734 build cutting out

I know this is a rhino forum but and this is a grizzly , but there are allot more 734 builds on rhinos than grizzlys so i thought I would ask the question over here also. This is what I got , Trinity 734 with a je piston , I had EHS racing port the head with custom grind cam and + 2 valves , +3 tb and I'm running the EHS fuel controller . I completed the build and it fired right up no problem , after a little playing around with the controller the bike was running great , I'm talking about 15mph rolling wheelies ! After a few days of running great I start it up no problem but now it is cutting out at 3/4 to wot . I'm stumped , I played with the controller to no end and no improvement , I even put in a new tps but still no dice . I've ruled out the reveres switch and put fresh gas , pulled the tb back off checked all the connections , I turned off the fuel controller and it was way lean down low and still cutting out on the top . I also pulled the injector out and tryed to clean it but looked clean . After I put the injector back in It seemed to get worse , I mean started to bog at more like 1/2 throttle . Any you 734 guys have any tips for me ? I'm stumped .

It is possible you still have an a/f ratio problem. Does the EHS controller you are using have the proper map for that build or is it just their standard map?

Nate
Alba Racing

could be fuel pump maybe...i have seen air leaks around the injector after replacement and they will run like shit.that may be why it ran worse after that.take injector back out lube oring and check for any tear

The base map is close for my build and like I said it was running like a top one day and the next it's cutting out. I'll check out the o-ring on the injector , Thanks for the tip on that . I rented a fuel presser tester but was set up for a fuel rail with a bunch of different fittings , I'm unsure how accurate the readings I got but 30 lbs is the highest reading I could get when turning on the key.

Took tb off and the injector , the o-ring looks good but I went ahead and lubed it put every thing back together but still cutting out.

I wish I could add to this thread, but I am watching it closely. My 734 runs great. My first thought was that it was a fueling issue. Do you have a A/F ratio gauge to see what's going on when the symptom occurs? If it's lean, then we need to figure out why. The controller might have took a dump. The fuel pump might not be able to supply the flow and pressure needed at high load.

Good luck bro! I have always wondered what a good 734 would do in a Grizzly. It transformed my Rhino into a RZR eater. I can only what it does in a Grizzly!

You need at least 40 lbs of fuel presure to run right, I would check into replacing or checking the operation of your fuel pump.

46.1 i think is min.

Wow ! 46.1 , not even close ! I'm going to borrow a different tester this afternoon and see what I get . So when I get this tester hooked up should I be trying to start so the pump is pumping or just turn the key on and see what the presser is ?

ChrisH wrote:

I wish I could add to this thread, but I am watching it closely. My 734 runs great. My first thought was that it was a fueling issue. Do you have a A/F ratio gauge to see what's going on when the symptom occurs? If it's lean, then we need to figure out why. The controller might have took a dump. The fuel pump might not be able to supply the flow and pressure needed at high load.

Good luck bro! I have always wondered what a good 734 would do in a Grizzly. It transformed my Rhino into a RZR eater. I can only what it does in a Grizzly!

More power than a 2012 can ham 800r. No I don't have a a/f meter on it yet but I found a PCV with auto tune for $250 on another forum that I'm thinking about but then this happened ...

turn key on and see...then make sure it has full pressure at wot too

I took off the fuel line at the tank and put a piece of fuel line on and ran to the tester . Does this sound right ?

Ok the pump checks out fine at idle and wot .Injector maybe ? Or maybe the fuel controller went kaput ?

it sounds exactly what my rhino is doing and its stk tried pump,disasembled fuel rail,cleaned all connections,waiting on cdi and see what that does

I'm going to go ahead and look at the valves to see if there still in spec. If that's not it I'm thinking it's the controller . I took it to yamaha for a look over to see what they think it is , they say it's in the clutch but I've had those clutches on and off back to stock ect , I even looked at the wet clutch and looks fine . IDK

I found the problem , the purple spring was the problem , along with 4 14 gr and 4 16 gr weights making me hit the rev limiter. Put the stock spring back in and still hit the limiter fora a sec , then went all 16gr and the limiter is gone . I think I still need some heaver weights seems I lost a little performance from my stock sheave with 4 660 and 4 700 weights.