1979 cr250 carb

4/4/2020 1:20pm
If you were replacing the stock Keihin carb on a Red Rocket what make and model would you recommend?
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tydog
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8/26/2007
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Monticello, GA US
4/4/2020 3:31pm
36 Mikuni, Mossbarger reeds. My 2 cents.
4/5/2020 7:22am
tydog wrote:
36 Mikuni, Mossbarger reeds. My 2 cents.
The main man in Britain that deals with Red Rockets sells Mikuni carbs for them but it is the 38mm he sells Wonder why he went with the 38mm compared to the 36mm one?
tydog
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Monticello, GA US
4/5/2020 9:58am Edited Date/Time 4/5/2020 9:58am
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it might provide, for their types of tracks. I am 99% certain mine is a 36 and I am very happy with the crispness and throttle response. I have not done any trials between 36 and 38, pipes, reeds and ignitions but I might should. When I built it I went 36 and Mossbarger and have been damned happy; maybe just scared or too lazy to start fuggn with it 😂😂
1

The Shop

4/5/2020 11:51am Edited Date/Time 4/5/2020 11:52am
An old trick from the two stroke flat track days was to put on a big carb to kill the low end power for big tracks. Wonder what true flow numbers are for 36-38? When the Lectrons came out way back, their 36 flowed almost as well as a 38 Mikuni supposedly.


My older brother had a 36 Mikuni that was bored to 37.75 on an A/C 400 Yamaha. That thing would go.
4/5/2020 1:12pm
tydog wrote:
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it...
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it might provide, for their types of tracks. I am 99% certain mine is a 36 and I am very happy with the crispness and throttle response. I have not done any trials between 36 and 38, pipes, reeds and ignitions but I might should. When I built it I went 36 and Mossbarger and have been damned happy; maybe just scared or too lazy to start fuggn with it 😂😂
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!!

Personally, I wouldn't fit a Mikuni to anything with a Honda badge, I really don't like them! But I do understand that in some areas/organisations you have no choice to use one, but you will be constantly chasing jetting.

The absolute best carb to use is a 38mm PWK Airstriker, 2nd would be the normal 38mm PWK, then the 38mm PJ from the mid 80-90's CR's. They completely transform the bike. They will fit straight on out of the box, but they fit a little better with a 5min mod on a milling machine.

They will start easier, rev 1000RPM higher and be crisper and more responsive than you thought possible for a 40yr old Motocross bike has any right to be.

Stevie
2
4/5/2020 2:05pm
tydog wrote:
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it...
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it might provide, for their types of tracks. I am 99% certain mine is a 36 and I am very happy with the crispness and throttle response. I have not done any trials between 36 and 38, pipes, reeds and ignitions but I might should. When I built it I went 36 and Mossbarger and have been damned happy; maybe just scared or too lazy to start fuggn with it 😂😂
StevieD113 wrote:
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!! Personally, I wouldn't fit a Mikuni to anything with a Honda...
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!!

Personally, I wouldn't fit a Mikuni to anything with a Honda badge, I really don't like them! But I do understand that in some areas/organisations you have no choice to use one, but you will be constantly chasing jetting.

The absolute best carb to use is a 38mm PWK Airstriker, 2nd would be the normal 38mm PWK, then the 38mm PJ from the mid 80-90's CR's. They completely transform the bike. They will fit straight on out of the box, but they fit a little better with a 5min mod on a milling machine.

They will start easier, rev 1000RPM higher and be crisper and more responsive than you thought possible for a 40yr old Motocross bike has any right to be.

Stevie
Thanks to all for advice especial Stevie Do you have the Airstriker in stock? If not and you are going to order carbs in the future let me know on this thread and i will phone you my card number I am in no rush in the slightest Would like to buy it from you to get the mod done by you
tydog
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Monticello, GA US
4/5/2020 3:58pm
As always SteveO, much respect from one old machinist to another! Cheers mate!
450exc115
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Location
Hebron, CT US
4/6/2020 4:53am
99/00 Honda CR250R PWKs can be had for $215ish . Wonder how close the jetting is? That is what I plan to use on my 80 CR250. Smile
FreshTopEnd
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4/6/2020 11:08am
I've wondered about the 38's on the older bikes; power valves on the modern bikes temper the low end compromise on with a bigger carb. Maybe it's just a question of riding it with a little more wrist depending on conditions.
TTperra
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SE
4/6/2020 2:50pm
tydog wrote:
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it...
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it might provide, for their types of tracks. I am 99% certain mine is a 36 and I am very happy with the crispness and throttle response. I have not done any trials between 36 and 38, pipes, reeds and ignitions but I might should. When I built it I went 36 and Mossbarger and have been damned happy; maybe just scared or too lazy to start fuggn with it 😂😂
StevieD113 wrote:
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!! Personally, I wouldn't fit a Mikuni to anything with a Honda...
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!!

Personally, I wouldn't fit a Mikuni to anything with a Honda badge, I really don't like them! But I do understand that in some areas/organisations you have no choice to use one, but you will be constantly chasing jetting.

The absolute best carb to use is a 38mm PWK Airstriker, 2nd would be the normal 38mm PWK, then the 38mm PJ from the mid 80-90's CR's. They completely transform the bike. They will fit straight on out of the box, but they fit a little better with a 5min mod on a milling machine.

They will start easier, rev 1000RPM higher and be crisper and more responsive than you thought possible for a 40yr old Motocross bike has any right to be.

Stevie
How about a carb from 83/84 CR250, are they better than 79 model?
(have to be round slide)
4/8/2020 12:17pm
tydog wrote:
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it...
I assume you mean Stevie Denton? Stevie knows his stuff for sure and is a great guy!!! I assume they prefer the extra top that it might provide, for their types of tracks. I am 99% certain mine is a 36 and I am very happy with the crispness and throttle response. I have not done any trials between 36 and 38, pipes, reeds and ignitions but I might should. When I built it I went 36 and Mossbarger and have been damned happy; maybe just scared or too lazy to start fuggn with it 😂😂
StevieD113 wrote:
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!! Personally, I wouldn't fit a Mikuni to anything with a Honda...
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!!

Personally, I wouldn't fit a Mikuni to anything with a Honda badge, I really don't like them! But I do understand that in some areas/organisations you have no choice to use one, but you will be constantly chasing jetting.

The absolute best carb to use is a 38mm PWK Airstriker, 2nd would be the normal 38mm PWK, then the 38mm PJ from the mid 80-90's CR's. They completely transform the bike. They will fit straight on out of the box, but they fit a little better with a 5min mod on a milling machine.

They will start easier, rev 1000RPM higher and be crisper and more responsive than you thought possible for a 40yr old Motocross bike has any right to be.

Stevie
Maicoman07 wrote:
Thanks to all for advice especial Stevie Do you have the Airstriker in stock? If not and you are going to order carbs in the future...
Thanks to all for advice especial Stevie Do you have the Airstriker in stock? If not and you are going to order carbs in the future let me know on this thread and i will phone you my card number I am in no rush in the slightest Would like to buy it from you to get the mod done by you
We don't keep 'em in stock Maicoman. We can get them next day, under "normal" circumstances. At the moment we're not sure! Everything is kinda weird at the moment! And we've no idea who has what, If they are open, or even if the post is going to deliver stuff (had a customer who's parts were shipped 1st class, they took 5 days to arrive and were delivered at 5.30 in the evening!!) But, if you wanted to give us a call at the 'shop we can have a chat about the mods. And as if we can get something sorted for you.

Stevie
4/8/2020 1:20pm
StevieD113 wrote:
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!! Personally, I wouldn't fit a Mikuni to anything with a Honda...
I don't think Maicoman is referring to me Tydog, but thank you for the endorsement!!

Personally, I wouldn't fit a Mikuni to anything with a Honda badge, I really don't like them! But I do understand that in some areas/organisations you have no choice to use one, but you will be constantly chasing jetting.

The absolute best carb to use is a 38mm PWK Airstriker, 2nd would be the normal 38mm PWK, then the 38mm PJ from the mid 80-90's CR's. They completely transform the bike. They will fit straight on out of the box, but they fit a little better with a 5min mod on a milling machine.

They will start easier, rev 1000RPM higher and be crisper and more responsive than you thought possible for a 40yr old Motocross bike has any right to be.

Stevie
Maicoman07 wrote:
Thanks to all for advice especial Stevie Do you have the Airstriker in stock? If not and you are going to order carbs in the future...
Thanks to all for advice especial Stevie Do you have the Airstriker in stock? If not and you are going to order carbs in the future let me know on this thread and i will phone you my card number I am in no rush in the slightest Would like to buy it from you to get the mod done by you
StevieD113 wrote:
We don't keep 'em in stock Maicoman. We can get them next day, under "normal" circumstances. At the moment we're not sure! Everything is kinda weird...
We don't keep 'em in stock Maicoman. We can get them next day, under "normal" circumstances. At the moment we're not sure! Everything is kinda weird at the moment! And we've no idea who has what, If they are open, or even if the post is going to deliver stuff (had a customer who's parts were shipped 1st class, they took 5 days to arrive and were delivered at 5.30 in the evening!!) But, if you wanted to give us a call at the 'shop we can have a chat about the mods. And as if we can get something sorted for you.

Stevie
Thanks Looking to buy a few other things off of you Will phone you with order next week

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