XR4 MODS?

[fla.viper]

after doing some research on line, it seems turning my XR4 into a 200hp takes only some head work, and rejetting the carbs? is anybody fimilar with this? can anybody recomend a machine shop experienced with this modification? what is the difference between a 2.4 bridgeport and a regular 2.4. tx, mike

[77viper]

The 150 and 200 are completely different in bore sixe and porting. As far as mods go have the heads cut, that's the best bang for the buck. Put fiber reeds in it as a preventative measure, remove the exhaust liner if you want it a little louder. That will give you a little boost without hurting reliability. If you want more out of it than that it is more cost effective to just go with a 200.

A bridgeport has such a wide exhaust port it needs a bridge in the middle to keep the rings from catching. The porting is a lot different than a fishing motor 2.4.

[fla.viper]

on the hydrostream.org page under tech talk i found this :
" As for the Virage, the best thing you could do is get the larger 1:86 ratio gearcase. The little XR4 1:78 gearcase doesn't carry the boat very well. Next just port the XR4 to 200 spec and you'll have what you desire. You can re-jet the carbs or find a set off a late model 2.4 200 and just bolt them on. Both of your props will be perfect for skiing and the speed runs. But this is with the big gearcase. Sounds like the local builder doesn't quite know how to 200ize the XR4. This would explain his reluctance, as it is a simple operation. If you go the "new" 200 route, the rev limiter is a control box on the powerhead and can be removed. The 2.5 has the 40 amp charge system like your XR4, so no difference.

Randy "

posted by randy pierson http://www.hydrostream.org/TechTalk/2Streams.htm

when he says port the XR4 to 200 specs, does he mean the heads? or would the block have to come apart?
anybody know what hes talking about?
tx, mike

[Fast Viper]

With the reed change and the liner removal would the carbs need to be rejetted on my 2.4 200 ?

[77viper]

on the hydrostream.org page under tech talk i found this :
" As for the Virage, the best thing you could do is get the larger 1:86 ratio gearcase. The little XR4 1:78 gearcase doesn't carry the boat very well. Next just port the XR4 to 200 spec and you'll have what you desire. You can re-jet the carbs or find a set off a late model 2.4 200 and just bolt them on. Both of your props will be perfect for skiing and the speed runs. But this is with the big gearcase. Sounds like the local builder doesn't quite know how to 200ize the XR4. This would explain his reluctance, as it is a simple operation. If you go the "new" 200 route, the rev limiter is a control box on the powerhead and can be removed. The 2.5 has the 40 amp charge system like your XR4, so no difference.

Randy "

posted by randy pierson http://www.hydrostream.org/TechTalk/2Streams.htm

when he says port the XR4 to 200 specs, does he mean the heads? or would the block have to come apart?
anybody know what hes talking about?
tx, mike

I'm not a fan of Randy's work myself way too many horror stories. A 150 is a 2.0 liter block and a 200 is a 2.4 or a 2.5. Just cut the heads enough to give you 145 psi of cranking compression, that way you can get away with fresh 91 octane fuel. Anything above that requires a lot of work and even more$.

[77viper]

With the reed change and the liner removal would the carbs need to be rejetted on my 2.4 200 ?

Short answer is yes I started 3 sizes up but will come down to stock or leaner on a hot race day. You will want to play with it a bit but once it's set the average person can leave it a tad rich on hot days so that on cool days you don't need to rejet.

[Fast Viper]

I hear you sell carbon fiber reeds , what are the advantage to those ?

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[77viper]

I hear you sell carbon fiber reeds , what are the advantage to those ?

[ Post made via BlackBerry Curve ]

They are not carbon, just fiberglass made by Chris Carson. The main advantage is if they break it will go through the motor without damaging it where a stock steel one will tear sh*t up on it's way through. A lot of motors will idle smoother and have a better feeling midrange. I will not say they are a big performance gain just to sell them.

[fla.viper]

thanks chet, you are the best! i actualy thought my motor was a 2.4. i. guess ill run it on the virage, till the viper is ready for it, while i figure out the best way to replace it. i still have the '99 3.0 250 efi on my seabird. iv seen another virage with a 3.0. what do you think?
tx, mike

[Fast Viper]

Thanks a lot for the lnfo on the reeds and everything else. Seeing as my motor is. 24 yrs old its time to put in a set of new fiberglass reeds. How much do you charge for a set ?

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