Thinking of doing a conversion.029/039

[Kenskip1]

So the other day I stopped by a local pawn shop. There sat a 029 that appeared to have been run hard and put away wet.The compression felt reasonable, so I got to thinking about doing a conversion.Well the shop sales associate asked if he could help. Price was $150. Just by running the chain around I could tell the rim sprocket needs replacement if it had one.So there I let it sit.My offer of $65 was refused so out the door I went.Now a sponsor of this site has the conversion kits available for under $100. Are they worth the cost? Should I find another brand like Meteor? Amazon has them listed but I do not remember the price.What about the carburetor. Will I have to replace it with a different one or simply richen it up?If anyone has some spare knowledge that they are willing to spread around I will be most grateful. Thanks, Ken

 

[Lightning Performance]

A used 310 top is the one you want imo The 390 is not as smooth imo. Some people have good kits and those who build them know what to buy. Be aware it's best to use oem clips and wrist pin bearing in aftermarket kits. Known weak links.

 

[Dub11]

If you can do a pop up piston.
http://opeforum.com/threads/ms390-039-pop-up-piston.9517/

 

[Nutball]

I was wondering just yesterday what the weight difference is between a 029 and 039. Is the engine the ONLY difference? I have a couple cross popup pistons in case I ever acquire a 290/390.

 

[Kenskip1]

If you can do a pop up piston.
http://opeforum.com/threads/ms390-039-pop-up-piston.9517/

After viewing several pages I did not notice a price or a place to order from.Thanks Ken

 

[Nutball]

They tend to be about $10 when listed on Deal of the Day on HLSproparts

https://www.hlsproparts.com/Stihl-039-MS390-Pop-Up-Piston-Kit-p/cp31039.htm

 

[Dub11]

I was wondering just yesterday what the weight difference is between a 029 and 039. Is the engine the ONLY difference? I have a couple cross popup pistons in case I ever acquire a 290/390.

Not sure on the weights but the only difference I know of through the years was oiler was up graded at some time and theirs a thread on how to do it you self some where around here. Now here is some information on the HD carbs in general.

 

[huskihl]

I found an 039 cylinder and used a Cross popup in a ported one I did this spring. Ported 039 was twice as fast as a stock 029. The air filter held it back another 10% or so. They dont flow quite enough

 

[Stump Shot]

I heard a good report yesterday from a Cross 039 P&C kit that ran exceptionally well.

 

[beaglebriar]

I've done a pile of these and have another one here to do actually. I've used OEM, Cross Performance and Hyway top ends all with the cross pop up.

The Hyway cylinder is a clear winner IMO and the strongest one I've built so far. It also produced the most compression, around 185psi IIRC. A healthy muffler mod, timing advance and some careful port widening really wakes them up. Like Wayne said it's a good idea to use OEM clips and bearings. That'll keep them going for a long time.

044 carb is also a good upgrade but like Kevin said it's kinda hampered by the *s-wordty air filter.

 

[Nutball]

I've been upgrading all my filters to nylon mesh which flows at least 2-4 times better.

How often have you heard of AM bearings fail in 390's? I'm curious.

 

[huskihl]

I've been upgrading all my filters to nylon mesh which flows at least 2-4 times better.

How often have you heard of AM bearings fail in 390's? I'm curious.

Is there such a critter for an 029?

 

[Nutball]

I make them critrers

 

[Lightning Performance]

I make them critrers

Easier to buy one

 

[Nutball]

Cheaper not to...if you plan on doing a few.

 

[Lightning Performance]

Cheaper not to...if you plan on doing a few.

Rain gutter cover nylon mesh has bigger holes than house screen.

 

[Lightning Performance]

How often have you heard of AM bearings fail in 390's? I'm curious.

I installed a set once. They fell on the crank and motor was out of spec. Three years ago you didn't get much for six bucks. ymmv

 

[beaglebriar]

I make them critrers

Pics?

 

[Nutball]

2188/385 filter


Echo 303t


Echo 355t



I have plans to do my kit 660 filter next.

 

[redline4]

I heard a good report yesterday from a Cross 039 P&C kit that ran exceptionally well.

I got the same report.
And if it had turned out like crap, he wouldn't sugar coat it either.