Track Tac

Fuel Pump and Top Plate....

M

mikey56

New member
So i'm looking at this hunk of metal called a top plate and wondering....does it have to be this big and wide? is there any reason for the fuel pump to be mounted to it other than convenience or can it be mounted to say the side of the blower cover? if you mount it on the side, does the length of the pulse line from the valve cover (where the majority pull the pulse from) to the pump matter? also...one problem that I seem to have is the heat shield/chain guard pulling them two small bolts out of the side cover...yeah...I know...keep them tight, use red locktite and all that jazz......but what about mounting it higher up and affixing it to the top plate? then maybe run a piece down along the side between the clutch and seat to give more protection? higher up and my arm don't feel like a lobster at a tea party....

just wondering and although I know that some will give the ages old "it because" answer, i'm still wondering and looking at modifying both the shield and top plate to give me a little more protection and more stability...could be that my grumpy old butt needs to back to bed too...lol!!

thanks!!
 
I don't think that a clone's top plate needs to be so big and wide, nor that the fuel pump has to be mounted on it. I think that the popular design is a result of an easy to imagine and fabricate answer to "how do I mount this stuff?" and people were satisfied with it so they copy it. We used to mount fuel pumps for modified flatheads on the engine cover with good results. I'd think that keeping the pulse line as short as possible should aid how the pump works since the pulse should be stronger, but I admit I haven't done experiments with that yet. You could simply fabricate and mount a thin strip of metal just strong enough to support your throttle arm instead of the whole plate. Would there be any benefit? Maybe better engine cooling (because of less shrouding), but usually we're taping up air intakes to build engine heat so cooling might be a mistake...

Your heat shield / chain guard idea is intriguing. Protecting your arm better while reducing potential side cover bolt failure are worthwhile goals. Maybe the shield / guard shouldn't even be mounted to the engine at all... if it was mounted to the kart then you'd only need one setup instead of separate pieces for each engine, and it would place no strain on engine parts, and might even be cooler since it might end up spaced farther away from the exhaust pipe. Sounds like a good project for over the winter since the season is ending for a lot of us.
 
that's what i'm thinking too...if you look at the guard from the clutch side, the bolt on the right hand side failed....dropping the guard into the clutch basket and chewing on that a bit...no big deal, didn't kill anything....but I drilled two holes and wired the guard to the top plate...and it brought the shoulder area guard up higher and actually felt better all the way up until I got tagged and lost the right rear (snapped all three studs)...got me to thinking about making some changes to the top plate, fuel pump and chain guard.....

thanks for answering....wonder if anyone else has any thoughts....
 
Most places (including my engine builder) are putting on smaller top plates, but still mount the fuel pump to it! One of the reason and maybe the most important is, it keeps the pulse line as short as possible and the fuel outlet from pump to carb short as well!
 
could very well be....that's what I kinda thought too....i'm not talking about doing away with the top late, but making a sort of combination top plate/shield/guard....still in the planning and thinkin stages right now, but i'm not going to mount the shield back up to the block for this last race...got me some brackets and going to do some drillin and screwin (get your minds outta the gutter! lol!) and trying to bring the guard up, keep it stable and to give me a little more shoulder bolster....plus keeping me safe in the seat!!
 
The top plate actually has multiple purposes, it holds the throttle arm assembly, fuel pump, and acts as a brace for the block. The top plate helps prevent the block from flexing, which might not matter much in a stock build but does matter when you get into a more modified engine. When you modify them, like an open clone or S/A, you need as much bracing as you can get on the block, the top plate helps brace the top of the block and the jug. Hopefully Sneaks and a few others will chime in on this, as they can provide alot better explanation than I can about this. I suppose if you can find a way to mount the fuel pump to the recoil housing or somewhere close by so the lines will stay short, it would still work fine. I have added diamond plate aluminum to the chain guard shield before to extend it further up, and have tapped the bottom section so that the guard also catches the threaded hole in the side cover that Is a few inches to the right of the 2 that we already use for holding the guard on. I use the longest 5/16" bolts I can fit into the side cover holes to bolt the chain guard up, and don't use any locktite or anything like that on them because I don't want to have to heat the bolts just to get them back out everytime I decide to pull the engine apart for a rebuild. It really isn't needed if you torque the bolts properly.
 
my thing is that i have the side cover studded and it doesn't let the shield rest flat against the block. right or wrong, i think there is a better way to mount the thing so that i don't have to worry about it....the thought i have is to make it kind of hinged to allow the racer to undo a couple of bolts and swing the shield out of the way to get to the clutch easier and to the side cover bolts in case of any need to tighten them. it's workable and doable, but i have to sit down and really look at it over the off season to make sure that i do it first with safety in mind and second to have it mounted securely. i have some ideas that i want to explore before i put the first wrench to the shield, but the other thing that i'm looking at is a shield between the seat and the clutch area and incoporating a cooling vent or cooling hose directing air from the nose (up by the top, not down on the nose where it would affect handling) to the shield to help keep the clutch cool....

any other ideas? i'm also looking for ways to mount the fuel pump to isolate it from any heat that comes up off the block and keeping the line run short....

this is where it starts in my mind...racers thinking out of the box instead of relying on "its been that way forever and why mess with it?".....because there is always a way to improve what you have!!
 
mikey56 said:
my thing is that i have the side cover studded and it doesn't let the shield rest flat against the block. right or wrong, i think there is a better way to mount the thing so that i don't have to worry about it....the thought i have is to make it kind of hinged to allow the racer to undo a couple of bolts and swing the shield out of the way to get to the clutch easier and to the side cover bolts in case of any need to tighten them. it's workable and doable, but i have to sit down and really look at it over the off season to make sure that i do it first with safety in mind and second to have it mounted securely. i have some ideas that i want to explore before i put the first wrench to the shield, but the other thing that i'm looking at is a shield between the seat and the clutch area and incoporating a cooling vent or cooling hose directing air from the nose (up by the top, not down on the nose where it would affect handling) to the shield to help keep the clutch cool....

any other ideas? i'm also looking for ways to mount the fuel pump to isolate it from any heat that comes up off the block and keeping the line run short....

this is where it starts in my mind...racers thinking out of the box instead of relying on "its been that way forever and why mess with it?".....because there is always a way to improve what you have!!
Click to expand...

My blocks are studded also, the studs i use dont stick out or rest against the chain guard, the nuts are flush against the end of the studs when i torque the nuts down. Sounds like your studs may be a little too long, i cut the excess off to where the studs are flush with the end of the nuts, then clean up the threads.
 
going to do that very thing during the off season....i have broad shoulders and bringing the heat shield up further protects my arm better....

what brought this is was at the last race, the motor got hot and several of the bolts backed off...one heat shield/guard bolt came completely out, so i had to wire the guard up in a hurry to make my heat....everything was running great until i took a hit in the right rear, sanpping the studs....but because my arm was protected more than before, it got me to thinking about the way the guard was mounted, how i could mount it better and bring it up more to protect my arm better...

just some ideas that i'm kicking around to make things better for me....might not work in every case, but what the hey! we're racers!! give us enough bubblegum, bailing wire and a roll of duct tape and we can rebuild and race anythign!!
 
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