Lost.Lost.Lost.[img]i/expressions/face-icon-small-sad.gif[/img]

 

one step at a time - verify the actual compression you're getting with a compression gauge with throttle wide open, decompressor disabled, turning over several times until pressure maxes out. let us know what you get and what cams you had in during the test (very important). on gas, the jetting is crucial in making power and in throttle response. i'd make sure the jetting is on. a dyno with air/fuel reading is one way. if you plan on doing your own carb tuning that no-one has done, you can install an air/fuel gauge to help you. an egt gauge helps too. double check cams are not off a tooth.

 

All i know is that I got 205 lbs. of compression at 900 ft elevation and 212 with a wet test.

 

it's to bad you live on the east coast, i'd come hang out with you for a couple rides we'd get that thing tuned up good. guess we just need to keep hearing the problems and work it out.

 

Boomer your right I wanted to run pump gas but I didn't want that low of compression. I guess I should have specified it. However when I talked to Gary when I got my kit and hammered him with questions I asked what kind of gas should I run and mentioned 100 octane and his response was yes use that (so I was under the assumption I had a high compression piston). The valves where adjusted when I put the bike together but I have been told after you ride it again check it again (which I will hopefully this week).

Yes I'm running the snorkel. My lectron carb is in fact tuned by MRHP himself. I did change the metering rod when the bike was giving me problems back when I broke a cam. He did change the needle and last week I think I got her tuned in right. It doesn't idle funny anymore and it has a steady sound now. I was leaning it out to the point where when I hit the throttle it bogged. I'm going to get new plugs and pop them in. It was defintely running rich, hopefully I got it dialed in. Yard is too muddy from rain going to wait till it dries up some to test ride it. I also got a lighter spring from Fast By Gast so thumb won't kill me.

Scoob thanks for the info on compression tester.


Let me see how money pans out, I might just get that piston.

 

entomber, like boomer said, you are running the same piston as sandman. the piston is the not the end all, be all. you need to have the other pieces to the puzzle, i.e. cams, valves, race head, etc. sandman's 720 runs like a bat outta hell. he can probably beat me worse than i can beat an lt80. nothing but power and revs to the moon.

 

The PISTON should not be shy of the top of the cylinder. That is wrong! I dont care if it is 9:1 or 12:1 . It sounds to me like Gary has sent you the wrong piston. and if so he should make it right,and send you the right piston FREE!

Spending the $$$$$ on big valves is not going to help one bit, unless you want a drag racer,and then I still have my doubts(personally)

Sandman, wasnt that happy with his 720, until he went to N20. and the reason he sees such big gains from N20 may very well be because he has a low compression motor. High compression motors dont respond to N20 near aswell as low compression motors.

I do however believe you need a bigger carb. 48mm mukuni should do you about right.

Do the compression check,and let us know what it reads.





Bigger.

 

A higher comp. piston sitting down in the hole is not gonna make much more if any power than the stock one you took out, sounds like you have the piston in there made for a stroker, they are probably trying to get by with using the same piston on both applications, which will not work.

 

it sounds like your compression is going to come out around 9.5:1. i'd look at options and get a new piston on it's way and a new head gasket if needed. maybe other TVI DS's out there that are using NOS could buy your low compression piston to use as a spare, that way it won't cost as much to get the new piston and avoids the hassle of trying to exchange it. didn't bigbaja use a MRHP piston in his TVI motor?

 

Yes I did, but you will have to have your cylinder bored to 105.5mm, It is the best way to go in my opinion.