Author Topic: FL350 Rebuild recommendations  (Read 29100 times)

hub350

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FL350 Rebuild recommendations
« on: March 27, 2009, 10:28:50 AM »
So I purchased a FL350 from a guy who said it "just needed some carb work"...right...about $800 later I have yet to fire it up. Here is what I've done so far. -I've got $1900 into it.

I am looking for advise or recommendations before I re-assemble it.

1. Compression test failed and I pulled the head off - Piston was fried on the exhaust side. I ordered a new piston and had the head bored one over.
2. The crank arm was loose so I opted to have the bottem end rebuilt with new seals, bealings and crank arm.
3. I have a new choke cable and ebrake cable, battery box, new battery and purchased a new comet clutch and the one on it looked bad (why mess with a crapy clutch) also picked up new rear tires 22-11-10.

So everything was coming together until they guy went to put the bored cylinder on and it turned out to be cracked - Looks to me like the guy dropped it - but whats done is done. Now I am working on a couple of options A- get another jug and get bored out to match psiton again - which I think I have found one for a small amount of $$. or B- Send the cylinder to LA Sleeve and get a new sleeve and bored to match the 80.50 piston.  -I might just do both but I will wait for the used jug.

So at this point the only other "un-proven"  component is the carb. I looked at the floats and its clean-
-Should the carb be gone through?
-Should it get re-jetted ?
- Should I get new reeds -which I think I will but then I will need to re-jet the carb -right?  
-Maybe leave carb as is and see how it runs first ???

Carb work and tuning I think I may be challenged to find to right shop to get this done.  So I would really appreciate any feedback on getting my oddy running.

Praying the trany is solid

It has a new starter at least and electrical is intact.

Anything else I should do before I reasemble?
 
Thanks for any feedback.

nuke em

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« Reply #1 on: March 28, 2009, 06:31:44 AM »
Hi
  and welcome to the site! Where are you located? Sounds like the guy really left an egg for you to fix but maybe he really didn't know the bottom end was worn out. Either way with a new bottom end, you should get another 25 years riding out of her!

If you have a sleeve replaced(been there, done that) expect to spend $300 or more plus shipping both ways($30 or more). Weisco pistons go from 80 to 82mm in .50 increments. Honda/Art pistons go from 78 through 79.50 in the same increments, if memory serves. The other jug, depending on the bore is probably a cheaper route.

Is the carb and reeds stock, what do they look like? Pictures will help a lot. What are you planning on doing with the 350? I mean, what kind of riding are you going to be doing?Duning, trails, wife and kids puttering around, MX racing, ect? That will all help in what kind of mods and setup for it. Here, I'll cut and paste a previous writeup i did back in the day, lots of good info to read through.

Here is my basic run down on 350 upgrades vs stock stuff cut from a previous post...still have questions, just ask and we'll try to clarify.

Ok, I will chime in and give my 2 cents worth. I have over 15 years of experience messing with the 350s and have have found out (mostly the hard way) what works well for my riding style. I am on a tight military budget so most parts I use are either fabbed or bought used from Ebay. Not everyone will agree on the best mods, or good mods so use whatever you like. These are my personal suggestions and opinions. Nows thats a disclaimer! LOL

1. Air Box Mods... The factory airbox, snorkel and tail light box. Great for keeping out dirt, mud, rain ect., but extremely air flow restrictive especially in hopped up machines where you need increased air flow. There are alot of posted pictures of snorkel mods, each a little different and all fix the restrictive problem. Probably best bang for the $15 spent! Avoid any type of "Ram Air" or scoop mod, the air being forced into system will make jetting a nightmare. The engine WILL pull what it needs with the fore mentioned snorkel mod.

2. Air Filters. Hot debate topic with different views, all require proper oiling and regular cleanings, especially in a dusty environments. A pair of oiled K&N filters with prechargers on a dual snorkel mod with the dual layered oiled foam filter in the box is the best/safest filtering that can be done with excellent air flow, in my opinion.

Factory foam filter(In box) --probably the best filtering but most restrictive because its a very dense type of foam filter over a metal screen cage inside.
Dual stage, Uni foam filters--most commonly used, great flow and good filtration.
K&N filters-- most air flow but least filtering even with the optional outer precharger covers. most expensive also.

pod filters(No box)--again, debatable, you may lose power by removing the box because of the two stroke pulsewave/resonance, loosing the box makes access to the carb much easier, the filter is exposed the elements and needs to be covered when not in use, generally does not like water covered trails!

3. Carbs--again 32mm(stock)is too small for hopped up engines but fine for stockers. If you want your engine for torque(hard launches, steep climbing, ect) stay small 34-36MM, if you want your engine to rev high and really pull on top end, ie duning, go big 38MM-41MM. Of course you will want your port job, larger or smaller carb, reeds, stuffer or no stuffer, and your exhaust pipe to all be matched to the setup you want to run...high rev or torque.

The more modern flat slide type carbs (PJ, PWK, quadvent(Airstryker), TMX(Mikuni),etc, give a better throttle response than the stock type round slide carbs(PE). I prefer Keihin over Mikuni,mainly because the 350 choke and throttle cables hook up without having to buy adaptors or new cables...and I am used to the jet size numbers.

4. Exhaust pipes-- Stock works well and is the quietest but is restrictive when hopped up. DG, PowerPros and Bills are some that I have tried, and all give good gains. The DG silencer(or lack there of) is horribly loud and has to be swapped out ASAP, generally with a long FMF large CC 2 stroke quad/bike silencer. Turbine 2 cores are a popular choice. Again, some have been tuned/designed for rev or torque.

5. Reeds--Stock are steel and very trust worthy but restrictive on built engines. Boysene makes replacement fiberglass reed pedals for the stock cage in either rev or torque pretty cheap. Also most 250R, CR250, TRX250, ATC250R and pilot reed cages will fit in the 350. I personally prefer the 4 pedal cages(best flow). I also have used a straightened neck boysene Rad Valve, G-3(Mossbarger 8 petal), ESR, Boysene fiberglass on stock cage, and Delta V Force reeds, all with increased power and throttle response over stockers. There has been some verified cases of the V force cage getting sucked into the engines. I don't recall if they were version 1,2, or 3. I have used the 2nd version for years with no problems, yet. Knock on wood. Reeds do not generally make huge power differences, just smooth out a power band, IMHO.

6. Clutches--Again another topic of debate, all require proper cleaning and lube occasionally for proper operation and long clutch life
--- Salisburys (stock) good ol reliable but a lower engagement bogs the engine for racing but perfect for kids or general puttering around.
---94C-great all round clutch, draw backs are its not easily tunable, but parts can be changed. Most popular swap if you just want to replace the stock unit.
---102C- great for racing because you can adjust engagement and different areas of the powerband by changing springs or cam arms. Draw backs-expensive, without the dustcover can wear parts quickly.
---HRD & Alt--good simple design clutch(very similar to the 94C) except you can adjust puck weights for tuning easier, priced between the 102 and 94. Drawbacks tends to tear up the "D" slot on the cover and possibly has ties to Pilot main bearing failures, none know damage on 350s yet.

7. Porting-- The heart and sole of the engine, can be mild to full race(wild). If not done correctly, you can ruin an engine. It needs to be done by a knowledgeable person, not a shade tree(like me). You can take a dremel and clean up casting flaws and other imperfections inside the jug, polish up the exhaust port and make better flow thru the engine(better power) but avoid changing the size and shape of the openings. That is the timing and could spell disaster if you do it wrong. There are a lot of articles written on porting work so if you want to do it, better do the homework...or send to a reputable place such as EEE and not a shady type lurking about(no names, just ask).

8. The little tricks-- here are just a few I use.
--- The stock head gasket is actually three layers. I use only 1 which bumps up the compression some.
---Always use a quality synthetic oil at 40 or 32:1 with fresh premium gas.
--- Run a liq cooled head and radiator to help control heat especially with a built up engine.
--- I use an EGT and a water temp gauge to help monitor things.
---Run .190 aluminum rims and lighter weight tires if not in rough/rocky areas, less kinetic mass which allows more power to reach the ground.
---Putting you rubber manifolds and curved air box to carb rubber boot in boiling water for a short period will aid in attaching them to a larger carb.
---When your cylinder needs the next bore, go to the next size up, do not jump straight to the max bore(82MM). 2 strokes need flow to make big power. Power increase from 78.5MM to 82MM would be very minimal and when that bore is done, you will need to replace the sleeve(expensive).
---Be sure to have the exhaust bridge relieved and cooling holes drilled on the piston during rebuild time. Don't forget to smooth out all ports and transfers edges after a bore job. Hoser(website owner) will bore your cylinder for free, doesn't get any better than that! Huge "Thank You" for helping out the board members and keeping these great machines alive and kicking.
---Do a leakdown test at least annually or after a long vacation of riding. That should catch seals going bad before your engine leans out and seizes.
---early CR250 Mossbarger/Elsinore bikes(78/79) used a straight intake manifold and works well for increased flow and larger carbs.
---I do a compression check after every trip and keep it in a log so I know approximate hrs and notice changes in compression(long term ring/cylinder wear)
---If rebuilding with a Honda(Art) piston (78.5-79.5), bore .003, if rebuilding with a Wiesco piston(80-82mm), bore .004-.005 with liq cooling and .005 air cooling. That is due to piston material content and the Wiesco expand more, not the .003 they claim. Trust me, been there done that too many times. Wiesco also claims you should replace the piston after every 20 hrs of run time, or some crummy disclaimer crap like that. They are not bad pistons when run properly.

There is a good start of info to absorb and I am sure other will add to the list too. I am sure I have forgot things too. Good luck and keep us posted,
Gary

nuke em

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« Reply #2 on: March 28, 2009, 06:38:14 AM »
Sorry, that was very long! lol Anyway, pictures are always good, helps us a lot. Any sign of black oil in the starter or that area? Also, after getting the thing running, ride it for a while then change the tranny oil while still hot!!!!! That way all the metal particles are still suspended in the oil and will be drained.

Carb tuning is easy once you understand whats going on. Let us know when you are ready for that info. Yellowdog racing has a great tech writeup on how to do it with pics to make it easy.

Gary

PilotHawK

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« Reply #3 on: March 28, 2009, 07:30:13 AM »
Excellent write-up. You missed shocks ;). I liked the post so much I made it a "sticky" Hopefully future readers will be able to find it that way easily.

hub350

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« Reply #4 on: March 28, 2009, 11:20:36 AM »
Thanks for the welcome and replies - I live just North of dallas- we are planning a big trip to Little Sahara in OK this summer - I have two FL250 for my boys and just got the 350 for me so I could keep up with them!

Thanks for the great info - WOW that really helps - I will post pictures of the engine and carb.

**I believe the carb and reeds are stock. Do you think I should replace the reeds now or wait?  I was thinking I would replace them now since its a bear getting to it later.  But whats the impact if I replace them without modifiying the carb?**

I will post pictures next-

New shocks would be great but -wow those works shocks cost a pretty penny - anyone have any used ones laying around?  :lol:

I spent about an hour reading through the 6 pages of the tech 350 forum and found alot of great info including the yellow dog racing page -Thanks!

hub350

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« Reply #5 on: March 28, 2009, 11:23:42 AM »
Also I drailed the oil and it looked fine - The tranny oil looks fresh so fingers crossed I have no probs there - I will take your advice and change it when I get it running.

hub350

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« Reply #6 on: March 29, 2009, 06:18:18 AM »
Here are some reed pics - I am assuming these are stock - not sure if they're in bad shape.
[/img]

PilotHawK

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« Reply #7 on: March 29, 2009, 09:23:40 AM »
Those aren't stock FL350 reeds fot sure, but they look to be OK from what can be seen in the pics. Look at the very tips of the reeds and if you can see light coming through they are worn. If possible with the ones in the pic, you can flip them over to get a better seal at the tips of the reeds. They sure are dirty! Did they come out that way or did they get dirty from the engine and shop?

hub350

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« Reply #8 on: March 29, 2009, 11:44:45 AM »
Thanks for your assessment! I did not clean them and I put them in a plastic bag upon removal -  I will clean up and do as you recommend.

hub350

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Carb Pics
« Reply #9 on: March 29, 2009, 11:51:12 AM »
Here are a few pics of the carb. I took the botton 17mm cover off the bottom but couldn't get the needle loose. Felt like I was going to break it so I backed off for now.  need to get something on it to loosen it up. For now here is what I have:

hub350

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Engine
« Reply #10 on: March 29, 2009, 11:56:13 AM »
Here are pics of the Bottom end with the new piston on, the bored "broken" cylinder and the head.

nuke em

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« Reply #11 on: March 29, 2009, 12:09:53 PM »
Those are Boysene power reeds mounted on a stock reed frame. Look to be in good shape from the pics. Like Hawk said, if there is a gap or light coming through them, flip them over. They might seal better, but they look good to me, just dirty. Stock reed pedals are actually steel and have a metal limiting frame to allow them to open only so far. Those are a very good upgrade in my opinion and always worked great for me.

Yup, missed to shocks, damn. I'll add to that later. I rode on stock frozen up shocks for quite a while back in the day(too cheap for Works). They are a real nice investment and your back will thank you. I bought some front Works from Ebay years ago so they are around but far and few in between. I got New Works a couple of years ago with the adj preloads and rezzies, just sweet!

 First things first, we will get you running right. You will be chasing your boys around on 250s so the stock suspension is still way better than what they will be having. lol

hub350

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Sending Cylinder to LA Sleeve
« Reply #12 on: March 30, 2009, 07:47:58 AM »
Well today I opted to bite the bullet and send my cylinder to LA Sleeve.  I think thats my best solution at this point.  

I do have a question for you on my bottom end rebuild.  I took the piston out to send with the Cylinder to LA Sleeve and I can not even move the crank arm up and down. Now prior to the rebuilt I could turn it by hand like a 10 speed bicycle crank arm, now its very tight and won't move. Is this normal right after putting it back together or is this a problem.

Here are a couple of pictures without the piston. Can not move it out of the lower position.

nuke em

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« Reply #13 on: March 30, 2009, 08:03:48 PM »
That is definitely not right. When you say you you just put it back together, do you mean that you separated the bottom end cases  to do a good inspection or replace all the bearings and seals? If you did clean out all the bearings with carb cleaner, you need to add a few drops of 2 stroke oil and work them into everything. Is the rod movable or is the crank froze in place? Sorry, you will probably have to open it back up, but you will have plenty of time to figure it out. Did you do the frozen bearing/oven baked trick installing? Please tell me you didn't beat them in with a hammer. Let us know, I want to help.

Did you down load a manual yet or buy one?

You can't go wrong with a new sleeve and having them install it, they are the pro's. Let me know what they charge you, if you do not mind posting it. I have a 420CC 350 race jug that needs a new sleeve real soon(on my last bore now, 88.50MM). Just curious how bad its going to sting, lol.  :shock:

I do like LS Ok too, maybe hook up there sometime for a group ride.

Gary

hub350

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« Reply #14 on: March 30, 2009, 08:22:05 PM »
I had a shop redo seals and bearings - the whole bopttom end - he said its normal everything is tight - whats not normal is that its almost seized - I will take it back to him this week and have him fix it before my cylinder is finished. Not sure what process he used putting them back in.

I did print out the shop manual and index it.

The sleeve is $125 plus $160 labor to install and bore.

I'll let you know when we go to LS - sometime in June.

Thanks