the ebay seller is talking about is the exact same tip I bought from him and I will say this, IT DOES NOT POINT DOWNWARD WHATSOEVER, it comes straight out just like the one you purchased. The only difference between his tip and the other one being sold is, his tip has a 1-5/8" opening versus a 2" opening and his is billeted aluminum versus stainless steel like you bought. I have put on over 200 miles with my tip and airbox valves, and my plastic still looks like the day I brought it home. I would however recommend keeping a good eye on it just incase, but im almost positive you should be fine.
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