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I have heard alot about the 39mm FCR carb and not really as much as I would have expected about the 40mm or any of the others that are aval. on the 450r. anything like perf better or wear prw. is delivered would be great.
-thanks
 

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The 40 off the CRF is the way to go -- it's cheaper than the aftermarket 39 & is already setup for this engine.

Mine was a very easy install & out of the box was jetted better for my HRC kit than the jets that came with the HRC setup for my stock carb.

Power seems way up - especially throttle response & bottom end. It'll be interesting to see what it did to my 300' drag times next weekend --- but even if it didn't affect the quad at the strip (doubtful), it's worth it for the improvement in throttle response.

Overall the quad's power feels much more crisp, it starts even easier (I think the HRC setup was a touch lean on the pilot), and just overall runs great.

I have approx $415 in my FCR conversion.
 

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Originally posted by 86atc250r@Jun 1 2004, 09:12 AM
The 40 off the CRF is the way to go -- it's cheaper than the aftermarket 39 & is already setup for this engine.

Mine was a very easy install & out of the box was jetted better for my HRC kit than the jets that came with the HRC setup for my stock carb.

Power seems way up - especially throttle response & bottom end.  It'll be interesting to see what it did to my 300' drag times next weekend --- but even if it didn't affect the quad at the strip (doubtful), it's worth it for the improvement in throttle response.

Overall the quad's power feels much more crisp, it starts even easier (I think the HRC setup was a touch lean on the pilot), and just overall runs great.

I have approx $415 in my FCR conversion.
thats a dang good price for that....
 

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Originally posted by 86atc250r@Jun 1 2004, 10:12 AM
The 40 off the CRF is the way to go -- it's cheaper than the aftermarket 39 & is already setup for this engine.

Mine was a very easy install & out of the box was jetted better for my HRC kit than the jets that came with the HRC setup for my stock carb.

Power seems way up - especially throttle response & bottom end.  It'll be interesting to see what it did to my 300' drag times next weekend --- but even if it didn't affect the quad at the strip (doubtful), it's worth it for the improvement in throttle response.

Overall the quad's power feels much more crisp, it starts even easier (I think the HRC setup was a touch lean on the pilot), and just overall runs great.

I have approx $415 in my FCR conversion.
Are you running the tps or did you just eliminate it? I'm a do-it-yourselfer also so i might have to ask you a couple of questions about it. Does it matter what year carb you get for it? Thanks!
 

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You must use the TPS if you want the 450R to run correctly - so with that said, yes, I used it.

I used a 2003 year model carb - but only because it was the most inexpensive year carb available.

If you're not comfortable with making some minor modifications to the carb (i.e. filing the lip and epoxying on an airbox adapter, modifying the TPS wiring, and interchanging some hot start parts), then you may be better off buying a kit from someone like GT Thunder for a little more money (I believe he sells his kit for $550).

If you are comfortable doing your own modifications I can help explain what needs to be done.
 

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Thanks Gabe, did you have to order the hotstart cable through baldwin like everyone else says to do, or can you just order on for a certain kind of dirtbike or something? I might just order the finished product, I had a couple of good commissions come in this week so who knows.
 

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The only special parts I had to order were the carb itself and an airbox adapter.

With that, everything else can be made to work, easily....

Everything's functional on mine - TPS, Hot start, choke, etc... Using stock throttle cable and stock hot start setup.

I was expecting more problems, especially with the hot start and throttle cable - but the conversion went very smoothly.
 

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Thanks, everyone acted like you had to have a different hot start cable, thanks for clearing that up for me.
 

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I think very few have actually done the conversion, so there isn't much good info out there.

I just jumped in and bought the stuff I knew I'd need - I decided I could probably figure out the rest if need be. Was pleasantly surprised.
 

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I used my stock hotstart cable and it worked fine. I know with the 39 my Honda guy had to change some of the wiring on the new carb so the mapping would be the same for the TPS. :D
 

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Gabe, I will be buying a carb soon, can I talk you out of the instructions for the TPS? Thats my only concern, Did you buy the adaptor from JH?
 

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Noss Machine - that's where JH gets them.

Yes, when you're ready let me know and I'll give you the wiring for the TPS.

I just rewired mine, but after doing it I realized that the stock one may just bolt right onto the FCR - not sure. Either way it's no big deal.
 

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I have a few quetions first being, wats tps, secong being, i have always herd more flow = more hp, and going from a 42mm carb to a 39 or 40, wouldnt this reduce the flow??? and how does the power chaange on bottom mid and top by switching the carb, thanks for the info
 

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Holeshot -- I'll have the quad at the strip this coming Saturday & I'll know then if it improved my times at all.

Currently I typically run about 5.3 ET (not figuring in any RT). 6.0 flat is a typical total time with R/T figured in. We typically run the pro tree and ET vs RT changes basically on how you stage, shallow or deep (shallow increases RT, but decreases ET and vice versa). 6.0 total time is pretty typical though - so if I can break into the 5's (total time) then it made a positive difference on drag acceleration (I know for a fact that it made a great improvement everywhere else).

40mm vs 42mm - the 40mm FCR does not have any obstructions in the air path like the stock carb. Power feels up everywhere, especially in throttle response.

TPS - throttle position sensor. This allows the quad to have a 3D timing map. As you open the throttle toward full, the ignition timing decreases. This allows increased timing advance under lighter engine loads which improves part throttle power and overall throttle response.

On a quad like the 400ex that doesn't have a TPS - ignition advance has to be run with "worst case" in mind - i.e. full throttle (since the CDI has no feedback to know throttle position or engine load)- so you end up running decreased full throttle advance at all times.
 

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40mm vs 42mm - the 40mm FCR does not have any obstructions in the air path like the stock carb. Power feels up everywhere, especially in throttle response.[/b]
He's right about flow and remember the FCR is a better carb. The FCR is a race carb where the stock one is not! B)
 

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So with the CRFs 40mm you where able to just bolt everything on and that was just about it...right.....?????

Did you use the Thumb throttle or a Twist.... if you used the Thumb how much harder is it to push......????
 

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After you get the adapter, yes, it bolts on pretty easily. I rewired the TPS and used the stock hot start and throttle.

Throttle pull is not harder than stock.
 

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Originally posted by 86atc250r@Jun 7 2004, 12:30 AM
Holeshot -- I'll have the quad at the strip this coming Saturday & I'll know then if it improved my times at all.

Currently I typically run about 5.3 ET (not figuring in any RT). 6.0 flat is a typical total time with R/T figured in. We typically run the pro tree and ET vs RT changes basically on how you stage, shallow or deep (shallow increases RT, but decreases ET and vice versa).  6.0 total time is pretty typical though - so if I can break into the 5's (total time) then it made a positive difference on drag acceleration (I know for a fact that it made a great improvement everywhere else).

40mm vs 42mm - the 40mm FCR does not have any obstructions in the air path like the stock carb.  Power feels up everywhere, especially in throttle response.

TPS - throttle position sensor. This allows the quad to have a 3D timing map.  As you open the throttle toward full, the ignition timing decreases.  This allows increased timing advance under lighter engine loads which improves part throttle power and overall throttle response.

On a quad like the 400ex that doesn't have a TPS - ignition advance has to be run with "worst case" in mind - i.e. full throttle (since the CDI has no feedback to know throttle position or engine load)- so you end up running decreased full throttle advance at all times.
nevermind...I was just confused...
 
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