Salutations to the org....


this weekend was the 2nd run on the rebuilt 511 and all was perfect.... until... the end of the second day. I noticed a slight occasional ping coming from what sounded like the rear end of the quad. being the knucklehead i am i rode for a lil bit more before my better sense kicked it. After jumpin off the quad i noticed what looked like a little bit of coolant had leaked down onto the right side of the engine case. I let the motor cool... added water to the radiator cap and proceeded to oldsmobile hill. This time... the red high temp light flashed on and off semi frequently (when i slowed down). At the hill..i decided enough was enough and shut the bike down. I let it cool again... added water again... and let it idle and again.. steam emanated from the radiator cap. at that point i decided it was probably best to call it a night and tow the beast back to camp. i must admit i was goaded into making a single hard run up to olds 30 mins after the bike cooled. All the power remains... it just steams from the cap and from a hose or two...

what are the things i should be examining?

Thanks in advance.

Im thinking head gasket Vince.

maybe you will get lucky and the radiator cap is bad. how does the spring feel and is the seal in good condition.

take the rad cap off and start it. make sure the radiator is full. does it start spitting coolant out when the thermostat opens? this could point towards a blown head gasket or crack

not going towards your question but could you please tell me why you think hot rods crank bearings are pieces of sh%t. I am in the process of my rebuild and was leaning toward a hotrods crank.

Back to your topic. I had a similar problem when i was out at little sahara. I could smell coolant and it was plastered all over my head/cylinder and cases. I let the bike cool and tried to figure out where it was coming from. I tried putting water back in her and switching out the radiator cap which i thought may have been the problem. Same problem i had coolant spilling out from somewhere and my overheat light coming on and off. I checked all hoses and to make sure my overflow was extremely full. No solutions came to mind so i loaded up and went home. When i got my bike home my more intelligent friend and i pulled my head and found a cracked head gasket. So thats where my problem was. Hope it helps.

i'm with gary, bad head gasket sealing sounds like the most likely deal.....

if the coolant overflow bottle fills up to the point of overflow ... something isn't sealing .....

I had what sounds like the exact same thing happen to my bike and it was either a bad base gasket or the head gasket I can't remember now..

had the exact same issue.. found a very very small leak in head gasket..

The reason i believe the hot rods crank bearings are piece of shitz is because they failed me within a total of 3 hours.

thanks to all who replied...

i'll be sending my bike back with my buddy. ill tell him what you guys said.


im making enough power that i have to sit on the gas tank to keep the front down while running up oldsmobile hill (at 260lbs) . the problem with that is... the rear end loses traction and thats not good.


It should also be said that i will be going with a plus 2 extended swing arm plus 4 axle and plus 2 a arms. I need to harness all this power Venom has provided me with.

just to help out with cooling issues i recommend engine ice coolant.i use it in my 450 and it seems to help it run cooler....

Yeah... that engine ice is the business. I ran the engine ice in the bike last time and just forgot to run it this time. I won't forget to use it the next time that's for sure.

Ii think I forgot to mention that I noticed my an wasn't turning on either? What's the fix or the test for the fans operation?. I know the fan should have come on with the motor getting that hot.

What do u guys think about adding a switch to keep the fan running all the time. I know heat is the enemy and with a build like mine... I have to be generating more heat and doing so much more quickly. Is it overkill with the engine ice and a constant fan or good cheap insurance?

to check to see if the fan works all you have to do is ground out the wire coming from the thermostat. i have mine on a switch and have an esr temp gauge so i can monitor the temps. if it gets higher than i would like i cut the fan on and watch the temps go down.

vince.... you ever get that monster on rollers yet????

could'nt remember if you had.

curious as to why gasket would'nt seal???

as you said..... lots of heat is present. plus the fan not kicking on.

maybe a lean issue??? i dont know. just throwing it out there. that would create excess heat as well.

get that thing fixed. lol i wanna hear a report that is a full day of kicking ass. lol

sadly, i have not put the beast on a dyno. i went and met with garrett at fci but i just havent made it happen. ill will though... i think im just a lil concerned i wont break the 60 mark... and i know i shouldnt care... but im funny like that. if i dont crack 60...ill have to spend more money making sure i do. so for now... ill enjoy the power for what it is... too much for my stock swinger

Your fan shouldn't have come on as your bike was not overheating err... it wasn't a hot enough temp for the fan to kick on. The reason you were blowing / overflowing coolant is becasue your coolant system was pressurized. Most likely from a blown base or head gasket. I'd almost garuntee it. I have an 06 and have had the exact same thing happen with mny 100mm bore. With that big of bore you are reducing the amount of contact area for the gasket, hence making it more prone to problems over the stock bore or even over tne smaller bore 04-05 builds.

interesting point... i didn't consider that.

i guess its good to know that the bike didn't overheat... that's good for my internal parts.

The culprit has been discovered.... its the base gasket.

So now the question is... why did this happen? Anyone... anyone?

Did you reuse this Gasket?

Are your side cylinder to case bolts tight?

And wait.......you can launch a 511 build with a stock swingarm @ 260 Pounds and not have it wheelie??
-Kip

No... I will not be reusing the base gasket. It failed me once... I won't let the same gasket fail me again.

And NO... I cannot keep the front end down on my 511 even with my big 260 pound arese. 1st and 2nd gears are incredible. When I'm halfway up the hill in thied and i sit in the middle to get the rear tires to hook better... it'll wheelie there too.

I need the extended swingwer so I can better manage the powere. I know I'm still gonna have to learn how to feathe clutch a lil more but I believe a more dialed suspension will help me do that.

100mm bore is a pretty big bore. You are definitely reducing the amount of contact area available for the gasket. In my experience with this bore it's the base gasket that is failing not the head gasket. I had the exact same thing happen to my 06 with a 100mm bore. I had a blown base gasket and the sucker pressurized my coolant system and spewed fluid out of the over flow like it was on crack.

Which is why my next cylinder will be o-ringed. Might be something to look into Vince if you keep having issues with yours.

Was this in Sand Lake last August?

You should have bought Johns (07lightning) 101mm o-ringed cylinder. It was a good deal.

You may have mentione it before, but what cylinder are you running??

My thread is being hijacked....

Can I get some opinions on what I need to do to keep this base gasket from blowing again

I still am interested to know what cylinder you are running. Sorry if that is hijacking...

As for your base gasket problem, I think the blowing base gasket is a farely rare problem. Here is my procedure for base gaskets. NEW base gasket, both the top of the case and cylinder COMPLETELY clean and dry of any debris, oils, coolant, etc.... Then when I torque the head bolts on a big bore/high compression motor, I start out at 15lbf-ft and work up in 10lb incriments with a final torque of 45lbf-ft. (compared to the stock setting of only 40)

I have used this procedure with many different TRX's varying from 470 to 501cc's in displacement. Sometimes with a used base gasket and never I have had a base gasket problem.

My bad... I thought you were talking to the other guy about his o ringed cylinder.I am running the nmotions cylinder. Ill pass along your install procedure to my buddy (mechanic). Thanks for the reply.

i wipe all the surfaces off with alcohol. removes grease and evaporates quick.

naptha works good as well. you can get it at a hardware store.

Maybe try coating the base gasket with some of the Permatex copper spray gasket sealer? Might help some...

Other than that, as has been stated above, make sure you have clean surfaces, use correct torque, etc. One other suggestion would be to
re-torque after the first good heat cycle.

Later- Kris

My apologies for an off topic post -

Yes my base gasket was blown on that trip. That coupled with the first trip on a newly bored unjetted 43mm carb made for a real headache.