My new mill, an OBR 30.5

[phreerider]

Finally fouled iridium plug , right back to cmr 7h definitely gives back a fraction more topend . And as luck would have it with recent talk of 990 shaft blowout ...leak has reached the untunable suckin' end . Mountain of time on it well beyond 500 hours for 35$ that ain't bad. Doubt I will go to bearing set already have a few of these so it will go into harvest for parts . The final blow was the leak , no other issues other than a few tear downs to clean the screens. Easy tune ,wide range of power applications hard to beat for most the money. ..pulled time on stock, pro stock, and race ported. An easy off air filter makes starting brainless.

 

[designed2survive]

Lots of info, thanks Pheerider!

 

[phreerider]

unfortunate news OBR billet case bearing failure.

the reality <150hours on prostock setup, not happy...the concurrent good news the HY original stock case is into 3rd topend kit.



heres the original HY case and obr race port (left)

and the OBR/TR/ZEN prostock 30.5 with billet case (right)



the original case never had seizure, top end drops pressure around 250hours sawp it and RIGHT back to it!

the bearing swap (since ALL the case bolts heads all stripped!) on the billet case is around the corner but not before fresh top end for hy stock, fancy case turning into hassle.

 

[designed2survive]

Sorry to hear that! Have you tried contacting OBR? May be they will be able to help out.

 

[RampageHopUps]

150 hours on a motor is very, very good. OBR won;t be able to do anything but tell you to do some maintenance at 100 hours.

 

[phreerider]

the time was solid, just the stock case has SO much more time ..in terms of "clucthes"

prostock only got into a 2nd clutch, stock case just finished off its 6th and into 3rd topend !

no worries for OBR , i just ordered more junk from them, just the additional shipment TIME for one more thing is the hassle.

 

[alfred e numan]

botton ends

One thing i have noted about the H-Y bottom ends is the lack of crankshaft end play the one that came with my xb had very little play compaired to other brands of these hobby motors. this was a 2 bolt bottom end on the hy.

 

[alfred e numan]

budget 4 bolt top ends

i looked at large scale r-c site yesterday. they are selling new f-270 top ends for 25 bucks! this is not the most powerful mill, its set up for a 30mm crank. this engine reves to the moon too. at this price, you can afford to mess around with leaner gas- oil ratios, fuel screw settings with out too much worries if you smoke it. just saying.

 

[BertR]

Speaking of top ends...does the 36cc head share the same case as the 30.5. If it does that may be a option to look into for serious torque..

 

[RampageHopUps]

The 36cc case was different. It had more clearance for the crank.

 

[phreerider]

hy definitely pulling a ton more tow as well. bearing on billet case dropped after 2 tanks on tow.

did see the 27 tops, lots pulloff/harvest stuff to go thru! i should live long enough to get to them all!

meanwhile on the bench...



with fx'd case bolts...not much of fight overr in a flash, but lots of pieces!



oh and zen top , billet case, and crank CY? (and cy cover) expected zen crank.

 

[phreerider]

right to it with 2 bolt top end

cylinder not too bad , would run this again with new piston/ring.



top thats clean!



skirt



all buttoned up ready to go fresh 2 bolt race port by OBR 30.5

 

[phreerider]

hy 30.5 with fresh race port just finished breakin and running 7500 spring. its amazing how after the fourth heat cycle it just rips effortless into power band..obr goodness!

and fresh billet case bearings



seals, crank



a little switch in the setup. instead of using case bolts with flange seats(hard to find 10.9) just went with regular hex fat heads M5x40mm and will have to hack the fins on flywheel a fraction, but its what i want so i can open the case without a hassle.



top ready to go on , this is the 4 bolt prostock obr 30.5 cc top end kit



all buttoned up ready to rock , gonna set the clutch next.. AND DDM made good on the LIFETIME 9500 spring ! thank you DDM!

serial pics on clutch/spring details around the corner...2 mills down for a week plus+ ,man!.... time to session!

 

[phreerider]

heres the modded flywheel to accommodate the hex heads



worked out nice did some adhesive screening to simplify the debris covers ..need pics!

 

[phreerider]

clutch spring 6000, 6000,6000,6000,10K broken, 9500new , 9500sprung

 

[phreerider]

heres a clutch spring change series



spring added to one shoe



twisted to add other shoe(should be a little loose )



shoes with slight tension at shoe rest



next post for compression slide

 

[phreerider]

here the compression with channel locks to slide shoes into rest position



resting in closed position on shoe stops



9500 spring ready for action test pry to open



release pry , shoes return to resting closed

 

[phreerider]

jetpro side mount on obr 30.5

this is the MCD side mount pipe from dino

 

[designed2survive]

jetpro side mount on obr 30.5this is the MCD side mount pipe from dino

Nice pipe! I see you went with the raw finish. Keep it oiled, it rusts easily!

 

[phreerider]

thanks! fire up tomorrow and see what we got. solid build.