Hi Guys, I am having trouble with my 3pt r spec motor going out of tune. I have replaced the exhaust gaskets, done the fuel tube o ring needle trick and tried a pressure test. I get fuel coming out the front bearing when blowing through the pressure line and blocking carb/exhaust holes.

Is this possibly the problem? is it time for a new front bearing? the motor has only done maybe 3 galons tops.

The engine has been running flawlessly untill a few weeks ago when it just seemed to turn really rich mid tank. I had to lean it up quite a bit on the hsn to clear it. After replacing the seals etc i ran it on the weekened hoping to solve the issue , reset the needles to standard and started to retune. One lap it would be screaming the next back to top end rich.

When running it on the starter box if i ran through the rev range it would seem to have a brief dead spot about half to 3/4 throttle, almost as if at the transition between the low and hsn point. Leaning the hsn was the only way to make it any better.

I have ordered some new orings from massive so will wait to put them in and then have another go at it, but just wondered about the front bearing. It doesnt leak during running so cant see it being a problem.

I have the long lsn and using a T3 go plug .6 total head shim and massive mod fuel 25% 0801 plug. Using pinch test cuts out between 3-4 secs.

Sorry if i have rambled on and been a bit random but just trying to give as much info as possible to get some opinions.

Hey thanks for that Mike. Nice set up
Tag - that's pretty much what I was talking about. You will be surprised just how much throttle you DON'T need to get around your track. I started using 10% throttle exponential and the 6.5 restrictor on my buggy and my lap times have come down as a result. Less wheelspin, no back end breaking loose, better lines around the track.
Notice the temps - not to much strain on the motor.
On the subject of temps - I know we don't tune to a temperature, but it seems from a lot of the posts on here that us guys in the Southern Hemisphere run our motors a little cooler. I can get 10 + mins easy and my motor comes in temping at around 98 - 110 deg C, pretty much the same as Mike's - and there making good power for sure I know the A-Main fuel runs a little cooler because of it's make up, but it does seem to be a general thing. I remember reading a post back a week or so ago, saying you weren't getting good power unless you were running the GO's at 250 deg F or so, which is pretty warm - yes / no ??
Guess it depends on oil content in fuels etc, plus where you live (height above sea level). Anyone have any comments on this subject

Thanks, well in theory I sealed everything just before race, even made new o rings (Grizz style), tank is quiet new, tried pressure test was ok...

Yes good idea, will check hsn seat.

If I put 6.5mm insert, will it affect much HSN settings or it will stay anyway at around .5 in?

Today we have bank holiday, so definitely afternoon will go to get that 5port back in life

P.S. Just got my new Grenade engine(99% 5port Go) and grenade pipe, does somebody tried to compare grenade pipe VS 086, as I was happy with 086 , but maybe to give a try for grenade pipe, before I run in new engine?

No No one of my go 21 7pts gets awesome performance at 205f while the other seems to like to run a little hotter thats what i meant. I am going up for practice tomorrow so ill change to some of this and see what it does for me. Thanks alot guys

Do the MM go's come modded or no? If no who has a good mod?

Hi Tony, have you checked the HSN for a blockage. Pull out the needle and give it a good blow through the jet then re-install. Blockage here can cause all sorts of tuning dramas. If it's going good one lap then not the next it sounds more like a blockage or something rather than incorrect tune.
If the bearing doesn't leak when racing don't sweat it. They will sometimes ooze a little bit if you are running too rich on the bottom due to excess fuel build up at low revs.

Check out the modified section on the MMods web page -

http://www.massivemods.com.au/index....3061c3849c78ec

You can get anything from a stock motor to a blow your socks off MG66
The most popular are the Stage 5 Mods. With the exchange rate and shipping included you are getting a good price for a quality modded motor.

okey grizz i have read about head shims now obviously afer my engine has completely run on on both of my motors i will recheck the head shim clearance so i all i really need is a .1 or .2 head shim to give me a total clearance of .4 0r .5 on my 3 and 7 port .....

that will be good for a medium hot/plug and 25% nitro

is this what you done befor ?

I believe grizz runs 3mm shim stack with 25% nitro. I run 3mm shim stack 30%nitro os-p3 plug. I have also used a od-77t plug[odonnell] On my ebmodded 5 port I use the 6.5 mm resticter and set epa at 65%. Still tons of power and run times hang around 12.5-13 minutes. Thats per tank using sidewinder worlds nitro. I switched to byrons gen2 prodriver and got a little bit better all around performance. I had to lean slightly and the engine seems crisper,fuel burns cleaner? Not sure how to describe it.I also use dynamite 086 pipe header combo on all 3 of my go-tecs.

What one is better on fuel 5port or 7port. I race on a huge moto style track! Thanks for any/all help!

5 port has the most bottem end 7 very smoot my brother with his 7 port in his buggy 12m50 run time in his losi 8 2.0.....
if yo put a five port in your buggy moded will be the way to go :have a look at MM website

Tank times on the 7 and 5 will be about the same. The modded 5 port has extended top end over the stock motor, but I reckon for pure top end performance on a big open track you would have to go with the 7 Port. Run a 7 Port (either stock or modded) with the new 2072 pipe, and there won't be many motors (if any) that will pull you in at the top end, plus it will have more than enough bottom end for any situation you will come up against.

Yep, I run .3mm shim for a total of .6mm head clearance on 25%. With the 25% fuel I didn't really want to go any less than .6mm total head clearance, just to have a safety margin. I got more power than I know what to do with now . It was more an exercise in cooler pipe temps and a little more run time for me.

thanks grizz when i get back i will check what shims i have in as i need to run in my 7 port and i will put the brake in shim in

Thanks for the help! Going with the mm 5port!

pierson I think you should go with the 7pt turbo. It will give you crazy top end and the bottom end is awesome as well. You wont be dissapointed with either though

Huge track 7 port all day and really I see no need to mod any GO I am just a junkie LOL. But the 7 port stock allday can hang with anything out there, so can the 5 and 3. The 5 for buggy I do think should be modded to smooth out the bottum. I tried the 3 port and am 1/2 way through break in now, I had a really crazy mod job done on it so im hoping it is gonna be a nasty little thing when broke in all the way. I mainly am looking for killer runtimes out of it, and that is what I asked the modder for along with some power LOL.