Author Topic: change carb or no? (Read 13232 times)

benoladdict · « **on:** April 19, 2015, 05:15:59 PM »

86trx250r 2nd ive ever owned. Stock carb ported engine. Looking for a few more ponies I have 35mm a.s. carb as well as 35mm pwk at my disposal was wandering if it would be worth the swap my bike currently has the stock airbox with lid and im not against deleting it all together. So is it worth the extra 1mm plus newer style carb?

fearlessfred · « **Reply #1 on:** April 19, 2015, 11:15:13 PM »

I think you would definitely have a noticeable difference with either carb and lid off ,its just an air pump ,the more you can get in and out the better its going to run.the pwk and a/s are basically the same carb ,the a/s supposedly being the better of the two

Jerry Hall · « **Reply #2 on:** April 20, 2015, 12:28:19 AM »

Quote from: benoladdict;53327

86trx250r 2nd ive ever owned. Stock carb ported engine. Looking for a few more ponies I have 35mm a.s. carb as well as 35mm pwk at my disposal was wandering if it would be worth the swap my bike currently has the stock airbox with lid and im not against deleting it all together. So is it worth the extra 1mm plus newer style carb?

If the 35mm carbs are free I would use one of them. If you are going to buy a carb, I would increase it to a 39 or larger. One mm larger on a ported motor is not going to do much.

The_Steve_Man · « **Reply #3 on:** April 20, 2015, 04:18:19 AM »

I put a Mikuni TMX 38 from a cr250 on my bike with a ported stock cylinder and I like it a lot better than the keihins I had on it.

jcs003 · « **Reply #4 on:** April 20, 2015, 05:17:09 AM »

38 a/s, cr ignition, uni filter, rad valve and a good pipe to match what you have in your engine and you will notice a huge improvement everywhere.

john

benoladdict · « **Reply #5 on:** April 20, 2015, 07:42:39 AM »

Thanks for the input and yes the carbs are left over from my twin cylinder. So they are just sitting around. Ill try and find a used 38mm to buy or trade thanks to all

hontrx265r · « **Reply #6 on:** April 20, 2015, 09:37:12 AM »

I have a 38mm a/s bought new a couple months ago, still perfect condition 175.00 shipped

benoladdict · « **Reply #7 on:** April 20, 2015, 10:30:07 AM »

Thanks I ha e a buddy who has a 38mm mikuni carb hes going to check and see if he can find it and ill try that out has to be better than the 34pj

2ndmoto · « **Reply #8 on:** April 21, 2015, 12:28:07 AM »

You will find more info on jetting the kehin pwk. More common than any other after market carb. What type of riding are you doing?

Best regards
-Jason

benoladdict · « **Reply #9 on:** April 21, 2015, 08:45:49 AM »

We do mostly open trails but it always ends in drag races hahaha I have jets already for the kehin but dnt wanna spend anymore money if I can get the 38mikuni for free. Ill keep a look out for a good used kehin

The_Steve_Man · « **Reply #10 on:** April 21, 2015, 09:00:28 AM »

Most people use the keihins because there is a ton of info on jetting on the Rs. I was never really happy with the jetting and and performance of the keihins I had. I didn't use a new one. I decided to do some research on mikunis on my own since there not much out there for the r. I set it with specs for the cr250 and won't go go back to keihin on this motor. I don't know what style of mikuni he has but just research jetting on a 250 for that carb and that should get you close. If it is one like I have, I can give you the jetting I used.

Don't be afraid to try the mikuni espcially if its free.

Tbone07 · « **Reply #11 on:** April 21, 2015, 09:09:15 AM »

Quote from: benoladdict;53403

We do mostly open trails but it always ends in drag races hahaha I have jets already for the kehin but dnt wanna spend anymore money if I can get the 38mikuni for free. Ill keep a look out for a good used kehin

Quote from: The_Steve_Man;53404

Most people use the keihins because there is a ton of info on jetting on the Rs. I was never really happy with the jetting and and performance of the keihins I had. I didn't use a new one. I decided to do some research on mikunis on my own since there not much out there for the r. I set it with specs for the cr250 and won't go go back to keihin on this motor. I don't know what style of mikuni he has but just research jetting on a 250 for that carb and that should get you close. If it is one like I have, I can give you the jetting I used.

Don't be afraid to try the mikuni espcially if its free.

I wouldn't mind trying a Mikuni too. I know from previous posts that Jerry Hall likes using them more than the Keihins

benoladdict · « **Reply #12 on:** April 21, 2015, 09:18:16 AM »

Yea cant beat free actually the motor has hpr on the side of it im happy with the stock carb but im trying to beat a bigbore z400 its supposed to be quick im nt sure. I have kehins on my banshee but am completely new to the mikunis I hear they are super easy to tune. Im pretty sure anything is easier than the air strikersstrikersn I dont know of any good tuners in north florida and most here dnt even know what a 250r is.

The_Steve_Man · « **Reply #13 on:** April 21, 2015, 09:37:23 AM »

This is the style I used. It is off of a 02 cr250. 01-03 are the same but the needle and needle jet are different between years. I used the jetting specs on the Pro Circuit website for the 02 and only just raised the needle. It runs amazing on my bike. If you post on any R site about a mikuni, all you will here is "throw it away and put a keihin on it".

I'm not saying it is the end all be all but there are other options that work.

JesseA420 · « **Reply #14 on:** April 21, 2015, 09:42:50 AM »

i use keihins because i am familiar with them, but my brother is running a 38mm tmx on his 310 mx port and it has amazing throttle response for still using a stock trx ignition. he picked it up along time ago when eddie used to sell them, great carbs.