Yamaha 225 Carburetor specs?

GOTHREECAR

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I'm attempting to rebuild my carbs on a 91 yamaha 225xtrp. I noticed that the carbs have different main jets installed. All different sizes 160,164,168,174. My Clymer manual states 154 throughout. A Yamaha parts kit states 174 throughout. What gives? The 3Carbs are stamped 6R501 and I have another set of 3 marked 6K701 which has the same strange set up. I've searched the posts and havn't seen anything related. I would like to get it right the first time and buy the right jets. Any help would be greatly appreciated.
 

rodbolt

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Re: Yamaha 225 Carburetor specs?

hello<br /> why are you buying jets?<br /> look at the parts break down in the parts book. yamaha used a lot of different jets in the 6 locations back then. always carefully note the jet size and location when doing carb work.<br /> good luck and keep posting
 

Ray Neudecker

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Re: Yamaha 225 Carburetor specs?

The Clymer manual is not correct. That would be for a 200. The Yamaha parts list shows 174 for all. The earlier models had 160 in port side and 168 in the starboard. They have made a lot of changes in the jetting over the years as they have made other changes to the engine such as the intake. There is no reason not to clean the jets you have and reuse. The parts kit you need does not include the main jets. I don't know of a model which came from the factory with the jetting you are listing in those style carbs which they went away from in the 93 or 94 model years. I have seen some strange (to me) combinations that various dealers in different parts of the country have installed to adjust for operating conditions. Those jets are over $15.00 each by the way.
 

GOTHREECAR

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Re: Yamaha 225 Carburetor specs?

Thanks for the fast reply. I don't want to buy additional jets if I can avoid it, but I want to do it right. I didn't want to reinstall a mixed bag of jets that a "tuner" had laying around.(I'm the 2nd owner). I wrote down all locations of the jets prior to dismantle in case I was re-using them. It just seems odd to me that the main air jets are all the same(270), the pilots the same,everything is the same except the mains.I appreciate the help and I will post my results.
 

Ray Neudecker

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Re: Yamaha 225 Carburetor specs?

Those horizantal(sp) intakes were somewhat crossmilled from the factory and resulted in some different jetting to compensate for this. My experience with jetting modified motors would make me belive that the 174's were too rich and hurt low end performance.
 

GOTHREECAR

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Re: Yamaha 225 Carburetor specs?

Ray,<br /> I'm going to try the 160 port and 168 starboard as you suggested. It sounds like a good starting point. I can always reinstall the ones I took out if it does'nt work. The reason for the rebuild was a bad hesitation from idle up. It would stall sometimes and I would have to feather the throttle to get it to midrange. Sounded like it was flooding. Plugs were wet, one carb was a little gummy so I figured I'd do the carbs. I also rebuilt the fuel pumps, changed all lines and filters to boot. The jetting issue confused me, but I think the posts helped alot. Thanks.
 

Ray Neudecker

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Re: Yamaha 225 Carburetor specs?

Good luck. I would check the plugs after running to be sure they were coloring properly after this change. I know of no change they made internally that would have warranted going to the 174 jets. After a mild (to me)porting,168 and 174's have been the combination that worked best in this area. I have seen some costal area motors with a 156 and 164 combination that someone had installed and were seemingly jetted correctly. That would be too lean for our crisp cool Spring and Fall air where the Bass boaters tend to make long wide open runs.
 

GOTHREECAR

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Re: Yamaha 225 Carburetor specs?

Ray,<br /> Good call on the jet sizes. I did the 160-168 combo you suggested and it runs better than ever. I put the carbs back to factory specs(float heights,pilot screws)and it ran perfect from the get go. The first plug check revealed 6 plugs all with the proper color(not wet as before).I really appreciate the help. Thanks again.
 
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